INSTALLATION, OPERATION, MAINT. Millennium TM AIR COOLED SCREW LIQUID CHILLERS AIR COOLED SCREW HERMETIC Supersedes: 201.10-NM1 (496) Form 201.10-NM1 (697) 140 - 250 TON MODELS (Standard Efficiency) 215 - 260 TON MODELS (High Efficiency)* 60 HERTZ STYLE D 200, 230, 460 & 575 Models With EPROM 031-01714-001 (Standard, Brine & Metric Models, Combined) 27960A 28507A ® M A N U F A C T U R E R C E R T IFIE D T O A R I A S C O M P L Y I N G W I T H A R I S T A N D A R D 5 9 0 C E N T R I F U G A L A N D R O TARY SCREW W AT E R C H I L L I N G PACKAGES • • C E R TIFIC ATIO N S E C TIO N S O F *During model development, the following models received updated nomenclature: OLD NEW YCAS 316 YCAS 216X YCAS 336 YCAS 236X YCAS 366 YCAS 266X
Transcript
INSTALLATION, OPERATION, MAINT.
Millennium TM
AIR COOLED SCREW LIQUID CHILLERSAIR COOLED SCREW HERMETIC
Supersedes: 201.10-NM1 (496) Form 201.10-NM1 (697)
140 - 250 TON MODELS (Standard Efficiency)215 - 260 TON MODELS (High Efficiency)*
60 HERTZSTYLE D
200, 230,460 & 575 Models
With EPROM 031-01714-001 (Standard, Brine & Metric Models, Combined)
27960A
28507A
®MA
NU
FAC
TU
RER
CERTIFIED TO ARI AS
COM
PLY
ING
WIT
H
ARI STANDARD 590
CENT
RIFU
GAL
AND ROTARY SCREW WATER
CHILLING
PACKAGES• •CERTIFICATION SECTIONS OF
*During model development, the following models received updated nomenclature:OLD NEW
Temperature Conversion Table ......................................................................... 144
FORM 201.10-NM1
3YORK INTERNATIONAL
The 140-260 Millennium Air Cooled Screw liquid chiller iscompletely assembled with all interconnecting refrigerantpiping and internal wiring, ready for field installation. Theunit is pressure-tested, evacuated, and fully charged withRefrigerant-22, and includes an initial oil charge. Afterassembly, an operational test is performed with waterflowing through the cooler to check that each refrigerationcircuit operates correctly.
GENERAL CHILLER INFORMATION
The unit structure is heavy gauge, galvanized steel,covered with a baked-on enamel. Base rails are of formeddouble thickness, painted plate steel. Units are designedin accordance with ARI 550, NFPA 70 (National ElectricalCode), ASHRAE/ANSI 15 Safety code for mechanicalrefrigeration, ASME, and U.L. (200, 230, 460 and 575-3-60 models). Units are rated in accordance with ARIStandard 550.
27960A
28507A
®MA
NU
FAC
TU
RER
CERTIFIED TO ARI AS
COM
PLY
ING
WIT
H
ARI STANDARD 590
CEN
TRIF
UGAL
AND
ROTARY SCREWWATER
CHILLING
PACKAGES• •CERTIFICATION SECTIONSOF
4 YORK INTERNATIONAL
UNIT NOMENCLATURE
The model number denotes the following characteristics of the unit:
YC A S 140 X - 46 Y D
YORK ChillerDesign Series
Air Cooled
Type StartY = WYE-DeltaX = Across-the-Line
Compressor Design SeriesS = Screw
Unit ModelVoltage Code:
17 = 200-3-60Class 28 = 230-3-60
Blank = Standard Efficiency 46 = 460-3-60X = High Efficiency 58 = 575-3-60
FORM 201.10-NM1
5YORK INTERNATIONAL
NOMENCLATURE
Engineering Data (stamped on unit nameplate) denotes the following characteristics of the components of the unit:
4 M 2 A 3 H L 6 A
2 Compressor “W” Chiller Refrigerant CodeConfiguration containing A = R-224 Fans & 8 Coils per Module B = R-134a
10 = 60 Hz, Economized, 3 Module in both systemsM =32" x 83"
4 row deep coilsGear in System #1 XHS 120 Compressor in System #1
(A, M, F, H, P or S) 3 row deep coilsin System #2
N = 32" x 83"4 row deep coils
in both systems
Motor in 60 HzSystem#1 Compressor Max. KW
0 = 101 Frame, 7" Long N/A1 = 101 Frame, 8" Long 85 Cooler Code2 = 101 Frame, 9" Long 105 H = 16" Cooler3 = 101 Frame, 9.5" Long N/A K = 18" Cooler4 = 101 Frame, 10" Long 126 N = 20" Cooler5 = 101 Frame, 10.75" Long 1506 = 124 Frame, 9.5" Long (G) 1847 = 124 Frame, 9.5" Long (K) 2198 = 124 Frame, 10.75" Long (P) 263 Motor in System #2 Compressor9 = 124 Frame, 10.75" Long (M) N/A (See System #1 motor list)
Gear in System #2 XHS 120 Compressor(A, M, F, H, P or S)
6 YORK INTERNATIONAL
OPERATIONAL LIMITATIONS(English)
LD01087
FIG. 1A – COOLER WATER PRESSURE DROP
VOLTAGE LIMITATIONS
The following voltage limitations are absolute and opera-tion beyond these limitations may cause serious dam-age to the compressor.
1. Clearances - Recommended YORK clearances for peak performance, reliable operation and maintenance:Side to wall 8'–0"*; Rear to wall 8'–0"; Control Panel End to wall 5'–0"*; Over the top - No obstructions allowed; Distance betweenadjacent units 12'–0", (Walls should be no higher than the unit.)*No more than one high wall can be higher than the top of the unit. The area within the clearances shown above and area under the unitmust be kept clear of all obstructions or clutter that would impede air flow to the unit. In installations where winter operation is intendedand snow accumulations are expected, additional unit height must be provided to insure air flow.NOTE: Reduced clearances may be used due to jobsite restrictions or competitive recommendations. The unit will unload to prevent thecondenser pressure and motor current from exceeding the maximum limits and will continue to operate without nuisance high pressureor motor current cutouts even though the air flow will be restricted at these conditions.
2. Cooler liquid connection sizes (inlet and outlet) 8" victaulic for all models.
3. Dimensions are in inches.
4. Spring isolators (OPTIONAL) will increase overall height of unit.
5. Modules have 1-1/8" of space between to facilitate maintenance.
LD01445(R)
LD01447
FORM 201.10-NM1
11YORK INTERNATIONAL
YCAS 140-246 DIMENSIONS(English)
LD01444
LD01446
12 YORK INTERNATIONAL
YCAS 140-246 DIMENSIONS(SI)
NOTES:
1. Clearances - Recommended YORK clearances for peak performance, reliable operation and maintenance:Side to wall 2438 mm*; Rear to wall 2438 mm; Control Panel End to wall 1524 mm*; Over the top - No obstructions allowed; Distancebetween adjacent units 3658 mm, (Walls should be no higher than the unit.)*No more than one high wall can be higher than the top of the unit. The area within the clearances shown above and area under the unitmust be kept clear of all obstructions or clutter that would impede air flow to the unit. In installations where winter operation is intendedand snow accumulations are expected, additional unit height must be provided to insure air flow.NOTE: Reduced clearances may be used due to jobsite restrictions or competitive recommendations. The unit will unload to prevent thecondenser pressure and motor current from exceeding the maximum limits and will continue to operate without nuisance high pressureor motor current cutouts even though the air flow will be restricted at these conditions.
2. Cooler liquid connection sizes (inlet and outlet) 8" victaulic for all models.
3. Dimensions are in mm.
4. Spring isolators (OPTIONAL) will increase overall height of unit.
5. Modules have 28.6 mm of space between to facilitate maintenance.
LD01441(R)
LD01443
FORM 201.10-NM1
13YORK INTERNATIONAL
YCAS 140-246 DIMENSIONS(SI)
LD01440
LD01442
14 YORK INTERNATIONAL
YCAS 216X - 266X DIMENSIONS(English)
NOTES:
1. Clearances - Recommended YORK clearances for peak performance, reliable operation and maintenance:Side to wall 8'–0"*; Rear to wall 8'–0"; Control Panel End to wall 5'–0"*; Over the Top - No obstructions allowed; Distance betweenadjacent units 12'–0", (Walls should be no higher than the unit.)*No more than one wall can be higher than the top of the unit. The area within the clearances shown above and area under the unit mustbe kept clear of all obstructions or clutter that would impede air flow to the unit. In installations where winter operation is intended andsnow accumulations are expected, additional unit height must be provided to unsure air flow.NOTE: Reduced clearances may be used due to jobsite restrictions or competitive recommendations. The unit will unload to prevent thecondenser pressure and motor current from exceeding the maximum limits and will continue to operate without nuisance high pressureor motor current cutouts even though the air flow will be restricted at these conditions.
2. Cooler liquid connection sizes (inlet and outlet) 8" victaulic for all models.
3. Dimensions are in inches.
4. Spring isolators (OPTIONAL) will increase overall height of unit.
5. Modules have 1-1/8" of space between to facilitate maintenance.
LD01455
LD01453(R)
FORM 201.10-NM1
15YORK INTERNATIONAL
YCAS 216X - 266X DIMENSIONS(English)
LD01454
LD01454
16 YORK INTERNATIONAL
YCAS 216X - 266X DIMENSIONS(SI)
LD01451
LD01449(R)
NOTES:
1. Clearances - Recommended YORK clearances for peak performance, reliable operation and maintenance:Side to wall 2438 mm*; Rear to wall 2438 mm; Control Panel End to wall 1524 mm*; Over the top - No obstructions allowed; Distancebetween adjacent units 3658 mm, (Walls should be no higher than the unit.)*No more than one high wall can be higher than the top of the unit. The area within the clearances shown above and area under the unitmust be kept clear of all obstructions or clutter that would impede air flow to the unit. In installations where winter operation is intendedand snow accumulations are expected, additional unit height must be provided to insure air flow.NOTE: Reduced clearances may be used due to jobsite restrictions or competitive recommendations. The unit will unload to prevent thecondenser pressure and motor current from exceeding the maximum limits and will continue to operate without nuisance high pressureor motor current cutouts even though the air flow will be restricted at these conditions.
2. Cooler liquid connection sizes (inlet and outlet) 8" victaulic for all models.
3. Dimensions are in mm.
4. Spring isolators (OPTIONAL) will increase overall height of unit.
5. Modules have 28.6 mm of space between to facilitate maintenance.
FORM 201.10-NM1
17YORK INTERNATIONAL
YCAS 216X - 266X DIMENSIONS(SI)
LD01450
LD01448
18 YORK INTERNATIONAL
STYLE SYSTEM #1 FIELD SUPPLIED WIRINGMODEL VOLTS
MCA1 MIN NF D.E. FU C.B. (LUGS) WIRE RANGE COMPRESSOR FANS60 Hz DISC SW2 MIN.3 MAX.4 MIN.5 MAX.6 WYE-DELTA7 ACR-LINE 7 RLA Y LRA X LRA FLA (EA)
STANDARD DUAL POWER SUPPLY(Each Power Supply Individually Protected with Field Supplied Branch Circuit Protection)
NOTES for Electrical Data, pages 18 - 25:1. Minimum circuit ampacity (MCA) is based on 125% of the rated load amps for the largest motor plus 100% of the rated load amps for all
other loads included in the circuit, per N.E.C. Article 430-24. If a Factory Mounted Control Transformer is provided, add the following to thesystem #1 MCA values in the YCAS Tables: -17, add 10 amps; -28, add 9 amps; -40, add 5 amps; -46, add 4 amps; -58, add 3 amps.
2. The recommended disconnect switch is based on a minimum of 115% of the summation rated load amps of all the loads included in thecircuit, per N.E.C. 440-12A1.
3. Minimum fuse size is based on 150% of the largest motor RLA plus 100% of the remaining RLA’s (U.L. Standard 1995, Section 36.1).4. Maximum dual element fuse size is based on 225% maximum plus 100% of the rated load amps for all other loads included in the circuit,
per N.E.C. 440-22.
5. Minimum circuit breaker is 150% maximum plus 100% of rated load amps included in the circuit, per circuit per U.L. 1995 Fig. 36.2.
6. Maximum circuit breaker is based on 225% maximum plus 100% of the rated load amps for all loads included in the circuit, per circuit, perU.L. 1995 Fig. 36.2.
7. The Incoming Wire Range is the minimum and maximum wire size that can be accommodated by unit wiring lugs. The (1), (2) or (3)indicated the number of termination points or lugs which are available per phase. Actual wire size and number of wires per phase must bedetermined based on ampacity and job requirements using N.E.C. wire sizing information. The above recommendations are based on theNational Electric Code and using copper connectors only. Field wiring must also comply with local codes.
8. A ground lug is provided for each compr. system to accommodate field grounding conductor per N.E.C. Article 250-54. A control circuitgrounding lug is also supplied. Incoming ground wire range is #6 - 350 MCM.
9. The supplied disconnect is a “Disconnecting Means” as defined in N.E.C. 100.B, and is intended for isolating the unit from the availablepower supply to perform maintenance and troubleshooting. This disconnect is not intended to be a Load Break Device.
FORM 201.10-NM1
19YORK INTERNATIONAL
STYLE SYSTEM #2 FIELD SUPPLIED WIRINGMODEL VOLTS
MCA1 MIN NF D.E. FU C.B. (LUGS) WIRE RANGE COMPRESSOR FANS60 Hz DISC SW2 MIN.3 MAX.4 MIN.5 MAX.6 WYE-DELTA7 ACR-LINE 7 RLA Y LRA X LRA FLA (EA)
OPTIONAL SINGLE SERVICE DISCONNECT SWITCH(Single Point Power with Factory Mounted (Non-Fuse) Disconnect Switch Only and Factory Supplied Compressor Fuse Protection)
See page 18 for notes.
FORM 201.10-NM1
23YORK INTERNATIONAL
LEGEND VOLTAGE CODEACR-LINE ACROSS THE LINE 17 = 200-3-60CB CIRCUIT BREAKER 28 = 230-3-60DE FU DUAL ELEMENT FUSE 40 = 380-3-60DISC SW DISCONNECT SWITCH 46 = 460-3-60FACT MOUNT CB FACTORY MOUNTED CIRCUIT BREAKER 58 = 575-3-60FACT MOUNT FUSE FACTORY MOUNTED FUSESFLA FULL LOAD AMPSHZ HERTZMAX MAXIMUMMCA MINIMUM CIRCUIT AMPACITYMIN MINIMUMMIN NF MINIMUM NON-FUSEDRLA RUNNING LOAD AMPSS.P. WIRE SINGLE POINT WIRINGUNIT MTD SERV SW UNIT MOUNTED SERVICE (NON FUSED DISCONNECT SWITCH)WYE-DELTA WYE-DELTA STARTXLRA ACROSS-THE-LINE INRUSH LOCKED ROTOR AMPSYLRA WYE-DELTA INRUSH LOCKED ROTOR AMPS
STYLE D SYSTEM #1 SYSTEM #2MODEL VOLTS FACTORY MOUNT FUSE COMPRESSOR FANS FACTORY MOUNT FUSE COMPRESSOR FANS60 HZ MIN.6 MAX.6 RLA Y LRA X LRA FLA(EA) MIN. 6 MAX.6 RLA Y LRA X LRA FLA (EA)
OPTIONAL SINGLE SERVICE DISCONNECT SWITCH(Single Point Power with Factory Mounted (Non-Fuse) Disconnect Switch Only and Factory Supplied Compressor Fuse Protection)
See page 18 for notes.
FORM 201.10-NM1
25YORK INTERNATIONAL
LEGEND VOLTAGE CODEACR-LINE ACROSS THE LINE 17 = 200-3-60CB CIRCUIT BREAKER 28 = 230-3-60DE FU DUAL ELEMENT FUSE 40 = 380-3-60DISC SW DISCONNECT SWITCH 46 = 460-3-60FACT MOUNT CB FACTORY MOUNTED CIRCUIT BREAKER 58 = 575-3-60FACT MOUNT FUSE FACTORY MOUNTED FUSESFLA FULL LOAD AMPSHZ HERTZMAX MAXIMUMMCA MINIMUM CIRCUIT AMPACITYMIN MINIMUMMIN NF MINIMUM NON-FUSEDRLA RUNNING LOAD AMPSS.P. WIRE SINGLE POINT WIRINGUNIT MTD SERV SW UNIT MOUNTED SERVICE (NON FUSED DISCONNECT SWITCH)WYE-DELTA WYE-DELTA STARTXLRA ACROSS-THE-LINE INRUSH LOCKED ROTOR AMPSYLRA WYE-DELTA INRUSH LOCKED ROTOR AMPS
STYLE D SYSTEM #1 SYSTEM #2MODEL VOLTS FACTORY MOUNT FUSE COMPRESSOR FANS FACTORY MOUNT FUSE COMPRESSOR FANS60 HZ MIN.6 MAX.6 RLA Y LRA X LRA FLA(EA) MIN. 6 MAX.6 RLA Y LRA X LRA FLA (EA)
LD01092NOTE: *On newer production chillers, this valve will not be located on the compressor.
COMPRESSOR TOP VIEW
COMPRESSOR FRONT VIEW COMPRESSOR REAR VIEW
36 YORK INTERNATIONAL
FIG. 2 – COMPRESSOR GAS FLOW
LD01093
GAS OFF ECONOMIZERHEAT EXCHANGER
OIL INJECTION
DISCHARGE
SUCTION
LIQUIDINJECTION
MOTORTERMINAL
BOX
FORM 201.10-NM1
37YORK INTERNATIONAL
LD01285
FIG. 3 – SCREW CHILLER REFIGERANT FLOW DIAGRAM
38 YORK INTERNATIONAL
GENERALGENERAL DESCRIPTION
The Air Cooled Screw Chiller utilizes many componentswhich are the same or nearly the same as a standardreciprocating chiller of a similar size. This includesmodular frame rails, condenser, fans and evaporator.
The chiller consists of two screw compressors in twoseparate refrigerant circuits, a single shell and tube DXevaporator, economizers, an air cooled condenser, andexpansion valves. Standard efficiency chillers have 4fans per refrigerant system and operate in pairs. Highefficiency chillers have 6 fans per refrigerant system andoperate in groups of 3 (trio).
COMPRESSOR
The Frick semi-hermetic rotary twin-screw compressorutilizes a twin screw design with a single slide valve forcapacity control. The compressor is a positivedisplacement type characterized by two helically groovedrotors. The 60 Hz motor operating at 3570 RPM drives ageared speed increaser to drive the male rotor between4125 - 7600 RPM. The female rotor is driven by the malerotor on a light film of oil. Compressors with gear setsrunning at higher speeds will have greater capacity.
Refrigerant gas is injected into the void created by the un-meshing of the 5 lobed male and 7 lobed female rotor.Further meshing of the rotors closes the rotor threads tothe suction port and progressively compresses the gas inan axial direction toward the discharge port. The gas is
compressed in volume and increased in pressure beforeexiting at a designed volume at the discharge end of therotor casing. Since the intake and discharge cyclesoverlap, a resulting smooth continuous flow of gas ismaintained.
Contact between the male and female rotor is primarilyrolling on a contact band on each of the rotors pitch circle.This results in virtually no rotor wear and increasedreliability, a trademark of the screw compressor.
The compressor incorporates a complete anti-frictionbearing design for reduced power input and increasedreliability. Four separated, cylindrical, roller bearingshandle radial loads. Angular-contact ball bearings handleaxial loads. Together they maintain accurate rotorpositioning at all pressure ratios, thereby minimizingleakage and maintaining efficiency. A check valve isinstalled in the compressor discharge housing to preventcompressor rotor backspin due to system refrigerantpressure gradients during shutdown.
Motor cooling is accomplished by injecting intermediatepressure wet vapor into the motor which allows for betterefficiency than the traditional use of lower pressuresuction gas which requires more energy to raise todischarge pressure. On demand high pressure liquidinjection provides additional motor cooling when internaloil temperatures ruse. Addtional motor cooling requiredduring low load operation is supplied by a 5 ton TXV. Adrain line drains excess liquid from the motor housing andfeeds it into the gear cavity.
The compressor is lubricated by removing oil from therefrigerant using an external oil separator. The pressur-ized oil is then piped back to the compressor forlubrication. The compressor design working pressure is144 PSIG on the discharge side. Each chiller receives a300 PSIG low side and 450 PSIG high side factory test.A 500 watt (115-1-60) immersion heater is located in thecompressor. The heater is temperature activated toprevent refrigerant condensation.
EVAPORATOR
The system uses a Shell and Tube type Direct ExpansionEvaporator. Each of the two refrigerant circuits consistsof 4 passes with the chilled liquid circulating back andforth across the tubes from one end to the other. Thedesign working pressure of the cooler shell on the liquidside is 150 PSIG, and 235 PSIG for the tube (refrigerantside). The cooler is equipped with a heater to providefreeze protection to -20°F (-28.8°C).
Water connections are grooved to accept victauliccouplings.
FIG. 4 – COMPRESSOR ROTORS
LD01095
ACTUALROTOR
ASSEMBLY
27936A(D)
FORM 201.10-NM1
39YORK INTERNATIONAL
CONDENSER
The air cooled condenser coils use state-of-the-artlouvered fins for heat transfer. Eight fans move air throughthe coils. Design working pressure of the condenser is450 PSIG.
ECONOMIZER
A plate and frame heat exchanger (Economizer) isinstalled in the high side of each system for subcooling ofthe primary refrigerant liquid to the evaporator. Thisincreases the efficiency of the system.
The wet vapor to the economizer is supplied by a small 15ton TXV set for 10°F superheat that flashes off 10 - 20%of the liquid from the condenser. 10 - 12 tons are utilizedfor subcooling liquid refrigerant and 2-3 tons for motorcooling. The wet vapor for motor cooling is at anintermediate pressure between discharge and suctionand therefore requires little energy to pump it back throughthe compressor to condenser pressure. This results in avery small loss to system efficiency.
The economizer provides approximately 20°F ofadditional subcooling (15°F in, 35°F out) to the liquidrefrigerant which flows to the evaporator at 95° ambient,55°F RWT, 44°F LWT. Subcooling will drop to approx-imately 0°F below 90°F ambient. The subcooled liquid isthen fed to the primary TXV in the system. This additionalsubcooling results in a significant increase in theefficiency of the system. The design working pressure ofthe economizer is 450 PSIG. The economizer liquidsupply solenoid is activated on start-up coincident withthe liquid line solenoid, after pumpdown.
OIL SEPARATOR / SYSTEM
The external oil separator, with no moving parts anddesigned for minimum oil carry-over, is mounted in thedischarge line of the compressor. The high pressuredischarge gas is forced around a 90 degree bend andthrough centrifugal action, oil is forced to the outside ofthe separator and captured on wire mesh where it drainsto the bottom of the oil separator and into the compressor.
The oil (YORK “E” oil - used for R-22 applications), whichdrains back into the compressor through a replaceable 0.5- 3.0 micron oil filter, and oil supply solenoid (energizedwhen the compressor starts), is at high pressure. Thishigh pressure “oil injection” forces the oil into thecompressor where it is gravity fed to the gears andbearings for lubrication. After lubricating the gears andbearings, it is injected through orifices on a closed threadnear the suction end of the rotors. The oil is automaticallyinjected because of the pressure difference betweendischarge pressure and the reduced pressure at thesuction end of the rotors. This lubricates the rotors as wellas provides an oil seal against leakage around the rotors
to assure refrigerant compression (volumetric efficiency).The oil also provides cooling by transferring much of theheat of compression from the gas to the oil keepingdischarge temperatures down and reducing the chancefor oil breakdown. Oil injected into the rotor cage flows intothe rotors at a point about 1.2x suction. This assures thata required minimum differential of at least 30 PSID existsbetween discharge and 1.2x suction, to force oil into rotorcase, a minimum 10 PSI differential is all that is requiredto assure protection of the compressor. Oil pressure ismeasured as the difference between discharge pressureand the pressure of the oil entering the rotor case.
Maximum working pressure of the oil separator is 450PSIG. A relief valve is installed in the oil separator piping.This will soon be incorporated into the oil separator. Oillevel should be above the midpoint of the “lower” oil sightglass when the compressor is running. Oil level should notbe above the top of the “upper” sight glass.
Oil temperature control is provided through liquid injectionactivated by the microprocessor, utilizing a dischargetemperature sensor, and a solenoid valve.
OIL COOLING / LIQUID INJECTION SYSTEM
A liquid injection system is utilized to maintain oiltemperature and proper oil viscosity. Liquid injection iscontrolled by the microprocessor on a demand basis toprovide stable oil, discharge, and motor temperaturecontrol. Liquid injection is fed directly into the motor coveralong with the economizer wet vapor.
A discharge temperature sensor on the compressorsends an analog signal to the microprocessor to allow themicro to monitor oil temperature. The micro in turncontrols a solenoid which injects liquid whenever thedischarge temperature rises above 180°F and turns it offwhen temperature falls to 160°F. In most circumstances,liquid injection will not energize during part load operation.
CAPACITY CONTROL
The function of the compressor capacity control systemis to automatically adjust the pumping capacity of thecompressor to satisfy the cooling load to regulate leavingwater temperature (LWT) within the programmed ControlRange (CR). Capacity control is accomplished by movinga slide valve with a series of load and unload pulses whichchanges the entrance point of the suction gas entering therotors. This allows refrigerant gas to be injected atvirtually any point on the rotors, keeping in mind that aminimum capacity of 20% load per compressor (10% totalchiller) is maintained on a compressor for oil return. Themicro also attempts to sequence compressor loading tomaximize efficiency and minimize compressor cycling.
Movement of the slide valve is accomplished by forcingpressurized oil against a piston which drives the slide
40 YORK INTERNATIONAL
valve open to load the compressor. Electrical pulses opena solenoid valve, allowing oil pressure to move the pistonwhich operates the slide valve. The pulses originate at themicro and are a function of the required load on the chillerin response to leaving water temperature.
The micro must repetitively pulse the slide valve tomaintain a constant load. This is required becausedischarge pressure is always present on the other end ofthe slide valve, trying to force it closed.
To unload the compressor, a second solenoid is opened,which vents oil pressure away from the piston. Byreleasing the pressure on the piston, the dischargepressure is able to push the valve toward the closed orunload position.
It will be noted that slide valve movement is greater at highdischarge pressures. This is due to higher oil pressurewhich is directly proportional to discharge pressure.Higher oil pressures exert more pressure on the slidevalve causing greater movement as the slide valve ispulsed with oil. This condition is normal. Also normal anda result of compressor design is non-linear movement atvarious points in the slide valve travel as the slide valveis pulsed. Closely monitoring the movement will show thatthe slide valve will move easier at the ends and in thecenter of its travel range.
When the compressor is shut down, a check valvereleases oil from the piston. Since no discharge pressureis available to push the valve closed, the slide valve willmaintain the position it was in when the compressorstopped. To assure the compressor starts unloaded, themicro sends an unload signal to the slide valve on start-up. In some cases, oil pressure may not be high enoughat start-up to move the slide valve. This means thecompressor could start-up partially loaded. This willseldom occur and will not hurt the motor due to the extratorque built into the design.
STARTER
Two types of compressor motor starting are available:
Across-the-line and optional Wye-Delta Closed TransitionStarter. The Across-the-line starters will utilize onecontactor per compressor.
The optional Wye-Delta starter utilizes 4 contactors, atime delay relay, and wire wound power resistors for eachcompressor. See Fig. 5.
The Wye-Delta start allows inrush current to be limited toapproximately 33% LRA for the first 15 seconds withcurrent increasing to normal running current when theDelta connection is completed.
When the micro initiates a start signal to run acompressor, the 1CR (SYS 1) or 2CR (SYS 2) relay isenergized. At the same time, the 1TR (SYS 1) or 2TR(SYS 2) “15 second” time delay relay is energized andbegins timing. The transition of the 1CR (SYS 1) or 2CR(SYS 2) contactor also energizes 1S (SYS 1) or 2S (SYS2) normally open auxiliary interlock contacts afterapproximately 16ms which in turn energizes the 1M (SYS1) or 3M (SYS 2) motor contactor after approximatelyanother 16ms. This completes the “WYE” connection ofthe motor start. At the same time, the normally closed 1Sor 2S auxiliary interlock open, preventing 2M (SYS 1) or4M (SYS 2) from energizing.
The “WYE” connection of the motor start is enabled forapproximately 15 seconds. When the 1TR or 2TR timertimes out after 15 seconds, the interlock contactsenergize 1A (SYS 1) or 2A (SYS 2) “TRANSITION”contactor which puts the resistance networks acrosseach winding of the “WYE” connection. At the same time,the normally closed 1A or 2A auxiliary interlock contactsde-energize 1S or 2S after approximately 16ms. Thenormally closed auxiliary interlock contacts on 1S or 2Swill close energizing 2M or 4M after approximately 16ms.
With the 1M or 3M contactors already held in by the 1Mor 3M auxiliary contacts and 2M or 4M energized, thenormally closed auxiliary interlock contact on 2M or 4Mcontactor holding in the 1A or 2A “TRANSITION” contactoropens removing the resistor network and completing the“DELTA” connection of the “WYE-DELTA” start.
FIG. 5 – POWER PANEL (WITH WYE-DELTA STARTING) 27963A
FORM 201.10-NM1
41YORK INTERNATIONAL
INSTALLATION
WARNING
To protect warranty, this equipment must be installedand serviced by an authorized YORK servicemechanic or a qualified service person experienced inchiller installation. Installation must comply with allapplicable codes, particularly in regard to electricalwiring and other safety elements such as relief valves,HP cut-out settings, design working pressures, andventilation requirements consistent with the amountand type of refrigerant charge.
Lethal voltages exist within the control panel. Beforeservicing, open and tag all disconnect switches.
INSTALLATION CHECK LIST
The following items, 1 thru 5, must be checked beforeplacing the units in operation.
1. Inspect the unit for shipping damage.
2. Rig unit per Fig. 6A or 6B. Remove unpainted shippingbraces.
3. Open the unit only to install water piping system. Donot remove protective covers from water connectionsuntil piping is ready for attachment. Check waterpiping to insure cleanliness.
4. Pipe unit using good piping practice (see ASHRAEhandbook section 215 and 195 or YORK ServiceManuals for detailed piping).
5. Check to see that the unit is installed and operatedwithin LIMITATIONS.
The following pages outline detailed procedures to befollowed to install and start up the chiller.
HANDLING
These units are shipped as completely assembled unitscontaining full operating charge, and care should be takento avoid damage due to rough handling.
The units are shipped with export crating unless it isspecified by Sales Order.
A unit should be lifted by inserting hooks through the holesprovided in unit base rails. Spreader bars should be usedto avoid crushing the unit frame rails with the liftingchains. (See Fig. 6A & 6B)
INSPECTION
Immediately upon receiving the unit, it should beinspected for possible damage which may have occurredduring transit. If damage is evident, it should be noted inthe carrier’s freight bill. A written request for inspection bythe carrier’s agent should be made at once. See “Instruc-tion” manual, Form 50.15-NM for more information anddetails.
