Water-Cooled Screw Compressor Chiller · 6 WHS 155A - 220A Product Manual WHS Sound Levels...

Product Manual PM WHS

Group: Chiller

Effective: February 1999

Supersedes: New

© 1997 McQuay International

Water-Cooled Screw Compressor Chiller

WHS 155A - WHS 200A, R-22, 150 to 200 Tons (525 to 700 kW)WHS 220A, R-410A, 220 Tons (770 kW)60 Hertz

2 WHS 155A - 220A Product Manual WHS

Table of Contents

Introduction..............................................................................................3

Features and Benefits...............................................................................3

Design Details..........................................................................................4

Sound Levels ...........................................................................................6

Selection Procedure .................................................................................7

Performance Adjustment Factors.............................................................8

Performance Data, I-P Units....................................................................9

Performance Data, SI Units...................................................................10

Part Load Data .......................................................................................11

Pressure Drop Curves ............................................................................12

Electrical Data........................................................................................14

Physical Data..........................................................................................18

Dimensional Data ..................................................................................19

Application Data ....................................................................................23Chiller Water System ..........................................................................................................................23Condenser Water Systems...................................................................................................................26Electrical .............................................................................................................................................28

Options...................................................................................................30

Product Specification.............................................................................33

"McQuay" is a registered trademark of McQuay International1997 McQuay International

"Illustrations cover the general appearance of McQuay International products at the time of publication and we reserve the right tomake changes in design and construction at anytime without notice"

Product Manual WHS WHS 155A - 220A 3

Introduction

The McQuay WHS Rotary-Screw Chiller Package is a water-cooled, self-contained fluid chiller,suitable for cooling chilled water for air conditioning duty and for cooling other fluids for industrialprocess and ice storage applications. The package consists of two McQuay single-rotor screwcompressors operating in parallel on a single evaporator and condenser, a MicroTech control system,compressor starters, and refrigerant piping with all necessary refrigeration specialties. The vessels areavailable with a wide selection of tube types and water head arrangements.

Nomenclature

W H S - XXX A

ARI Standard 550/590-98 CertifiedFeatures and Benefits

Unit Features Owner BenefitsIndustry’s Lowest Sound Levels Less stringent sound barriers-eliminates tenant

complaints-diversity of application

High Efficiency Reduced energy costs-meets or exceedsindustry standard ASHRAE B90.1

Single Rotor Design Virtually vibration free-greater reliability,longer life, no oil separation system required

Dual Compressors Built-in redundancy, superb part-load efficiency

Compliant Gates Provide protection against occasional flooding

MicroTech Control System Industry leader in unit controls allows efficientprecise control of the unit and many satellitecomponents

Open Protocol/Remote Monitoring Compatible with most building managementsystems and/or in-depth remote monitoringcapability via hard-wire or modem

Quality Standards Units manufactured to ASME Standards. Themanufacturing plant has achieved the covetedISO 9002 Quality Certification

Full Factory Testing Ensures trouble-free startup and operation

Options Choose an economical air-conditioning unit ora customized, process specific, custom chiller

Water-Cooled

Dual

Rotary-Screw Compressor

Design Vintage

Nominal Capacity


Design Details

RefrigerantsThe WHS line of chillers uses two different refrigerants:

• R-22 for models WHS 155A through 200A, 150 to 200 tons (525 to 700 kW).

• R-410A for model WHS 220A, 220 tons (770 kW)

The properties of R-410A allow an increase in the capacity of a compressor by 50 percent over thecompressor’s capacity with R-22. Chillers using R-410A have the equivalent compressordisplacements as the R-22 units but are equipped with larger heat exchangers and produce morecapacity.

CompressorsTwo single-rotor screw compressors operating in parallel on a single evaporator and condenser.Liquid refrigerant injection system coupled with a unique oil management system eliminates oilseparators, oil pumps, oil coolers and associated piping and fittings. The motors are liquid refrigerantcooled and the unloading slide valves are refrigerant actuated.

VesselsShell-and-tube construction with individually replaceable tubes. Standard construction consists of0.025 inch wall copper evaporator tubes and 0.028 inch wall copper condenser tubes. 90-10 Cupro-nickel, titanium, and 304 stainless steel tubes are also available. The standard vessel connections arevictaulic with flanged connections optional. Marine water boxes are also available. Evaporators havea single spring-loaded relief valve and condensers have dual relief valves mounted on a three-wayselector valve.

Refrigerant PipingEach compressor is equipped with a suction and discharge shutoff valve and the liquid lines containking valves, allowing the refrigerant to be pumped down and isolated in the condenser. The condenseris sized to hold the entire unit charge. An electronic expansion valve controlled by the unitmicroprocessor meters refrigerant. Replaceable core filter-dryers and sight glass/moisture indicatorsare standard.

ControlSafety and operating control functions are executed by the highly regarded McQuay MicroTech controlsystem as summarized below.

Safety controlsSafety shutoff is provided for high and low refrigerant pressures, lack of flow, sensor failure, andelectrical inconsistencies.


DisplaysAll operating parameters and control settings are displayed on selectable menus. These readingsinclude refrigerant pressures and temperatures, subcooling and superheat values, all watertemperatures, amperage, compressor loading, yearly operating schedule, setpoints, failure mode withall operating parameters at failure and a revolving eight failure memory, trend logging, operating mode(local or remote, load limiting, manual or automatic), compressor run time and number of starts.

Programmable FunctionsLead-lag, full calendar with holidays start-stop, load limiting, internal or external chilled water reset,safeties with default boundaries.

MicroTech Control SystemThe MicroTech control system provides many modes of operability and interface with chilled watersystem components, building management systems, and remote monitoring.

A standalone unit is a completely self-contained operation with the ability to read and display unitconditions, load/unload and start/stop. Has manual on/off with many programmable functions.Digital interconnects to enable unit start/stop, transmit alarms, start/stop chilled and condenser waterpumps and control up to four cooling tower fans. Optional analog interconnects for chilled waterreset and load limit functions are available.