LOCATION AND CLEARANCES
These units are designed for outdoor installations onground level, rooftop, or beside a building. Locationshould be selected for minimum sun exposure and toinsure adequate supply of fresh air for the condenser. Theunits must be installed with sufficient clearances for airentrance to the condenser coil, for air discharge awayfrom the condenser, and for servicing access.
In installations where winter operation is intended andsnow accumulations are expected, additional height mustbe provided to insure normal condenser air flow. (SeeDIMENSIONS.)
FIG. 6A – RIGGING THE CHILLER (2-MOD)
LD01096
FIG. 6B – RIGGING THE CHILLER (3-MOD)
LD01439
42 YORK INTERNATIONAL
FOUNDATION
The unit should be mounted on a flat and level foundation,floor, or rooftop capable of supporting the entire operatingweight of the equipment. See PHYSICAL DATA foroperating weight. If the unit is elevated beyond the normalreach of service personnel, a suitable catwalk must becapable of supporting service personnel, their equipment,and the compressors.
GROUND LEVEL LOCATIONS
It is important that the units be installed on a substantialbase that will not settle. A one piece concrete slab withfooters extended below the frost line is highlyrecommended. Additionally, the slab should not be tied tothe main building foundations as noise and vibration maybe transmitted.
Mounting holes are provided in the steel channel forbolting the unit to its foundation. (See DIMENSIONS.)
For ground level installations, precautions should betaken to protect the unit from tampering by or injury tounauthorized persons. Screws and/or latches on accesspanels will prevent casual tampering. However, furthersafety precautions such as a fenced-in enclosure orlocking devices on the panels may be advisable. Atamper proof kit is available as an option. Check localauthorities for safety regulations.
ROOFTOP LOCATIONS
Choose a spot with adequate structural strength to safelysupport the entire weight of the unit and servicepersonnel. Care must be taken not to damage the roof.
Consult the building contractor or architect if the roof isbonded. Roof installations should have wooden beams(treated to reduce deterioration), cork, rubber, or vibrationisolators under the base to minimize vibration.
NOISE SENSITIVE LOCATIONS
Efforts should be made to assure that the chiller is notlocated next to occupied spaces or noise sensitive areaswhere chiller noise level would be a problem. Chiller noiseis a result of compressor and fan operation. Con-siderations should be made utilizing noise levelspublished in the YORK Engineering Guide for the specificchiller model. If questions arise, contact YORKPRODUCT MARKETING.
SHIPPING BRACES
A single painted shipping bracket on the opposite end ofthe control panel runs diagonally along the end of the unit.This may be removed once the unit is mounted on itsfoundation, however, it may remain in place.
SPRING ISOLATORS (OPTIONAL)
When ordered, eight (8) spring isolators will be furnished.
1. Identify the isolator and locate at the proper mountingpoint see pages 44 - 51.
2. Block up the equipment so as to install spring mountswith the pin on top of the housing into the chillermounting holes.
3. The Mounting Adjustment Nut is inside the isolatormount located just below the top plate of the mount.Turn the nut 2 turns clockwise (down) to load thespring mount at each location.
4. Take additional turns on the Adjustment Nut of eachlocation.
5. Repeat Step No. 3 as many times as necessary tobring the height of the isolator to the proper height.
6. Take additional turns on the mounts at the low side orcorner to level the equipment.
COMPRESSOR MOUNTING
The compressors are mounted on four (4) vibrationisolators. (See Fig. 7) The mounting bolts should NEVERbe loosened or adjusted at installation of the chiller.
CHILLED LIQUID PIPING
General – When the unit has been located in its finalposition, the unit liquid piping may be connected. Normalinstallation precautions should be observed in order toreceive maximum operating efficiencies. Piping shouldbe kept free of all foreign matter. All liquid evaporatorpiping must comply in all respects with local plumbingcodes and ordinances.
Since elbows, tees and valves decrease pump capacity,all piping should be kept as straight and as simple aspossible.
FIG. 7 – COMPRESSOR VIBRATION ISOLATOR
27974A
COMPRESSORVIBRATION ISOLATOR
FORM 201.10-NM1
43YORK INTERNATIONAL
Hand stop valves should be installed in all lines tofacilitate servicing.
Piping to the inlet and outlet connections of the chillershould include high-pressure rubber hose or piping loopsto insure against transmission of water pump vibration.This is optional and the necessary components must beobtained in the field.
Drain connections should be provided at all low points topermit complete drainage of the liquid cooler and systempiping.
A small valve or valves should be installed at the highestpoint or points in the chilled liquid piping to allow anytrapped air to be purged. Vent and drain connectionsshould be extended beyond the insulation to make themaccessible.
The piping to and from the cooler must be designed to suitthe individual installation. It is important that the followingconsiderations be observed:
1. The chilled liquid piping system should be laid out sothat the circulating pump discharges directly into thecooler. The suction for this pump should be taken fromthe piping system return line and not the cooler. Thispiping scheme is recommended, but is notmandatory. Keep in mind that a pump whose suctionis taken from the evaporator may suffer performanceproblems.
2. The inlet and outlet cooler connection sizes are 8".
3. A strainer, preferably 40 mesh, must be installed inthe cooler inlet line just ahead of the cooler. This isimportant to protect the cooler from entrance of largeparticles which could cause damage to theevaporator.
4. All chilled liquid piping should be thoroughly flushed tofree it from foreign material before the system isplaced into operation. Use care not to flush any foreignmaterial into or through the cooler.
5. As an aid to servicing, thermometers and pressuregauges should be installed in the inlet and outlet waterlines. One connection point (plugged) is provided ineach cooler nozzle. Thermometers and gauges arenot furnished by other suppliers.
6. The chilled liquid lines that are exposed to outdoorambients should be wrapped with supplementalheater cable and insulated to protect against freeze-up during low ambient periods, and to preventformation of condensation on lines in warm humidclimates.
7. A chilled water flow switch, (either by YORK or others)MUST be installed in the leaving water piping of thecooler. There should be a straight horizontal run of atleast 5 diameters on each side of the switch. Adjustthe flow switch paddle to the size of the pipe in whichit is to be installed. (See manufacturer’s instructionsfurnished with the switch.) The switch is to be wired toterminals in the control panel as shown in the WIRINGDIAGRAM.
WARNING
The Flow Switch MUST NOT be used to start and stopthe chiller. It is intended only as a safety switch.
COMPRESSOR INSULATION
In high humidity environments, compressor sweatingmay be noted. In most applications, this is of no concern.However, if it is undesirable, it is the responsibility of theinstaller to make provisions to field insulate thecompressors or install factory insulation when the optionbecomes available. Contact YORK Factory Marketing foravailability of factory supplied kits.
ELECTRICAL WIRING
Liquid Chillers are shipped with all factory mountedcontrols wired for operation.
Field Wiring – Power wiring must be provided througha fused disconnect switch to the unit terminals (or optionalmolded disconnect switch) in accordance with N.E.C. orlocal code requirements. Minimum circuit ampacity andmaximum dual element fuse size are given in theELECTRICAL DATA tables. A 115-1-60, 20 amp sourcemust be supplied for the control panel through a fuseddisconnect when a control panel transformer (optional) isnot provided. Refer to Wiring Diagram (Page 52) in thismanual or Form 201.10-W1.
Affiliated apparatus, such as chilled water flow switch,auxiliary contacts from the chilled water pump starter,alarms, etc., should be interlocked into the control panelcircuit. These field modifications may be made as shownon the WIRING DIAGRAM.
MULTIPLE UNITS
For increased compressor protection and to reduce powerinrush at start-up on multiple chiller installations,provisions must be made to prevent simultaneous start-up of two or more units. Also, some method must beemployed to automatically cycle one or more of the unitson or off to permit more efficient operation at part loadconditions.
44 YORK INTERNATIONAL
TYPE MAX. LOAD SPRING DEFL& SIZE LBS. COLOR IN.
CP-2-31 2200 GRAY 0.83
WEIGHT DISTRIBUTIONS (LBS.) AND ISOLATOR LOCATIONYCAS 140 - 246 CHILLERS WITH ALUMINUM CONDENSER COILS
CP-2-31 LD01089
MODELOPERATING WEIGHT DISTRIBUTION (LBS.) AND ISOLATOR LOCATION
A B C D E F G H
YCAS140 2021 1956 1890 1824 2006 1941 1875 1810
YCAS160 2021 1956 1890 1824 2006 1941 1875 1810
YCAS170 2043 1977 1912 1847 2085 2019 1952 1886
YCAS180 2043 1977 1912 1847 2085 2019 1952 1886
YCAS190 2043 1977 1912 1847 2085 2019 1952 1886
YCAS216 2043 1977 1912 1847 2085 2019 1952 1886
YCAS236 2043 1977 1912 1847 2085 2019 1952 1886
YCAS246 2043 1977 1912 1847 2085 2019 1952 1886
LD01445(R)
NOTE: USE CP-2-31 ISOLATORS AT ALL LOCATIONS
FORM 201.10-NM1
45YORK INTERNATIONAL
TYPE MAX. LOAD SPRING DEFL& SIZE LBS. COLOR IN.
CP-4-26 2400 PURPLE 1.17
WEIGHT DISTRIBUTIONS (LBS.) AND ISOLATOR LOCATIONYCAS 140 - 246 CHILLERS WITH COPPER CONDENSER COILS
CP-4-26LD01168
MODELOPERATING WEIGHT DISTRIBUTION (Kg) AND ISOLATOR LOCATION
A B C D E F G H
YCAS140 2306 2240 2174 2108 2291 2225 2160 2094
YCAS160 2306 2240 2174 2108 2291 2225 2160 2094
YCAS170 2327 2262 2197 2132 2369 2303 2237 2171
YCAS180 2327 2262 2197 2132 2369 2303 2237 2171
YCAS190 2327 2262 2197 2132 2369 2303 2237 2171
YCAS216 2327 2262 2197 2132 2369 2303 2237 2171
YCAS236 2327 2262 2197 2132 2369 2303 2237 2171
YCAS246 2327 2262 2197 2132 2369 2303 2237 2171
LD01445(R)
NOTE: USE CP-4-26 ISOLATORS AT ALL LOCATIONS
46 YORK INTERNATIONAL
WEIGHT DISTRIBUTIONS (KG) AND ISOLATOR LOCATIONYCAS 140 - 246 CHILLERS WITH ALUMINUM CONDENSER COILS
TYPE MAX. LOAD SPRING DEFL& SIZE Kg COLOR mm
CP-2-31 997.9 GRAY 21.0
CP-2-31 LD01089
LD01441(r)
MODELOPERATING WEIGHT DISTRIBUTION (Kg) AND ISOLATOR LOCATION
A B C D E F G H
YCAS140 917 887 857 827 909 880 850 821
YCAS160 917 887 857 827 909 880 850 821
YCAS170 927 897 867 838 946 916 885 855
YCAS180 927 897 867 838 946 916 885 855
YCAS190 927 897 867 838 946 916 885 855
YCAS216 927 897 867 838 946 916 885 855
YCAS236 927 897 867 838 946 916 885 855
YCAS246 927 897 867 838 946 916 885 855
NOTE: USE CP-2-31 ISOLATORS AT ALL LOCATIONS
FORM 201.10-NM1
47YORK INTERNATIONAL
CP-4-26
WEIGHT DISTRIBUTIONS (KG) AND ISOLATOR LOCATIONYCAS 140 - 246 CHILLERS WITH COPPER CONDENSER COILS
LD01441(r)
MODELOPERATING WEIGHT DISTRIBUTION (Kg) AND ISOLATOR LOCATION
A B C D E F G H
YCAS140 1046 1016 986 956 1039 1009 980 950
YCAS160 1046 1016 986 956 1039 1009 980 950
YCAS170 1056 1026 997 967 1075 1045 1015 985
YCAS180 1056 1026 997 967 1075 1045 1015 985
YCAS190 1056 1026 997 967 1075 1045 1015 985
YCAS216 1056 1026 997 967 1075 1045 1015 985
YCAS236 1056 1026 997 967 1075 1045 1015 985
YCAS246 1056 1026 997 967 1075 1045 1015 985
TYPE MAX. LOAD SPRING DEFL& SIZE Kg COLOR mm
CP-4-26 1088.6 PURPLE 29.7
NOTE: USE CP-4-26 ISOLATORS AT ALL LOCATIONS
LD01168
48 YORK INTERNATIONAL
TYPE MAX. LOAD SPRING DEFL& SIZE LBS. COLOR IN.
CP-2-27 1500 ORANGE 1.06
CP-2-31 2200 GRAY .83
CP-2-27 / CP-2-31LD01089
WEIGHT DISTRIBUTIONS (LBS.) AND ISOLATOR LOCATIONYCAS 216X - 266X CHILLERS WITH ALUMINUM CONDENSER COILS
LD01453)R)
MODELOPERATING WEIGHT DISTRIBUTION (LBS.) AND ISOLATOR LOCATION
1. Field wiring to be in accordance with the current edition of theNational Electrical Code as well as all other applicable codes andspecifications.
2. Numbers along the right side of a diagram are line identificationnumbers. The numbers at each line indicate the line numberlocation of relay contacts. An unlined contact location signifies anormally closed contact. Numbers adjacent to circuit lines arethe circuit identification numbers.
3. Any customer supplied contacts must be suitable for switching24VDC. (Gold contacts recommended.) Control Wiring must notbe run in the same conduit with any line voltage wiring.
4. To cycle unit on and off automatically with contact shown, installa cycling device in series with the flow switch (FSLW). See Note3 for contact rating and wiring specifications. Also refer to cau-tions on the following page.
5. To stop unit (Emergency Stop) with contacts other than thoseshown, install the stop contact between 5 and 1. If a stop deviceis not installed, a jumper must be connected between terminals 5and 1. Device must have a minimum contact rating of 100VA at115 volts A.C.
6. Alarm contacts are for annunciating alarm/unit malfunction. Con-tacts are rated at 115V, 100VA, resistive load only, and must besuppressed at load by user.
7. See Installation, Operation and Maintenance Manual when op-tional equipment is used.
8. Control panel to be securely connected to earth ground.
9. Us 2KVA transformer in optional transformer kit unless there areoptional oil separator sump heaters which necessitates using a3KVA transformer.
LEGEND
Transient Voltage Suppression
Terminal Block for Customer Connections
Terminal Block for Customer Low Voltage(Class 2) Connections. See Note 2
Terminal Block for YORK Connections Only
Wiring and Components by YORK
Optional Equipment
Wiring and/or Components by Others
T S
LD01461(D)
LD01461(D)
FORM 201.10-NM1
53YORK INTERNATIONAL
FIG. 8 – CONTINUED
CAUTION:No Controls (relays,etc.) should bemounted in the SmartPanel enclosure orconnected to powersupplies in the controlpanel. Additionally, con-trol wiring not con-nected to the SmartPanel should not be runthrough the cabinet.This could result in nui-sance faults.
CAUTION:Any inductive devices(relays) wired in serieswith the flow switch forstart/stop, into theAlarm circuitry, or pilotrelays for pump start-ers wired through mo-tor contactor auxiliarycontacts must be sup-pressed with YORKP/N 031-00808-000suppressor across therelay/contactor coil.
Any contacts con-nected to flow switchinputs or BAS inputs onterminals 13 - 19 orTB3, or any other ter-minals, must be sup-pressed with a YORKP/N 031-00808-000suppressor across therelay/contactor coil.
CAUTION:Control wiring con-nected to the controlpanel should never berun in the same con-duit with power wiring.
ELEMENTARY DIAGRAM
LD1464
MAX NON-
CONTROL MIN DUAL FUSEDUNIT
POWER CIRCUIT ELEMENT DISC.VOLTAGE
SUPPLY AMP. FUSE SWITCH
SIZE SIZE
ALL MODELS115-1-50/60 20A 20A 250V 30A 240V
W/O TRANS.
MODELS -17 200-1-60 15A 15A 250V 30A 240V
WITH -28 230-1-60 15A 15A 250V 30A 240V
TRANS. -46 400-1-60 8A 8A 600V 30A 480V
* -58 575-1-60 8A 8A 600V 30A 600V
* All primary and secondary wiring between transformer andcontrol panel included.
CONTROL POWER SUPPLY
54 YORK INTERNATIONAL
FIG. 9 – SYSTEM WIRING
YCAS 140 - 246 CONNECTION DIAGRAM (SYSTEM WIRING)
LD01466(D)
FORM 201.10-NM1
55YORK INTERNATIONAL
FIG. 9 – CONTINUED
YCAS 140 - 246 COMPRESSOR TERMINAL BOX
ACROSS-THE-LINE START
WYE-DELTA START
LD01466(D)
LD01459(D)
56 YORK INTERNATIONAL
FIG. 10 – ELEMENTARY DIAGRAM – WYE-DELTA START
YCAS 140 - 246 WIRING DIAGRAMWYE-DELTA START
NOTES:
1. Field wiring to be in accordance with the current edition of theNational Electrical Code as well as all other applicable codes andspecifications.
2. Numbers along the right side of a diagram are line identificationnumbers. The numbers at each line indicate the line numberlocation of relay contacts. An unlined contact location signifies anormally closed contact. Numbers adjacent to circuit lines arethe circuit identification numbers.
3. Any customer supplied contacts must be suitable for switching24VDC. (Gold contacts recommended.) Control Wiring must notbe run in the same conduit with any line voltage wiring.
4. To cycle unit on and off automatically with contact shown, installa cycling device in series with the flow switch (FSLW). See Note3 for contact rating and wiring specifications. Also refer to cau-tions on the following page.
5. To stop unit (Emergency Stop) with contacts other than thoseshown, install the stop contact between 5 and 1. If a stop deviceis not installed, a jumper must be connected between terminals 5and 1. Device must have a minimum contact rating of 100VA at115 volts A.C.
6. Alarm contacts are for annunciating alarm/unit malfunction. Con-tacts are rated at 115V, 100VA, resistive load only, and must besuppressed at load by user.
7. See Installation, Operation and Maintenance Manual when op-tional equipment is used.
8. Control panel to be securely connected to earth ground.
9. Us 2KVA transformer in optional transformer kit unless there areoptional oil separator sump heaters which necessitates using a3KVA transformer.
LEGEND
Transient Voltage Suppression
Terminal Block for Customer Connections
Terminal Block for Customer Low Voltage(Class 2) Connections. See Note 2
Terminal Block for YORK Connections Only
Wiring and Components by YORK
Optional Equipment
Wiring and/or Components by Others
T S
LD01457(D)
LD01457(D)
FORM 201.10-NM1
57YORK INTERNATIONAL
FIG. 10 – CONTINUED
CAUTION:No Controls (relays,etc.) should bemounted in the SmartPanel enclosure orconnected to powersupplies in the controlpanel. Additionally, con-trol wiring not con-nected to the SmartPanel should not be runthrough the cabinet.This could result in nui-sance faults.
CAUTION:Any inductive devices(relays) wired in serieswith the flow switch forstart/stop, into theAlarm circuitry, or pilotrelays for pump start-ers wired through mo-tor contactor auxiliarycontacts must be sup-pressed with YORKP/N 031-00808-000suppressor across therelay/contactor coil.
Any contacts con-nected to flow switchinputs or BAS inputs onterminals 13 - 19 orTB3, or any other ter-minals, must be sup-pressed with a YORKP/N 031-00808-000suppressor across therelay/contactor coil.
CAUTION:Control wiring con-nected to the controlpanel should never berun in the same con-duit with power wiring.
LD01480
ELEMENTARY DIAGRAM
MAX NON-
CONTROL MIN DUAL FUSEDUNIT
POWER CIRCUIT ELEMENT DISC.VOLTAGE
SUPPLY AMP. FUSE SWITCH
SIZE SIZE
ALL MODELS115-1-50/60 20A 20A 250V 30A 240V
W/O TRANS.
MODELS -17 200-1-60 15A 15A 250V 30A 240V
WITH -28 230-1-60 15A 15A 250V 30A 240V
TRANS. -46 400-1-60 8A 8A 600V 30A 480V
* -58 575-1-60 8A 8A 600V 30A 600V
* All primary and secondary wiring between transformer andcontrol panel included.
1. Field wiring to be in accordance with the current edition of theNational Electrical Code as well as all other applicable codes andspecifications.
2. Contacts must be suitable for switching 24VDC (gold contactsrecommended). Wiring shall not be run in the same conduit withany line voltage wiring.
3. To cycle unit on and off automatically with contact shown, installa cycling device in series with the flow switch (FLSW). See Note2 for contact rating and and wiring specifications.
4. To stop unit (emergency stop) with contacts other than thoseshown, install the stop contact between terminals 5 and 1. If astop device is not installed, a jumper must be connected be-tween terminals 5 and 1. Device must have a minimum contactrating of 100VA at 115 Volts A.C.
5. Alarm contacts are for annunciations alarm/unit malfunction. con-tacts are rated at 115V, 100VA, resistive load only, and must besuppressed at load by user.
6. See installation, operation and maintenance manuals when op-tional equipment is used.
7. Use 2 KVA transformer inoptional transformer kit unless thereare optional oil separator sump heaters which necessitates us-ing 3 KVA transformers.
8. Power factor correction capacitors may be installed on the chillerelectrical system (as shown) as a field supplied option. The powerfactor correction capacitors must be installed in accordance withthe National Electrical Code Article 460 as well as all other appli-cable codes and specifications. Power factor correction capaci-tors may be installed only on the line side of the chiller electricalsystem with correction not to exceed a PF of more than 0.96. Aseparate disconnect switch, over current protection and dis-charge resistors are required.
LEGEND
Transient Voltage Suppression
Terminal Block for Customer Connections
Terminal Block for Customer Low Voltage(Class 2) Connections. See Note 2
Terminal Block for YORK Connections Only
Wiring and Components by YORK
Optional Equipment
Wiring and/or Components by Others
T S
FORM 201.10-NM1
63YORK INTERNATIONAL
FIG. 13 – CONTINUED
ELEMENTARY DIAGRAMCAUTION:No Controls (relays,etc.) should bemounted in the SmartPanel enclosure orconnected to powersupplies in the controlpanel. Additionally, con-trol wiring not con-nected to the SmartPanel should not be runthrough the cabinet.This could result in nui-sance faults.
CAUTION:Any inductive devices(relays) wired in serieswith the flow switch forstart/stop, into theAlarm circuitry, or pilotrelays for pump start-ers wired through mo-tor contactor auxiliarycontacts must be sup-pressed with YORKP/N 031-00808-000suppressor across therelay/contactor coil.
Any contacts con-nected to flow switchinputs or BAS inputs onterminals 13 - 19 orTB3, or any other ter-minals, must be sup-pressed with a YORKP/N 031-00808-000suppressor across therelay/contactor coil.
CAUTION:Control wiring con-nected to the controlpanel should never berun in the same con-duit with power wiring.
LD01204
MAX NON-
CONTROL MIN DUAL FUSEDUNIT
POWER CIRCUIT ELEMENT DISC.VOLTAGE
SUPPLY AMP. FUSE SWITCH
SIZE SIZE
ALL MODELS115-1-50/60 20A 20A 250V 30A 240V
W/O TRANS.
MODELS -17 200-1-60 15A 15A 250V 30A 240V
WITH -28 230-1-60 15A 15A 250V 30A 240V
TRANS. -46 400-1-60 8A 8A 600V 30A 480V
* -58 575-1-60 8A 8A 600V 30A 600V
* All primary and secondary wiring between transformer andcontrol panel included.
POWER CIRCUIT OPTIONS STANDARD DUAL COMPRESSOR POWER SUPPLIES
LD01201(D)
LD01201(D)
NOTES:
1. Field wiring to be in accordance with the current edition of theNational Electrical Code as well as all other applicable codes andspecifications.
2. Contacts must be suitable for switching 24VDC (gold contactsrecommended). Wiring shall not be run in the same conduit withany line voltage wiring.
3. To cycle unit on and off automatically with contact shown, installa cycling device in series with the flow switch (FLSW). See Note2 for contact rating and and wiring specifications.
4. To stop unit (emergency stop) with contacts other than thoseshown, install the stop contact between terminals 5 and 1. If astop device is not installed, a jumper must be connected be-tween terminals 5 and 1. Device must have a minimum contactrating of 100VA at 115 Volts A.C.
5. Alarm contacts are for annunciations alarm/unit malfunction. con-tacts are rated at 115V, 100VA, resistive load only, and must besuppressed at load by user.
6. See installation, operation and maintenance manuals when op-tional equipment is used.
7. Use 2 KVA transformer inoptional transformer kit unless thereare optional oil separator sump heaters which necessitates us-ing 3 KVA transformers.
8. Power factor correction capacitors may be installed on the chillerelectrical system (as shown) as a field supplied option. The powerfactor correction capacitors must be installed in accordance withthe National Electrical Code Article 460 as well as all other appli-cable codes and specifications. Power factor correction capaci-tors may be installed only on the line side of the chiller electricalsystem with correction not to exceed a PF of more than 0.96. Aseparate disconnect switch, over current protection and dis-charge resistors are required.
LEGEND
Transient Voltage Suppression
Terminal Block for Customer Connections
Terminal Block for Customer Low Voltage(Class 2) Connections. See Note 2
Terminal Block for YORK Connections Only
Wiring and Components by YORK
Optional Equipment
Wiring and/or Components by Others
T S
FORM 201.10-NM1
67YORK INTERNATIONAL
FIG. 15 – CONTINUED
ELEMENTARY DIAGRAM
LD01200
CAUTION:No Controls (relays,etc.) should bemounted in the SmartPanel enclosure orconnected to powersupplies in the controlpanel. Additionally, con-trol wiring not con-nected to the SmartPanel should not be runthrough the cabinet.This could result in nui-sance faults.
CAUTION:Any inductive devices(relays) wired in serieswith the flow switch forstart/stop, into theAlarm circuitry, or pilotrelays for pump start-ers wired through mo-tor contactor auxiliarycontacts must be sup-pressed with YORKP/N 031-00808-000suppressor across therelay/contactor coil.
Any contacts con-nected to flow switchinputs or BAS inputs onterminals 13 - 19 orTB3, or any other ter-minals, must be sup-pressed with a YORKP/N 031-00808-000suppressor across therelay/contactor coil.
CAUTION:Control wiring con-nected to the controlpanel should never berun in the same con-duit with power wiring.
MAX NON-
CONTROL MIN DUAL FUSEDUNIT
POWER CIRCUIT ELEMENT DISC.VOLTAGE
SUPPLY AMP. FUSE SWITCH
SIZE SIZE
ALL MODELS115-1-50/60 20A 20A 250V 30A 240V
W/O TRANS.
MODELS -17 200-1-60 15A 15A 250V 30A 240V
WITH -28 230-1-60 15A 15A 250V 30A 240V
TRANS. -46 400-1-60 8A 8A 600V 30A 480V
* -58 575-1-60 8A 8A 600V 30A 600V
* All primary and secondary wiring between transformer andcontrol panel included.
The YORK Millennium Computer Control Center is amicroprocessor based control system capable of multi-circuit control to maintain chilled liquid temperature andprovide safety control.
A 40 character display (2 lines of 20 characters) allows theoperator to display system operating parameters as wellas access programmed information already in memory. Akeypad for programming and accessing setpoints,pressures, temperatures, motor current, cutouts, dailyschedule, options, and fault information is provided.
A master switch is available to activate or de-activate thechiller system. Separate system (SYS) switches for eachrefrigerant system (up to 4) are provided on theMicroprocessor Board.
Remote cycling, current limiting, and chilled watertemperature reset can be accomplished by user supplieddry contacts.
Compressor starting, stopping, loading and unloadingdecisions are performed by the Microprocessor tomaintain leaving water temperatures. These decisionsare a function of temperature deviation from setpoint andthe rate of change of temperature.
MICROPROCESSOR BOARD
The Microprocessor Board is the controller and decisionmaker in the control panel. System inputs from pressuretransducers and temperature sensors are connecteddirectly to the Microprocessor Board. Other inputs fromthe I/O Expansion Board such as slide valve position, oiltemperature, etc. are multiplexed on the Expansion Boardand are also sent to the Microprocessor Board. TheMicroprocessor Board circuitry multiplexes all of theseanalog inputs, digitizes them, and constantly scans themto keep a constant watch on chiller operating conditions.From this information, the Microprocessor then issuescommands to the Relay Output Board to activate and de-activate contactors, solenoids, etc. for chilled liquidcontrol and safety control.
FIG. 18 – Millennium CONTROL CENTER
28164A
FORM 201.10-NM1
73YORK INTERNATIONAL
Keypad commands are acted upon by the micro tochange setpoints, cut-outs, scheduling, operatingrequirements, and to provide displays.
A +12VDC REG supply voltage from the Power SupplyBoard is converted to +5V REG by a voltage regulatorlocated on the Microprocessor Board. This voltage isused to operate the integrated circuitry on the board.
Four system switches located on the MicroprocessorBoard activate and deactivate the individual systems(compressors).
I/O EXPANSION BOARD
The I/O Expansion Board allows additional analog inputsto be tied to the Microprocessor Board. Without thisboard, the Microprocessor is limited to a specific numberof individual inputs that can be connected withoutenlarging of the board. The expansion board is basicallya multiplexer that allows a group of inputs to be connectedto the expansion board and then rout these inputs to theMicroprocessor Board on a single data line. The individualinputs are multiplexed according to the selection made bythe Microprocessor by means of address lines.
Signals routed through the I/O Expansion Board includeDischarge Temperature, Oil Temperature, and OptionalMixed Water Temperature.
POWER SUPPLY BOARD
The on-board switching power supply protected by fuse 2FU converts 24VAC from the 2T transformer to +12VREG which is supplied to the Microprocessor Board,Relay Output Board, and the 40 character display tooperate the integrated circuitry.
24VAC is filtered, but not regulated, to provideunregulated +24VDC to supply the flow switch, PWMremote temperature reset, PWM remote current reset,lead / lag select, and remote print circuitry which isavailable to be used with user supplied contacts.
24VAC is also filtered and regulated to +24VDC to beused by the optional BAS Circuit Boards for remotetemperature or remote current reset.
Individual rectifier and filtering circuits are present whichreceive the C.T. signals for each phase of motor currenton each compressor. These circuits rectify and filter thesignals to variable DC. A phase rotation circuit for eachcompressor is also present to assure that the screwcompressors do not run in the wrong direction. All of thesesignals are sent to the I/O Expansion Board whichmultiplexes them and then feeds them to theMicroprocessor Board.
RELAY OUTPUT BOARD
Two Relay Output Boards are required to operate thechiller. These boards convert 0 - 12VDC logic levelsoutputs from the Microprocessor Board to 115VAC levelsused by motor contactors / starters, solenoid valves,expansion valves, etc. to control system operation. Thecommon side of all relays on the Relay Output Board isconnected to +12VDC REG.
The open collector outputs of the Microprocessor Boardenergize the DC relays or triacs by pulling the other sideof the relay coil to ground. When not energized, both sidesof the relay coils or triacs will be at +12VDC potential.Triacs are used for load and unload slide valve solenoidsas well as liquid line solenoid or electronic expansionvalves when fitted. Triacs are more suitable than relayswhen high frequency switching is required.
CURRENT TRANSFORMER (C.T.)
C.T.s on each of the 3 phases of the power wiring of eachmotor send AC signals proportional to motor current to thePower Supply Board which rectifies and filters the signalsto variable DC Voltage (analog). These analog levels arethen fed to the Microprocessor Board to allow it to monitormotor currents for low current, high current, imbalancedcurrent, and single phasing.
40 CHARACTER DISPLAY
The 40 Character Display (2 lines of 20 characters) is aliquid crystal display used for displaying systemparameters and operator messages. The display has alighted background for night viewing as well as a specialfeature which intensifies the display for viewing in directsunlight.
KEYPAD
An operator keypad allows complete control of thesystem from a central location. The keypad offers amultitude of commands available to access displays,program setpoints, and initiate system commands.
BATTERY BACK-UP
The Microprocessor Board contains a Real Time Clockintegrated circuit chip with an internal battery back-up.The purpose of the battery back-up is to assure anyprogrammed values (setpoints, clock, cut-outs, etc.) arenot lost during a power failure regardless of the timeinvolved in a power outage or shutdown period.
74 YORK INTERNATIONAL
FIG. 19 – MICROCOMPUTER CONTROL CENTER
27962A
I/O EXPANSION BOARD
POWERSUPPLYBOARD
RELAYOUTPUTBOARD #1
RELAYOUTPUTBOARD #2
TB4TERMINALBLOCK(TERMINALS13 - 19)FLOW SWITCH,TEMP PWM,LEAD/LAG, ETC.
SYS 1POWER WIRING CONNECTIONSNOTE: SYS 2 CONTACTORS NOT VISIBLE
EARTHGROUNDCONNECTIONS
SYS 2POWER WIRING CONNECTIONSNOTE: SYS 2 CONTACTORS NOT VISIBLE
SYS 210, 11 & 12 C.T.’S(MOTOROVERLOAD)
27963A
76 YORK INTERNATIONAL
DISPLAY KEYS
FIG. 21 – “DISPLAY” KEYS
GENERAL
The Display keys allow the user to retrieve systempressures, system motor currents, chilled liquidtemperatures, saturated temperatures, superheat tem-peratures, outdoor ambient temperature, compressorrunning times, number of compressor starts, and optioninformation on the chiller package. This data is useful formonitoring chiller operation, diagnosing potential futureproblems, troubleshooting, and commissioning thechiller.
Displayed data will be real-time data displayed on a “40”character display consisting of 2 lines of 20 characters.The display will update about every “2” seconds.
When a Display key is pressed, the correspondingmessage will be displayed and will remain on the displayuntil another key is pressed.
Display Messages may show characters indicating“greater than” (>) or “less than” (<). These charactersindicate the actual values are greater than or less than thelimit values which are being displayed.
If a message is required to be updated faster than every2 seconds, the appropriate key for the desired displaymay be pushed and held. Updating will be at 0.4 secondintervals.
Each of the keys and an example of the typicalcorresponding display messages will be discussed in thetext which follows.
Chilled Liquid Temps
A display indicating chiller leaving and return watertemperature is provided when the key is pressed.
The minimum limit on the display is 9.1°F (-12.7°C). Themaximum limit on the display is 84.2°F (29.0°C).
Ambient Temp
The outdoor ambient temperature is displayed when thiskey is pressed.
The minimum limit on the display is -4.6°F (-20.3°C). Themaximum limit on the display is 137.9°F (58.8°C).
AMBIENTTEMP
28164A
L W T = 4 9 . 2 ° FR W T = 5 2 . 0 ° F
A M B I E N T A I R= 7 1 . 9 ° F
DISPLAYKEYS
CHILLEDLIQUID TEMPS
FORM 201.10-NM1
77YORK INTERNATIONAL
System 1Pressures / Temperatures
Oil pressure, suction pressure, discharge pressure,suction temperature*, discharge temperature, oil tem-perature, saturated discharge temperature, saturatedsuction temperature, slide valve position and superheaton System 1 will be displayed when this key is repetitivelypressed. The key must be pressed 6 times to scrollthrough the 6 displays required to display these operatingparameters.
Temperatures and pressures may be measured directlyby transducers and temperature sensors. Others arecomputed from these measurements:
• Differential oil pressure is measured by subtracting oilpressure measured by a transducer located in the oilline after the oil filter from the discharge pressure. (Oilin the oil separator is at discharge pressure.)
Ideally, oil injected after the filter, is at dischargepressure. This makes ideal differential oil pressure 0PSID. However, a pressure drop occurs across the oilfilter. Typically, the drop will be 0 - 10 PSID. As the filterbecomes clogged, oil pressure will eventually riseabove 40 PSID.
• Saturated Discharge Temperature is computed byconverting discharge pressure to temperature.
• Saturated Suction Temperature is computed byconverting suction pressure to temperature.
• Slide Valve Position is computed internally by analgorithm in the micro based on average % FLA motorcurrent, programmed motor current equal to 100%FLA, actual condensing temperature, programmedcondensing temperature for a particular chiller model,and the number of load pulses sent by the micro.
NOTE: Slide valve position is approximate and shouldbe used for reference only.
• Superheat is computed by subtracting saturated suc-tion temperature from suction temperature.
Shown below are the 6 pressure / temperature displays:
Minimum and maximum limits or values on the displaysare shown below. When a minimum limit or value isexceeded, a “ < “ sign will appear before the numericalvalue. In the case of maximum limits or values,exceeding them will cause a “ > ” sign to appear.
NOTE: Minimum and maximum values may change assoftware (EPROM) revisions are made.
SYSTEM 1PRESS / TEMP
MIN. LIMITS MAX. LIMITSOIL PRESSURE 208 PSID 0 PSID (O BARD)SUCTION PRESSURE 0 PSIG (O BAR G) 199 PSIG (13.7 BAR G)DISCHG. PRESSURE 0 PSIG (O BAR G) 399 PSIG (27.5 BAR G)
* NOTE: Below 9.0°F (-12.8°C), the Suction Temp. display willdisappear. This will in turn cause the Superheat display todisappear.
System 2Pressures / Temperature
Oil pressure, suction pressure, discharge pressure,suction temperature**, discharge temperature, oiltemperature, saturated discharge temperature, saturatedsuction temperature, slide valve position, and superheaton system 2 will be displayed when this key is pressed.The key must be pressed 6 times to scroll through the 6displays required to display these operating parameters.
Temperatures and pressures may be measured directlyby transducers and temperature sensors. Others arecomputed from these measurements:
• Differential oil pressure is measured by a subtractingoil pressure measured by a transducer located in the oilline after the filter, from the discharge pressure. (Oil inthe oil separator is at discharge pressure.)
Ideally, oil injected after the filter, is at dischargepressure. This makes ideal differential oil pressure 0PSID. However, a pressure drop occurs across the oilfilter. Typically, the drop will be 0 - 10 PSID. As the filterbecomes clogged, oil pressure will eventually riseabove 40 PSID.
• Saturated Discharge Temperature is computed byconverting discharge pressure to temperature.
SYSTEM 2PRESS/TEMP
S Y S 1 O I L = 5 0 P S I DS P = 5 5 D P = 2 4 8 P S I G
S Y S 1 S U C = 3 6 . 2 ° FD S C H = 1 2 1 . 2 ° F
O I L T E M P 1 = 7 7 . 9 ° F
S A T D I S H 1 = 1 3 0 . 0 ° FS A T S U C T 1 = 2 4 . 3 ° F
S Y S # 1 S U P E R H E A T= 1 2 . 2 ° F
S Y S 1 S L I D E V A L V EP O S I T I O N = 1 0 0 %
78 YORK INTERNATIONAL
• Saturated Suction Temperature is computed byconverting suction pressure to temperature.
• Slide Valve Position is computed internally by analgorithm in the micro based on % FLA motor current,actual condensing temperature, and programmedcondensing temperature for a particular chiller model.
NOTE: Slide valve position is approximate.
• Superheat is computed by subtracting saturatedsuction temperature from suction temperature.
Shown below are the 6 pressure / temperature displays(Also see Sys 1 information on previous page):
Minimum and maximum limits on the displays are shownbelow. When a minimum value is exceeded, a “ < ” signwill appear before the numerical value. In the case ofmaximum limits, exceeding them will cause a “ > ” sign toappear.
NOTE: Minimum and maximum values may change assoftware (EPROM) revisions are made.
% Motor Current
Compressor current in amps, % FLA, individual % FLA ofeach phase, ISN current limit, EMS current limit, and ISNlag compressor start % will be displayed when this key ispressed. The key must be pressed 5 times to scrollthrough the 5 displays related to motor current. Anexample of each display is shown below along with anexplanation of its meaning.
These two displays show the approximate averagecurrent (% FLA) and the approximate % FLA of eachindividual phase (L1, L2, and L3) on each compressor.
NOTE: Due to typical large variations in dischargepressure, a compressor running “fully loaded”may run over a wide range of currents and %FLAs. Also, FLA is approximately equal to 1.2 xRLA. This means amps equal to RLA of thecompressor will only be approximately 80% FLA.
Demand limit can be accomplished remotely by a YORKISN system or an external PWM (dry contact closure)from an EMS system connected to the micro. Thisdisplay shows the % current limiting that may be in effectfrom these devices.
This display indicates the ISN programmed value of %FLA of the lead compressor, where the lag compressorwill start. This is user selectable. The lower the value of“START %”, the less loaded the lead compressor will bewhen the lag is called to start. See page 92 for moreinformation.
This display provides a readout of the approximate % FLAcurrent as measured by the 3 C.T.s and the equivalentapproximate full load amps.
NOTE: Due to typical large variations in dischargepressure, a compressor running “fully loaded”may run over a wide range of currents and %FLAs. Also, FLA is approximately equal to 1.2 xRLA. This means amps equal to RLA of thecompressor will only be approximately 80% FLA.
MIN. LIMITS MAX. LIMITSOIL PRESSURE 208 PSID 0 PSID (O BARD)SUCTION PRESSURE 0 PSIG (O BAR G) 199 PSIG (13.7 BAR G)DISCHG. PRESSURE 0 PSIG (O BAR G) 399 PSIG (27.5 BAR G)
** NOTE: Below 9.0°F (-12.8°C), the Suction Temp. display willdisappear. This will in turn cause the Superheat displayto disappear.
S Y S 2 O I L = 5 2 P S I DS P = 5 9 D P = 2 3 6 P S I G
S Y S 2 S U C = 4 3 . 5 ° FD S C H = 1 2 2 . 9 ° F
O I L T E M P 2 = 8 7 . 3 ° F
S A T D I S H 2 = 1 2 5 . 7 ° FS A T S U C T 2 = 2 9 . 2 ° F
S Y S 2 S L I D E V A L V EP O S I T I O N = 1 0 0 %
S Y S 2 S U P E R H E A T= 1 2 . 0 ° F
C O M P 1 = A V G ; P H L , 1 , 2 , 31 0 0 ; 9 9 , 1 0 1 , 1 0 1 % F L A
C O M P 2 = A V G ; P H L , 1 , 2 , 39 7 ; 9 7 ; 9 7 , 9 8 % F L A
I S N C R N T L I M I T : N O N EE M S C R N T L I M I T : N O N E
I S N L A G C O M P R E S S O RS T A R T % N O N E
C O M P 1 = 2 8 1 A M P S 1 0 0 % F L AC O M P 2 = 2 7 5 A M P S 9 7 % F L A
% MOTORCURRENT
FORM 201.10-NM1
79YORK INTERNATIONAL
Operating HoursStart Counter
Accumulated running hours and starts on eachcompressor is displayed. The hours counter for anindividual system count to a total of 99,999 hours beforerollover. A total of 99,999 starts can be logged on asystem before the start counter will rollover.
The numbers “1” and “2” on the display indicatecompressor #1 and compressor #2.
These counters are zeroed at the factory, but mayindicate run time and number of starts logged duringfactory testing prior to shipment.
Options
The OPTIONS key provides a display of options whichhave been selected by the user. These options areselected by the S1 Dip Switch on the MicroprocessorBoard (Fig. 22). Proper programming of the switch isimportant during the commissioning of the chiller. TheOPTIONS display allows a means of verifying the DipSwitch positions without looking at or handling the
Microprocessor Board. It also eliminates visualinspection of the sometimes difficult to determine DipSwitch position.
When the OPTIONS key is pressed, the followingmessage will first be displayed for 3 seconds:
Eight (8) Option Messages will then follow. Each will bedisplayed for 3 seconds before the next display isautomatically indexed. When all messages aredisplayed, the display message will automatically changeto show a chiller STATUS message, just as if theSTATUS key was pressed.
Refer to Table 1 for a list of the displays and thecorresponding switch positions in the order they appear.Two possible messages may appear for each of the eightmessages depending on the Dip Switch position.
A detailed explanation of the meaning of each messageand a guide to programming the associated switch isprovided on page 80.
Fig. 22 shows the location and verification of switchpositioning of S1.
OPERATING HRS.START COUNTER
H R S 1 = 1 4 3 , 2 = 3 8 2S T R 1 = 1 1 7 , 2 = 1 1 2
A C R O S S - T H E - L I N EM O T O R S T A R T I N G
W Y E D E L T AM O T O R S T A R T I N G
E N G L I S H U N I T SR E A D O U T
S I U N I T SR E A D O U T
T H E R M A L E X P A N S I O NV A L V E S
T H E R M A L E X P A N S I O NV A L V E S
L O C A L C O N T R O LM O D E
R E M O T E C O N T R O LM O D E
S T A N D A R DA M B I E N T
L O W A M B I E N TC O N T R O L
W A T E RC O O L I N G
B R I N EC O O L I N G
TABLE 1 – SWITCH POSITION AND DISPLAY
80 YORK INTERNATIONAL
SWITCH 1
OPEN:
This mode is used for most applications and allow thechilled liquid temperature setpoint to be programmed from38 - 70°F. Selecting this mode also fixes the Low ChilledLiquid Cut-out at 36.0°F and the Suction Pressure Cut-outat 44 PSIG.
CLOSED:
This mode is used primarily for chilled liquid temperaturesetpoints below 38°F. The chilled liquid setpoint can beprogrammed from 10 - 70°F. This mode also allows theLow Chilled Liquid Cut-out to be programmable from 8 -36°F and the Suction Pressure Cut-out from 20 - 70 PSIG.
SWITCH 2
OPEN:
This mode fixes the low ambient cut-out at 25°F and mustbe selected when a Low Ambient Kit is NOT installed.
CLOSED:
A Low Ambient Kit MUST be installed to use this mode.The low ambient cut-out is programmable from 0 - 50°F.
W A T E RC O O L I N G
B R I N EC O O L I N G
S T A N D A R DA M B I E N T
L O W A M B I E N TC O N T R O L
FIG. 22 – DIP SWITCH LOCATION AND POSITION
26001A
LD01098
TOP VIEW
SIDE VIEWRTC
031-
0171
4-00
1
DIMPLEAT TOP
EPROM
TOP SIDE
“OPEN” POSITION(LEFT SIDE OF SWITCHIS PUSHED DOWN)
“CLOSED” POSITION(RIGHT SIDE OF SWITCHIS PUSHED DOWN)
S1
FORM 201.10-NM1
81YORK INTERNATIONAL
SWITCH 3
OPEN:
“LOCAL” mode allows an ISN or an RCC (Remote ControlCenter) option panel to receive chiller data from the chillerthrough the RS-485 port, but not change programmablesetpoint values remotely.
CLOSED:
“REMOTE” mode allows an ISN or an RCC (RemoteControl Center) option panel to receive chiller data fromthe chiller through the RS-485 port. This mode will alsoallow loading, unloading, shutdown, Leaving WaterSetpoint Reset, Current Limit Setpoint, and Lag StartSetpoint from an ISN or RCC. If communications is lostto the ISN or RCC, the micro will run the chiller on themicro panel programmed values.
SWITCH 4
OPEN:
This switch is presently disabled. In the future, it will allowselection of control from either thermal expansion valvesor electronic expansion valves.
CLOSED:
This switch is presently disabled. In the future, it will allowselection of control from either thermal expansion valvesor electronic expansion valves.
SWITCH 5
OPEN:
Display messages will show units of measure in Englishunits (°F, PSI, etc.).
CLOSED:
Display messages will show units of measure in ScientificInternational (Metric) units (°C, BAR, etc.)
SWITCH 6
OPEN:
This mode MUST be selected for chillers with Across-the-line starters where only one contactor per compressoris present in the power panel.
CLOSED:
This MUST be selected for chillers with Wye-Deltastarters where three contactors and wire wound powerresistors are present for each compressor in the powerpanel.
L O C A L C O N T R O LM O D E
E N G L I S H U N I T SR E A D O U T
R E M O T E C O N T R O LM O D E
S I U N I T SR E A D O U T
T H E R M A L E X P A N S I O NV A L V E S
A C R O S S - T H E - L I N EM O T O R S T A R T I N G
T H E R M A L E X P A N S I O NV A L V E S
W Y E D E L T AM O T O R S T A R T I N G
82 YORK INTERNATIONAL
SWITCH 7
OPEN:
SYS 1 can be selected as the lag compressor by closinga user supplied contact between terminals 13 and 19. SeeFig. 17.
CLOSED:
In this mode, the micro determines which compressor isassigned to the lead and the lag. A new lead / lagassignment is made whenever a compressor shuts down.The micro will then assign the “lead” to the compressorwith the shortest anti-recycle time. If both compressorsare shut down, the micro will start the first availablecompressor in an effort to maintain control of temperatureas soon as possible.
SWITCH 8
OPEN:
This switch position MUST be selected, if the refrigeranttype is R134A. Incorrect selection of this switch maycause catastrophic damage to the chiller.
CLOSED:
This switch position MUST be selected, if the refrigeranttype is R22. Incorrect selection of this switch may causecatastrophic damage to the chiller.
M A N U A LL E A D / L A G
R E F R I G E R A N T T Y P ER 1 3 4 A
A U T O M A T I CL E A D / L A G
R E F R I G E R A N T T Y P ER 2 2
FORM 201.10-NM1
83YORK INTERNATIONAL
STATUS KEY
GENERAL
Pressing the STATUS key will enable the operator todetermine current chiller operation status as a whole andas individual systems. The messages displayed willinclude running status, cooling demand, fault status,external cycling device status, load limiting, and anti-recycle timer status. The display will be a single messagerelating to the highest priority message as determined bythe microprocessor. Status messages fall into thecategories of General and Fault Status with each of thecategories discussed below.
GENERAL STATUS MESSAGE
Each of the general status messages with a descriptionof its meaning will follow. In the case of messages whichapply to individual systems, SYS 1 and SYS 2 messageswill both be displayed and may be different. “X”s in thesample displays indicate numerical values that willappear in the actual displays.
This message informs the operator that the “UNIT” switchon the Control Panel is in the OFF position which will notallow the chiller to run.
The DAILY SCHEDULE SHUTDOWN message indicatesthat the daily schedule programmed into the Clock - SETSCHEDULE / HOLIDAY is keeping the chiller fromrunning.
Run Permissive is an indicator that an external cyclingcontact or flow switch connected in series with terminals13 and 14 is open. Whenever the contact(s) is (are) open,the NO RUN PERM will be displayed.
This message informs the operator that the chilled liquidtemperature is below the point (determined by the setpointand control range) that the micro will bring the lead systemon, and / or that the micro has not loaded the system farenough into the loading sequence to be ready to bring thelag system ON. The lag system will display this messageuntil the loading sequence is ready for the lag system tostart.
U N I T S W I T C H I S I NT H E O F F P O S I T I O N
D A I L Y S C H E D U L ES H U T D O W N
S Y S 1 N O C O O L L O A DS Y S 2 N O C O O L L O A D
S Y S 1 N O R U N P E R MS Y S 2 N O R U N P E R M
FIG. 23 – STATUS KEY28164A
STATUSKEY
84 YORK INTERNATIONAL
The COMP RUNNING message indicates that therespective compressor is running due to demand.
The anti-recycle timer message shows the amount oftime left on the respective anti-recycle timer.
The anti-coincident timer is a software feature that guardsagainst 2 compressors starting simultaneously. Thisassures instantaneous starting current does not becomeexcessively high due to simultaneous starts. The microlimits the time between compressor starts to 1 minuteregardless of demand and anti-recycle timers that aretimed out. The time shown on the anti-coincident timer isthe time left on the timer before the respective system willstart. It will only appear when the anti-recycle timer hastimed out.
The Motor Current Limiting message indicates a systemis being unloaded by the micro even though demandrequires loading. Used as a safety, this feature assuresthat motor current does not become excessively highcausing compressor shutdown. The safety will activatewhen the user programmed threshold is exceeded,providing as much capacity as possible up to the limitprogrammed. Additional loading will take place whenmotor current drops below the threshold. In mostcircumstances, this safety will never activate if currentlimiting is programmed for 100% -115%. However, inextremely high ambients, high chilled liquid temperature,and situations where the condenser becomes dirty, theprotection provided by this safety will assure thatcompressor shutdown does not result in total cooling lossby limiting loading until the usually short term situationcausing the problem clears.
This message also indicates unloading due to currentlimiting where the user has the programmed unload pointset below 100% to utilize the programmable unload for“demand limiting”. Resetting of current limit unloadingmay be done through the “PROGRAM” mode on theControl Panel.
Discharge Pressure Limiting takes affect when dischargepressure nears the point at which the high pressure cut-
out will shut the system down causing total loss ofcooling. When this message appears, discharge pressurehas exceeded the “user” programmable threshold and themicro is unloading the affected system to preventshutdown on a manual high pressure cut-out. Reloadingwill take place when discharge pressure has dropped 60PSIG below the threshold.
The Suction Temperature Limiting Message indicatesthat the microprocessor is in the water temperaturecontrol mode and is sensing that the saturated suctiontemperature has dropped to a point (29°F) where furthertemperature reduction could cause some icing of thetudes. This control will not operate in the brine mode sinceicing of the tubes is not a problem if proper bineconcentration is maintained. This saturated suctiontemperature is conputed by the micro by convertingsuction pressure to temperature.
When the micro senses that saturated suction temp-erature has dropped below 29°F, the micro will inhibitloading for the first 3 minutes during which the conditionoccurs to allow time fo the temperature to rise. If thecondition persists for more than 3 min., the micro will seta 5 minute timer. During this 5 minute period, it will takeaction to cause the saturated suction temperature to riseabove 31°F. As this 5 minute timer counts down to zero,the micro will pulse the slide valve to unload every 5seconds as long as the temperature is below 31°F. If thetemperature rises above 31°F, the micro will inhibitloading for the remainder of the 5 minute period.
If after the 5 minute period the saturated suctiontemperature is above 29°F, the micro will allow thecompressor to load to assure that the leaving chilled waterrequirements are satisfied. Otherwise, the micro will resetthe 5 minute timer and start the process over again.
To assure that leaving chilled water requirements aresatisfied while one compressor is under suction templimiting control, the micro will start or load the othercompressor as necessary.
This message indicates the current limiting is in effectthrough the Current Limit PWM input on Terminals 13 and16 of the Microprocessor Board. As long as this input isactivated, the micro will not allow loading beyond thePWM % that has been sent to the microprocessor throughthe PWM input. Generally, this input is used for purposesof demand limit. Details of the use of this feature areoutlined on page 130.
S Y S 1 C O M P R U N N I N GS Y S 2 C O M P R U N N I N G
S Y S 1 D S C H L I M I T I N GS Y S 2 D S C H L I M I T I N G
S Y S 1 A R T I M E R X X X SS Y S 2 A R T I M E R X X X S
S Y S 1 A C T I M E R X X SS Y S 2 A C T I M E R X X S
S Y S 1 C R N T L I M I T I N GS Y S 2 C R N T L I M I T I N G
S Y S 1 S T E M P L I M I T I N GS Y S 2 S T E M P L I M I T I N G
S Y S 1 E M S L I M I T I N GS Y S 2 E M S L I M I T I N G
FORM 201.10-NM1
85YORK INTERNATIONAL
ISN LIMITING allows load limiting through an ISNSystem. This feature controls loading under a number ofISN programmable values, enhancing the flexibility ofcontrolling the chiller to obtain desired results in the totalbuilding control scheme.
This message informs the operator that the systemswitch on the Microprocessor Board for the respectivesystem is in the OFF position. The switch for System 1and System 2 must be in the ON position for the systemsto operate. Switches for System 3 and 4 should be placedin the OFF position on 2 compressor chillers. See Fig. 24for the location of these switches.
S Y S 1 I S N L I M I T I N GS Y S 2 I S N L I M I T I N G
S Y S 1 S Y S S W I T C H O F FS Y S 2 S Y S S W I T C H O F F
FIG. 24 – LOCATION OF THE MICROPROCESSOR BOARD SYSTEM SWITCHES
26001A
SYSTEMSWITCHES
86 YORK INTERNATIONAL
This message indicates that the type of refrigerantprogrammed under the PROGRAM key does not match
R E P R O G R A M T Y P E O FR E F R I G E R A N T T O R U N
C H I L L E R F A U L T :L O W W A T E R T E M P
S Y S 1 H I G H D S C H P R E SS Y S 2 H I G H D S C H P R E S
S Y S 1 L O W C U R R / M P / H PS Y S 2 L O W C U R R / M P / H P
S Y S 1 H I G H O I L T E M PS Y S 2 H I G H O I L T E M P
S Y S 1 H I G H M T R C U R RS Y S 2 H I G H M T R C U R R
S Y S 1 H I G H D S C H T E M PS Y S 2 H I G H D S C H T E M P
S Y S 1 M T R C U R R U N B A LS Y S 2 M T R C U R R U N B A L
C H I L L E R F A U L T :V A C U N D E R V O L T A G E
S Y S 1 P H A S E R O T A T I O NS Y S 2 P H A S E R O T A T I O N
C H I L L E R F A U L T :L O W A M B I E N T T E M P
S Y S 1 L O W S U C T I O NS Y S 2 L O W S U C T I O N
C H I L L E R F A U L T :H I G H A M B I E N T T E M P
S Y S 1 H I G H O I L D I F FS Y S 2 H I G H O I L D I F F
S Y S 1 L O W O I L D I F FS Y S 2 L O W O I L D I F F
the type of refrigerant selected on the S1 dip Switches onthe Microprocessor Board. Selections on the S1 DipSwitches on the Microprocessor Board can be viewed bypressing the OPTIONS key (Page 79). The chiller will notoperate until this situation is corrected. Also see page 59to change the refrigerant type in the PROGRAM mode.
FAULT STATUS MESSAGES
Thirteen possible fault messages may appear when theSTATUS key is pressed. Whenever a fault messageappears, the safety thresholds on the chiller have beenexceeded and the entire chiller or a single system will beshut down and locked out. A detailed explanation of theshutdown thresholds and associated information related
to each fault is covered in the “System Safeties” section.
Chiller shutdown faults will shut the entire chiller down andlock it out, while system shutdown faults will only shutdown and lock out the affected system (compressor).
A list of the fault messages is shown below:
FORM 201.10-NM1
87YORK INTERNATIONAL
ENTRY KEYS
GENERAL
The ENTRY key allows the user to change numericalvalues programmed in as chiller setpoints, cut-outs,clock, etc.
Cancel Key
The CANCEL key allows the user to change errors in thedata being programmed into memory.
When the CANCEL key is pressed, the cursor will al-ways return to the first character to be programmed inthe display message. This allows the operator to beginreprogramming. When the CANCEL key is pressed, thevalues already keyed in will be erased and the original orinternally programmed default values will appear. In otherinstances the display will remain the same and the onlyreaction will be the cursor returning to the first character.
AM/PM Key
The AM / PM key allows the user to change AM / PMwhile programming the correct time in the SET TIMEdisplay. The same key allows changing the AM / PMschedule while programming daily chiller start and stoptimes in the SET SCHEDULE / HOLIDAY display.
Advance Day Key
The ADVANCE DAY key advances the day when theSET TIME display is being programmed. The day is nor-mally advanced to correspond to the current day of theweek. The day will advance one day at a time, each timethe key is pressed.
Numerical Keypad
The NUMERICAL keypad providesall keys necessary to program nu-merical values as required intomemory.
The “ * ” key is used to designateholidays when programming special start and stop timesfor designated holidays in the SET SCHEDULE / HOLI-DAY display.
The “+/-” key allows programming -C setpoints andcut-outs in the metric display mode.
Enter Key
The ENTER key must be pushed after any change ismade to setpoints, cut-outs, or system clock. Pressingthis key tells the micro to accept new values into memory.If this is not done, the new values entered will be lostand the original values will be returned.
The ENTER key is also used to scroll through availabledata after any one of the following (4) keys is pressed:
28164AFIG. 25 – ENTRY KEYS
PROGRAM
SET SCHEDULE/HOLIDAY
ENTER
CANCEL
AM/PM
ADVANCEDAY
OPERDATA
HISTORY
ENTRYKEYS
1 2 3
4 5 6
7 8 9
* 0 +/-
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PROGRAM KEYS
PROGRAM KEY -USER PROGRAMMABLE VALUES
GENERAL
Pushing the PROGRAM key allows the user to program21 system operating values. These values include cut-out points for safeties, anticipatory unload points to avoidfaults, and anti-recycle timer duration.
After the PROGRAM key is pressed, the micro will firstrespond by displaying the following message:
Press the ENTER key to access the first programmabledisplay.
As the 21 values are displayed, they may be repro-grammed using the 12 Entry keys. New values will beprogrammed into memory when the ENTER key ispushed. The ENTER key must also be used to advancethe display on which the operator views the 21programmable values.
Each time the ENTER key is pushed, the display willadvance to the next programmable value.
Some programmable values are password protected dueto their critical nature. These are identified by the absenceof the cursor when the display is viewed. Programmable
values not password protected are identified by thepresence of the cursor under the first digit of the numericalvalue. Non password protected values may be keyed inby simply typing a new value and pressing the ENTERkey to program the new value into memory. Failure topress ENTER will cause the new value to be lost.
To reprogram password protected values where thecursor does not appear, the PROGRAM key must first bepressed. The micro will respond by displaying thefollowing message:
To access the password protected values, key in the 4digit code “7396” and press ENTER.
As “7396” is being keyed in, the display will show the digitsas Þs. See below:
Pressing ENTER, displays the first programmable value.Access to password protected values is indicated by thecursor positioned at the first digit of the numerical value.A new value may be keyed in for each value and placedinto memory by pressing ENTER. After a new value isentered, the display will advance to the nextprogrammable display.