With the addition of an analog output board (AOX), the standalone chiller is able to control a coolingtower bypass valve or read a proportional motor current signal. The AOX board is an option that canbe factory or field installed.

Open protocol interface is possible with virtually all building management systems (BMS) allowingread and write capability. When only one chiller is to be interfaced with a BMS, an open protocol sitelicense/software is required. When multiple chillers are to be interfaced with a BMS, an open protocolpanel and an open protocol site license/software are required.

Optional remote PC monitoring software to access unit using hard wire or modem-provides a variedarray of real-time displays and read/wrote capability.


Sound Levels

Objectionable sound or “noise” can no longer be treated lightly as some manufacturers may have donein the past. Many owners consider sound levels to be as important as unit efficiency. Withconcentrated efforts by McQuay product development engineers, the quietest water-cooled chiller linein the market has been developed and introduced with these WHS units. Unique compressor andsystem design allows the WHS chillers to produce sound levels much lower than competitivereciprocating or twin-rotor screw compressors units.

The McQuay gaterotor is manufactured from an advanced composite material. The resultingdifference in material density and coefficient of elasticity between the main rotor and this materialgreatly reduces the sound level produced in the compression chamber. In addition, the dischargehousing was designed as a “tuned sound attenuator” to cancel out pulsations. The elimination of oilseparators also helps reduce the unit sound emission.

The moving components in the compressor are purely rotational resulting in a very low vibration level(less than 0.14 IPS, or 3.56 mm/sec.). This means less movement to refrigeration lines and othercomponents and virtually no vibration transmission to the building.

Table 1, 60 Hz Sound Pressure LevelsWHS 60 Hz Sound Pressure Levels

Unit Percent Octave Band - Hz

Size Load 63 125 250 500 1000 2000 4000 8000 "A" WT

100% 65.0 65.0 67.5 76.5 78.5 75.0 65.0 59.5 81.5

155A 50% 66.0 64.5 67.0 73.0 75.0 74.0 66.5 61.0 79.0

100% 66.5 66.5 69.0 75.5 80.0 76.0 66.5 60.5 82.5

170A 50% 68.0 65.0 68.5 74.0 75.5 75.0 68.0 62.0 80.0

100% 68.5 67.0 70.0 78.5 80.0 76.0 67.5 61.5 83.0

180A 50% 70.5 68.5 70.0 76.0 76.0 75.0 68.5 63.0 80.5

100% 71.0 68.5 71.5 79.5 81.0 78.0 69.0 62.5 84.0

190A 50% 73.0 70.0 72.0 77.5 78.5 76.5 70.0 64.5 82.0

100% 72.5 71.0 73.0 80.0 81.5 80.0 70.5 64.5 84.5

200A 50% 75.0 72.5 74.0 78.0 78.5 78.0 72.0 66.0 82.5

100% 65.0 65.0 67.5 76.5 78.5 75.0 65.0 59.5 81.5

220A 50% 66.0 64.5 67.0 73.0 75.0 74.0 66.5 61.0 79.0

Notes:Sound pressure per ARI Standard 575Readings at 3 feet (1 meter) from side of the unit


Selection Procedure

Standard conditionsThe rating tables are based on ARI 550/590-98 standard conditions of:

• Chilled water at 2.4 gpm/ton (10 degree F delta-T), 0.0001 fouling factor

• Condenser water at 3.0 gpm/ton (10 degree F delta-T), 0.00025 fouling factor

• Vessels are two pass. For other pass arrangements, contact the local sales office.

The following information is necessary to select a unit.

A. Required load

B. Chilled water flow and temperatures

C. Condenser water flow and temperatures

Calculate any missing chilled water elements as follows:

GPMTons

Evap Temp Drop FL s

kWCapacity

Evap TempDrop C=

×

°=

× °

24

4.18. . ( )/

. ( ) OR

Calculate any missing condenser water elements as follows:

GPMTons

Cond Temp Drop FL s

kWCapacity

Cond Temp Drop C=

×

°=

× °

30

3 34. . ( )/

. . . ( ) OR

Ratings are contained in Table 6 for Inch-Pound (I-P) units and in Table 7 for SI units. Part load datain contained in Table 8. Make selections based on leaving chilled water temperature and enteringcondenser water temperature.

The minimum chilled water temperature setpoint without glycol is 40°F (4.4°C). For brineadjustment factors see Table 4 and Table 5.

Adjustment factorsUse the adjustment factors in Table 2 through Table 5 for delta-T other than 10 degrees, for other thanstandard fouling factors and for glycol anti-freeze solutions.

Selection example 60 Hertz

Given:

Required capacity = 185 tons444 gpm chilled water, 54ºF to 44ºF555 gpm condenser water, 85ºF to 95ºF0.0001 evaporator fouling factor0.00025 condenser fouling factor

From Table 6, a WHS 190A at the given conditions will produce 189.9 tons with a kW/ton of 0.686.

2. From Figure 1, evaporator pressure drop =15.5 ft.

3. From Figure 2, condenser pressure drop =13.5 ft.


Performance Adjustment Factors

Table 2, Adjustment for Chilled Water Delta T and FoulingChilled Water Fouling Factor Adjustment

Delta-T 0.0001 (0.0176) 0.00075 (0.132)

°F (°C) Capacity kW/Ton Capacity kW/Ton

6 (3.3) 0.994 1.009 0.944 1.060

8 (4.4) 0.997 1.004 0.949 1.054

10 (5.5) 1.000 1.000 0.955 1.050

12 (6.6) 1.003 0.997 0.959 1.044

14 (7.7) 1.005 0.994 0.963 1.039

Table 3, Adjustment for Condenser Water Delta T and FoulingCondenser

WaterFouling Factor Adjustment

Delta-T 0.00025 (0.044) 0.00075 (0.132)

ºF (°°C) Capacity kW/Ton Capacity kW/Ton

6 (3.3) 1.003 0.996 0.984 1.052

8 (4.4) 1.002 0.998 0.982 1.056

10 (5.5) 1.000 1.000 0.98 1.059

12 (6.6) 0.984 1.002 0.977 1.067

14 (7.7) 0.976 1.004 0.963 1.108

16 (8.8) 0.968 1.006 0.948 1.152

Table 4, Adjustment for Ethylene GlycolFreeze Point

% E.G. ºF ºC Cap kW/Ton Flow PD

10 23.0 -5 0.997 1.003 1.036 1.105

20 14.0 -10 0.988 1.014 1.053 1.245

30 1.4 -17 0.978 1.024 1.073 1.386

40 -13.0 -25 0.966 1.039 1.098 1.578

50 -34.6 -37 0.952 1.056 1.128 1.800

Table 5, Adjustment for Propylene GlycolFreeze Point

% E.G. ºF ºC Cap kW/Ton Flow PD

10 26 -3 0.993 1.009 1.008 1.109

20 19 -7 0.979 1.024 1.130 1.240

30 9 -13 0.96 1.044 1.017 1.399


Performance Data, I-P Units

Table 6, WHS 155 – 220, 60 Hz, I-P UnitsWHS Entering Condenser Water Temperature (deg F)

UNIT LWT 80°F 85°F 90°F 95°F

SIZE (deg F) Capacity Unit Capacity Unit Capacity Unit Capacity Unit

Tons kW/Ton Tons kW/Ton Tons kW/Ton Tons kW/Ton

40 142.5 0.650 138.0 0.725 133.5 0.809 128.9 0.901

42 148.3 0.622 143.7 0.694 139.1 0.774 134.4 0.862

WHS-155A 44 154.2 0.596 149.5 0.665 144.8 0.741 140.0 0.825

46 160.3 0.572 155.5 0.637 150.7 0.710 145.7 0.790

48 166.5 0.548 161.6 0.611 156.7 0.680 151.6 0.757

40 157.5 0.655 152.6 0.732 147.7 0.818 142.7 0.913

42 163.8 0.626 158.9 0.700 153.8 0.782 148.7 0.872

WHS-170A 44 170.3 0.599 165.3 0.670 160.1 0.748 154.9 0.834

46 177.0 0.573 171.8 0.641 166.5 0.716 161.2 0.798

48 183.8 0.549 178.5 0.614 173.1 0.685 167.7 0.764

40 171.6 0.668 166.4 0.748 161.2 0.837 155.8 0.934

42 178.5 0.639 173.2 0.715 167.8 0.800 162.3 0.893

WHS-180A 44 185.5 0.611 180.0 0.684 174.5 0.765 168.9 0.854

46 192.7 0.585 187.1 0.654 181.4 0.732 175.7 0.817

48 200.0 0.560 194.3 0.626 188.5 0.700 182.7 0.782

40 181.1 0.671 175.7 0.750 170.2 0.837 164.6 0.934

42 188.3 0.642 182.7 0.717 177.1 0.801 171.4 0.893

WHS-190A 44 195.6 0.614 189.9 0.686 184.2 0.766 178.3 0.855

46 203.1 0.588 197.3 0.657 191.4 0.734 185.4 0.818

48 210.8 0.563 204.8 0.630 198.8 0.703 192.7 0.784

40 190.5 0.673 184.9 0.752 179.2 0.839 173.4 0.935

42 198.0 0.644 192.2 0.719 186.4 0.803 180.4 0.895

WHS-200A 44 205.6 0.617 199.7 0.689 193.7 0.769 187.7 0.856

46 213.4 0.592 207.4 0.660 201.3 0.736 195.1 0.820

48 221.4 0.568 215.2 0.633 209.0 0.706 202.6 0.786

40 211.1 0.655 203.1 0.733 195.0 0.821 186.7 0.921

42 219.6 0.627 211.5 0.702 203.1 0.787 194.6 0.881

WHS-220A 44 228.4 0.601 220.0 0.672 211.5 0.753 202.7 0.843

46 237.4 0.576 228.8 0.645 220.0 0.722 211.1 0.808

48 246.6 0.553 237.8 0.619 228.8 0.692 219.6 0.774

NOTES:1. Blocked areas certified in accordance with ARI standard 550/590-98.2. Ratings based on evaporator fouling factor of 0.0001 and condenser fouling factor of 0.00025, evaporator water flow of 2.4 GPM/ton, condenser

water flow of 3.0 GPM/ton. Consult McQuay for ratings outside these parameters and temperatures outside the table3. Ratings based on 2-pass evaporator and 2-pass condenser.


Performance Data, SI Units

Table 7, WHS 155A – 220A, 60 Hz, SI UnitsWHS Entering Condenser Water Temperature (deg C)