FIG. 26 – PROGRAM KEY28164A
P R O G R A M M O D EP R O G R A M M O D E
P R O G R A M M O D EQQQQQ QQQQQ QQQQQ QQQQQ
PROGRAMKEY
FORM 201.10-NM1
89YORK INTERNATIONAL
Once accessed, the display will stay in the passwordprotected mode until a DISPLAY, PRINT, SETPOINT, orCLOCK key is pressed.
If the operator attempts to enter an unacceptable value,the micro will respond with a momentary messageindicating the selected value has been ignored. This errormessage is shown below:
The 21 programmable displays are shown and describedbelow in the order in which they appear along with therange of values which the microprocessor will accept foreach. THE PROGRAMMABLE VALUES UNDER THEPROGRAM KEY MUST BE CHECKED AND PROP-ERLY PROGRAMMED WHEN COMMISSIONING THECHILLER. FAILURE TO PROPERLY PROGRAMTHESE VALUES MAY CAUSE DAMAGE TO THECHILLER OR OPERATING PROBLEMS.
REFRIGERANT TYPE
The REFRIGERANT TYPE display message allows theuser to program the chiller for the type of chiller. ThisMUST be programmed according to the type refrigerantused in the chiller. Failure to program this value correctlywill cause catastrophic damage to the chiller.
The type of refrigerant used is noted in the EngineeringData stamped on the unit nameplate. See page 5.
Whenever R22 is programmed, it is required to first key ina “0”. Example: 022.
To program the type of refrigerant, access the passwordprotected values as described previously. Key in the typerefrigerant and press the ENTER key. The new value willbe entered into memory and the display will advance tothe next user programmable value.
NOTE: The type of refrigerant programmed must matchthe refrigerant selected on the S1 Dip Switcheson the Microprocessor Board. These selectionscan be viewed by pressing the OPTIONS key(Page 79). If these two selections do not match,the following message will appear.
The chiller will not operate until this situation is corrected.
DISCHARGE PRESSURE CUT-OUT
The DISCHARGE PRESSURE CUT-OUT is amicroprocessor back-up for the mechanical high pressurecut-out located in each refrigerant circuit. Typicallychillers with air-cooled condensers should have the cut-out set at 395 PSIG (275 PSIG for R134a).
To program the DISCHARGE CUT-OUT, access thepassword protected values as described previously. Keyin the desired discharge pressure cut-out and press theENTER key. The new value will be entered into memoryand the display will advance to the next userprogrammable value.
The micro will accept a range of programmable valuesbetween 200 - 399 PSIG (128 - 275 PSIG for R134a) forthis cut-out. For this cut-out to be functional, theDischarge Pressure Read-out Option must be installed.
More details on this safety are provided in the “SystemSafeties” section.
LOW AMBIENT CUT-OUT
The LOW AMBIENT CUT-OUT allows the user to selectthe chiller low ambient temperature cut-out point. If theambient temperature falls one degree below this point, thechiller will shut down. Restart can occur, if demandallows, when temperature rises more than one degree Fabove the cut-out. This only applies to outdoor air-cooledchillers.
For normal ambient applications, the cut-out is set at 25°Fand is NOT programmable. However, some users mayset the cut-out higher to shut down the chiller and takeadvantage of other less costly cooling sources. In thiscase, S1 Dip Switch #2 on the Micro Logic Board must bein the CLOSED position for “Low Ambient Control” whichallows programming the cut-out above 25°F.
Low ambient operation capability of less than 25°F isstandard on the chiller. If low ambient operation is requiredbelow 25°F, S1 Dip Switch #2 on the Micro Logic Boardmust be in the CLOSED position for LOW AMBIENTCONTROL which allows programming of the cut-outbetween 0 - 50°F. If operation is occasionally neededbelow 0°F, the cut-out should be set at 00.0°F. This willallow operation at any temperature since the micro is onlyable to recognize temperatures above 1°F and will neverdisplay temperatures below 1°F.
O U T O F R A N G ET R Y A G A I N !
R E F R I G E R A N T T Y P E2 2 0 R 1 3 4 2 2
R E P R O G R A M T Y P E O FR E F R I G E R A N T T O R U N
D I S C H A R G E P R E S S U R EC U T O U T = 3 9 5 . 0 P S I G
L O W A M B I E N T T E M PC U T O U T = 2 5 . 0 ° F
90 YORK INTERNATIONAL
NOTE: Operation below 0°F may cause nuisance lowpressure safety shutdowns. Occasional shut-downs can usually be tolerated since the need forsustained operation at these low temperatures isunlikely and temperatures rarely stabilize for anylength of time below 0°F.
To program the LOW AMBIENT CUT-OUT, access thepassword protected values as described previously. Keyin the desired low ambient cut-out and press the ENTERkey. The new value will be entered into memory and thedisplay will advance to the next user programmable value.
The micro will accept a range of programmable valuesbetween 00.0 - 50.0°F for this cut-out, if Dip Switch #2 onthe Micro Logic Board is in the CLOSED position. In theOPEN position, a fixed 25°F cut-out is recognized.
HIGH AMBIENT CUT-OUT
The HIGH AMBIENT CUT-OUT is selectable to establishthe chiller high ambient cut-out point. If the ambient risesmore than one degree above this point, the chiller will shutdown. Restart can occur when temperature drops morethan one degree F below the cut-out. This only applies tooutdoor air cooled chillers.
This cut-out is normally set at 130°F to allow operation tothe absolute maximum temperature capability of theelectro-mechanical components.
To program the OUTSIDE AIR TEMP HIGH CUTOUT,access the password protected values as describedpreviously. Key in the desired high ambient cutout andpress the ENTER key. The new value will be entered intomemory and the display will advance to the next userprogrammable value.
The micro will accept a range of programmable valuesbetween 100.0 - 130.0°F for this cut-out.
DISCHARGE PRESSURE UNLOAD
The DISCHARGE PRESSURE UNLOAD point is aprogrammable limit to keep the system from faulting onthe high discharge pressure cut-out should a systemproblem or chiller problem occur. A typical problem wouldbe dirty condenser coils. Pressure would rise and
eventually cause the chiller to fault causing a total loss ofcooling. By unloading the compressors at high dischargepressures, the chiller is allowed to continue to runautomatically at reduced capacity until the dirtycondenser coils can be attended to.
When the unload point is reached, the micro willautomatically totally unload the affected compressor.Typical maximum programmed limits would be 375 PSIGfor air cooled chillers with a 395 or 405 PSIG high pressurecut-out.
Reloading will occur when the discharge pressure dropsto 60 PSIG below the programmed unload pressure andwill increment loading one stage at a time as indicated bythe loading timers.
To program the DISCHARGE PRESSURE UNLOAD,access the password protected values as describedpreviously. Key in the desired discharge pressure unloadvalue and press the ENTER key. The new value will beentered into memory and the display will advance to thenext user programmable value.
The micro will accept a range of programmable valuesbetween 200 - 390 PSIG (128 - 270 PSIG for R134a) forthe unload point.
AVERAGE CURRENT UNLOAD
The AVERAGE CURRENT UNLOAD point is aprogrammable limit designed to assure that the motorcurrent safety does not cause shutdown of thecompressor.
If motor current rises above the programmed motorcurrent unload point, the micro will automatically begin tounload the affected compressor at 5 second intervals untilthe current draw on the motor falls below the unload point.This will assure that the motor operates under acceptableconditions insuring maximum motor life. Reloading willoccur when the motor average current drops below 90%of the programmed unload point.
This feature may also be used in instances where demandlimiting is required. By programming the unload pointbelow the % current drawn when the compressors are fullyloaded, the compressors will be prevented from fullyloading which reduces energy consumption.
To program the MOTOR CURRENT UNLOAD, key in thedesired value and press the ENTER key. The new valuewill be entered into memory and the display will advance
H I G H A M B I E N T T E M PC U T O U T = 1 3 0 . 0 ° F
D I S C H A R G E P R E S S U R EU N L O A D = 3 6 0 . 0 P S I G
A V E R A G E C U R R E N TU N L O A D = 1 0 5 % F L A
FORM 201.10-NM1
91YORK INTERNATIONAL
to the next programmable value. This value is notpassword protected and can be programmed anytime thePROGRAM key is pressed.
The micro will accept a range of programmable valuesbetween 30 - 115% for the unload point. Keep in mind thatthe motor current safety will shut the compressor downwhenever current exceeds 115%. Typically, this setpointwill be set at 100 - 105%. It is not recommended toprogram a value greater than 105%. For maximummotor protection, programming for 100% is advisable.
NOTE: When programming values from 30 - 99%, it isrequired to first key in a “0”. Example: 085%.
ANTI-RECYCLE TIME
The ANTI-RECYCLE TIME selection allows the user toselect the compressor anti-recycle time best suited to hisneeds. Motor heating is a result of inrush current when themotor is started. This heat must be dissipated beforeanother start takes place or motor damage will result. Theanti-recycle timer assures the motor has sufficient time tocool before it is again restarted. An adjustable timerallows for the motor cooling required, but gives the userthe ability to extend the timer to cut down on cycling. Insome applications, fast compressor start response isnecessary. In others it is not. These needs should be keptin mind and the timer should be adjusted for the longestperiod of time tolerable. Although 300 seconds isadequate motor cooling time, longer periods will alloweven more heat dissipation, reduce cycling, and possiblyincrease motor life. 600 seconds is recommended.
To program ANTI-RECYCLE TIME, key in the desiredvalue and press the ENTER key. The new value will beentered into memory and the display will advance to thenext user programmable value. This value is notpassword protected and can be programmed anytime thePROGRAM key is pressed.
The micro will accept a range of programmable valuesbetween 300 - 600 seconds for this operating control.
LEAVING WATER TEMP CUT-OUT
The LEAVING WATER TEMP CUT-OUT protects thechiller from an evaporator freeze-up should the chilled
liquid temperature drop below the freeze point. Thissituation could occur under low flow conditions or if theMicro Panel Setpoint values are improperly programmed.Anytime the leaving chilled liquid temperature (water orglycol) drops below the cut-out point, the chiller will shutdown. The chiller will be re-enabled when temperaturerises more than four degrees above the cut-out.
For chilled water applications (WATER COOLING – SW1CLOSED), the cut-out is automatically set at 36°F andcannot be reprogrammed. This covers applications whereleaving water temperatures are not designed to go below40°F. If the chilled liquid (glycol) temperatures arerequired below 40°F (BRINE COOLING – SW1 OPEN),the cut-out should be programmed 4°F below the LowLimit Water Temp of the programmed CR (Control Range).See page 79 on Low Limit Water Temp of Control Range(CR).
To program the LEAVING WATER TEMP CUT-OUT theBRINE COOLING (SW1 OPEN) must be selected. Also,the password protected PROGRAM values must beaccessed as described previously. Key in the desired cut-out value and press the ENTER key. The new value willbe entered into memory and the display will advance tothe next programmable value.
The micro will accept a range of programmable valuesbetween 08.0 - 36.0°F for this cut-out.
SUCTION PRESSURE CUT-OUT
The SUCTION PRESSURE CUT-OUT protects the chillerfrom an evaporator freeze-up should the system attemptto run with a low refrigerant charge. Anytime the suctionpressure drops below the cut-out point for 90 seconds, thesystem will shut down.
NOTE: During the first four and a half minutes ofoperation, operation of this cut-out will differ fromthe operation outlined above. Details are outlinedin the “System Safeties” section.
For chilled water applications, the cut-out should be set at44 PSIG. If glycol or brine is utilized with leaving watertemperature designs below 40°F, the cut-out should beadjusted according to concentration. A rule-of-thumb cut-out design is to drop the cut-out 1 PSIG below 44 PSIGfor every degree of leaving glycol below 40°F. In otherwords, 30°F glycol requires a 34 PSIG suction pressurecut-out.
To program the SUCTION PRESSURE CUT-OUT,access the password protected values as described
A N T I R E C Y C L E T I M E= 6 0 0 S E C S
L E A V I N G W A T E R T E M PC U T O U T = 3 6 . 0 ° F
S U C T I O N P R E S S U R EC U T O U T = 4 4 . 0 P S I G
92 YORK INTERNATIONAL
previously. Key in the suction pressure cut-out value andpress the ENTER key. The new value will be entered intomemory and the display will advance to the next userprogrammable value.
In the WATER COOLING MODE (SW1 OPEN), the cut-out is programmable values between 44 - 70 PSIG (19 -36 PSIG for R134a). In this mode, 44 PSIG isrecommended.
In the BRINE COOLING MODE (SW1 CLOSED), the cut-out is adjustable from 20 - 70 PSIG (4.5 - 36 PSIG forR134a).
LAG COMPRESSOR START POINT
Selection of the LAG COMPRESSOR START POINT %primarily allows the user to either allow the leadcompressor to fully load to 99% FLA or Slide Valve,(whichever is programmed, see following) before the lagcompressor is started or start the lag compressor at a leadcompressor % FLA less than 99%.
Selecting a LAG COMPRESSOR START POINT % of99% assures that the lead compressor is fully loadedbefore the lag compressor is brought on. If very low loadsare expected, less compressor cycling will be noted byselecting a high slide valve percentage. 99% would be therecommended % to reduce cycling.
If due to system conditions the lead compressor does notreach the programmed %, even though the lead systemis fully loaded, the lag compressor will start regardless ofthe programmed % after 5 minutes of operation wheneverthe lead compressor cannot bring the LWT to within 2.0°Fof the high end of the Control Range (CR). Once the lagcompressor is started, equalizing loading and unloadingof the two compressors will occur. This assures that thechiller will fully load and maintain chilled liquidtemperature.
Selecting a LAG COMPRESSOR START POINT % lessthan 99% increases the efficiency of chiller operation. Atlower percentages, the lead compressor is loaded to theprogrammed % and the lag compressor will come on andbe brought up to a % equal to the lead compressor. At thispoint, the loading of both compressors will be adjusted upor down to maintain capacity and equalize loading on thetwo compressors. Running both compressors partiallyloaded makes more efficient use of the evaporator thanrunning one compressor fully loaded with the other idle.
Running both compressors partially loaded assures thatthe entire evaporator is being utilized and is the mostefficient condition for operating the chiller system.
However, keep in mind that once the lag compressor isstarted, equalized loading at part load is alwaysmaintained by the microprocessor even with the LAGCOMPRESSOR START POINT programmed at 99%.
If a % less than 99% is selected for efficiency purposes,a value of 70% is recommended. This will typically assurethat the lag compressor will start before the lead is fullyloaded.
To program the LAG COMPRESSOR START POINT %,key in the desired value and press the ENTER key. Thenew value will be entered into memory and the display willadvance to the next user programmable value. This valueis not password protected and can be programmedanytime the PROGRAM key is pressed.
The micro will accept a range of programmable valuesbetween 40 - 99% for this operating control.
LAG COMPRESSOR DIFFERENTIAL OFF %
This control allows the operator to select the range overwhich the lead and lag compressor load share equally.Once the lag compressor is brought on and loads up to a% equal to the lead compressor, if demand allows,sharing of the load will continue as the load drops until aprogrammed differential % below the LAG COMPRES-SOR START POINT % is reached.
For example: If a LAG COMPRESSOR START POINT %of 70% is selected, and a LAG COMPRESSORDIFFERENTIAL OFF % of 50% is selected, the lead andlag compressor will both load share the % (FLA or SlideValve, whichever is programmed, see page 62) of the leadcompressor drops to 20% (70% - 50% = 20%). At thispoint, the micro will unload only the lag compressor untilit reaches a point at which the micro determines it is fullyunloaded and load does not require its continuedoperation and it will cycle off.
The larger the % differential programmed, the moreefficient the use of the cooler. For efficiency purposes,50% is recommended. Cycling of the lag compressor willalso be minimized since equalized unloading operatesover a wider range.
A small % differential, will increase cycling and lowerefficiency slightly. For example: If 10% LAGCOMPRESSOR DIFFERENTIAL OFF % is selected witha LAG COMPRESSOR START POINT % of 70%, the lagwill start when the lead % FLA reaches 70%. The lagloading will be brought up to equalize the lead of 70% ifdemand requires. Both compressors will increase inloading proportionately as demand increases. When the
L A G C O M P R E S S O RS T A R T P O I N T 7 0 %
L A G C O M P R E S S O RD I F F E R E N T I A L O F F 5 0 %
FORM 201.10-NM1
93YORK INTERNATIONAL
load drops, both compressors will unload to 60%. At thispoint, only the lag compressor will be unloaded asdemand drops. It will unload until it reaches a point atwhich the micro determines it is fully unloaded and loaddoes not require its continued operation and thecompressor will be cycled off.
A minimum % point is built into the micro to only allow loadsharing to operate to a minimum of 20% of the leadcompressor. Therefore the LAG COMPRESSOR STARTPOINT % minus the LAG COMPRESSOR DIFFEREN-TIAL OFF % cannot be less than 20% or an out of rangemessage will appear.
To program the LAG COMPRESSOR DIFFERENTIALOFF %, key in the desired value and press the “ENTER”key. The new value will be entered into memory and thedisplay will advance to the next user programmable value.This value is not password protected and can beprogrammed anytime the PROGRAM key is pressed.
The micro will accept a range of programmable valuesbetween 0 - 50% for this operating control, provided theLAG COMPRESSOR START POINT % minus the LAGCOMPRESSOR DIFFERENTIAL OFF % does not equalless than 20%.
FAN CONTROL DISCHARGE PRESSURE SETPOINT
The FAN CNTRL DSCH PRESS SET POINT isprogrammable to allow the operator to program thedischarge pressure at which the first pair or trio of fansstarts. The first pair or trio of fans will run in the reversedirection. Selection of the discharge pressure should bedone keeping in mind oil return and proper TXV operation.
Generally, the recommended point of fan starting is 230PSIG. Too low of a setting will cause low dischargepressures which in turn causes oil return problems andTXV operation problems. Both of these can lead tocatastrophic compressor failure.
To program the FAN CONTROL DISCHARGEPRESSURE SETPOINT, access the passwordprotected values as described previously. Key in thepressure setpoint and press the ENTER key. The newvalue will be entered into memory and the display willadvance to the next user programmable value.
The micro will accept a range of programmable valuesfrom 149 - 351 PSIG (72 - 203 PSIG for R134a).
After the first pair or trio of reverse fans are brought on,discharge pressure must rise 20 PSIG above the FANCNTRL DSCH PRESS SETPOINT before a second pair
or trio of fans (first pair or trio of forward fans) will bebrought on in the forward direction.
The pair or trio of reversing fans will turn off at this point.
After discharge pressure rises 40 PSIG above the FANCNTRL DSCH PRESS SETPOINT, the second pair ortrio of forward fans will turn on and operate. These are thereversing fans operating in the forward direction. The firstpair or trio of forward fans will also continue to run.
FAN ON / OFF PRESS DIFF
The FAN ON/OFF PRESS DIFF determines the “OFF”pressure at which each pair or trio of fans will cycle off. Ifa differential of 50 PSIG is selected, the second pair or trioof forward fans that cycled on (Example: 270 PSIG) willcycle off when discharge pressure drops 50 PSIG belowthe “ON” pressure (Example: 220 PSIG). The first pair ortrio of forward fans to start (Example: 250 PSIG) will cycleoff at 50 PSIG below the on pressure (Example: 200PSIG). When this pair or trio of fans cycles off, thereversing fans will not come on until the pressure reachesthe FAN CONTROL DISCHARGE PRESSURESETPOINT (Example: 230 PSIG).
If the reversing fans are operating, they too will turn off ona pressure drop. In the example above, if the reversingfans turned on at 230 PSIG and are operating, they wouldturn off at 180 PSIG.
A FAN ON/OFF PRESSURE DIFFERENTIAL of 50 - 70PSIG is recommended.
SYSTEM 1 MOTOR CURR
SYSTEM 1 MOTOR CURR allows the operator to displaythe approximate current that the motor is drawing bypressing the Display key labeled % MOTOR CURRENT.
SYSTEM 1 MOTOR CURR also allows the motor currentto be programmed at 100% full load to permit the micro todetermine the approximate slide valve position whencontrolling loading/unloading. This is important to allowload sharing.
Select the actual current at 100% load by selecting thechiller model and voltage from Table 2 and itscorresponding AMPS at 100% RLA. Multiply RLA x 1.2 todetermine 100% FLA current.
F A N C N T R L D S C H P R E S SS E T P O I N T = 2 3 0 P S I G
F A N O N / O F F P R E S SD I F F = 5 0 P S I G
S Y S T E M 1 M O T O R C U R R1 8 3 A M P S = 1 0 0 % F L A
94 YORK INTERNATIONAL
To program the SYSTEM 1 MOTOR CURR, access thepassword protected values as described previously. Keyin the current value that equals 100% FLA and press theENTER key. The new value will be entered into memoryand the display will advance to the next userprogrammable value.
SYSTEM 2 MOTOR CURR
SYSTEM 2 MOTOR CURR allows the operator to displaythe approximate current that the motor is drawing bypressing the Display key labeled % MOTOR CURRENT.
SYSTEM 2 MOTOR CURR also allows the motor currentto be programmed at 100% full load to permit the micro todetermine the approximate slide valve position whencontrolling loading/unloading. This is important to allowload sharing.
Select the actual current at 100% load by selecting thechiller model and voltage from Table 2 and itscorresponding AMPS at 100% RLA. Approximate FLAcan be determined by formula: RLA x 1.2 = 100% FLA.
To program the SYSTEM 2 MOTOR CURR, access thepassword protected values as described previously. Keyin the current value that equals 100% FLA and press theENTER key. The new value will be entered into memoryand the display will advance to the next userprogrammable value.
LIQUID INJECTION TEMP LIMIT
LIQUID INJECTION TEMP LIMIT programs thedischarge temperature at which the liquid injectionsolenoid is energized to allow liquid to be injected into the
compressor for oil cooling. This assures that temper-atures of the oil are maintained low enough to assureproper lubrication and compressor cooling.
The recommended program point is 180°F (82.1°C).
To program the LIQUID INJECTION TEMP LIMIT,access the password protected values describedpreviously. Key in the value and press the ENTER key.The new value will be entered into memory and the displaywill advance to the next programmable value.
Once on, the liquid injection will turn off 20°F below the“ON” temperature.
SYSTEM 1 COND TEMP
If loading/unloading is selected utilizing slide valve %, thedesign condensing temperature (discharge pressureconverted to temperature or CTP) at 100% load must beprogrammed for each system for the specific model ofchiller that is utilized.
To program SYSTEM 1 COND TEMP, access thepassword protected values as previously described. Keyin the value for the specific model number from Table 3and press the ENTER key. The new value will be enteredinto memory and the display will advance to the nextprogrammable option.
NOTE: Proper operation is dependent on properprogramming of this value.
Shown below is an example of this display:
SYSTEM 2 COND TEMP
If loading/unloading is selected utilizing slide valve %, thedesign condensing temperature (discharge pressureconverted to temperature or CTP) at 100% load must beprogrammed for each system for the specific model ofchiller that is utilized.
S Y S T E M 2 M O T O R C U R R1 8 3 A M P S = 1 0 0 % F L A
L I Q U I D I N J E C T I O NT E M P L I M I T = 1 8 0 . 0 ° F
S Y S T E M 1 C O N D T E M P1 1 9 . 0 ° F = 1 0 0 % L O A D
TABLE 2 – CHILLER SYS 1 AND SYS 2 MOTOR CURRENT = 100% FLA
To program SYSTEM 2 COND TEMP, access thepassword protected values as previously described. Keyin the value for the specific model number from Table 3and press the ENTER key. The new value will be enteredinto memory and the display will advance to the nextprogrammable option.
NOTE: Proper operation is dependent on properprogramming of this value.
Shown below is an example of this display:
COMMUNICATIONS MODE
COMMUNICATIONS MODE allows the operator to selectcommunications with a (1) ISN System or (2) an RCC(Remote Control Center Option). To program theCOMMUNICATIONS MODE, key in the correspondingnumber and press the ENTER key. The programmedmode will be entered into memory and the display willadvance to the next programmable value. This is notpassword protected and can be programmed anytime thePROGRAM key is pressed.
LOAD SHARE BASED ON?
Selection of the LOAD SHARE BASED ON ? determineswhether loading/unloading (load sharing based on % FLAor % slide valve). Generally, each should operate
satisfactory in most applications. The default methodutilizes % FLA and is simpler and requires lessprogramming. It is also less affected by ambient andsystem conditions.
To select a method of load sharing, program a “1” for SV%(slide value %) or a “2” for % FLA (motor current) and pressENTER. The mode of control will be entered into memoryand the next programmable value will appear. Thisselection is not password protected and can beprogrammed at any time under the PROGRAM key.
Additional details regarding selection of this programoption are detailed starting on page 88.
ECONOMIZER VALVE ON POINT(15-Ton TXV Liquid Supply Solenoid)
The Economizer Valve Solenoid On/Off points areprogrammable by the user. At low load, the 15-ton TXVsolenoid is shut off to prevent feeding excessive liquid tothe compressor. As load rises, the 15-ton TXV solenoidvalve is energized, providing additional subcoolingneeded for efficiency and additional motor cooling.
The recommended settings assume that compressorstart points are controlled by % FLA. Under theseconditions, the recommended ON Point is 50%.
To program the ECONOMIZER VALVE ON POINT,access the password protected values describedpreviously. Key in the value and press “ENTER” key. Thenew value will be entered into memory and the display willadvance to the next programmable value.
ECONOMIZER VALVE OFF POINT(15-Ton TXV Liquid Supply Solenoid)
The Economizer Valve Solenoid On/Off points areprogrammable by the user. At low load, the 15-ton TXVsolenoid is shut off to prevent feeding excessive liquid tothe compressor. As load rises, the 15-ton TXV solenoidvalve is energized, providing additional subcoolingneeded for efficiency and additional motor cooling.
The recommended settings assume that compressorstart points are controlled by % FLA. Under theseconditions, the recommended OFF Point is 40%.
To program the ECONOMIZER VALVE OFF POINT,access the password protected values described
S Y S T E M 2 C O N D T E M P1 1 9 . 0 ° F = 1 0 0 % L O A D
C O M M U N I C A T I O N S M O D E1 = I S N, 2 = R C C , 2
L O A D S H A R E B A S E D O N ?1 = S V % , 2 = % F L A 2
previously. Key in the value and press ENTER key. Thenew value will be entered into memory and the display willadvance to the next programmable value.
“DEFAULT” VALUE PROGRAMMING IN THEPROGRAM MODE
Programmable values may be individually programmedat start-up or anytime thereafter. For ease ofprogramming, once the type of refrigerant is programmedin under the PROGRAM key, a password may beprogrammed in to automatically program default valuesinto the micro. This will preset all programmable valuesunder the PROGRAM key to values that will allowoperation of the chiller under most operating conditions.This allows quick start-up programming for typical chilledwater applications.
To program the default values into the micro after therefrigerant type has been programmed, press thePROGRAM key, key in the numbers “6140”, and pressENTER. As the numbers are keyed in, Qs will appear:
When the ENTER key is pressed, the following messagewill appear:
Key in a “1” for YES, if default setpoints in Table 4 aredesired. Key in a “0” for NO, if individually programmedvalues are desired. After the desired option isprogrammed, press ENTER to store the selection intomemory.
NOTE: Keep in mind that it is often easier to selectDefault Setpoints and then reprogram a few thatrequire changing, versus programming eachindividual program option.
If a “0” is selected, the display will return to the STATUSdisplay. If a “1” is selected, the display will momentarilydisplay the message shown below before returning to theSTATUS display.
A list of the default values entered into memory, if thisprogram option is selected, is shown in Table 4.P R O G R A M M O D E
QQQQQ QQQQQ QQQQQ QQQQQ
D E F A U L T S E T P O I N T S ?1 = Y E S , 0 = N O , 1
P R O G R A M O P T I O N S S E TT O D E F A U L T V A L U E S
TABLE 4 – PROGRAM MODE DEFAULT VALUES
PROGRAMMABLE OPTION PROGRAM 6140 DEFAULTREFRIGERANT TYPE N/ADISCHARGE PRESSURE CUTOUT (R-22) 399 PSIGDISCHARGE PRESSURE CUTOUT (R-134a) 275 PSIG
LOW AMBIENT TEMP CUTOUT0°F (LOW AMBIENT)
25°F (STANDARD AMBIENT)HIGH AMBIENT TEMP CUTOUT 130°FDISCHARGE PRESSURE UNLOAD (R-22) 375 PSIGDISCHARGE PRESSURE UNLOAD (R-134a) 255 PSIGAVERAGE CURRENT UNLOAD 105%ANTI RECYCLE TIME 600 SEC.
LAG COMPRESSOR START POINT 70%LAG COMPRESSOR DIFFERENTIAL OFF 50%FAN CONTROL DISCHARGE PRESSURE SET POINT (R-22) 230 PSIGFAN CONTROL DISCHARGE PRESSURE SET POINT (R-134a) 102 PSIGFAN ON/OFF DIFFERENTIAL 50 PSIGSYSTEM 1 MOTOR CURRENT FLA N/ASYSTEM 2 MOTOR CURRENT FLA N/ALIQUID INJECTION TEMP LIMIT 180°FSYSTEM 1 FULL LOAD CONDENSER TEMPERATURE N/ASYSTEM 2 FULL LOAD CONDENSER TEMPERATURE N/ACOMMUNICATIONS MODE N/ALOAD SHARING MODE 2ECONOMIZER VALVE ON POINT 50%ECONOMIZER VALVE OFF POINT 40%
FORM 201.10-NM1
97YORK INTERNATIONAL
SETPOINT KEYS
GENERAL
The microprocessor utilizes leaving chilled liquid controlto maintain chilled liquid temperature within the pro-grammed CONTROL RANGE (CR). Regulating leavingchilled liquid temperature within the CR is accomplishedthrough capacity control of the compressor’s slide valve.A series of load and unload pulses are sent to the com-pressor slide valve to maintain LWT within a desiredrange. Attention is also provided by the micro to maxi-mize efficiency and minimize compressor cycling. Thecontrol algorithm in the micro combines control zonesand internal timers to maintain chilled liquid temperaturesand minimize cycling of the two compressors. Thismethod of control is suitable for both water and brinecooling. Control setpoints (CONTROL RANGE) are pro-grammed into the panel to establish the desired range ofleaving chilled operating temperatures. A description ofthe operation and programming follows.
PROGRAMMING CHILLED LIQUID TEMP / RANGE
Chilled Liquid/Temp Range
When the CHILLED LIQUID TEMP / RANGE key ispressed, one of the following messages will be displayedfor 3 seconds:
This message will inform the user that the chiller is se-lected to be controlled by a LOCAL (Control Panel)Setpoint control or REMOTE (FAX 4500, Remote PWMSignal, or Remote Control Center) Setpoint control.
Selection is made on the S1 Dip Switch on the Micropro-cessor Board (Page 80). Normally, unless a FAX 4500,Remote PWM Signal or Remote Control Center is con-nected to the Micropanel, the Local Mode will be se-lected.
The display will then scroll to a second message whichwill display the desired CONTROL RANGE (CR) and the“TARGET” temperature.