UNIT LWT 26°C 29°C 32°C 35°C

SIZE (deg C) Capacity Unit Capacity Unit Capacity Unit Capacity Unit

kW COP kW COP kW COP kW COP

5 515.1 5.667 497.9 5.048 480.5 4.488 462.9 3.992

6 533.7 5.892 516.2 5.250 498.4 4.668 480.4 4.154

WHS-155A 7 552.7 6.122 534.8 5.456 516.7 4.853 498.4 4.320

8 572.2 6.359 553.9 5.668 535.4 5.043 516.7 4.490

9 591.9 6.602 573.3 5.885 554.5 5.237 535.3 4.664

5 569.1 5.632 550.5 5.005 531.7 4.439 512.5 3.943

6 589.5 5.862 570.5 5.210 551.3 4.622 531.8 4.105

WHS-170A 7 610.4 6.099 591.0 5.421 571.3 4.810 551.4 4.273

8 631.7 6.343 611.9 5.639 591.8 5.003 571.5 4.445

9 653.4 6.593 633.2 5.862 612.7 5.202 591.9 4.622

5 620.1 5.521 600.1 4.899 579.9 4.341 559.3 3.852

6 642.1 5.749 621.7 5.102 601.0 4.520 580.0 4.011

WHS-180A 7 664.5 5.984 643.7 5.310 622.6 4.705 601.2 4.175

8 687.5 6.226 666.2 5.525 644.7 4.895 622.8 4.344

9 710.8 6.474 689.1 5.746 667.1 5.091 644.8 4.517

5 654.2 5.499 633.4 4.888 612.3 4.336 590.9 3.851

6 677.2 5.722 656.0 5.086 634.4 4.512 612.6 4.008

WHS-190A 7 700.7 5.950 679.0 5.289 657.0 4.693 634.7 4.170

8 724.6 6.185 702.5 5.499 680.0 4.880 657.3 4.336

9 749.0 6.425 726.4 5.713 703.5 5.071 680.3 4.506

5 688.0 5.476 666.4 4.873 644.4 4.327 622.2 3.846

6 711.9 5.692 689.9 5.067 667.5 4.501 644.8 4.002

WHS-200A 7 736.4 5.915 713.8 5.266 691.0 4.679 667.8 4.161

8 761.3 6.143 738.3 5.470 715.0 4.861 691.3 4.324

9 786.7 6.376 763.2 5.679 739.4 5.048 715.3 4.492

5 764.2 5.632 733.6 4.998 702.4 4.419 670.4 3.904

6 791.8 5.855 760.4 5.195 728.5 4.594 695.7 4.062

WHS-220A 7 819.9 6.082 787.9 5.398 755.2 4.774 721.7 4.224

8 848.7 6.315 815.9 5.604 782.5 4.960 748.2 4.390

9 878.0 6.550 844.5 5.816 810.3 5.152 775.3 4.560

NOTES:1. Ratings based on evaporator fouling factor of 0.0176 and condenser fouling factor of 0.044,

Evaporator and condenser temperature range of 5.6°CConsult McQuay for ratings outside these parameters and temperatures outside the table

2. Ratings based on 2-pass evaporator and 2-pass condenser.


Part Load Data

Table 8, Part Load Data, 60 HzUNIT SIZE % LOAD CAPACITY POWER

TONS kWi kW/Ton IPLV

100.0 149.5 99.4 0.665

WHS155 75.0 112.1 64.1 0.571 0.579

50.0 74.8 40.9 0.548

25.0 37.4 28.7 0.769

100.0 165.3 110.7 0.670WHS170 75.0 124.0 71.9 0.580 0.567

50.0 82.7 43.1 0.522

25.0 41.3 30.3 0.734

100.0 180.0 123.1 0.684WHS180 75.0 135.0 78.0 0.577 0.583

50.0 90.0 49.6 0.551

25.0 45.0 34.8 0.773

100.0 189.9 130.4 0.686WHS190 75.0 142.4 83.6 0.587 0.573

50.0 95.0 50.0 0.526

25.0 47.5 35.3 0.744

100.0 199.7 137.6 0.689WHS200 75.0 149.8 87.5 0.584 0.591

50.0 99.9 55.7 0.558

25.0 49.9 39.5 0.790

100.0 220.0 148.0 0.672

WHS220 75.0 165.0 90.6 0.549 0.554

50.0 110.0 57.7 0.524

25.0 55.0 39.7 0.722

Note: Part load data based on ARI Standard 550/590-98


Pressure Drop Curves

Figure 1, Evaporator 2-Pass


Figure 2, Condenser 2-Pass


Electrical Data

Table 9, Compressor Amp DrawWHS Compressor Rated Compressor Locked Rotor Amps

Unit Load Amps Delta-Delta Start

Size Volts Hz Comp. 1 Comp. 2 Comp. 1 Comp. 2

208 179 179 934 934

230 162 162 1042 1042

155A 380 60 98 98 604 604

460 81 81 489 489

575 65 65 377 377

208 179 223 934 934

230 162 202 1042 1042

170A 380 60 98 122 604 604

460 81 101 489 489

575 65 81 377 377

208 223 223 934 934

230 202 202 1042 1042

180A 380 60 122 122 604 604

460 101 101 489 489

575 81 81 377 377

208 223 254 934 934

230 202 230 1042 1042

190A 380 60 122 139 604 604

460 101 115 489 489

575 81 92 377 377

208 254 254 934 934

230 230 230 1042 1042

200A 380 60 139 139 604 604

460 115 115 489 489

575 92 92 377 377

208 286 286 934 934

230 259 259 1042 1042

220A 380 60 157 157 604 604

460 130 130 489 489

575 104 104 377 377NOTES:1. Allowable voltage is within ±10 % of nameplate rating.2. Compressor RLA values are for wiring sizing only. They do not reflect normal operating current draw at unit rated capacity.


Table 10, Customer Wiring Information, WHS 155A - 200AWHS Wiring to Unit Power Block Wiring to Disconnect Switch

Unit Volts Hz Power Block Optional Disconnect Switch

Size Terminal Size Connector Wire Range (per phase) Size Wire Range (per phase)

Amps (Copper Wire Only) (Copper Wire Only)

208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

230 665 (1) #6-350 MCM & (1) #4-500 MCM 400 (2) 3/0-250 MCM

155A 380 60 335 (1) #6-400 MCM 250 (1) #4-350 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM

575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

170A 380 60 335 (1) #6-400 MCM 400 (2) 3/0-250 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM

575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

180A 380 60 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM

575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

190A 380 60 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM

575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

200A 380 60 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

460 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

Table 11, Customer Wiring Information, WHS 220AWHS Wiring to unit Power Block Wiring to Main Circuit Breaker

Unit Volts Hz Power Block Optional Main Circuit Breaker

Size TerminalSize Amps

Connector Wire Range (per phase)(Copper Wire Only)

Size Wire Range (per phase)(Copper Wire Only)

Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2

208 665 / 665 (1) # 6-350 MCM & (1) # 4-500 MCM & NA NA

(1) # 6-350 MCM & (1) # 4-500 MCM

230 665 / 665 (1) # 6-350 MCM & (1) # 4-500 MCM & NA NA

220A 60 (1) # 6-350 MCM & (1) # 4-500 MCM

380 665 (1) # 6-350 MCM & (1) # 4-500 MCM 400 (2) 3/0-250 MCM

460 335 (1) # 6-400 MCM 400 (1) 2/0-500 MCM

575 335 (1) # 6-400 MCM 250 (1) #4-350 MCM

Note:Allowable voltage is within ±10 percent of nameplate rating.


Table 12, Electrical Data, WHS 155A - 200AWHS Minimum Power Supply Field Fuse Size

Unit Volts Hz Circuit Field Wire Recom-

Size Ampacity (MCA) Qty. Wire Gauge mended Maximum

208 403 6 250 450 500

230 365 6 3/0 450 500

155A 380 60 221 3 4/0 250 300

460 183 3 3/0 225 250

575 147 3 1/0 175 200

208 458 6 250 600 600

230 415 6 250 500 600

170A 380 60 251 3 250 300 350

460 208 3 4/0 250 300

575 167 3 2/0 200 225

208 502 6 250 600 700

230 455 6 250 600 600

180A 380 60 275 3 300 350 350

460 228 3 4/0 300 300

575 183 3 3/0 225 250

208 541 6 300 700 700

230 490 6 250 600 700

190A 380 60 296 3 350 350 400

460 245 3 250 300 350

575 196 3 3/0 225 250

208 572 6 350 700 800

230 518 6 300 600 700

200A 380 60 313 3 400 400 450

460 259 3 300 300 350

575 207 3 4/0 250 250

Table 13, Electrical Data, WHS 220AWHS Minimum Power Supply Field Fuse SizeUnit Volts Hz Circuit Ampacity Field Wire Recom- MaximumSize (MCA) Qty. (3) Wire Guage mended

Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2208 358 / 358 6 / 6 3/0 / 3/0 450 / 450 600 / 600230 324 / 324 6 / 6 2/0 / 2/0 400 / 400 500 / 500

220A 380 60 353 6 3 / 0 400 500460 293 3 350 350 400575 234 3 250 300 300

NOTES:1. Allowable voltage range is within ±10% of nameplate rating.2. Minimum circuit ampacity is equal to 125% of the RLA of the largest motor plus 100% of the RLA of all other loads in the

circuit.3. Recommended power lead wire sizes based on three conductors per conduit at 100% conductor ampacity using 75°C wire

and no more than 3 conductors per conduit.4. For six conductors per conduit current carrying capacity id reduced ny 20%. Consult the National Electical Code for wire

sizing. All terminal block connections must be made with copper wire (type THW or THHN).5. Recommended time delay fuse size or circuit breakers (Canadian units only) is equal to 150% of the largest compressor-

motor RLA plus 100% of all other loads on the circuit. Maximum time delay fuse size or circuit breakers (Canadian units only)is equal to 225% of the largest compressor-motor RLA plus 100% of all other loads on the circuit.


Figure 3, Typical Field Wiring


Physical Data

Table 14, Physical Data, WHS 155A - 180AData 155A 170A 180A

BASIC DATAUnit Capacity @ ARI Conditions, tons

(kW)148.3 (519) 163.8 (573) 178.2 (624)

Refrigerant HCFC-22 HCFC-22 HCFC-22Unit Operating Charge, lb. (kg) 661 (300) 653 (296) 653 (296)Min Pumpdown Capacity, lb. (kg) 882 (400) 822 (373) 822 (373)Cabinet Dimensions 162.7 x 42 x 76.9 162.7 x 42 x 76.9 162.7 x 42 x 76.9L x W x H, in. (mm) 4134 x 1067 x 1953 4134 x 1067 x 1953 4134 x 1067 x 1953Operating Weight (with starters),lb.(kg) 9970 (4522) 9970 (4522) 9970 (4522)Shipping Weight, (with starters),lb.(kg) 9567 (4339) 9567 (4339) 9567 (4339)COMPRESSORS, SCREW, SEMI-HERMETICNominal Tons, (kW) 70 (250) 70 (250) 70 (250) 85 (300) 85 (300) 85 (300)FLOODED EVAPORATORQuantity, (Number of Water Passes) 1 (2) 1 (2) 1 (2)Shell Diameter – Tube Length 18 - 12 18 - 12 18 - 12 in. (mm) ft. (mm) (457 - 3658) (457 - 3658) (457 - 3658)Water Volume, gallons (L) 42 (160) 42 (160) 42 (160)Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)Max. Refrigerant Pressure, psi (kPa) 250 (1725) 250 (1725) 250 (1725)Water Connections (Victaulic), in (mm) 6 (152) 6 (152) 6 (152)CONDENSERQuantity, (Number of Water Passes) 1 (2) 1 (2) 1 (2)Shell Diameter -- Tube Length 18 - 12 18 - 12 18 - 12 in. (mm) ft. (mm) (457 - 3658) (457 - 3658) (457 - 3658)Water Volume, gallons (L) 45.2 (171) 51.6 (196) 51.6 (196)Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)Max. Refrigerant Pressure, psi (kPa) 300 (2070) 300 (2070) 300 (2070)Water Connections (Victaulic), in (mm) 6 (152) 6 (152) 6 (152)

Table 15, Physical Data, WHS 190A - 220AData 190A 200A 220A

BASIC DATAUnit Capacity @ ARI Conditions, tons(kW)

187.9 (658) 197.3 (691) 218.0 (763)