The CONTROL RANGE (CR) is the programmed varia-tion in leaving chilled liquid temperature which is accept-able to the user for the system application. The example
CHILLED LIQUID/TEMP RANGE
L O C A LW A T E R T E M P C O N T R O L
R E M O T EW A T E R T E M P C O N T R O L
C R = 4 2 . 0 T O 4 6 . 0 ° FT A R G E T = 4 4 . 0 ° F
FIG. 27 – SETPOINT KEYS
28164A
SETPOINTKEYS
98 YORK INTERNATIONAL
above has a programmed CR of 42.0 - 46.0°F. The user’sdesired leaving chilled temperature (“TARGET”) will be44.0°F or the midpoint of the CR. This midpoint tempera-ture will be referred to as the “TARGET” temperature inthe following description.
The LOW LIMIT WATER TEMPERATURE is the mini-mum user acceptable leaving water temperature as de-fined by the programmed CONTROL RANGE (CR). TheLOW LIMIT WATER TEMP. must be programmed intothe Micropanel to establish the low end of the CR. In theexample above, 42.0°F is programmed.
The HIGH LIMIT WATER TEMPERATURE is the maxi-mum user acceptable leaving water temperature as de-fined by the programmed CONTROL RANGE (CR). Inthe example above, the HIGH LIMIT WATER TEMPERA-TURE is programmed in the CR at 46°F.
Refer to Fig. 28 to aid in understanding the relationshipof the LOW LIMIT WATER TEMP. (LLWT), HIGH LIMITWATER TEMP. (HLWT), CONTROL RANGE (CR) andTARGET Temp.
To assure that the chilled liquid temperatures stay withinthe CONTROL RANGE (CR), The micro will attempt tocontrol leaving chilled liquid temperature to an even tightertemperature band than the low and high limits of theCONTROL RANGE (CR). This temperature band is knownas the NEUTRAL ZONE. When chilled liquid is in theNEUTRAL ZONE, the micro will only initiate loading/un-loading pulses if temperature is rising or falling fasterthan rate control limits internal to the micro.
As mentioned before, the user’s desired leaving watertemperature is known as the “TARGET” temperature andis a temperature, midpoint in the CONTROL RANGE.The “TARGET” is also midpoint in the NEUTRAL ZONE.The NEUTRAL ZONE temperature band is not program-mable but can be calculated as follows:
Example:Neutral = Target +/- HLWT - LLWTZone 4
From the example:
Neutral = 44°F +/- 46°F - 42°FZone 4
Neutral = 44°F +/- 1°FZone
In the example above, with a CR = 42.0 to 46.0°F, the“TARGET” temperature will be 44.0°F with a Neutral Zoneof 44.0°F +/- 1°F. Refer to Fig. 29 to aid in understandingthe relationship between the LOW LIMIT WATER TEMP.,HIGH LIMIT WATER TEMP., “TARGET”, CONTROLRANGE (CR), and NEUTRAL ZONE.
As mentioned previously, no loading or unloading willoccur in the NEUTRAL ZONE unless internal non-pro-grammable rate control is exceeded. Limited loading willoccur in the temperature range between the top end ofthe NEUTRAL ZONE and the HIGH LIMIT WATER TEMP.(HLWT). Normal loading, dictated by internal timers willoccur above the CONTROL RANGE (CR). Limited un-loading will occur when temperature falls between thebottom of the NEUTRAL ZONE and the LOW LIMITWATER TEMP. (LLWT). Normal unloading, dictated by in-ternal timers will occur below the CONTROL RANGE (CR).
To program the CONTROL RANGE (CR), press theCHILLED LIQUID TEMP. / RANGE key. For 3 seconds,the display will show either that Local or Remote WaterTemp. Control is selected. The display will then automati-cally scroll to the CONTROL RANGE (CR) and “TAR-GET” temperature with the cursor stopping at the firstdigit of the CONTROL RANGE (CR). Key in the Low Limitof the CONTROL RANGE (CR) that is acceptable in thesystem. See below:
Low Limit Water Temperature
The micro will accept a range of programmable valuesfrom 10.0 - 70.0°F. To program setpoints below 38°F, DipSwitch S1, Switch #1 on the Microprocessor Board must
FIG. 28 – CONTROL RANGE
FIG. 29 – NEUTRAL ZONE
C R = 4 2 . 0 T O 4 6 . 0 ° FT A R G E T = 4 4 . 0 ° F
46.0°F
44.0°F
42.0°F
“TARGET”TEMP.
CONTROLRANGE
(CR)
HIGH LIMITWATER TEMP
LOW LIMITWATER TEMP
USERACCEPTABLELEAVINGCHILLEDLIQUIDOPERATINGRANGE
46.0°F
45.0°F
44.0°F
43.0°F
42.0°F
“TARGET”TEMP.
CONTROLRANGE
(CR)
HIGH LIMITWATER TEMP
LOW LIMITWATER TEMP
NEUTRAL ZONE(No Loading/Unloading Occurs)
ÿ
ÿ
ÿ
ÿÿ
ÿ
ÿ
ÿ
FORM 201.10-NM1
99YORK INTERNATIONAL
be properly programmed for Brine Cooling (see page 80).If the switch is incorrectly selected, when setpoints be-low 38°F are entered, as well as when unacceptable val-ues are entered, the following message will be displayed:
After the LOW LIMIT WATER TEMP. (LLWT) is keyed in,the cursor will automatically advance to the final entrywhich is the upper limit (HIGH LIMIT WATER TEMP.) ofthe CONTROL RANGE (CR). This value should be pro-grammed for the highest leaving water temperature whichis acceptable in the system application. Typically 4°Fabove the LLWT is acceptable. The micro will accept avalue 1 - 5°F above the LLWT. 4°F above the LLWT is thedefault value.
Key in the upper limit HIGH LIMIT WATER TEMP (HLWT)of the CR and press the ENTER key. After pressing theENTER key, the display will continue to show the mes-sage until another key is pressed. See below:
High Limit Water Temperature
This display will automatically show the “TARGET” tem-perature which is the desired leaving chilled liquid tem-perature and the actual chilled liquid temperature the microwill attempt to control to. The “TARGET” temperature willalways be the midpoint of the CONTROL RANGE (CR).
Target Water Temperature
NOTE: Failure to press the ENTER key will cause thenewly programmed values to not be entered intomemory.
CAUTION: A Control Range (CR) selection that is toosmall for the application will result incompressor(s) cycling and hunting of the slidevalve. If this situation occurs, leaving chilledliquid temperature may vary considerably. Itis recommended that a CR of less than 3.0°Fbe avoided. Increase the CR as needed toreduce cycling and hunting.
NOTE: Whenever reprogramming the CR, keep in mindthat the desired leaving chilled liquid tempera-ture, or “TARGET” will be the midpoint of the CR.
COMPRESSOR LOADING AND UNLOADING
The micro loads and unloads individual compressors bypulsing the slide valve solenoid which controls oil flow tothe slide valve. The slide valve solenoid provides oil pres-sure assist to the port of the slide valve which eitherincreases or decreases capacity.
Whenever temperature is above the Neutral Zone, load-ing pulses will be applied to open the loading port on thecontrol solenoid allowing oil pressure to move the slidevalve to increase capacity. Every 10 - 120 seconds, themicro will pulse the slide valve with a 0.4 - 5 secondpulse. The time between pulses will be a function of thetemperature deviation from the “TARGET” chilled liquidtemperature. The duration of the pulse will be a functionof the deviation from “TARGET” chilled liquid tempera-ture, rate of water temperature change, suction pressure,discharge pressure, and % load current. Pressure is afactor since the amount of slide valve movement for agiven pulse is dependent on the discharge pressure. Motorcurrent is a factor to assure the slide valve positionchanges do not cause the compressor to exceed thecurrent limit unload point. For the first two and a halfminutes of compressor operation, no loading will occur.
Whenever temperature is below the Neutral Zone, un-loading pulses will be sent to open the unloading port onthe control solenoid to relieve oil pressure on the slidevalve. This allows oil pressure to move the slide valve todecrease capacity. Every 6 - 70 seconds, the micro willpulse the slide valve with a 0.4 - 5 second pulse. Theduration and length of the pulse will be a function of thedeviation from setpoint. The larger the deviation, the longerthe pulse. Limited loading/unload may occur in the Neu-tral Zone, if internal software “rate” control limits regulat-ing abrupt changes in leaving chilled liquid are exceeded.
SEQUENCE OF CHILLER LOADING AND UNLOADING
Three programmable options dictate the loading sequenceof the two compressors. These options allow Load Shar-ing by the two compressors based on % FLA or SlideValve %, selection of the Lag Compressor Start %, andselection of the Differential OFF %.
The loading sequence of the two compressors is pro-grammable to operate from either % FLA or % Slide ValvePosition. Over much of the range of loading of the twocompressors, the micro will attempt to load each com-pressor equally based on % FLA or % Slide Valve forefficiency purposes. This is accomplished by selectingthe type of load sharing desired, based on the % of FLAMotor Current or by the % Slide Valve Position. The typeof loading is programmable under the “PROGRAM” keyby selecting a “1” for SV% (slide valve %) or “2” for %FLA (motor current) when the display showing “LOADSHARE BASED ON ?” is accessed.
O U T O F R A N G ET R Y A G A I N !
C R = 4 2 . 0 T O 4 6. 0 ° FT A R G E T = 4 4 . 0 ° F
C R = 4 2 . 0 T O 4 6 . 0 ° FT A R G E T = 4 4 . 0 ° F
100 YORK INTERNATIONAL
Selection of the LAG COMPRESSOR START POINT %under the PROGRAM key, allows the user to select theloading point of the lead compressor at which the lagcompressor starts. Once the lag compressor starts,equalized load sharing will begin.
Selection of the DIFFERENTIAL OFF % determines therange of unloading over which load sharing will occur.
Two Control Schemes may be selected. Load Sharing,programming of the start point %, and differential off %will first be discussed in CONTROL SCHEME 1 utilizing% FLA Motor Current and then in CONTROL SCHEME2 utilizing % Slide Valve. Each one should be reviewedbefore a selection is made. Both control schemes shouldwork well for most applications.
For simplicity of programming to eliminate manual pro-gramming required in each of the two Control Schemes,the “DEFAULT” programming points (page 58) may beselected. This selects LOAD SHARING BASED ON %FLA as the control means for load sharing with a LAGCOMPRESSOR START POINT % of 70% FLA. It alsoselects a LAG DIFFERENTIAL OFF % of 50%. Thesecontrol points may be programmed individually under thePROGRAM key without selecting all “Default” values asmentioned on page 96.
CONTROL SCHEME 1
Loading And Unloading Utilizing % FLA Control
The LAG COMPRESSOR START POINT % (FLA), isprogrammable in the Program mode. By selecting a LAGCOMPRESSOR START POINT % (FLA), the user isactually selecting the % FLA at which the lead compres-sor is allowed to load, before the lag compressor is broughton. This % is programmable from 40 - 99%.
The micro will start the lead compressor whenever thechilled liquid temperature is above the High Limit of theCONTROL RANGE (CR) and the 3 minute “Start Timer”has timed out. The 3 minute “Start Timer” is the minimumamount of time that the compressor must remain off af-ter a cycling shutdown (Anti-Recycle Timer Timed Out)or after power is first applied. Once started, the microwill pulse the slide valve to load the lead compressor tobring the chilled liquid within the Neutral Zone.
If temperature is not brought down to within the NeutralZone, the lag compressor will be brought on by the microafter the lead compressor loads up to the programmedLAG COMPRESSOR START POINT % as determinedand programmed by the user.
If due to system conditions, the lead compressor doesnot reach the programmed %, even though the lead com-pressor may be fully loaded, the lag compressor will start
regardless of the programmed Start % after 5 minutes ofoperation. This will occur whenever the lead compressorcannot bring the LWT to within 2.0°F of the high end ofthe CONTROL RANGE (CR). Once the lag compressoris started, equalized loading and unloading of the twocompressors will occur based on % FLA.
The 5 minute default for lag compressor start assuresthat the lag compressor will start and load in situationswhere the lead compressor % FLA does not reach theprogrammed LAG COMPRESSOR START POINT %.These situations may be common because as ambientsdrop, actual % FLA at full load will drop at 100% slidevalve. Actual operating % FLA for a compressor that isfully loaded may often be 65 - 85% of the motor FLA atambients below 95°F.
As mentioned above, after the lead compressor startsand loads up to the programmed 40 - 99%, if tempera-ture is still above the CONTROL RANGE (CR), the lagcompressor will come on. It will then be brought up to a% FLA equal to the lead compressor provided demanddictates. At this point, the loading of both compressorswill be adjusted up or down to maintain capacity andequalize loading.
NOTE: Under most operating conditions, viewing %FLA of each compressor will show a differ-ence in the FLA of each compressor which attimes may be significant. This condition willexist even though equalized loading/unload-ing should be observed. This is due to themicro constantly pulsing slide valves of eachcompressor to control temperature and dif-ferences in operating conditions of the twocompressors, such as discharge pressurewhich causes each compressor’s slide valveto move a different amount with a pulse of aspecific duration. Other system pressures andmechanical tolerances within compressorswill also contribute to differences. Regard-less of the differences in % FLA, the microwill still assure that leaving chilled liquid tem-perature is properly controlled.
Also, in some cases, the micro will not be programmedto attempt to control equalized unloading over the entireloading range which will affect the unloading sequenceslightly. Refer to page 102, “Selecting The LAG COM-PRESSOR DIFFERENTIAL OFF %” for details.
Approximate loading time for each compressor on a hotwater start is about 5 minutes per compressor at worstcase conditions. If the load drops, both compressors willeach unload equally to a point as determined by the LAGCOMPRESSOR DIFFERENTIAL OFF %. When furthercapacity reduction is required, the lag compressor willcontinue to unload, and shutdown while the lead com-pressor maintains its % FLA loading point. When fully
FORM 201.10-NM1
101YORK INTERNATIONAL
unloaded, the lag compressor will shut down under 2conditions:
1. When chilled liquid temperature drops below the Neu-tral Zone.
2. When chilled liquid temperature drops below the “TAR-GET” temperature and the rate of change exceeds theinternally programmed rate limits.
The micro may also shut down the lag compressor be-fore it is totally unloaded to avoid cut-out of the entirechiller on a Low Water Temp. Fault. This will occur under 2conditions:
1. The leaving chilled liquid temperature falls below thelow end of the CONTROL RANGE (CR) for 37 sec-onds.
2. The leaving chilled liquid temperature drops below thelow end of the CONTROL RANGE (CR) minus CR/4.
Individual compressor loading is computed by the microbased on counting load/unload pulses. The micro basesloading on a 50 pulse scale. After 50 loading pulses,from total unload, the micro assumes full load at “50” onthe scale of 0 - 50 pulses. Unload pulses subtract fromthe numerical value on the scale, whatever it may be. “0”is fully unloaded on the 0 - 50 pulse scale. As loadingand unloading pulses are sent, the micro continues tokeep track by adding and subtracting pulses on the 0 -50 pulse scale.
After the lag compressor is shut down, the lead com-pressor loading will be adjusted up or down to controltemperature within the Neutral Zone. As load drops, themicro will keep track of the load pulses sent to the leadcompressor. At minimum loading, the lead compressorwill shut down when temperature drops below the lowlimit of the CONTROL RANGE (CR).
The lead compressor may also shut down while partiallyloaded to avoid cut-out on a Low Water Temperature Fault,if temperature drops 2 degrees below the low limit of theCONTROL RANGE (CR) or if temperature drops CR/2below the low limit of the CONTROL RANGE (CR).
Selecting The LOAD SHARE BASED ON ?
Selection of the LOAD SHARE BASED ON ? is accom-plished under the PROGRAM key. To control from % FLAmotor current, key in a “2” as shown below and press theENTER key.
This programmable display is not password protected.
Selecting The LAG COMPRESSOR START POINT %
Selection of the LAG COMPRESSOR START POINT %under the PROGRAM key primarily allows the user toeither allow the lead compressor to fully load before thelag compressor is started, or start the lag compressor isfully loaded.
Key in a start point % and press the ENTER key. Asample display is shown below:
This programmable display is not password protected.
Selecting a LAG COMPRESSOR START POINT % of99% assures that the lead compressor is fully loadedbefore the lag compressor is brought on. If very low loadsare expected, less compressor cycling will be noted byselecting a high slide valve percentage. 99% would berecommended for absolute minimum cycling. If due tosystem conditions, the lead compressor does not reachthe programmed %, even though the lead compressor isfully loaded, the lag compressor will start regardless ofthe programmed % after 5 minutes of operation when-ever the lead compressor cannot bring the leaving chilledliquid within 2.0°F of the high end of the CONTROLRANGE (CR). This assures that the lag compressor startsif demand is present, regardless of the program points.Once the lag compressor is started, equalized loadingand unloading will occur as previously described. Thisassures that the chiller will fully load and maintain chilledliquid temperature.
Selecting a LAG COMPRESSOR START POINT % lessthan 99% increases the efficiency of the chiller. At lowerpercentages, the lead compressor is loaded to the pro-grammed % and the lag compressor is started andbrought up to a % motor FLA equal to the lead compres-sor as load permits. At this point the loading of both com-pressors is adjusted up or down to maintain capacityand equalize loading. Running both compressors partiallyloaded makes more efficient use of the evaporator bundlethan running one compressor fully loaded with the otheridle. This assures that the entire evaporator is being uti-lized and maximum chiller efficiency is achieved. How-ever, keep in mind that as more capacity is required, thelag compressor will start regardless of the programmed% and equalized loading at part load will still be achieved,even with a programmed % of 99%.
If a LAG COMPRESSOR START POINT % of less than99% is desired, a value of 70% is recommended. Thiswill typically assure that the lag compressor will startbefore the lead compressor is fully loaded in mostoperating conditions.
L O A D S H A R E B A S E D O N ?1 = S V % , 2 = % F L A 2
L A G C O M P R E S S O RS T A R T P O I N T 7 0 %
102 YORK INTERNATIONAL
Selecting TheLAG COMPRESSOR DIFFERENTIAL OFF %
Selection of the LAG COMPRESSOR DIFFERENTIALOFF % under the PROGRAM key allows the operator toselect the range over which the lead and lag compressorload shares equally. This affects the loading sequence atlow loads. Once the lag compressor is brought on andloads up to a % FLA equal to the lead compressor, ifdemand allows, Load sharing of the compressors willbegin. Load sharing will continue until loading of the com-pressors drops to the programmed differential % belowthe LAG COMPRESSOR START POINT %.
For example: If a LAG COMPRESSOR START POINTof 70% is selected, and a LAG COMPRESSOR DIF-FERENTIAL OFF % of 50% is selected, the lead and lagcompressor will both load share until the % FLA of thelead compressor drops to 20% (70% - 50% = 20%). Atthis point, the micro will unload only the lag compressoruntil it reaches a point at which the micro determines it isfully unloaded and the load does not require its contin-ued operation. The micro will then cycle the lag compres-sor off. It will also cycle off as described previously, ifthe micro determines that chilled liquid temperature isdropping too low.
The larger the differential programmed, the more efficientthe use of the evaporator. For efficiency purposes, 50%is recommended. Cycling of the lag compressor will alsobe minimized since equalized unloading operates for alonger period of the loading/unloading scheme.
A small % differential will increase cycling and lower ef-ficiency slightly. For example: If 10% LAG COMPRES-SOR DIFFERENTIAL OFF % is selected with a LAGCOMPRESSOR START POINT % of 70%, the lag com-pressor will start when the lead % FLA reaches 70%.The lag loading will be brought up to equalize the lead of70% if demand requires. Both compressors will increasein loading proportionately as demand increases. Whenthe load drops, both compressors will unload to 60% (70%- 10% = 60%). At this point, only the lag compressor willbe unloaded as demand decreases. It will unload to apoint at which the micro determines it is fully unloaded. Ifload does not require its continued operation, the com-pressor will cycle off.
A minimum % FLA point is built into the micro to onlyallow load sharing to operate to a minimum of 20% FLAof the lead compressor. Therefore, the LAG COMPRES-SOR START % MINUS THE LAG COMPRESSOR DIF-FERENTIAL OFF % cannot be less than 20% or an OUTOF RANGE message will appear.
To program the LAG COMPRESSOR DIFFERENTIALOFF % under the “PROGRAM” key, key in the desiredvalue and press the “ENTER” key. The new value will be
entered into memory. This value is not password pro-tected and can be programmed anytime the PROGRAMkey is pressed. Shown below is an example of this dis-play:
The micro will accept a range of programmable valuesbetween 0 - 50% for this operating control, provided theLAG COMPRESSOR START POINT % minus the LAGCOMPRESSOR DIFFERENTIAL OFF % does not equalless than 20%.
CONTROL SCHEME 2
Loading And Unloading Utilizing % FLA And Con-densing Temperature To Predict Slide Valve Position
This control method uses a slightly more complex schemeto control loading/unloading and requires slightly moreprogramming. This scheme was derived from a computermodel and actual tests under controlled conditions toplot slide valve position versus motor current and con-densing temperature (CTP). The chiller sensors involvedin the control scheme are the motor current C.T.’s anddischarge pressure transducers. Actual condensing tem-perature is derived from system discharge pressure.
Slide valve position calculation requires that the microbe programmed to know a specific chiller’s RLA at 100%load at design conditions. This is required for each indi-vidual refrigerant system. The system Motor Current =100% RLA value will vary from chiller to chiller and shouldbe programmed according to the model number and volt-age from Table 5.
Access the password protected values and key in thecurrent that equals 100% RLA and press the ENTERkey. The new value will be entered into memory and thedisplay will advance to the next programmable value.Repeat for the other system.
The displays for each system programmable value willappear as shown below:
To compute slide valve position, the DESIGN CONDTEMP. must be entered under the PROGRAM key. TheCondensing Temperature is entered as °F / °C equatingto 100% load at design conditions. The temperature tobe programmed will vary from chiller to chiller and shouldbe programmed according to Table 6.
L A G C O M P R E S S O RD I F F E R E N T I A L O F F 5 0 %
S Y S T E M M O T O R C U R RA M P S = 1 0 0 % F L A
S Y S T E M 2 M O T O R C U R RA M P S = 1 0 0 % F L A
FORM 201.10-NM1
103YORK INTERNATIONAL
NOTE: It will be required to program a value for eachsystem.
The allowable range of DESIGN COND TEMP. is 100 -140°F (37.7-60°C) with the default set for 125°F (51.7°C).
The DESIGN SYSTEM COND TEMP. is password pro-tected under the PROGRAM key. The displays will ap-pear as follows:
Program the design temperature for the respective sys-tem and press ENTER. Repeat for the other system. Thisvalue is not password protected and can be programmedanytime the PROGRAM key is pressed.
The LAG COMPRESSOR START POINT % is program-mable in the Program mode. By selecting a LAG COM-PRESSOR START %, the user is actually selecting the% slide valve at which the lead compressor is allowed toload, before the lag compressor is brought on. This % isprogrammable from 40 - 99%.
NOTE: This is in contrast to Scheme 1 where LAGCOMPRESSOR START % relates to % FLA.
The micro will start the lead compressor whenever thechilled liquid temperature is above the High Limit of theControl Range (CR) and the 3 minute “Start Timer” hastimed out. The 3 minute “Start Timer” is the minimumamount of time that the compressor must remain off af-ter a cycling shutdown (Anti-Recycle Timer Timed Out)or after power is first applied. Once started, the microwill pulse the slide valve to load the lead compressor tobring the chilled liquid temperature within the NEUTRALZONE.
If temperature is not brought down to within the “NeutralZone”, the lag compressor will be brought on by the mi-cro after the lead compressor loads up to the programmedLAG COMPRESSOR START POINT % as determinedand programmed by the user.
If due to system conditions, the lead compressor doesnot reach the programmed %, even though the lead com-pressor may be fully loaded, the lag compressor will startregardless of the programmed Start % after 5 minutes ofoperation. This will occur whenever the lead compressorcannot bring the LWT to within 2.0°F of the high end ofthe CONTROL RANGE (CR). Once the lag compressoris started, equalized loading and unloading of the twocompressors will occur based on slide valve %.
The 5 minute default for lag compressor start assuresthat the lag compressor will start and load in situationswhere error is introduced into the micro calculation forcomputing slide valve %. These situations may occurdue to tolerances in discharge pressure transducers,ambients, dirt on coils, subcooling, superheat, etc.
As mentioned above, after the lead compressor startsand loads up to the programmed 40 - 99%, if tempera-ture is still above the CONTROL RANGE (CR), the lagcompressor will come on. It will then be brought up to a
TABLE 5 – CHILLER SYS 1 AND SYS 2 MOTOR CURRENT = 100% FLA
% slide valve equal to the lead compressor provideddemand dictates. At this point, the loading of both com-pressors will be adjusted up or down to maintain capac-ity and equalize loading.
NOTE: Under most operating conditions, viewing %slide valve of each compressor will show adifference in the % slide valve of each com-pressor which at times may be significant.This condition will exist even though equal-ized loading / unloading should be observed.This is due to the micro constantly pulsingslide valves of each compressor to controltemperature and differences in operating con-ditions of the two compressors, such as dis-charge pressure which causes eachcompressor’s slide valve to move a differentamount with a pulse of a specific duration.Other factors such as tolerances in dischargepressure transducers and mechanical toler-ances within compressors will also contrib-ute to differences. Regardless of the differ-ences in % slide valve, the micro will stillassure that leaving chilled liquid temperatureis properly controlled.
Also, in some cases, the micro will not be programmedto attempt to control equalized unloading over the entireloading range which will affect the unloading sequenceslightly. Refer to page 105, “Selecting The LAG COM-PRESSOR DIFFERENTIAL OFF %” for details.
Approximate loading time for each compressor on a hotwater start is about 5 minutes per compressor at worstcase conditions. If the load drops, both compressors willeach unload equally to a point as determined by the LAGCOMPRESSOR DIFFERENTIAL OFF %. When furthercapacity reduction is required, the lag compressor willcontinue to unload, and shutdown while the lead com-pressor maintains its % slide valve loading point. Whenfully unloaded, the lag compressor will shut down under2 conditions:
1. When chilled liquid temperature drops below the Neu-tral Zone.
2. When chilled liquid temperature drops below the “TAR-GET” temperature and the rate of change exceeds theinternally programmed rate limits.
The micro may also shut down the lag compressor be-fore it is totally unloaded to avoid cut-out of the entirechiller on a Low Water Temp Fault. This will occur under 2conditions:
1. The leaving chilled liquid temperature falls below thelow end of the CONTROL RANGE (CR) for 37 sec-onds.
2. The leaving chilled liquid temperature drops below thelow end of the CONTROL RANGE (CR) minus CR/4.
Individual compressor loading is also computed by themicro based on counting load/unload pulses. The microbases loading on a 50 pulse scale, after 50 loading pulsesfrom total unload, the micro assumes full load at “50” onthe scale of 0 - 50 pulses. Unload pulses subtract fromthe numerical value on the scale, whatever it may be. “0”is fully unloaded on the 0 - 50 pulse scale. As loadingand unloading pulses are sent, the micro continues tokeep track by adding and subtracting pulses on the 0 -50 pulse scale.
After the lag compressor is shut down, the lead com-pressor loading will be adjusted up or down to controltemperature within the Neutral Zone. As load drops, themicro will keep track of the load pulses sent to the leadcompressor. At minimum loading, the lead compressorwill shut down when temperature drops below the lowlimit of the CONTROL RANGE (CR).
The lead compressor may also shut down while partiallyloaded to avoid cut-out on a Low Water Temperature Fault,if temperature drops 2 degrees below the low limit of theCONTROL RANGE (CR) or if temperature drops CR/2below the low limit of the CONTROL RANGE (CR).
Selecting The LOAD SHARE BASED ON ?
Selection of the LOAD SHARE BASED ON ? can bemade under the PROGRAM key. To control from slidevalve %, key in a “1” as shown below and press theENTER key.
This programmable display is not password protected.
Selecting The Lag Compressor Start Point %
Selection of the LAG COMPRESSOR START % underthe PROGRAM key primarily allows the user to eitherallow the lead compressor to fully load before the lagcompressor is started, or start the lag compressor fullyloaded.
Key in a start % and press ENTER key. A sample dis-play is shown below:
This programmable display is not password protected.
Selecting a LAG COMPRESSOR START % of 99% as-sures that the lead compressor is fully loaded before thelag compressor is brought on. If very low loads are ex-pected, less compressor cycling will be noted by select-
L O A D S H A R E B A S E D O N ?1 = S V % , 2 = % F L A 1
L A G C O M P R E S S O RS T A R T P O I N T 7 0 %
FORM 201.10-NM1
105YORK INTERNATIONAL
ing a high slide valve percentage. 99% would be recom-mended for absolute minimum cycling. If due to systemconditions, the lead compressor does not reach the pro-grammed %, even though the lead compressor is fullyloaded, the lag compressor will start regardless of theprogrammed % after 5 minutes of operation. This willoccur whenever the lead compressor cannot bring theleaving chilled liquid within 2.0°F of the high end of theCONTROL RANGE (CR). Once the lag compressor isstarted, equalized loading and unloading will occur aspreviously described. This assures that the chiller willfully load and maintain chilled liquid temperature.
Selecting a LAG COMPRESSOR START % less than99% increases the efficiency of the chiller. At lower per-centages, the lead compressor is loaded to the pro-grammed % and the lag compressor is started andbrought up to a % slide valve equal to the lead compres-sor. At this point the loading of both compressors is ad-justed up or down to maintain capacity and equalize load-ing. Running both compressors partially loaded makesmore efficient use of the evaporator bundle than runningone compressor fully loaded with the other idle. This as-sures that the entire evaporator is being utilized andmaximum chiller efficiency is achieved. However, keepin mind that as more capacity is required, the lag com-pressor will start regardless of the programmed % andequalized loading at part load will still be achieved, evenwith a programmed % of 99%.
If a LAG COMPRESSOR START % of less than 99% isdesired, a value of 70% is recommended. This willtypically assure that the lag compressor will startbefore the lead compressor is fully loaded in mostoperating conditions.
Selecting The LAG COMPRESSOR DIFFERENTIALOFF %
Selection of the LAG COMPRESSOR DIFFERENTIALOFF % under the PROGRAM key allows the operator toselect the range over which the lead and lag compressorload shares equally. This affects the loading sequence atlow loads. Once the lag compressor is brought on andloads up to a % Slide Valve equal to the lead compres-sor, load sharing of the compressor will begin. Load shar-ing will continue until loading of the compressor drops tothe programmed differential % below the LAG COMPRES-SOR START POINT %.
For example: If a LAG COMPRESSOR START POINTof 70% is selected, and a LAG COMPRESSOR DIF-FERENTIAL OFF % of 50% is selected, the lead and lagcompressor will both load share until the % Slide Valveof the lead compressor drops to 20% (70% - 50% = 20%).At this point, the micro will unload only the lag compres-sor until it reaches a point at which the micro determines
it is fully unloaded and the load does not require its con-tinued operation. The micro will then cycle the lag com-pressor off. It will also cycle off as described previously,if the micro determines that chilled liquid temperature isdropping too low.