Refrigerant HCFC-22 HCFC-22 HFC-134aUnit Operating Charge, lb. (kg) 653 (296) 653 (296) 857 (389)Min Pumpdown Capacity, lb. (kg) 822 (373) 822 (373) 915 (415)Cabinet Dimensions 162.7 x 42 x 76.9 162.7 x 42 x 76.9 163.7 x 43.9 x 84.2L x W x H, in. (mm) 4134 x 1067 x 1953 4134 x 1067 x 1953 4159 x 1115 x 2140Operating Weight (with starters),lb.(kg) 9970 (4522) 9970 (4522) 12060 (5469)Shipping Weight, (with starters),lb.(kg) 9567 (4339) 9567 (4339) 11300 (5125)COMPRESSORS, SCREW, SEMI-HERMETICNominal Tons, (kW) 85 (300) 100 (350)) 100 (350) 100 (350) 105 (365) 105 (365)FLOODED EVAPORATORQuantity, (Number of Water Passes) 1 (2) 1 (2) 1 (2)Shell Diameter – Tube Length 18 - 12 18 - 12 22 - 12 in. (mm) ft. (mm) (457 - 3658) (457 - 3658) (559 - 3658)Water Volume, gallons (L) 42 (160) 36.9 (140) 62.2 (236)Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)Max. Refrigerant Pressure, psi (kPa) 250 (1725) 250 (1725) 400 (2760)Water Connections (Victaulic), in (mm) 6 (152) 6 (152) 8 (204)CONDENSERQuantity, (Number of Water Passes) 1 (2) 1 (2) 1 (2)Shell Diameter -- Tube Length 18 - 12 18 - 12 20 - 12 in. (mm) ft. (mm) (457 - 3658) (457 - 3658) (508 - 3658)Water Volume, gallons (L) 51.6 (196) 45.2 (171) 61.3 (232)Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)Max. Refrigerant Pressure, psi (kPa) 300 (2070) 300 (2070) 475 (3278)Water Connections (Victaulic), in (mm) 6 (152) 6 (152) 6 (152)


Dimensional Data

Figure 4, WHS 155A - 200A, R-22 Refrigerant

All dimensions are shown ininches and (mm).

Overall LengthA

Overall OverallWidth

1 & 3 2 & 4 Pass 2 & 4 Pass Height WithPass Head Conn.

On Same EndHead Conn.Both Ends

(Note 12) Starter

169 1/4 162 3/4 169 1/4 76 7/8 42(4299) (4134) (4299) (1953) (1067)

Center of Gravitywith Starter Weight

sX Y Z lb (kg)

Operating 79 3/8 35 1/2 13 7/8 9970(2016) (902) (353) (4522)

Shipping 79 5/8 34 5/8 14 9567(2023) (880) (356) (4334)

See notes on next page


WHS 155A - 200A Continued

Vessel Code Head Connection U.S. PipeSize

AA BB

Evap. Cond. 1P 2P 3PE1812 8 6 5 4 7/8

(124)4 7/8(124)

C1812 N.A. 6 5 4 7/8(124)

4 7/8(124)

Notes:1. One half inch (13) FPT evaporator and condenser relief valves must be piped per ANSI/ASHRAE 15. (1 for each evaporator, 2 for

each condenser).2. 144 inches (3658) is required at either end of the tubesheet for tube replacement. 36 inches (914) is recommended on all other

sides and top for service clearance.3. Final connections must allow for manufacturing tolerance.4. Standard heads are shown. For dimensions of high pressure construction, water boxes, or flange type connections, contact your

representative.5. For dimensions of different condenser or evaporator pass see table.6. Unit is shipped with an operating charge of refrigerant and oil.7. Six 2 1/2 inch (64) dia. Lifting holes are provided.8. All water connections are given in standard U.S. Pipe sizes. Standard connections are suitable for welding or victualic couplings.9. Vibration isolator pads are provided for field installation 0.25 inches (6) thick when loaded.10. If main power wiring is brought up through the floor, this wiring must be outside the envelope of the unit.11. Pumpdown capacity is determined in accordance with ANSI/ASHRAE 15 for the maximum tube count.12. The shipping skid adds 4 inches (102) to the overall unit height.


Figure 5, WHS 220A, R-410A Refrigerant

All dimensions are shownin inches and (mm)

Overall LengthA Overall

OverallWidth

1 & 3 2 & 4 Pass 2 & 4 Pass Height WithPass Head Conn

on same endHead Conn.both ends

(Note 12) Starter

169 1/4 163 3/4 169 1/4 84 3/4 43 7/8(4299) (4159) (4299) (2141) (1114)

Center of Gravitywith Starter Weights

X Y Z lb (kg)Operating 78 3/8 38 1/2 15 1/2 12,060

(1991) (978) (394) (5464)Shipping 78 5/8 37 7/8 15 5/8 11,300

(1997) (962) (397) (5125)

See Notes on Next Page.


WHS 220A Continued

Vessel Code Head Connection U.S. PipeSize

AA BB

Evap. Cond. 1P 2P 3P

E2212 10 8 6 5 3/4(145)

6 3/8(161)

C2012 N.A. 8 5 5 5/8(143)

6 3/16(157)

Notes:1. One half inch (13) FPT evaporator and condenser relief valves must be piped per ANSI/ASHRAE 15. (1 for each evaporator, 2

for each condenser).2. 144 inches (3658) is required at either end of the tubesheet for tube replacement. 36 inches (914) is recommended on all

other sides and top for service clearance.3. Final connections must allow for manufacturing tolerance.4. Standard heads are shown. For dimensions of high pressure construction, water boxes, or flange type connections, contact

your representative.5. For dimensions of different condenser or evaporator pass see table.6. Unit is shipped with an operating charge of refrigerant and oil.7. Six 2 1/2 inch (64) dia. Lifting holes are provided.8. All water connections are given in standard U.S. Pipe sizes. Standard connections are suitable for welding or victualic

couplings.9. Vibration isolator pads are provided for field installation 0.25 inches (6) thick when loaded.10. If main power wiring is brought up through the floor, this wiring must be outside the envelope of the unit.11. Pumpdown capacity is determined in accordance with ANSI/ASHRAE 15 for the maximum tube count.12. The shipping skid adds 4 inches (102) to the overall unit height.


Application Data

Chiller Water SystemMcQuay strongly recommends that chilled water piping for its chillers be designed and installed inconformance to the system recommendations described in (American Society of Heating Refrigerationand Air-Conditioning Engineers, Inc.) ASHRAE Handbooks. Specifically the 1996 Edition, HVACSystems & Equipment, Chapter 12.