The larger the differential programmed, the more efficientthe use of the evaporator. For efficiency purposes, 50%is recommended. Cycling of the lag compressor will alsobe minimized since equalized unloading operates for alonger period of the loading/unloading scheme.
A small % differential will increase cycling and lower ef-ficiency slightly. For example: If 10% LAG COMPRES-SOR DIFFERENTIAL OFF % is selected with a LAGCOMPRESSOR START POINT % of 70%, the lag com-pressor will start when the lead % FLA reaches 70%.The lag loading will be brought up to equalize the lead of70% if demand requires. Both compressors will increasein loading proportionately as demand increases. Whenthe load drops, both compressors will unload to 60% (70%- 10% = 60%). At this point, only the lag compressor willbe unloaded as demand decreases. It will unload to apoint at which the micro determines it is fully unloaded. Ifload does not require its continued operation, the com-pressor will cycle off.
A minimum % FLA point is built into the micro to onlyallow load sharing to operate to a minimum of 20% SlideValve % of the lead compressor. Therefore, the LAGCOMPRESSOR START % MINUS THE LAG COMPRES-SOR DIFFERENTIAL OFF % cannot be less than 20%or an OUT OF RANGE message will appear.
To program the LAG COMPRESSOR DIFFERENTIALOFF % under the PROGRAM key, key in the desiredvalue and press the ENTER key. The new value will beentered into memory. This value is not password protectedand can be programmed anytime the PROGRAM key ispressed. Shown below is an example of the display:
To program the LAG COMPRESSOR DIFFERENTIALOFF % under the PROGRAM key, key in the desiredvalue and press the ENTER key. The new value will beentered into memory and the display will advance to thenext user programmable value. This value is not pass-word protected and can be programmed anytime thePROGRAM key is pressed.
The micro will accept a range of programmable valuesbetween 0 - 50% for this operating control, provided theLAG COMPRESSOR START POINT % minus the LAGCOMPRESSOR DIFFERENTIAL OFF % does not equalless than 20%.
L A G C O M P R E S S O RD I F F E R E N T I A L O F F 5 0 %
106 YORK INTERNATIONAL
SAFETIES
GENERAL
There are both System Safeties and Total Chiller Safe-ties programmed into the micropanel. System Safetiesmay either be Manual Reset or Anticipation Type. Chillersafeties will be Automatic Reset Type. These safetiesprotect the chiller from damage anytime a safety thresh-old is exceeded by either shutting the system(s) down orby altering system loading. Continuous monitoring by themicroprocessor assures that instantaneous reactionsresult. A status display message will indicate when asystem(s) or the entire chiller is shut down due to a faultor when Anticipation safeties are operating.
An explanation of these safeties follows.
MANUAL RESET SAFETIES
A Manual Reset Safety will shut the affected systemdown whenever the safety threshold is exceeded. Auto-matic restart will occur after the first 2 shutdowns whenthe anti-recycle timer times out, if temperature demandexists. After any combination of 3 Manual Reset Safe-ties in a 90 minute time period, the affected system willshut down and lock out on a FAULT.
After a system has shut down 3 times and locked out, afault display indicating the last system fault will appearon the STATUS display message. This is accessible bypressing the STATUS key.
NOTE: The High Motor Current Safety is a unique safetythat will lock out a system after only a singlefault.
To reset a locked out system, turn the affected systemswitch on the Microprocessor Board (Page 125) to theOFF position.
CAUTION: Before returning a locked out system to ser-vice, a thorough investigation of the causeof the fault should be made. Failure to repairthe cause of the fault while manually allow-ing repetitive restarts may cause further ex-pensive damage to the system.
Each of the Manual Reset Safeties will be discussed indetail below.
Discharge Pressure Safety
The Discharge Pressure Safety assures that the systempressure does not exceed safe working limits which couldopen a relief valve or other pressure relief device caus-ing refrigerant loss.
This safety is a back-up for the mechanical High Pres-sure Cut-out in the system. The Discharge PressureSafety is bypassed for the first 5 seconds of operation.After 5 seconds, if the cut-out point is exceeded for 3seconds, the system will shut down.
The Discharge Pressure Safety Cut-out is programmableby the user (Page 89). An example of a discharge pres-sure fault display message is shown below:
Oil Pressure Safety
The Oil Pressure Safety assures that the compressor’smechanical components receive proper lubrication. Thissafety monitors the pressure drop across the oil filterand isolation valves that are present in the oil line be-tween the oil separator and the compressor. The microbegins monitoring compressor oil pressure after 3 min-utes of operation. If oil pressure increases above (pres-sure drops) the differential oil pressure cut-out thresholdfor more than 3 seconds, the system will shut down.
Under typical operation, the oil pressure display will nor-mally read less than 45 PSID. As oil pressure drops, thedifferential pressure on the display will increase, whichmeans that oil pressure is moving closer to suction pres-sure. Optimum oil pressure will approach 0 PSID on themicropanel display.
After 3 minutes of operation, oil pressure must be lessthan 45 PSID (R22) or 40 PSID (R134a) for as long asthe compressor continues to run. If the required oil pres-sure limits are not met, the system will shut down.
The micro computes “differential oil pressure” for thissafety by measuring discharge pressure as sensed bythe discharge transducer and subtracting oil pressure assensed by the oil transducer returning to the compressor(Discharge - Oil = Oil PSID).
An example of a high oil pressure fault display follows:
LOW OIL DIFFERENTIAL SAFETY
The LOW OIL DIFFERENTIAL SAFETY assures thatthe compressor’s mechanical components receive properlubrication. This is accomplished by monitoring the pres-
S Y S 1 H I G H D S C H P R E SS Y S 2 H I G H D S C H P R E S
S Y S 1 H I G H O I L D I F FS Y S 2 H I G H O I L D I F F
FORM 201.10-NM1
107YORK INTERNATIONAL
sure differential between oil and suction pressure. Lackof a differential indicates that the compressor is notpumping and no oil is being pumped through the com-pressor to lubricate the bearings and rotors.
This type of oil failure will not be picked up by the HighOil Differential Safety since no flow will cause the differ-ential through the oil piping to be zero, which would actu-ally satisfy the High Oil Differential Safety.
The low oil pressure safety is activated after 60 secondsof compressor operation. After 1 min., the oil pressuremust be greater than 10 PSID. After 2 min., greater than20 PSID, after 3 min., greater than30 PSID, and after 4min., 40 PSID. After 5 min. of operation and longer, oilpressure must remain higher than 50 PSID or the sys-tem will be shut down.
There is presently no display which allows the operatorto view the oil pressure differential.
The micro computes “differential oil pressure”, for thissafety by measuring oil pressure as sensed by the oiltransducer and subtracting suction pressure as sensedby the suction transducer (Oil - Suction = Oil PSID).
An example of a low oil pressure fault display is shownbelow:
Suction Pressure Safety
The Suction Pressure Safety assures that the system isnot allowed to operate under low refrigerant conditions ordue to a problem which will not allow proper refrigerantflow.
When a compressor starts, the micro ignores suctionpressure until a pumpdown is completed (pumpdown tocut-out or 30 sec., whichever comes first.). Afterpumpdown, the micro begins monitoring the suction pres-sure and continues to do so as long as the compressorruns. For operation periods in the first 270 seconds, it ispermissible for the suction pressure to be less than theprogrammed cut-out, but must be greater than:
Run Time + 103 x SPCO = Cut-out
100 Programmed
Example: Run time = 60 secondsProgrammed Cut-out = 44 PSIG
60 + 10 3 x 44 = 13.2 PSIG
100
A close examination of the formula indicates the suctionpressure cut-out increases with time for the first 270 sec-onds after the safety becomes active.
After 270 seconds, the suction pressure must be greaterthan the cut-out.
A transient timer is built into the software to assure thatshort term fluctuations in suction pressure due to fancycling, loading, etc. do not cause nuisance trips on lowsuction pressure.
After 270 seconds of operation, the transient timer isactivated. If suction pressure drops below the cut-outpoint, the 90 second transient timer begins timing andthe suction pressure must be greater than:
10 + (90 - transient time left) x SPCO100
Example: Transient timer has been in effect for30 sec. (60 sec. left)Programmed cut-out = 44 PSIG
10 + (90 - 60) x 44 = 17.6 PSIG100
The longer the transient timer times, the higher the suc-tion pressure must be. As long as the suction pressurestays above the cut-out point as dictated by the formula,the system will stay on line. 90 seconds after the tran-sient timer starts, suction pressure must exceed the pro-grammed cut-out. After the pressure exceeds SPCO + 5PSIG, the transient timer will reset. Should the pressurenot reach SPCO + 5 PSIG which resets the transienttimer, but still remain above the cut-out, the compressorwill continue to run until suction pressure drops belowthe cutout. At this time it will immediately shut down on alow pressure fault.
The Suction Pressure Safety Cut-out is programmableby the user (Page 91). An example of a suction pressurefault message is shown below:
High Motor Current Safety
The High Motor Current Safety shuts a system downand locks it out after only a single occurrence of a rise inaverage motor current above the cut-out point. The safetyattempts to provide motor protection should an overloadoccur due to a system or external problem. The micromonitors motor current with 3 C.T.’s per motor, one oneach phase T1, T2 and T3 in both WYE-Delta or Across-the-Line starters.
S Y S 1 L O W O I L D I F FS Y S 2 L O W O I L D I F F
S Y S 1 L O W S U C T I O NS Y S 2 L O W S U C T I O N
108 YORK INTERNATIONAL
High current conditions may result from power problems,contactor problems, wiring problems, refrigerant over-charge, very high chilled liquid temperatures, very highambients, or situations that cause high discharge pres-sures.
The micro begins monitoring “average” motor current af-ter 5 seconds of compressor operation on chillers withACROSS-THE-LINE start and after 20 seconds on chill-ers with WYE-DELTA starters. Between 5 - 7 seconds ofrun time (ACROSS-THE-LINE) or 20 - 22 seconds (WYE-DELTA) “average” motor current must be less than 120%FLA, or the micro will shut the compressor down. After 7seconds of operation (ACROSS-THE-LINE) or 22 sec-onds (WYE-DELTA), “average” motor current must be lessthan 115% FLA as long as the compressor continues torun. Anytime these current thresholds are exceeded for3 seconds, the system will shut down.
NOTE: Do not confuse FLA and RLA. FLA (full loadamps) is approximately 1.2 x RLA. RLA (runningload amps) specified on the motor / chiller name-plate is typical current demand under rated op-erating conditions in a fully loaded system. There-fore, do not expect to always see 100% FLAwhen the system is fully loaded. In a fully loadedcondition, motor currents may often run 65 - 85%FLA.
An example of the high current fault display message isshown below:
Phase Rotation Safety
The Phase Rotation Safety assures that the compressorrotates in the proper direction eliminating the possibilityof damage to the compressor.
The micro will shut the compressor down after 4 sec-onds of operation whenever the phasing of the incomingpower wiring is incorrect. Anytime this fault occurs, thesolution is to switch any two of the three incoming powerwires.
An example of the Phase Rotation Fault message isshown below:
High Discharge Temperature Safety
This safety assures that the compressor’s screws donot overheat and expand causing them to be damaged.
The compressor will not start or will shut down in the first5 seconds of operation if the discharge temperature ex-ceeds 225°F.
After 5 seconds of operation, a warning message will bedisplayed if discharge temperature exceeds 225°F. Thecompressor will shut down if the discharge temperatureexceeds 230°F.
This safety operates in conjunction with the Oil PressureSafety to assure proper oiling is taking place. If oiling islost for any reason, the oil seal between the two screwswill be lost and the compression ratio will drop. The lossin compression ratio will cause the discharge tempera-ture to rise.
An example of the High Discharge Temperature warningand fault message is shown below:
Low Motor Current Safety
This safety protects against system problems that causelow motor current, motor overheating, high motor current(overload) and high discharge pressure. These problemscould result in motor failure, compressor failure, and sys-tem malfunction.
Shown below is the display relating to this safety. Actualcurrent as well as MP (Motor Protector) and HP (HighPressure Cut-out) are related to this safety. A Motor Over-load Relay (OL) will also cause a low current fault.
Low “average” motor current may result from running withlow or no refrigerant. This safety protects against grossrefrigerant problems until the low pressure bypass is de-activated by the micro. Low current may also be due tocontactor or power problems or a compressor that is notpumping due to a mechanical malfunction. The micromonitors motor current with 3 C.T.’s per motor, one oneach phase T1, T2 and T3 in both Wye-Delta or Across-the Line starters.
The micro begins monitoring “average” motor current af-ter 5 seconds of compressor operation on chillers withACROSS-THE-LINE start and after 20 seconds on chill-ers with WYE-DELTA starters. After 5 seconds of opera-tion (ACROSS-THE-LINE) or 20 seconds (WYE-DELTA),“average” motor current must be greater than 5% (ambi-ent 25°F), 10% (ambient 26 - 45°F), or 15% (ambient45°F) FLA but less than 115% FLA as long as the com-pressor continues to run. Anytime these current thresh-olds are exceeded for 3 seconds, the system will shutdown.
S Y S 1 H I G H M T R C U R RS Y S 2 H I G H M T R C U R R
S Y S 1 P H A S E R O T A T I O NS Y S 2 P H A S E R O T A T I O N
S Y S 1 H I G H D S C H T E M PS Y S 2 H I G H D S C H T E M P
S Y S 1 L O W C U R R / M P / H PS Y S 2 L O W C U R R / M P / H P
FORM 201.10-NM1
109YORK INTERNATIONAL
NOTE: Do not confuse FLA and RLA. FLA (full loadamps) is approximately 1.2 x RLA. RLA (runningload amps) specified on the motor / chiller name-plate, is typical current demand under rated op-erating conditions in a fully loaded system. There-fore, do not expect to see 100% FLA when thesystem is fully loaded. In a fully loaded condi-tion, expect motor currents to run 65 - 85% FLA.
Six internal sensors are built into the motor (3 on eachend). These sensors are wired into the Motor ProtectorModule located inside the Motor Terminal Box. As thewindings heat and cool, the resistance of the motor tem-perature sensors will change. If the windings overheat,the change in resistance in the sensors will be sensedby the Motor Protector Module. The module will open itsMP contacts breaking the 115VAC fed to the 1CR (Sys1) or 2CR (Sys 2) control relay.When a control relay isde-energized, power is removed from the compressorcontactor which shuts the compressor off. When the motorcontactor de-energizes, motor current falls to zero. Thelow motor current is sensed by the microprocessor andthe system is shut down.
Auto-restart will not be permitted after shutdown or amotor protector module trip. The motor sensors mustcool and control power must be removed from thecontrol panel to reset the MP contacts. A fault lockoutwill automatically occur after the micro attempts 2 morestarts with the MP contacts open.
Each compressor is protected by an External Motor Over-load (OL) Relay responsive to motor current. When theoverload relay senses single phase operation, locked rotorcurrent in excess of 10 seconds, or sustained currentoverloads in excess of 140% of RLA, the device will trip.This opens the 1 OL (Sys 1) or 2 OL (Sys 2) contactswhich de-energizes 1CR (Sys 1) or 2CR (Sys 2) controlrelay. When a control relay de-energizes, power is re-moved from the compressor contactors which shuts thecompressor off. When the motor contactor de-energizes,motor current falls to zero. The low motor current is sensedby the microprocessor and the system is shut down.
The OL relay setting should never be altered. If for somereason the Overload Relay is replaced, the following pro-cedure is used for set-up.
A/L Start:
C.T’s sense total compressor current so
OL Relay Dial Setting = (1.1 x RLA)350
WYE-Delta Start:
C.T.’s sense 58% of total compressor current so
Relay Dial Setting = (1.1 x 0.58 x RLA)350
Anytime the External Motor Overload Relay trips, amanual reset of the device is required to restart the com-pressor. After the first fault, the micro will try two morerestarts, but with the External Motor Overload Relaytripped, no restart can occur. The micro will then lock outthe system. In addition to manually resetting the Exter-nal Motor Overload Relay, the fault will also require resetby turning the system switch of problem system off.Assure that the cause of the fault is determined beforereturning the system to service.
The HP (High Pressure) Cut-out will also cause the lowcurrent safety to activate. If discharge pressure exceeds405 PSIG (HP Cut-out), the cut-out will open. When thecut-out opens, 115VAC power will be removed from theMotor Protector Module. When power is removed fromthe module, its MP contacts will open, breaking the115VAC fed to the 1CR (Sys 1) or 2CR (Sys 2) controlrelay. When a control relay is de-energized, power is re-moved from the compressor contactors which shuts thecompressor off. When the motor contactor de-energizes,motor current falls to zero. The low motor current is sensedby the microprocessor and the system is shut down.
Auto-restart will be permitted after shutdown, when dis-charge pressure drops below 330 PSIG and the HP con-tacts close. A fault lock-out will result if safety thresh-olds are exceeded three times in a 90 minute period.
Motor Current Unbalance Safety
The Motor Current Unbalance Safety assures that cur-rent balance between each of the three phases is withinan acceptable limit. This provided further motor protec-tion by preventing operation which could overheat onewinding causing damage to the motor. It also provides anearly warning of problems such as contactor contact wear,loose power wiring connections, and voltage problems inbuilding power sources. This safety is an alternative andan enhancement to the internal thermal protection alreadyprovided by the motor protector.
After 1 second of operation, the current of any phasemust be within + or - 40% of the average current of thethree phases. Exceeding these limits for greater than 3seconds will cause the compressor to shut down.
An example of the Motor Current Unbalance Fault mes-sage is shown below:
High Oil Temperature Safety
This safety assures that oil temperature does not ex-ceed a safe operating temperature due to a system prob-lem in the oil cooling circuit which could cause damage
S Y S 1 M T R C U R R U N B A LS Y S 2 M T R C U R R U N B A L
110 YORK INTERNATIONAL
to the compressor. Typical oil temperature during normaloperation will be approximately 130 - 150°F.
For the first 2 minutes of operation, the oil temperaturesafety is bypassed. After 2 minutes of operation, if theoil temperature is above 225°F for more than 3 seconds,the compressor will shut down.
An example of the High Oil Temp fault message is shownbelow:
AUTOMATIC RESET SAFETIES
An Automatic Reset Safety will shut the entire chillerdown on a fault when the safety threshold is exceededand allows automatic restart after the condition causingthe shutdown clears. Restart will occur only after anti-recycle timers are satisfied and demand requires.
A reset hysteresis is built in to each safety so repetitivefaulting and clearing will not occur in a short time period.An example would be if ambient temperature droppedbelow the cut-out, temperature would have to rise 5°Fabove the cut-out before the fault lockout would clearand restart can occur.
When the chiller is shut down on one of these safeties, amessage will appear on the STATUS display informingthe operator of the problem. This is accessible by press-ing the STATUS key.
Details concerning each of the three Automatic ResetSafeties follow.
Low Water Temperature Safety
The Low Water Temperature Safety assures that theevaporator is not damaged from freezing due to improp-erly set control points. Whenever the chilled liquid tem-perature drops below the programmable cut-out, the chillerwill shut down. The chiller will be re-enabled and the faultwill clear when temperature rises 4°F above the cut-outpoint.
The Low Water Temperature Safety Cut-out is program-mable by the user (Page 91). An example of the LowWater Temperature Fault display message is shown be-low:
Low Ambient Temperature Safety
The Low Ambient Temperature Safety assures that thechiller does not run in low ambients where potential dam-age could result due to low system pressures. It canalso be used to shut down the chiller at a temperaturewhere continued running of the chiller is not economicalas compared to the use of free cooling.
The Low Ambient Cut-out is programmable by the user(Page 89). If the outdoor ambient temperature drops 1°Fbelow the cut-out, the chiller will shut down. The fault willclear when the temperature rises 1°F above the cut-out.An example of the Low Ambient Temperature Fault dis-play message is shown below:
High Ambient Temperature Safety
The High Ambient Temperature Safety assures that thechiller does not run in ambients above 130°F where po-tential malfunction of system mechanical and electricalcomponents may result.
The High Ambient Cut-out is programmable (Page 90)and may be adjusted for cut-outs below 130°F. The cut-out may be programmed to cut-out at temperatures from100 - 130°F. Whenever the ambient rises more than onedegree F above the cut-out, the chiller will shut down.
Restart will occur when temperature drops one degree Fbelow the cut-out. An example of the High Ambient Tem-perature Fault display message is shown below:
AC Under Voltage Safety
The Under Voltage Safety assures that the system is notoperated at voltages where malfunction of the micropro-cessor could result in system damage. Whenever themicroprocessor senses an onboard control power supplyfailure while a compressor is running, the chiller is shutdown. The microprocessor circuitry is capable of operat-ing at voltages 10% below the nominal 115VAC supplyto the panel.
Auto-restart of the chiller will occur when power is reap-plied after a 2 minute start-up timer elapses. This timerassures that the motor has a minimum of 2 minutes tocool under any circumstances, allowing much of the in-ternal heating due to starting to be dissipated before an-other start occurs.
S Y S 1 H I G H O I L T E M PS Y S 2 H I G H O I L T E M P
C H I L L E R F A U L T :L O W W A T E R T E M P
C H I L L E R F A U L T :L O W A M B I E N T T E M P
C H I L L E R F A U L T :H I G H A M B I E N T T E M P
FORM 201.10-NM1
111YORK INTERNATIONAL
An example of the Under Voltage Safety display mes-sage is shown below:
Flow Switch
The microprocessor monitors the closure of the flowswitch to assure that water flow is present in the evapo-rator which prevents freeze-ups. The flow switch “dry”contacts are connected between terminals 13 & 14 (Fig.19). If the flow switch opens, the chiller will shut downand the following STATUS message will be displayed:
Closing of the flow switch, when flow is present, willcause the message to disappear and auto-start to occur.
CAUTION: NEVER BYPASS A FLOW SWITCH. THISWILL CAUSE DAMAGE TO THE CHILLERAND VOID ANY WARRANTIES.
Print-out On Fault Shutdown
If an optional printer is installed, the micro will automati-cally send the contents of the HISTORY Buffer #1 to theprinter anytime a fault shutdown occurs. This will allowrecord keeping of individual faults, even though they donot cause a lock-out of the system. This information maybe useful to identify developing problems and trouble-shooting.
The NO RUN PERM fault messages will not be stored inthe History Buffer and will not cause an auto print-out.
NOTE: Due to extreme operating conditions or sys-tems where control deficiencies are present,occasional faults may occur with the associ-ated printout. This may be normal and ex-pected. Do not become alarmed.
An example of this print-out is shown in Fig. 30.
C H I L L E R F A U L T :V A C U N D E R V O L T A G E
S Y S 1 N O R U N P E R MS Y S 2 N O R U N P E R M
FIG. 30 – AUTOMATIC FAULT PRINT-OUT
YORK INTERNATIONAL CORPORATIONMILLENNIUM SCREW CHILLER
ISN OPTION ENABLED
SOFTWARE VERSION W.04F.02.500.02
SAFETY SHUTDOWN NUMBER 1SHUTDOWN @11:07PM 01 JAN 96
CHILLER FAULT:VAC UNDER VOLTAGE SHUTDOWN
RETURN WATER TEMP 49.1 DEGFLEAVING WATER TEMP 49.3 DEGFLOW WATER CUTOUT 36.0 DEGFCOOLING RANGE 42.0 TO 44.0 DEGFTARGET TEMP 43.0 DEGFAMBIENT AIR TEMP 70.2 DEGFLOW AMBIENT CUTOUT 25.0 DEGFLOW PRESSURE CUTOUT 44 PSIGLEAD SYSTEM SYS 2LOCAL REMOTE SETTING: LOCAL
Anticipation controls are built into the software to pre-vent safety shutdowns by automatically overriding tem-perature controls, if system conditions approach safetythresholds. This allows the chiller capacity to avoid totalloss of cooling resulting from a lockout on a safety.
Anticipation safeties monitor suction and discharge pres-sure and unload the compressor’s as needed. The microwill display a message on the STATUS DISPLAY when-ever these controls are in operation.
Discharge Pressure Unloading
The purpose of this safety is to reduce the chance offaulting on the internal or external high discharge pres-sure cut-out which will cause total cooling loss in thesystem. The micro will unload the system in an effort tokeep the discharge pressure below the cut-out.
For the first 60 seconds of operation, the unloading safetyis ignored. After 60 seconds, if discharge pressure ex-ceeds the Discharge Pressure Unload setpoint pro-grammed by the user (Page 90), the micro will unload theaffected compressor by sending a one second unloadpulse to the slide valve. Continued unloading will occurevery 5 seconds until the discharge pressure drops be-low the programmed setpoint.
The micro will automatically extinguish the Status dis-play DSCH LIMITING and reload the compressor, if de-mand requires, when the discharge pressure drops be-low 90% of the programmed setpoint.
The operation of this safety becomes important if con-denser coils become dirty, a problem exists with con-denser fan operation, or if extreme ambient or load con-ditions occur. A STATUS message will be displayed when-ever discharge pressure unloading is in effect. An ex-ample of this message is shown below:
Motor Current Unloading
The purpose of this safety is to reduce the chance offaulting due to high motor current causing total loss ofcooling in the system. The micro will unload the systemin an effort to keep the motor current from exceeding thehigh motor Current Cut-out.
For the first 60 seconds of operation, the unloading safetyis ignored. After 60 seconds of operation, if motor cur-rent exceeds the Current Limit Setpoint programmed bythe user (Page 90), the micro will unload the affected
compressor by sending a one second unload pulse tothe slide valve. Continued unloading will occur every 5seconds until the motor current drops below the pro-grammed setpoint.
The micro will automatically extinguish the CURR LIMIT-ING Status display and reload the compressor if demandrequires and the motor current drops below 90% of theprogrammed cut-out.
The operation of this safety also becomes important whendemand limiting is critical due to power requirements orlimitations in the building.
In some cases current limiting may come into play ifabnormally high outdoor temperatures are encounteredand high discharge pressures cause motor currents torise near the safety cut-out point.
An example of the Current Limiting display message isshown below:
Suction Temp Limiting
SUCTION LIMITING is only operable when optional elec-tronic expansion valves are added to the chiller. If suc-tion pressure exceeds the programmed pressure, themicro will allow superheat to rise above the setpoint inan attempt to reduce suction pressures. This is done toassure that adequate motor cooling is provided. Normally,the default value is sufficient and programming is notnecessary. Details on programming this feature are out-lined on page 90.
An example of the SUCT LIMITING display message isshown below:
INTERNAL TIMERS AND PUMPDOWN CONTROLS
Anti-Recycle Timer
Anytime a compressor shuts down for any reason, re-start cannot occur until the programmable Anti-recycleTimer (Page 91) has timed out (timer starts with the com-pressor start). Even though the Anti-recycle timer hastimed out, a minimum of 2 minutes (2 - minute start-uptimer) must always elapse after a compressor shuts down,before it may again restart.
If a power failure occurs, the anti-recycle timers will re-set to 2 minutes after power is re-applied.
S Y S 1 D S C H L I M I T I N GS Y S 2 D S C H L I M I T I N G
S Y S 1 S U C T L I M I T I N GS Y S 2 S U C T L I M I T I N G
S Y S 1 C U R R L I M I T I N GS Y S 2 C U R R L I M I T I N G
FORM 201.10-NM1
113YORK INTERNATIONAL
If the anti-recycle timer is preventing a start, the timerposition in seconds may be viewed by pressing the “STA-TUS” key. A sample display follows:
Anti-Coincidence Timer
The Anti-Coincidence Timer assures that 2 compressorscan never start simultaneously which limits excessivecurrent demand. A one minute time delay will alwaysseparate compressor starts.
The Anti-Coincidence Timer can be viewed, when it isactive, by pressing the “STATUS” key. A sample displayis shown below:
Pumpdown Controls
Each compressor has a pumpdown on start-up and apumpdown on shutdown feature. Pumpdown is incorpo-rated into the control scheme to assure that liquid doesnot enter the compressor on start-up, which could causedamage to the compressor.
The pumpdown on start-up control eliminates the needfor recycling pumpdown. Eliminating recycling pumpdownsaves energy, reduces the number of starts, and saveswear on the compressor/motor.
On start-up, the Compressor Slide Valve Unload Sole-noid will be energized to unload the compressor and thesystem will be pumped down to the programmed cut-outor will pump down for 30 seconds, whichever comes first,
before the Liquid Line Solenoid and Economizer LiquidSupply Solenoid is energized.
Pumpdown on normal shutdown is incorporated to fur-ther assure that liquid does not accumulate in the evapo-rator. On shutdown, the Compressor Slide Valve UnloadSolenoid will be energized to unload the compressor andthe Liquid Line Solenoid and Economizer Liquid Supplysolenoid will de-energize. The compressor will continueto operate until the suction pressure reaches the suctionpressure cut-out or a period of 30 seconds elapses.
Pumpdown on shutdown will occur on “normal” shutdowns.Normal shutdowns include non-safety shutdowns wherecooling demand has been satisfied or when a systemswitch on the Microprocessor Board is turned off (doesnot apply to the UNIT Switch).
Pumpdown on shutdown will also occur when a flow switchopens or run permissive is lost and when a Daily Sched-ule or a Remote Shutdown is called for.
The following message will be displayed on the STATUSdisplay when a non safety shutdown due to cooling de-mand, micro board system switch shutdown, or a runpermissive/flow switch shutdown occurs. After pumpdownis complete, the respective shutdown message will bedisplayed for the system.
No display indicating a pumpdown will be viewed when aDaily Schedule or a Remote Shutdown occurs. Shutdownmessages for Remote and Daily Schedule shutdown willbe displayed during pumpdown and after shutdown forthese two messages.
Manual pumpdown from the control panel is not possible.
S Y S 1 A R T M R 1 0 2 SS Y S 2 A R T M R 1 0 2 S
S Y S 1 C O M P R U N N I N GS Y S 2 A C T M R 5 6 S
S Y S 1 P U M P I N G D O W NS Y S 2 P U M P I N G D O W N
114 YORK INTERNATIONAL
PRINT KEYS
GENERAL
The Print keys allow the operator to obtain two differentremote hard copy print-outs. A print-out of real-time sys-tem operating data and a print-out of system history dataat the “instant of the fault” on each of the last three faultswhich occurred on the chiller is available. These print-outs are available by pressing the “OPER DATA” and “HIS-TORY” keys.
If a remote printer is not being used, and the desire is toobtain data locally at the panel, the same keys allowaccess to identical real-time operating data as well asfault information. This information is available by using acombination of the OPER DATA and HISTORY keys inconjunction with the ENTER key on the keypad.
An explanation of the use of the keys for remote printeror local data retrieval will follow. An optional printer willbe required for remote printout.
REMOTE PRINTOUT
Oper Data
The OPER DATA key allows the operator to remotelyobtain a printout of current system operating parameters
at the instant that the key is pressed. When the key ispressed, a snapshot will be taken of system operatingconditions as well as all of the user programming selec-tions. This data will be temporarily stored in memory,after which, transmission of this data will begin to theremote printer. As the data is transmitted from the micro-processor to the printer, it will be erased from the memorylocations where it is temporarily stored in the micropro-cessor. A sample printout is shown in Fig. 32.
History
The HISTORY key allows the operator to remotely obtaina printout of information relating to the last 3 Safety Shut-downs which occurred. The information is stored at theinstant of the fault, regardless of whether the fault causeda lockout to occur. The information is also not affectedby power failures (long term internal memory battery back-up is built into the circuit board) or manual resetting of afault lock-out.
When the HISTORY key is pressed, a Printout is trans-mitted of all system operating conditions which werestored at the “instant the fault occurred” for each of thelast 3 safety shutdowns.
The printout will begin with the most recent fault whichoccurred.
FIG. 31 – PRINT KEYS28164A
HISTORY
OPERDATA
PRINTKEYS
FORM 201.10-NM1
115YORK INTERNATIONAL
The most recent fault will always be stored as SAFETYSHUTDOWN NO. 1 (See printout Fig. 33). Identically for-matted fault information will then be printed for SAFETYSHUTDOWN NO. 2 and SAFETY SHUTDOWN NO. 3.
FIG. 32 – OPER DATA PRINT-OUT
P R E S S E N T E R T OD I S P L A Y D A T A
OPERDATA
L O A D T I M E R 7 0 S E CU N L O A D T I M E R 6 0 S E C
YORK INTERNATIONAL CORPORATIONMILLENNIUM SCREW CHILLER
ISN OPTION ENABLED
SOFTWARE VERSION W.04F.02.500.02
SYSTEM STATUS11:43PM 01 JAN 96
SYS 1 COMPRESSOR RUNNINGSYS 2 COMPRESSOR RUNNING
RETURN WATER TEMP 49.1 DEGFLEAVING WATER TEMP 49.3 DEGFLOW WATER CUTOUT 36.0 DEGFCOOLING RANGE 42.0 TO 44.0 DEGFTARGET TEMP 43.0 DEGFAMBIENT AIR TEMP 70.2 DEGFLOW AMBIENT CUTOUT 25.0 DEGFLOW PRESSURE CUTOUT 44 PSIGLEAD SYSTEM SYS 1LOCAL REMOTE SETTING: LOCAL
S M T W T F S Q=HOLIDAYSUN START=00:00AM STOP=00:00AMMON START=00:00AM STOP=00:00AMTUE START=00:00AM STOP=00:00AMWED START=00:00AM STOP=00:00AMTHU START=00:00AM STOP=00:00AMFRI START=00:00AM STOP=00:00AMSAT START=00:00AM STOP=00:00AMHOL START=00:00AM STOP=00:00AM
Information contained in the SAFETY SHUTDOWN Buff-ers is very important when attempting to troubleshoot asystem problem. This data reflects the system condi-tions at the instant the fault occurred and often revealsother system conditions which actually caused the safetythreshold to be exceeded. See Fig. 33 for a sample ofthe History Buffer Printout.
LOCAL DISPLAY READOUT
Oper Data
The OPER DATA key also allows the user to scroll throughadditional real time display information about the chillersystem which is not available from the “DISPLAY” keys.This information covers a wide range of data which in-cludes fan status, loading status, liquid line solenoid sta-tus, run time, etc. A total of 15 different displays areoffered.
When the OPER DATA key is pressed, the followingmessage will appear:
Repetitively pressing the ENTER key allows the opera-tor to scroll through the 15 available displays.
In the information that follows, a sample message alongwith an explanation of its meaning is provided for all 15messages.
The top message provides a real time display of the timeleft on the Load Timer. The Load Timer is a constantlyrecycling timer that the micro utilizes in conjunction with“rate control” and “temperature deviation from setpoint”to determine when loading should occur.
NOTE: This counter may appear to not count accordingto actual time. This is a result of the micro’s al-gorithm compensating for changing loading re-quirements.
The bottom message provides a real time display of thetime left on the Unload Timer. The Unload Timer is a con-stantly recycling timer that the micro utilizes in conjunc-tion with “rate control” and “temperature deviation fromsetpoint” to determine when unloading should occur.
NOTE: This timer may appear to not count according toactual time. This is a result of the micro’s algo-rithm compensating for changing unloading re-quirements.
116 YORK INTERNATIONAL
The top message indicates the difference (error) betweenleaving chilled liquid temperature and the TARGET tem-perature (Desired leaving chilled liquid temperature).
The bottom message indicates the rate of change of theleaving chilled liquid temperature in °F/minute. The (-)indicates a fall in temperature. No sign indicates a rise intemperature.
This message informs the operator which system is se-lected as the lead.
This message informs the operator that the micro hascommanded the auxiliary contacts (optional) for theevaporator water pump to close.
T E M P E R R O R 1 2 . 6 ° FT E M P R A T E – 0 . 9 ° F / M
L E A D S Y S T E M I SS Y S T E M N U M B E R 1
E V A P O R A T O R W A T E RP U M P S T A T U S O N
FIG. 33 – HISTORY PRINT-OUT
YORK INTERNATIONAL CORPORATIONMILLENNIUM SCREW CHILLER
ISN OPTION ENABLED
SOFTWARE VERSION W.04F.02.500.02
SAFETY SHUTDOWN NUMBER 1SHUTDOWN @11:07PM 01 JAN 96
CHILLER FAULT:VAC UNDER VOLTAGE SHUTDOWN
RETURN WATER TEMP 49.1 DEGFLEAVING WATER TEMP 49.3 DEGFLOW WATER CUTOUT 36.0 DEGFCOOLING RANGE 42.0 TO 44.0 DEGFTARGET TEMP 43.0 DEGFAMBIENT AIR TEMP 70.2 DEGFLOW AMBIENT CUTOUT 25.0 DEGFLOW PRESSURE CUTOUT 44 PSIGLEAD SYSTEM SYS 2LOCAL REMOTE SETTING: LOCAL
YORK INTERNATIONAL CORPORATIONMILLENNIUM SCREW CHILLER
ISN OPTION ENABLED
SOFTWARE VERSION W.04F.02.500.02
SAFETY SHUTDOWN NUMBER 3SHUTDOWN @ 2:25AM 01 JAN 96
CHILLER FAULT:VAC UNDER VOLTAGE SHUTDOWN
RETURN WATER TEMP 49.1 DEGFLEAVING WATER TEMP 42.9 DEGFLOW WATER CUTOUT 8.0 DEGFCOOLING RANGE 42.0 TO 44.0 DEGFTARGET TEMP 43.0 DEGFAMBIENT AIR TEMP 70.0 DEGFLOW AMBIENT CUTOUT 25.0 DEGFLOW PRESSURE CUTOUT 36 PSIGLEAD SYSTEM SYS 2LOCAL REMOTE SETTING: LOCAL
YORK INTERNATIONAL CORPORATIONMILLENNIUM SCREW CHILLER
ISN OPTION ENABLED
SOFTWARE VERSION W.04F.02.500.02
SAFETY SHUTDOWN NUMBER 2SHUTDOWN @10:39PM 01 JAN 96
SYS 1 HIGH OIL DIFF SHUTDOWNSYS 2 STATUS: NO FAULTS
RETURN WATER TEMP 49.1 DEGFLEAVING WATER TEMP 42.7 DEGFLOW WATER CUTOUT 8.0 DEGFCOOLING RANGE 42.0 TO 44.0 DEGFTARGET TEMP 43.0 DEGFAMBIENT AIR TEMP 70.2 DEGFLOW AMBIENT CUTOUT 25.0 DEGFLOW PRESSURE CUTOUT 36 PSIGLEAD SYSTEM SYS 1LOCAL REMOTE SETTING: LOCAL
This message informs the operator that the micro sensesthe outdoor ambient temperature is below 40°F and iscommanding the Evaporator Heater to turn on. Onceturned on, the heater will turn off at 45°F.
This message displays the accumulated Run Time onSYS 1 since the last start.
This time is recorded in Days (D), Hours (H), Minutes(M), and Seconds (S).
This message informs the operator that the SYS 1 Liq-uid Line Solenoid is “OFF” (De-energized/Closed) or “ON”(Energized/Open).
This message informs the operator that the micro is or isnot activating the liquid injection valve for SYS 1 for oilcooling.
This message informs the operator of the number of for-ward running pairs of condenser fans on SYS 1.
This message informs the operator whether the pair ofreversing condenser fans are running on SYS 1.
This message displays the accumulated Run Time onSYS 2 since the last start.
This time is recorded in Days (D), Hours (H), Minutes(M), and Seconds (S).
This message informs the operator that the SYS 2 Liq-uid Line Solenoid is “OFF” (De-energized/Closed) or “ON”(Energized/Open).
This message informs the operator that the micro is or isnot activating the liquid injection valve for SYS 2 for oilcooling.
This message informs the operator of the number of for-ward running pairs of condenser fans on SYS 2.
This message informs the operator whether the pair ofreversing fans are running on SYS 2.
History
The HISTORY key also allows the user to scroll throughthe SAFETY SHUTDOWN display information relatingto the last 9 Safety Shutdowns which occurred. Informa-tion contained in the micro’s SAFETY SHUTDOWN buff-ers is very important when attempting to troubleshoot asystem problem. This data reflects system conditions atthe instant the fault occurred.
Information is stored in the SAFETY SHUTDOWN buff-ers on every fault regardless of whether the fault causeda Lockout to occur. The stored information is also notaffected by power failures (long term internal battery back-up is built into the printed circuit board) or manual reset-ting of a fault lock-out.
When the HISTORY key is pressed, the following mes-sage will appear:
The operator must select which of the last three SAFETYSHUTDOWN’s is desired. When deciding this, keep inmind that SAFETY SHUTDOWN No. 1 is always the mostrecent fault. As new fault information is stored, it is as-signed as No. 1, No. 1 is assigned to No. 2, No. 2 isassigned to No. 3, up to No. 9, and information storedpreviously as No. 9 is discarded.
To select a SAFETY SHUTDOWN, simply press a “1”,“2”, “3”, etc. key and press ENTER. Repetitively press-ing the ENTER key will allow the operator to scroll throughthe information available in the SAFETY SHUTDOWNbuffer.
E V A P O R A T O R H E A T E RS T A T U S O F F
S Y S 1 R U N T I M E0 - 3 - 4 8 - 1 7 D - H - M - S
S Y S 1 L I Q U I D L I N ES O L E N O I D S T A T U S O N
S Y S 1 L I Q U I DI N J E C T I O N V A L V E O N
S Y S 1 F O R W A R D F A N SS T A T U S 2
S Y S 1 R E V E R S E F A NS T A T U S O F F
S Y S 2 R U N T I M E1 - 1 2 - 6 - 5 D - H - M - S
S Y S 2 L I Q U I D L I N ES O L E N O I D S T A T U S O N
S Y S 2 L I Q U I DI N J E C T I O N V A L V E O F F
S Y S 2 F O R W A R D F A N SS T A T U S O F F
S Y S 2 R E V E R S E F A NS T A T U S O F F
HISTORY
D I S P L A Y S A F E T Y S H U T -D O W N N O . 1 ( 1 T O 9 )
118 YORK INTERNATIONAL
In the information that follows, a sample message alongwith an explanation is provided for all available messages:
This message informs the operator of the time and dateof the fault.
This message informs the operator of the nature of thefault which occurred.
This message indicates the Return Water Temperature atthe time of the fault.
This message indicates the Leaving Water Temperatureat the time of fault.
This display shows the Low Water Cut-out (Leaving) whichwas programmed at the time of the fault.
This message shows the Cooling Range (CONTROLRANGE, CR) which was programmed at the time of thefault.
This display shows the TARGET Temperature which wasprogrammed at the time of the fault.
This message indicates the Outdoor Ambient Air Tem-perature at the time of the fault.
This display shows the Low Ambient Cut-out programmedat the time of the fault.
This display shows the Low Suction Pressure Cut-outprogrammed at the time of the fault.
This message indicates which system was in the lead atthe time of the fault.
This message shows whether remote or local communi-cations has been selected. “LOCAL” mode will allow anISN or an RCC option panel to receive chiller data fromthe chiller through the RS-485 port, but not change pro-grammed values remotely. REMOTE mode will allow anISN or an RCC option panel to receive chiller data andchange programmable values remotely.
This message indicates whether Compressor 1 was ONor OFF at the time of the fault.
This message shows the Run Time logged on SYS 1,since the last start, in Days (D), Hours (H), Minutes (M),and Seconds (S).
This message indicates SYS 1 % FLA and Average MotorCurrent at the time of the fault.
S H U T D O W N O C C U R R E D5: 5 9 A M 2 9 N O V 9 5
S Y S 1 H I G H O I L D I F FS Y S 2 N O F A U L T S
R E T U R N W A T E R T E M P4 9 . 3 ° F
L E A V I N G W A T E R T E M P4 4 . 6 ° F
L O W W A T E R C U T O U T3 6 . 0 ° F
C O O L I N G R A N G E4 2 . 0 T O 4 6 . 0 ° F
T A R G E T T E M P4 4 . 0 ° F
A M B I E N T A I R T E M P7 7 . 6 ° F
L O W A M B I E N T C U T O U T0 . 0 ° F
L O W P R E S S U R E C U T O U T4 4 P S I G
L E A D S Y S T E MS Y S 1
L O C A L R E M O T E S E T T I N GR E M O T E
S Y S 1 C O M P R E S S O RO N
S Y S 1 R U N T I M E0 - 0 - 2 - 4 7 D - H - M - S
S Y S 1 A V G M O T O R A M P S1 0 0 % F L A 9 0 A M P S
FORM 201.10-NM1
119YORK INTERNATIONAL
This message shows SYS 1 % FLA Motor Current inPhase L1 at the time of the fault.
This message shows SYS 1 % FLA Motor Current inPhase L2 at the time of the fault.
This message shows SYS 1 % FLA Motor Current inPhase L3 at the time of the fault.
This display shows the Oil Pressure of SYS 1 at thetime of the fault.
This display shows the Suction Pressure of SYS 1 atthe time of the fault.
This message indicates the Saturated Suction Tempera-ture of SYS 1 at the time of the fault.
This message indicates SYS 1 Suction Line Tempera-ture at the time of the fault.
This message indicates SYS 1 superheat at the time ofthe fault.
This message indicates SYS 1 Discharge Pressure atthe time of the fault.
This message indicates SYS 1 Saturated Discharge Tem-perature at the time of the fault.
This message indicates SYS 1 Discharge Gas Tempera-ture in the oil separator at the time of the fault.
This display shows the Oil Temperature of SYS 1 at thetime of the fault.
This message indicates that the Liquid Injection Sole-noid Valve of SYS 1 was either energized (ON) or de-energized (OFF) at the time of the fault.
This display indicates the number of pairs of fans SYS 1which were running in the forward direction at the time ofthe fault.
This message indicates whether a pair of fans on SYS 1were running in the reverse direction at the time of thefault.
This display informs the operator whether SYS 1 liquidline solenoid valve was energized (ON) or de-energized(OFF) at the time of the fault.
S Y S 1 D S C H P R E S S2 2 7 P S I G
S Y S 1 P H A S E L 29 9 % F L A 8 9 A M P S
S Y S 1 P H A S E L 39 9 % F L A 8 9 A M P S
S Y S 1 O I L P R E S S U R E1 2 P S I D
S Y S 1 S U C T I O N P R E S S5 9 P S I G
S Y S 1 S A T S U C T T E M P3 4 . 1 ° F
S Y S 1 S U C T I O N T E M P4 4 . 1 ° F
S Y S 1 S U P E R H E A T1 2 . 5 ° F
S Y S 1 P H A S E L 19 9 % F L A 8 9 A M P S
S Y S 1 S A T D S C H T E M P6 5 . 2 ° F
S Y S 1 D I S C H A R G E T E M P1 8 7 . 2 ° F
S Y S 1 O I L T E M P1 4 7 . 8 ° F
S Y S 1 L I Q U I DI N J E C T I O N V A L V E O F F
S Y S 1 F O R W A R D F A N S2
S Y S 1 R E V E R S E F A N SO F F
S Y S 1 L I Q L I N EO N
120 YORK INTERNATIONAL
This message informs the operator if SYS 1 Run Per-missive (flow switch, remote START/STOP) was in theRUN mode (ON/closed) or “STOP” mode (OFF/open).
This message indicates whether Compressor 2 was ONor OFF at the time of the fault.
This message shows the Run Time logged on SYS 2,since the last start, in Days (D), Hours (H), Minutes (M),and Seconds (S).
This message indicates SYS 2 % FLA and Average Mo-tor Current at the time of the fault.
This message shows SYS 2 % FLA Motor Current inPhase L1 at the time of the fault.
This message shows SYS 2 % FLA Motor Current inPhase L2 at the time of the fault.
This message shows SYS 2 % FLA Motor Current inPhase L3 at the time of the fault.
This display shows the Oil Pressure of SYS 2 at thetime of the fault.
This display shows the Suction Pressure of SYS 2 atthe time of the fault.
This message indicates the Saturated Suction Tempera-ture of SYS 2 at the time of the fault.
This message indicates SYS 2 Suction Line Tempera-ture at the time of the fault.
This message indicates SYS 2 superheat at the time ofthe fault.
This message indicates SYS 2 Discharge Pressure atthe time of the fault.
This message indicates SYS 2 Saturated Discharge Tem-perature at the time of the fault.
This message indicates SYS 2 Discharge Gas Tempera-ture in the oil separator at the time of the fault.
This display shows the Oil Temperature of SYS 2 at timeof the fault.
S Y S 1 R U N P E R M I S S I V EO N
S Y S 2 C O M P R E S S O RO N
S Y S 2 R U N T I M E0 - 0 - 2 - 4 7 D - H - M - S
S Y S 2 A V G M O T O R A M P S1 0 0 % F L A 9 0 A M P S
S Y S 2 P H A S E L 19 9 % F L A 8 9 A M P S
S Y S 2 P H A S E L 29 9 % F L A 8 9 A M P S
S Y S 2 P H A S E L 39 9 % F L A 8 9 A M P S
S Y S 2 O I L P R E S S U R E1 0 P S I D
S Y S 2 S U C T I O N P R E S S5 9 P S I G
S Y S 2 S A T S U C T T E M P3 4 . 3 ° F
S Y S 2 S U C T I O N T E M P4 4 . 1 ° F
S Y S 2 S U P E R H E A T1 2 . 5 ° F
S Y S 2 D S C H P R E S S2 2 7 P S I G
S Y S 2 S A T D S C H T E M P6 5 . 2 ° F
S Y S 2 D I S C H A R G E T E M P1 8 7 . 2 ° F
S YS 2 O I L T E M P1 4 7 . 8 ° F
FORM 201.10-NM1
121YORK INTERNATIONAL
This message indicates that the Liquid Injection Sole-noid Valve of SYS 2 was either energized (ON) or de-energized (OFF) at the time of the fault.
This display indicates the number of pairs of fans onSYS 2 which were running in the forward direction at thetime of the fault.
This message indicates whether a pair of fans on SYS 2were running in the reverse direction at the time of thefault.
S Y S 2 L I Q U I DI N J E C T I O N V A L V E O F F
S Y S 2 F O R W A R D F A N SO N
S Y S 2 R E V E R S E F A N SO F F
This display informs the operator whether SYS 2 liquidline solenoid valve was energized (ON) or de-energized(OFF) at the time of the fault.
This message informs the operator if SYS 1 Run Per-missive (flow switch, remote START/STOP) was in the“RUN” mode (ON/closed) or “STOP” mode (OFF/open).
S Y S 2 L I Q L I N EO N
S Y S 2 R U N P E R M I S S I V EO N
122 YORK INTERNATIONAL
CLOCK KEYS
GENERAL
The CLOCK is an internal system feature that allows themicroprocessor to continuously monitor the time of theday. The micro will display the actual time as well as theday of the week and the date on the control panel dis-play, if programmed. The internal clock allows the micro-processor to provide an internal automatic time clockfeature for starting and stopping the chiller for each indi-vidual day of the week. Also provided is a HOLIDAY fea-ture which allows special start / stop programming fordesignated holidays.
The internal clock and schedule programming eliminatesthe need for an external time clock. Automatic chillerstart and stop will occur according to the programmedschedule.
If the user decides not to utilize the schedule feature,the SET SCHEDULE / HOLIDAY can be programmed torun the chiller on demand as long as the UNIT and SYSswitches are ON.
Typical display messages will be shown which apply toeach key.
PROGRAMMING THE DAY, SET TIME & THE DATE
Set Time
A message showing the day, time and date will be dis-played when the SET TIME key is pressed.
When the display appears, the cursor will be below thefirst digit of the time. Press the ADVANCE DAY key untilthe proper day appears. Key in the time (hour and minute).Be sure to key in a “0” before the other digits for timesbefore 10 o’clock. i.e. 08:31.
After the time is keyed in, the cursor will advance to theAM/PM designation. To reprogram, press the AM/PM key.When the key is pressed, the display will change to theopposite time period.
NOTE: The AM/PM key can be pressed once. If an er-ror is made, press the CANCEL key and beginagain.
T O D A Y I S M O N 1 1 : 1 2 A M1 9 F E B 9 7
FIG. 29 – CLOCK KEYS
28164A
SETTIME
CLOCKKEYS
FORM 201.10-NM1
123YORK INTERNATIONAL
After a change is made to the AM/PM, the cursor willautomatically move to the STOP time. If no change ismade to the AM/PM, begin keying in the first digit of thedesired stop time. The cursor will automatically move tothe STOP time, putting in the number which was pressedas the first digit. Key in the STOP TIME with the appro-priate AM/PM and press the ENTER key.
When the ENTER key is pressed, the new START / STOPtime is entered and the display will scroll to the next day.If an unacceptable time is entered, the following mes-sage will be displayed.
CAUTION: Any Start / Stop times entered for Mondaywill automatically be programmed in for thefollowing days of the week. Be aware of thisanytime the SCHEDULE is changed.
To scroll through the days to view times pro-grammed, use the ADVANCE DAY key, notthe ENTER key. This will assure that afterviewing MONDAY, the ENTER key is notpressed which will change times pro-grammed for the remainder of the week.
If the chiller is not cycled by the DAILY SCHEDULE, butis required to run whenever the system switches are on,all 00.00’s should be programmed into the daily sched-ule. This can be done manually for each day or by press-ing CANCEL and ENTER when the MONDAY START /STOP schedule appears.
NOTE: This will have no effect on the holiday schedule.
If the chiller is not required to run on a given day, theSTART time should be programmed for 00:00 AM andthe STOP time should be programmed for 12:00 AM.
Continue to program each day as needed. After SUN hasbeen entered, the HOLIDAY message will be displayed.
The Holiday (HOL) START / STOP allows the user todesignate a specific day(s) for special requirements. Thisis provided so that a day(s) needing special start / stoprequirements can be programmed without disturbing thenormal working schedule. The start / stop times for theHoliday schedule are programmed just as any other day.
NOTE: Only one start / stop time can be programmedwhich will apply to each of the days selected asa HOLIDAY.
After programming AM/PM or if no change is required,begin keying in the required date (the cursor will auto-matically skip to the first digit of the date (day) when a“number key” is pressed and the number will be placed inthe first digit of the day. The sequence of the display isday, month, and year. Two digits must always be enteredfor both the day and the year. Be sure to key in a “0” fordays 1-9 ie: 02 FEB 97.
Finish keying in the day. The cursor will automaticallyskip to the first digit of the year. Key in the year as re-quired. Finally, change the month as needed by repeti-tively pressing the “+/-” key until the proper month ap-pears. Once the desired information is keyed in, it maybe stored into memory by pressing the ENTER key.
The micro will accept any valid time or date. If an out ofrange value is entered, the micro will display the follow-ing message for 3 seconds before it reverts back to theSET TIME display message to let the user know thatanother try at reprogramming is necessary.
NOTE: The displayed time will not update when the SETTIME display is first pressed. The reason is thatthe micro is waiting for the time to be pro-grammed. To see the time update, press the SETTIME key a second time. The cursor will disap-pear and the “live” clock will be displayed.
PROGRAMMING THE DAILY START / STOP AND HOLI-DAY SCHEDULE
Set Schedule / Holiday
Messages showing the start / stop schedule of each dayof the week as well as the holiday start / stop schedulecan be displayed after the SET SCHEDULE / HOLIDAYkey is pressed. The display can be scrolled through day-by-day simply by repetitively pressing the ENTER orADVANCE DAY key. A typical daily schedule display isshown below:
To reprogram any of the daily schedules, key in the newSTART time. To change the AM/PM associated with theSTART time, press the AM/PM key. This will change theAM/PM message to the opposite time period. The AM/PM key can only be pressed once. If an error is made,press CANCEL and begin reprogramming again.
O U T O F R A N G ET R Y A G A I N !
M O N S T A R T = 0 6 : 0 0 A MS T O P = 0 5 : 3 0 P M
O U T O F R A N G ET R Y A G A I N !
H O L S T A R T = 0 8 : 3 0 A MS T O P = 1 2 : 0 0 P M
SET SCHEDULE/HOLIDAY
124 YORK INTERNATIONAL
After the ENTER key is pressed, a new message will bedisplayed to designate which days of the week are holi-days.
In the above sample display, an * designates Tuesday asa holiday.
When the display appears, the cursor will first stop be-hind Sunday. To designate a day as a holiday, press the“ * ” key. If a day is not to be a holiday, press the “0” key.Whenever the “ * ” or the “0” keys are pressed, the cursorwill advance to the next day. After all the holiday daysare programmed, press ENTER to store the new datainto memory. The display will then advance to the begin-ning of the Daily Schedule (MON).
The Holiday Schedule is only executed once by the mi-cro before it is erased from memory. This is done be-cause in most cases a special Holiday Schedule is onlynecessary once in a several month period. It also elimi-nates the need for operator intervention to erase the sched-ule after the holiday passes.
If an error is made while programming or a change isrequired, press CANCEL. This will clear the programmed(*) “Holiday” days. The schedule can then be repro-grammed.
The “0” key will not cancel out a “ * ” and cannot be usedfor correcting a programming error.
Manual Override
When the “MANUAL OVERRIDE” key is pressed, the DailySchedule programmed into the chiller will be ignored andthe chiller will start up when water temperature allows,unit switches permits, remote cycling device permits,and system switches permit.
Normally this key is not used unless an emergency forcesthe chiller to require operation during a period where theprogrammed Daily Schedule is calling for the chiller tobe OFF (Daily Schedule Shutdown).
Once activated, MANUAL OVERRIDE is only active fora period of 30 minutes. It is for servicing only and isdesignated so that if selected and operated unattended,the microprocessor will automatically return to the DailySchedule.
S M T * W T F SH O L I D A Y N O T E D B Y *
MANUALOVERRIDE
FORM 201.10-NM1
125YORK INTERNATIONAL
UNIT ON/OFF SWITCH, SYSTEM SWITCHESAND OTHER CONTROLS
UNIT ON/OFF SWITCH
A master UNIT ON/OFF switch is located on the keypad.This rocker switch allows the operator to turn the entirechiller OFF if desired. The switch must be placed in theON position for the chiller to operate.
Whenever the switch is placed in the OFF position, aSTATUS display indicating the condition will bedisplayed. This message is shown below:
SYSTEM SWITCHES
SYSTEM SWITCHES 1 - 4 are located on theMicroprocessor Board (See Fig. 36). These allow theoperator to selectively turn a given system on or off asdesired. On a 2-system chiller, switches 3 & 4 should beOFF. The System Switch for a designated system mustbe ON (Switch to the right) for the system to operate.
Whenever a switch is placed in the OFF position, aSTATUS message is displayed indicating that the
system does not have a Run Permissive signal. Anexample of this message is shown below:
NOTE: This message will not appear if the Anti-recycleor Anti-coincident timers are in effect and arebeing displayed.
ALARM CONTACTS (ANNUNCIATION ALARM)
“Dry” contacts connected to terminals 23 and 24 of TB1(Fig. 37) are supplied which will transition to function asa warning whenever a fault lock-out occurs on any systemor if power is lost to the control panel. The dry contacts arenormally open (N.O.) and will close when control power isapplied to the panel, if no fault conditions are present.When a fault occurs or power is lost, the contacts open.
A 28VDC or 120VAC external alarm circuit (supplied byothers) may be wired into the YORK supplied alarmcontacts. Any inductive load devices (relay or contactor)supplied by the user, which are connected to the dry alarm
FIG. 35 – UNIT ON/OFF SWITCH
28164A
U N I T S W I T C H I S I NT H E O F F P O S I T I O N
S Y S 1 S Y S S W I T C H O F FS Y S 2 S Y S S W I T C H O F F
UNITON / OFFSWITCH
126 YORK INTERNATIONAL
contacts, MUST be suppressed at the load. (Connect thesuppressor across the coil of the relay or contactor.) UseYORK P/N 031-00808-000 suppressor (Typically, severalare supplied loose with the panel). Failure to installsuppressors will result in nuisance faults and possibledamage to the chiller.
CAUTION: If the alarm circuit is applied in an applicationused for critical duty (such as process dutyor cooling other critical equipment) and thealarm circuit should fail to function, YORKwill not be liable for damages.
LEAD/LAG COMPRESSOR SELECTION
The chiller may be set up for AUTO or MANUAL Lead/Lag.This is accomplished by properly configuring the S1 DipSwitches on the Microprocessor Board. Details forconfiguring the switches are discussed in the “DisplayKey” Section under OPTIONS key.
When AUTO Lead/Lag is utilized, the micro attempts tobalance run time between the two compressors. Anumber of conditions can occur which will prevent this
FIG. 36 – LOCATION OF THE MICROPROCESSOR BOARD AND SYSTEM SWITCHES
27962A 26001A
LD01099
FIG. 37 – ALARM CONTACT CONNECTIONLOCATION TO TB1
TB1
MAIN ELECTRICALCONTROL PANEL
MICROPROCESSOR BOARD SYSTEM SWITCHES 1-4ON MICROPROCESSOR BOARD
FORM 201.10-NM1
127YORK INTERNATIONAL
from happening. Factors determining lead/lag selectionand the resulting lead/lag determination are discussedbelow:
1. The micro automatically defaults the lead to SYS 1 andthe lag to SYS 2 if both compressors are ready to start(Anti-recycle Timers timed out) and compressors haveequal run time.
2. If both compressors are ready to start (Anti-recycleTimers timed out), the compressor with the lowest runhours will start first.
3. If both compressors are waiting to start (Anti-recycleTimers are not timed out), the micro will assign the leadto the compressor with the shortest anti-recycle timein an effort to provide cooling quickly.
4. If the lead compressor is locked out, faulted andwaiting to restart, SYS switch on the micro board is off,or a run permissive is keeping an individual systemfrom running, the lag compressor is swapped to thelead. This is true regardless of whether the lagcompressor is on or off.