Multiple UnitsChillers are frequently installed in multiple. Doing so provides standby reliability and improvedperformance, and is recommended. Multiplicity of machines however can result in unexpectedproblems where chiller controls or capacity reduction are overlooked in the design. Single chillerinstallations are equally susceptible to application oversight. The following offers supplementalinformation to that discussed in ASHRAE for the purpose of minimizing installation problems.

Water FlowChilled water systems are normally designed with leaving chilled water temperatures of 40°F to 46°F,a 10°F water temperature difference, and 0.0001 fouling factor. Catalog tables display performance ofthe chillers at these conditions. Contact McQuay when actual design conditions are different.

Specifications and start-up procedures should:1. Confirm that the chilled water piping system had been properly flushed out before being

connected to the chiller vessel.

2. Confirm that the piping contains

a) A cleanable strainer to remove impurities before they reach the chiller vessel

b) An expansion tank in the piping, and

c) An air vent located at the system high point to purge off trapped air in the piping system. Anair vent is also located at the top of the direct expansion chiller vessel and in the water head ofa flooded vessel.

All water systems include air in solution with the water. The percentage of air that can be retained insolution is a function of the water temperature and water pressure. Since these two values change inboth chilled and hot water systems, the presence of both b and c components listed above are vital tothe successful operation of the system.

The presence of a cleanable filter or strainer (a above) in a chilled water piping system is frequentlytaken for granted. The fact is that the filter or strainer may be inadequate for the installation or maybeinstalled in the wrong location.

1. If the chilled water pump is located in the chilled water piping exiting the chiller vessel downstream of the chiller, and the strainer is in its normal position ahead of the chilled water pump,then system impurities will be drawn, unfiltered through the chiller vessel. Severe reduction inchiller performance is the probable result.

2. Many chiller installations today are replacements for older worn out or less efficient machines.Existing piping is drained down, opened to atmosphere, and reconnected to the new chiller vessel.Rust formed over the years and during the replacement process can break loose, pass through aconventional strainer, and settle in the chiller vessel that is frequently the lowest point in thepiping system. Not only is a higher capacity filter required for these installations, but chemicaltreatment of the water is recommended immediately.


Checking Water FlowThe simplest method of checking water flow, presuming the chiller vessel has not been fouled or is airbound, is to read the entering and leaving pressure drop and compare the actual pressure drop to thevalue published in the product catalog of the installation manual for the unit.

Pressure drops at the job are read in psi. Published values are displayed in feet of water. Use thefollowing formula to convert from one to another.

2.31 x psi = Feet of water

or

Feet of water x 0.433 = psi

System Water Quantity

Storage Tanks: when are they required and why?This question is often asked today and not satisfactorily answered, with the result that in someinstallations, a chilled water storage tank is installed when it is unnecessary and conversely not fittedwhen it is required.

Many air conditioning design engineers approach the question from the wrong angle by considering thestored water as a "reserve" of cooling capacity. In the event of a chiller failure, a few moments’thought ahead of time would clearly indicate that such a reserve is of such short duration as to bevirtually useless. For example, consider a 100 ton (30.5 kW) plant circulating 240 gpm (15 L/s) witha 10°F (5.5°C) temperature differential. It would theoretically require a storage tank of 7200 gallons(27 m3) to operate the plant for thirty minutes. This represents a stored volume of water of 965 cubicfeet (27 m3) or a tank of approximately 10 ft (3 m) wide by 10 ft (3 m) long by 10 ft (3 m) high.

To construct such a tank would be extremely costly, and in addition during the 30 minutes ofoperation, the temperature of the water leaving the tank will be rising at the rate of 1°F (.55°C) every 3minutes due to mixing of the water in the tank. If a storage tank is not an economic proposition toprovide a cooling reserve, when is it required? The answer is: A chilled water storage tank is requiredin installations in which the mass of chilled water in the system is comparatively low and where theminimum applied system load can fall below the minimum "off loaded" capacity of the compressor.

If the system is out of balance, i.e. running fully unloaded but with more heat being extracted by thecompressor than can be added to the system, the chilled water temperature will decrease. Thecompressor will cycle off and then on again to the detriment of the machine and its starting equipment.A storage tank is simply a means of increasing the water volume to be handled by the chiller andthereby increase the running and shut down times.

McQuay screw compressor chillers have anti-recycle timing of 15 minutes start-to-start and 5 minutesstop-to-start. The default lead-lag setting will even out starts so the compressor that just shut off willbe the second to come on and depending on how long it has been off, could start immediately, if thetemperature control called for cooling. The MicroTech control can be set for one compressor toalways be the lead; this is the worst case for short cycling problems.

Example: (In I-P units) Consider a 200-ton system utilizing a rotary screw packaged water chillerwith two 100 ton compressors circulating 480 gpm and assume that the minimum load can drop aslow as 10 tons. Question - Is it necessary to install a chilled water storage tank and if so, how large?

First of all calculate the volume of chilled water in the system:

Unit evaporator = 40 gal. (from Product Manual)

Piping: 50 ft. of 5 in. pipe = 45 gal.

Coils: 15 gal.

Total: 100 gal.


A leaving water thermostat with a control band of approximately 5 degrees controls the compressors.At minimum load the compressor runs at 25% capacity, in this case equal to 25 tons. The load is onlyadding 10 tons, so the chilled water temperature decreases until shut-off occurs (for a perioddependent on the water volume). While the unit is off, the chilled water temperature will rise due tothe imposed 10 ton load until the thermostat turn-on setting is reached (the period determined by thesystem water volume). Again, the chiller with one compressor in operation is extracting heat at agreater rate than the load is putting in and the cycle repeats.