If MANUAL Lead/Lag is selected, an external “dry”contact (switch) must be wired into the chiller. Thiscontact is field supplied. With the contact open, SYS 1 isplaced in the lead. When the contact is closed, SYS 2 willbe lead system.
MANUAL Lead/Lag selection will be automatically over-ridden by the micro to allow the lag compressor toautomatically become the lead anytime the selected leadcompressor shuts down due to a lock-out, lead systemfaults and is waiting to restart, lead system switch on themicro board is in the OFF position, or if a run permissiveis keeping the lead of the system off. Automaticswitchover in the MANUAL mode is provided to try tomaintain chilled liquid temperature as close to setpoint aspossible.
The “dry” contact for manual lead/lag selection is wiredinto terminals 13 and 19 of the TB3 Terminal Block. Thelocation of these contacts is shown in Fig. 38.
MEMORY BATTERY BACK-UP
The Microprocessor Board contains a Real Time Clock(RTC) I. C. Chip with an internal battery back-up. Thisbattery back-up assures that any programmed values(setpoints, etc.), clock, all fault information, andaccumulated information such as starts/run time, etc.stored in the RTC memory is not lost when a power failureoccurs, regardless of the length of the power loss.
The battery is a 10 year lithium type. The life of the batterywill depend upon whether the Real Time Clock’s internal
clock circuit is energized. With the clock OFF, a rated lifeof approximately 10 years can be expected. With theclock ON, approximately 5 years.
The clock is turned ON and OFF by a jumper on theMicroprocessor Board. While a chiller is operating, theclock must be ON. Otherwise the internal clock on themicroprocessor will not be active and the micro cannotkeep track of time, although all other functions will operatenormally. Failure to turn the Clock ON could result in thechiller not starting due to the time frozen on the clockfalling outside the START/STOP time window that isprogrammed in the DAILY SCHEDULE.
If the chiller is shut down for extended periods of months,it may be desirable to disable the clock to save batterylife. The clock can then be reactivated and reprogrammedwhen the chiller is returned to service.
NOTE: ALL PROGRAMMED VALUES AND STOREDDATA, OTHER THAN THE INTERNAL CLOCKTIME-KEEPING, WILL BE MAINTAINED INMEMORY REGARDLESS OF WHETHER THECLOCK IS ON OR OFF AND REGARDLESS OFTHE LENGTH OF THE POWER FAILURE.
To disable the clock, place the jumper (Fig. 39) in the OFFposition. To activate it, place the jumper in the ONposition.
FIG. 38 – TB3 LOCATION MANUAL LEAD LAG
27962ATB3
128 YORK INTERNATIONAL
On power-up the microprocessor will check the Real TimeClock (RTC Chip) battery to assure that the internalbattery is still operational. This is accomplished byperforming an RTC RAM location check. As long as thebattery checks out, the micro will continue on withbusiness without interruption.
If a check is made and the battery has failed, themicroprocessor will not allow the chiller to run and thefollowing STATUS message will appear:
Under low battery conditions, the only way to run thechiller is to press the “MANUAL OVERRIDE” key. The“MANUAL OVERRIDE” key will function differently thanit does in service situations where it overrides the dailyschedule for only 30 minutes. In a low battery condition,the “MANUAL OVERRIDE” key will zero out the dailyschedule to allow unlimited operation regardless of thetime on the internal clock. Default values will also beloaded into memory for all setpoints and cut-outs. Thesemay require reprogramming to assure they meet thechiller operating requirements for operation board 30minutes. In addition, the low battery message which isdisplayed for this condition will disappear.
NOTE: If a power failure should again occur, the aboveprocess will again need to be repeated to bringthe chiller back on line.
In the unlikely event the low battery message should everappear, it will require the RTC Chip U13 on theMicroprocessor Board (Fig. 39) to be replaced. Careshould be taken to assure that the chip is properlyinstalled. Pin 1 (dimple in the top of the chip) must beoriented as shown in Fig. 39. The part number of the RTCChip is 031-00955-000.
COMPRESSOR HEATER
The Compressor Heater in each compressor will be ONfor the first five minutes after the compressor is shutdown. Then the heater is controlled by dischargetemperature. If the heater is ON and the dischargetemperature rises above 170°F will shut off. If the heateris OFF and the discharge temperature falls below 100°F,it will turn ON. The heater is controlled by themicroprocessor.
The purpose of the heater is to prevent the migration ofrefrigerant into the compressor during shutdown, assuringproper lubrication of the compressor on start-up.
Anytime power is removed from the chiller for more thanan hour, 115VAC control power should be reapplied toallow the compressor heaters to remain on for 24 hoursprior to restart.
EVAPORATOR HEATER
The evaporator heater prevents water standing in theevaporator from, freezing. Whenever the outdoor ambienttemperature drops below 40°F, the microprocessor willturn the evaporator heaters ON. If temperature risesabove 45°F, the heater will be turned off.
METRIC DISPLAY
The control panel is capable of providing displays ofpressures and temperatures in metric values.Temperatures will be displayed in °C and pressures inBars.
A Metric to English temperature conversion table isprovided on the back cover of this manual. Pressure canbe converted from PSIG to Bars using the formula 1 Bar= 14.504 PSIG.
To obtain displays in Metric, Switch 5 Dip switch S1 on theMicroprocessor Board must be placed in the closed (on)position (Page 80). The positioning of this switch can beverified by pushing the OPTIONS key and verifying that“SI UNITS READOUT” is programmed (Page 79).
FIG. 39 – CLOCK JUMPER
26001A
! ! W A R N I N G ! !! ! L O W B A T T E R Y ! !
CLOCK JUMPER
PIN 1
RTC
FORM 201.10-NM1
129YORK INTERNATIONAL
EMS/BAS CONTROLS
The microprocessor is capable of REMOTE START/STOP, REMOTE SETPOINT RESET, and REMOTECURENT RESET. These functions can be easily utilizedby connecting user supplied “dry” contacts to theMicroprocessor Board.
REMOTE START/STOP BY A CYCLING DEVICE ORTIME CLOCK
Remote START/STOP is accomplished by connecting atime clock or other “dry” contact in series with the flowswitch on terminals 13 & 14 of TB4. See Fig. 19 for thelocation of the terminals. The contact must be closed toallow the chiller to run. Any time the contact opens, thechiller will shut down and the following status messagewill be displayed.
Wiring from these contact should not exceed 25 ft. andshould be run in grounded conduit that does not carry anywiring other than control wiring. Additionally, if aninductive device (relay, contactor) is supplying thesecontacts, the coil of the device must be suppressed witha user supplied YORK P/N 031-00808 suppressor.
REMOTE SETPOINT RESET(REMOTE RESET TEMP RANGE)
Remote Setpoint Reset allows resetting the setpointupward from the programmed value in memory. This isaccomplished by connecting a “dry” contact betweenterminals 13 & 17 of TB4. See Fig. 19 for the location ofthese terminals. Closing the contact for a defined periodof time allows reset of the setpoint upward by up to 40°Fabove the setpoint programmed in memory.
The maximum desired reset must be programmed intomemory and can be a value of 02 to 40°F. This value willvary according to the user’s requirements. To program thereset, press the REMOTE SETPOINT TEMP RANGEkey. The following message will appear.
The display will indicate the REM SETPOINT which isalways equal to the chilled liquid setpoint programmed bythe CHILLED LIQUID TEMP/RANGE key plus the offsetfrom the remote reset signal. The display will also showthe REM RANGE which is the same as the maximumreset required by the application. Key in the maximum
reset required for the application after REM RANGE andpress the ENTER Key to store the new value in memory.
Once the maximum reset is programmed, it will require acontact closure of 21 seconds to achieve the maximumreset. Closure for less than 21 seconds will provide asmaller reset. For noise immunity, the micro will ignoreclosures of less than 1 second.
To compute the offset for a given contact closure, use theformulas below:
1. Programmed max. reset = Reset per sec.20 seconds
2. (Time Closed-1) Reset per sec. = Reset
Example:
Programmed max reset - 30°; Time Closed = 9 sec.
1. 30° = 1.5° per sec.20 sec.
2. (9 sec. -1 sec.) 1.5° per sec. = 12° = Reset
To determine the new setpoints, add the reset to thesetpoint programmed into memory. In the exampleabove, if the programmed setpoint = 44°F, the newsetpoint after the 9 second contact closure would be 44°F+ 12°F = 56°F. This new setpoint can be viewed on thedisplay by pressing the REMOTE RESET TEMP/RANGE key.
To maintain a given offset, the micro must be refreshedevery 30 seconds - 30 minutes with a contact closure ofthe required time period. It will not accept a refresh soonerthan 30 seconds after the end of the last PWM signal, butmust be refreshed before a period of 30 minutes expiresfrom the end of the last PWM signal.
After 30 minutes, if no refresh is provided, the setpoint willchange back to its original value. A refresh is nothingmore than a contact closure for the period required for thedesired offset.
NOTE: After an offset signal, the new REM SETPOINTmay be viewed on the REMOTE RESET TEMPRANGE display. However, if this display is beingviewed when the reset pulse occurs, the setpointwill not change on the display. To view the newoffset, first press any other display key on thekeypad and then press the REMOTE RESETTEMP RANGE key. The new setpoint will thenappear.
Wiring from these contacts should not exceed 25 ft. andshould be run in grounded conduit that does not carry anywiring other than control wiring. Additionally, if an
S Y S # 1 N O R U N P E R MS Y S # 2 N O R U N P E R M
R E M S E T P O I N T = 2 0 . 0R E M R A N G E = 4 0 ° F
130 YORK INTERNATIONAL
inductive device (relay, contactor is supplying thesecontacts, the coil of the device must be suppressed witha user supplied YORK P/N 031-00808 suppressor.
NOTE: REMOTE SETPOINT RESET will not operatewhen a Remote Control Center Option Kit isconnected to the Micropanel. The RemoteControl Center will always determine thesetpoint.
REMOTE % CURRENT LIMIT SETPOINT RESET
Remote Current Reset allows resetting the % CurrentLimit downward from the programmed value in memory.This can be use for demand limiting, etc. Current Resetaccomplished by connecting a “dry” contact betweenterminals 13 & 16. See Fig. 19 for the location of theseterminals. Closing the contact for a defined period of timeallows reset of the % Current Limit downward.
Contact closure of 1 - 18 sec will allow % Current Limitingto be adjusted downward from 115% by a maximum of85%. This will allow current limiting to a minimum valueof 30% FLA (115%-85% = 30%).
The Current Limiting will operate independently of theProgrammable Current Limiting (See Average CurrentUnload, Page 90). The micro will always look at the twoCurrent Limit Setpointsand choose the lower of the two asthe controlling value, whenever Remote Current Limitingis utilized.
Contact closures of less than 1 second will be ignored. Aclosure of 18 seconds is the maximum allowable closureand provides a Current Limit reduction of 85%.
The required contact closure can be computed byfollowing the 4 steps beow:
1. Choose the % FLA desired for the Current Limit % FLA,after offset.
2. Subtract the desired Current Limit % FLA from 115%to calculate the required offset %. See the formulabelow:
Offset % = 115% - Desired Current Limit % FLA
3. Convert the offset % to a decimal equivalent bydividing by 100%. This will compute the offset. See theformula below:
Offset = Offset %100%
4. Calculate the Pulse Width (PW) in seconds required byutilizing the following formula:
PW seconds = (Offset x 20) + 1
Show below is an example where 75% FLA is DesiredCurrent Limit %:
1. 75% is the chosen Current Limit % FLA after offset.
2. Offset % = 115% - 75% = 40%
3. Offset = 40% = .40100%
4. PW = (.40 x 20) + 1 = 9 seconds
NOTE: The lowest Current Limit % FLA as dictated bythe Remote Current Limit Reset (EMS CurrentLimiting), or ISN Current Limiting.
Whenever current is being limited by a remote resetsignal, the following STATUS message will appear:
Wiring from remote contacts should not exceed 25 ft. andshould be run in grounded conduit that does not carry anywiring other than control wiring. Additionally, if aninductive relay contactor is supplying these contacts, thecoil of the device must be suppressed with a user suppliedYORK P/N 031-00808 suppressor.
NOTE: Remote EMS Reset will not operate when aRemote Control Center Option Kit is connectedto the micropanel. The Remote Control Centerwill always determine the setpoint.
To maintain a given offset, the micro must be refreshedevery 30 seconds - 30 minutes with a contact closure ofthe required time period. It will not accept a refresh soonerthan 30 seconds after the end of the last PWM signal, butmust be refreshed before a period of 30 minutes expiresfrom the end of the last PWM signal.
After 30 minutes, if no refresh is provided, the setpoint willchange back to its original value. A refresh is nothingmore than a contact closure for the period required for thedesired offset.
NOTE: After an offset signal, the new REM SETPOINTmay be viewed on the REMOTE EMS LIMITINGDISPLAY. However, if this display is beingviewed when the reset pulse occurs, the setpointwill not change on the display. To view the newoffset, first press any other display key on thekeypad and then press the REMOTE EMSLIMITING RANGE key. The new setpoint willthen appear.
S Y S 1 E M S L I M I T I N GS Y S 2 E M S L I M I T I N G
FORM 201.10-NM1
131YORK INTERNATIONAL
The standard efficiency chiller is equipped with 8 con-denser fans; 4 per system. Fan control from dischargepressure is standard. Fan start/stop pressures are pro-grammable in the PROGRAM Mode (page 93) under theFAN CONTROL DISCHARGE PRESSURE SETPOINTand FAN ON/OFF PRESS DIFF displays. Ambient tem-perature has no effect on fan cycling.
When discharge pressure reaches the programmedsetpoint, the first pair of fans on a respective systemstarts. After the first pair of fans are brought on in thereverse direction, discharge pressure must rise an addi-tional 20 PSIG above the setpoint before a second pairof fans will be brought on in the forward direction. Whenthis pair of fans starts, the reversing fans will turn off. Ifdischarge pressures rises 40 PSIG above the setpoint,a second pair of fans will start in the forward direction.This is the same pair of fans that originally ran in thereverse direction. The first pair of forward fans will alsocontinue to run.
The point at which each pair of fans cycles off is alsoprogrammable. This is accomplished in the PROGRAMMode when the FAN ON/OFF PRESS DIFF display ap-pears. The programmable “differential” establishes the
pressure at which each pair of fans turn off. The “differ-ential” is the amount the discharge pressure must dropbelow the pressure at which the fan turned on.
Locations of the fans and a table showing the operationis shown in Fig. 40.
FIG. 40 – YCAS 140 - 246 FAN LOCATION / OPERATION
LD01267
132 YORK INTERNATIONAL
YCAS 216X - 266X FAN CONTROL STRATEGY
The high efficiency chiller is equipped with 12 condenserfans; 6 per system. Fan control from discharge pressureis standard. Fan start/stop pressures are programmablein the PROGRAM Mode (page 93) under the FAN CON-TROL DISCHARGE PRESSURE SETPOINT and FANON/OFF PRESS DIFF displays. Ambient temperaturehas no effect on fan cycling.
When discharge pressure reaches the programmedsetpoint, the first trio of fans on a respective systemstarts. After the first trio of fans are brought on in thereverse direction, discharge pressure must rise an addi-tional 20 PSIG above the setpoint before a second trio offans will be brought on in the forward direction. When thistrio of fans starts, the reversing fans will turn off. If dis-charge pressures rises 40 PSIG above the setpoint, asecond trio of fans will start in the forward direction. Thisis the same trio of fans that originally ran in the reversedirection. The first trio of forward fans will also continueto run.
The point at which each trio of fans cycles off is alsoprogrammable. This is accomplished in the PROGRAMMode when the FAN ON/OFF PRESS DIFF display ap-pears. The programmable “differential” establishes thepressure at which each trio of fans turn off. The “differen-tial” is the amount the discharge pressure must drop be-low the pressure at which the fan turned on.
Locations of the fans and a table showing the operationis shown in Fig. 41.
FAN FAN RELAYPRESSURE
ON OFF1, 2 & 9 REV 9M, 10M & 21 M SETPOINT SETPOINT – DIFF.
CHECKING THE SYSTEM 24 HOURSPRIOR TO INITIAL START (No Power)
Unit Checks
q 1. Inspect the unit for shipping or installation dam-age.
q 2. Assure that all piping has been completed.
q 3. Check that the unit is properly charged and thatthere are no piping leaks.
q 4. Open each compressor suction service valve,discharge service valve, economizer servicevalve, liquid line stop valve, and oil line ball valves.
q 5. The compressor oil level should be maintainedso that an oil level is visible in either of the twooil separator sight glasses. In other words, oillevel should always be maintained, running or not,above the bottom of the lower sight glass andbelow the top of the upper sight glass.
NOTE: In actual operation, due to splashing, anoil level may be seen in both sight glasses.Run the compressor for a few minutes,shut the system down, and assure thereis an oil level showing in the bottom ortop sight glass with the compressor off.
If it is necessary to add oil, connect a YORK oilpump to the charging valve on the oil separator,but do not tighten the flare nut on the deliverytubing. With the bottom (suction end) of the pumpsubmerged in oil to avoid entrance of air, operatethe pump until oil drips from the flare nut joint,allowing the air to be expelled, and tighten theflare nut. Open the compressor oil charging valveand pump in oil until it reaches the proper levelas described above.
q 6. Assure water pumps are on. Check and adjustwater pump flow rate and pressure drop acrossthe cooler.
NOTE: Excessive flow may cause catastrophicdamage to the evaporator
q 7. Check the control panel to assure it is free offoreign material (wires, metal chips, etc.) .
q 8. Visually inspect wiring (power and control). Wir-ing MUST meet NEC and local codes. See Fig.20.
q 9. Check tightness of power wiring inside the powerpanel on both sides of the motor contactors andinside the motor terminal boxes.
q 10. Check for proper size fuses in main and controlcircuits.
q 11. Verify that field wiring matches the 3-phase powerrequirements of the compressor. See chiller name-plate (Page 4).
q 12. Assure 115VAC Control Power to TB1 has 30Aminimum capacity. See Fig. 20.
q 13. Be certain all water temp sensors are insertedcompletely in their respective wells and are coatedwith heat conductive compound.
q 14. Assure that evaporator TXV bulbs are strappedonto the suction lines at 4 or 8 o’clock positions.
q 15. Assure that 5 ton TXV bulbs are inserted fullyinto the wells in the compressors and that thebulbs are coated with heat conductive compound.
q 16. Assure that the 15 ton economizer TXV bulbsare strapped onto the compressor economizersupply lines at 4 or 8 o’clock positions.
134 YORK INTERNATIONAL
PANEL CHECKS(Power On – Both System Switches “OFF”)
q 1. Apply 3 phase power and verify its value (SeeFig. 20).
q 2. Apply 115VAC and verify its value on the termi-nal block in the lower left of the Power Panel.Make the measurement between terminals 5 and2 of TB1 (See Fig. 20.). The voltage should be115VAC +/- 10%.
q 3. Assure the heaters on each compressor are on.Allow the compressor heaters to remain on a mini-mum of 24 hours before startup. This is impor-tant to assure that no refrigerant is in the com-pressor oil at start-up!
q 4. Program the dip switches on the microprocessorboard for the desired operating requirements. SeePage 80. OPEN = Left side of switch pushed down.CLOSED = Right side of switch pushed down.
SW# OPEN CLOSED1 Water Brine
2 Std Amb Low Amb3 Local Remote4 N/A N/A
5 English SI (Metric)6 ACL Start W-D Start7 M Lead/Lag A Lead/Lag
8 R- 1 34a R-22
Verify the selections by pressing the OPTIONSKey on the control panel. Check them off.
CAUTION: Damage to the chiller could result ifswitches are improperly programmed.
q 5. Program the required twenty-two operating val-ues into the micro for cut-outs, safeties, etc. andrecord them in the chart below. See Page 88.
If Default Values are desired for programming con-venience, press the PROGRAM key, 6140, andENTER. This loads default values. Record thesevalues in the chart below.
Keep in mind that the Target temperature dis-played by the micro should equal the desired leav-ing water temperature.
q 7. Assure that the CLK jumper J18 on the Micropro-cessor Board is in the ON position (Top 2 pins).
q 8. Set the Time and Date.
q 9. Program the Daily Schedule start and stop times.
INITIAL START-UP
After the control panel has been programmed and thecompressor heater has been on for 24 hours prior tostart-up, the chiller may be placed into operation.
q 1. Place the System Switches on the Microproces-sor Board to the ON position.
FORM 201.10-NM1
135YORK INTERNATIONAL
q 2. The compressor will start and a flow of refriger-ant will be noted in the sight glass. After severalminutes of operation, the bubbles in the sightglass will disappear and there will be a solid col-umn of liquid when the TXV stabilizes. After thewater temperature stabilizes at desired operat-ing conditions, the oil should be clear.
q 3. Allow the compressor to run a short time, beingready to stop it immediately if any unusual noiseor adverse conditions develop. Immediately atstart-up, the compressor will make sounds dif-ferent from its normal high pitched sound. This isdue to the compressor coming up to speed andlubrication changing from liquid refrigerant to oil.This should be of no concern and lasts for only ashort time.
q 4. Check the system operating parameters. Do thisby selecting various displays such as pressuresand temperatures. Compare these to test gaugereadings.
CHECKING SUPERHEAT AND SUBCOOLING
The subcooling should always be checked when charg-ing the system with refrigerant and/or before setting thesuperheat.
When the refrigerant charge is correct, there will be nobubbles in the liquid sight glass with the system operat-ing under full load conditions, and there will be 10 - 15°Fsubcooled liquid leaving the condenser.
An overcharged system should be guarded against. Evi-dences of overcharge are as follows:
a. If a system is overcharged, the discharge pressurewill be higher then normal. (Normal discharge/con-densing pressure can be found in the refrigerant tem-perature/pressure chart; use entering air tempera-ture +30°F for normal condensing temperature.
b. The temperature of the liquid refrigerant out of thecondenser should be not be more than 15°F lessthan the condensing temperature (The temperaturecorresponding to the condensing pressure from therefrigerant temperature/pressure chart).
The subcooling temperature of each system should becalculated by recording the temperature of the liquid lineat the outlet of the condenser and subtracting it from therecorded liquid line pressure at the liquid stop valve, con-verted to temperature from the temperature/pressure chart.
Example:Liquid line pressure =
202 PSIG converted to 102°Fminus liquid line temp. - 87°F
SUBCOOLING = 15°F
The subcooling should be adjusted to 10 - 15°F.
q 1. Record the liquid line pressure and its correspond-ing temperature, liquid line temperature andsubcooling below:
SYS 1 SYS 2
Liq Line Press = _______ _______ PSIG
Temp = _______ _______ °F
Liq Line Temp = _______ _______ °F
Subcooling = _______ _______ °F
After the subcooling is set, the suction superheat shouldbe checked. The superheat should be checked only aftersteady state operation of the chiller has been established,the leaving water temperature has been pulled down tothe required leaving water temperature, and the unit isrunning in a fully loaded condition. Correct superheatsetting for a system is 10 - 15°F.
The superheat is calculated as the difference betweenthe actual temperature of the returned refrigerant gas inthe suction line entering the compressor and the tem-perature corresponding to the suction pressure as shownin a standard pressure/temperature chart.
Example:Suction Temp = 46°F
minus Suction Press60 PSIG converted
to Temp - 34°F12°F
The suction temperature should be taken 6" before thecompressor suction service valve, and the suction pres-sure is taken at the compressor suction service valve.
Normally, the thermal expansion valve need not be ad-justed in the field. If, however, adjustment needs to bemade, the expansion valve adjusting screw should beturned not more than one turn at a time, allowing sufficienttime (approximately 15 minutes) between adjustments forthe system and the thermal expansion valve to respondand settle out. Assure that superheat is set at 10 - 15°F.
q 2. Record the suction temperature, suction pressure,suction pressure converted to temperature, andsuperheat of each system below:
SYS 1 SYS 2
Suction temp = _______ _______ °F
Suction Pressure = _______ _______ PSIG
Temp = _______ _______ °F
Superheat = _______ _______ °F
136 YORK INTERNATIONAL
CHECKING ECONOMIZER SUPERHEAT(15 TON TXV)
The economizer superheat should be checked to assureproper economizer operation and motor cooling. Correctsuperheat setting is approx. 10 - 15°F.
The superheat is calculated as the difference betweenthe pressure at the Economizer Service Valve on thecompressor converted to the corresponding temperaturein a standard pressure/temperature chart and tempera-ture of the gas at the bulb on the entering piping to themotor housing.
Example:Motor Gas Temp = 90°F
minus Economizer Press139 PSIG converted
to Temp - 78°F12°F
Normally, the thermal expansion valve need not be ad-justed in the field. If however, adjustment needs to bemade, the expansion valve adjusting screw should beturned not more than one turn at a time, allowing suffi-cient time (approximately 15 minutes) between adjust-ments for the system and the thermal expansion valveto respond and settle out. Assure that superheat is setbetween 10 -15°F.
q 1. Record the motor gas temperature, economizerpressure, economizer pressure converted to tem-perature, and economizer superheat below:
SYS 1 SYS 2
Motor gas Temp = _______ _______ °F
Economizer Pressure = _______ _______ PSIG
Economizer Temp = _______ _______ °F
Superheat = _______ _______ °F
NOTE: This superheat should only be checked in anambient above 90°F. Otherwise, mid-range ad-justment (factory setting) is acceptable.
5 TON TXV SUPERHEAT SETTING
The 5 Ton TXV Superheat does not require checking. Itshould typically operate at 10 - 15°F. Since it is difficultto check, the factory set “mid-range adjustment” is ac-ceptable.
LEAK CHECKING
q 1. Leak check compressors, fittings, and piping toassure no leaks.
If the unit is functioning satisfactorily during the initialoperating period, no safeties trip and the compressorsload and unload to control water temperature, the chilleris ready to be placed into operation.
FORM 201.10-NM1
137YORK INTERNATIONAL
OPERATING SEQUENCE
The operating sequence described below relates to op-eration on a hot water start after power has been applied,such as start-up commissioning. When a compressorstarts, internal timers limit the minimum time before an-other compressor can start to 1 minute. Time before load-ing begins is also limited at start. No loading will takeplace until a compressor runs for 2-1/2 minutes. Afterthat, loading will take place every 10 - 120 seconds asneeded. Lag compressor start is also inhibited until thelead compressor start is also inhibited until the lead com-pressor reaches a programmable load percentage de-fined as the Lag Compressor Start Point %.
1. For the chiller system to run, all Manual Reset Cut-outs must be reset, the Flow Switch must be closed,any remote cycling contacts must be closed, the SYS-TEM Switches on the Microboard must be ON, theDaily Schedule must be scheduling the chiller to run,and temperature demand must be present.
2. As long as power is applied, the compressor heaterswil be on and stay on as long as a compressor is notrunning.
3. When power is applied to the system, the micropro-cessor will start a 2 minute timer. This is the sametimer that prevents an instanteous start after a powerfailure.
4. At the end of the 2 minute timer, the microprocessorwill check for cooling demand as well as check to seeif any system safeties are exceeded. If all conditionsallow for start, the lead compressor will start unloaded.
Coincident with the start, the programmable anti-cycletimer will be set and begin counting downward to “0”.The liquid line solenoid valve and the Economizer Liq-uid Supply Solenoid will open after the system pumpsdown to the suction pressure cut-out or after the com-pressor runs for 30 seconds, whichever comes first.
5. After 5 seconds of run time, the microprocessor be-gins to monitor system operating safeties. These safe-ties are described in detail in the “Safeties” section ofthe manual on Page 106.
6. After 2-1/2 minutes of run time, the lead compressorwill begin to load in intervals of 10 - 120 seconds asneeded to satisfy temperature.
7. The lag compressor may start 1 minute after the leadcompressor starts. However, the lag compressor isinhibited from the starting until the lead compressorloads to a % as programmed by the Lag CompressorStart Point %. This will normally only occur after the2-1/2 minute period after start where the lead com-pressor.
8. When the lead compressor loading reaches the LagCompressor Start Point %, the lag compressor startsand will begin to load, if required, after it has run for2-1/2 minutes.
9. Once both compressors are running, the micro willattempt to bring the lag compressor up to a load %equal to that of the lead. Once equalized, the microwill attempt to load and unload both compressorsequally to satisfy demand and optimizing efficiency.
138 YORK INTERNATIONAL
TROUBLESHOOTING
PROBLEM CAUSE SOLUTION
No display on panel. 1. No 115VAC to 2T. 1. Check wiring and fusesUnit will not operate. (IFU and 2 FU).
Check emergency stopcontacts 5 to 1 of TB1Terminal Block.
2. No 24VAC to Power Supply 2. Check wiring 2T toSupply Board. Power Supply Board.
3. 2T defective, no 3. Replace 2T24VAC output.
4. No + 12V output (J2) from 4. Replace Power SupplyPower Supply Board. Board or load on the board.
2. Faulty oil or discharge 2. Check / replacepressure transducers or transducers or repairwiring. wiring.
“HIGH AMBIENT TEMP” 1. High ambient cut-out 1. Re-program cut-out.FAULT is set too low.
Auto restart will occur after 2. Temperature sensed 2. Verify displayed ambienta drop in temperature. incorrectly by thermistor. temp. is within + or - 15°F
of a thermometer placednext to the OAT sensor.
3. Fans rotating backwards. 3. Air flow from forward fansmust be up. Correct fanrotation.
4. Air flow to unit restricted 4. Check recommendedor is being recirculated. installation clearances.
“LOW AMBIENT TEMP” 1. Temperature of outside air 1. No problem exists.FAULT is below cut-out.
Cut-out = 25°F for standard 2. Temperature sensed 2. Verify displayed ambientambient operation. incorrectly by thermistor. temperature is within + or -
15°F of a thermometerA Low Ambient Kit must be placed next to thebe installed for operation OAT sensor.below 25°F.
3. Low ambient cut-out set 3. Adjust as necessary.too high.
FORM 201.10-NM1
143YORK INTERNATIONAL
PROBLEM CAUSE SOLUTION
Compressor Won’t Load 1. Demand not great enough. 1. No problem. ConsultInstallation Manual to aidin understandingcompressor operation.
2. Low oil pressure. 2. Check oil circuit.Assure oil load solenoidvalve is working.Assure that dischargepressure is at least50 pounds over suction.Contact the local YORKservice representative.
3. Defective water 3. Compare the display withtemperature sensor. a thermometer. Should be
within + or - 2 degrees.
Lack of Cooling Effect 1. Fouled evaporator surface. 1. Contact the local YORKLow suction pressure service representative.will be observed.
2. Improper flow through the 2. Reduce flow to withinevaporator. chiller design specs.
3. Low refrigerant charge. 3. Check subcooling andLow suction pressure add charge as needed.will be noted.
The numbers in bold-face type in the center column refer to the temperature, either in Centigrade or Fahrenheit, which is to beconverted to the other scale. Converting Fahrenheit to Centigrade the equivalent temperature will be found in the left column.If converting Centigrade to Fahrenheit, the equivalent temperature will be found in the column on the right.