The Microtech default anti-recycle settings are as above, but a more prudent operating mode that willextend compressor life would call for a 20 to 30 minute period between starts. The recycle timingcould be increased to provide this but in systems with inadequate water volume the temperature riseduring the off cycle would probably cause loss of space conditions. The answer is to design sufficientthermal capacitance into the system from the beginning. The formula for determining the proper watervolume, taking into the operating characteristics explained above, is:

)221

(500HTD

HHTD

x

TsVw

+−

=

Where Ts =Time between starts (20 to 30 minutes)

Vw = Water volume (U.S. gallons)

H1 = Minimum operating capacity of chiller (BTU/hr)

H2 = Minimum applied system load (BTU/hr)

TD = Operating range of thermostats (5 degrees)

500 = pound/gpm/specific heat constant

For the example above:

.867)

000,1205

000,120000,3005

(500

30gal

xVw =

+−

=

Since the system has 100 gal. volume, 767 gal. should be added by a storage tank.

Freeze ProtectionMcQuay Model ALS air-cooled chillers are equipped with thermostatically controlled heat tape underthe insulation of the evaporator barrels. The heater comes from the factory connected to the controlpower circuit but can be rewired to a separate 110V supply. If this is done, the disconnect switchshould be clearly marked to avoid accidental deactivation of the heater during freezing temperatures.The heater will provide freeze protection to -20°F. However, this does not provide protection to theexposed chilled water piping. Unless the evaporator is flushed and drained as described in note 4 twoor more of the following recommendations should be part of the system design and be implemented.The WHS chiller is designed for a heated indoor location. If freezing conditions are possible, also takethe following precautions:

1. Continuous circulation of water through the piping and heat exchanger.

2. Addition of the required concentration of a glycol anti-freeze to the circuit. This will result indecreased capacity and increased pressure drop. Note: do not use automotive grade anti-freezesthat contain inhibitors harmful to chilled water systems.

3. Addition of insulation and heat to any exposed piping and equipment.

4. Draining and flushing the chiller with glycol.


Condenser Water Systems

PipingWHS evaporators and condensers are equipped with either victaulic or flange connections. Theinstalling contractor must provide matching connections.

CAUTIONRemove the solid-state temperature sensor and thermostat bulbs from the wells to preventdamage to those components when welding on the victaulic or flange connections.

Connect the condenser with the inlet water entering at the bottom to maximize subcooling. Thecondenser water will discharge from the top connection.

Support piping to reduce weight and strain on the fittings and connections. Be sure piping isadequately insulated. Install a cleanable 20-mesh water strainer in evaporator and condenser waterpiping. Install enough shutoff valves to permit draining water from the evaporator or condenserwithout draining the complete system.

CAUTIONFreeze Notice: The evaporator and condenser are not self-draining. Both must be blownout.Include thermometers at the inlet and outlet connections and air vents at the high points of piping. Thewater heads can be interchanges (end for end) allowing water connections to be made at either end ofthe unit. Use new head gaskets when interchanging water heads. When water pump noise isobjectionable, use rubber isolation sections at both the inlet and outlet of the pump. Vibrationeliminator sections in the condenser inlet and outlet water lines are not normally required. Wherenoise and vibration are critical, and the unit is mounted on spring isolators, flexible piping connectionsare necessary.

Filtering and TreatmentIf the unit is operating with a cooling tower, clean and flush the cooling tower. Make sure tower"blow-down" or bleed-off is operating. Atmospheric air contains many contaminants which increasesthe need for water treatment. The use of untreated water may result in corrosion, erosion, sliming,scaling, or algae formation. A water treatment service is recommended. McQuay International is notresponsible for damage or faulty operation from untreated or improperly treated water.

Head Pressure Control, Tower SystemThe entering water temperature to the condenser must not be lower than 75°F (24°C) at full towerwater flow assuming a 10 degree F (5.5 degree C) temperature rise. If lower temperature water isused, the flow must be reduced proportionally. Use a three-way bypass valve around the tower tomodulate the condenser water flow. Figure 2 shows a three-way pressure actuator water regulatingvalve for cooling applications. This regulating valve will assure an adequate condensing pressure ifthe inlet condenser water temperature falls below 75°F (24°C). An optional AOX-4 board located inthe MicroTech panel will control a cooling tower bypass valve or a variable speed condenser pump.

Head Pressure Control, Well Water SystemWhen using city or well water for condensing refrigerant, install a normally closed direct acting waterregulating valve in the outlet piping of the condenser. This regulating valve will assure an adequatecondensing pressure if the inlet condenser water temperature falls below 75°F (24°C). The condenserservice valve provides a pressure tap for the regulating valve. The valve can modulate in response tohead pressure. On shutdown, the valve closes, preventing water from siphoning off the condenser.Siphoning causes condenser waterside drying and accelerates fouling. If a valve is not used, Figure 3illustrates the recommendation of a loop at the outlet. Size the loop height (H) to offset the negativepressure caused by the siphoning effect. A vacuum breaker may be required.


Well water may require special tube material other than standard copper. If there is any question as tomaterial suitability, a water sample should be tested by a qualified laboratory and materialrecommendations followed.

Figure 6, Bypass Valve

Figure 7, Well Water System

TemperatureModel WHS water-cooled screw compressor chillers require an ample supply of clean condenser waterwithin specified temperatures for satisfactory operation. The water quantity must be sufficient todissipate the chiller heat rejection (evaporator tons plus motor input tons).

Motor input tons may be calculated from the kW input published for the performance conditionsselected. Since the compressor design virtually eliminates motor heat loss to ambient air, it can beassumed that 100 percent of the motor input energy reverts to the condenser.

Motor input tons = (kWi x 3413 BTU/kW) / 12,000 BTU/Ton or

Motor input tons = kWi / 3.516

To calculate the required condenser GPM:

GPM = (THR x 24) / water delta T THR = Total heat Rej.=Evaporator Tons + Motor Tons


Condenser water temperature difference (TD) is normally based on 10 degrees F, where cooling towersare used. Other values are accepted provided they are consistent with the cooling tower selectionvalues. Also, cooling tower water is normally assumed to have a basin water temperature of 85degrees F. This is presumed to be the entering condenser water temperature as well. If however theapplication has extensive condenser water piping, requiring a large horsepower condenser water pump,and the pump is located ahead of the condenser inlet, the pump input energy may elevate the enteringcondenser water temperature slightly. With this exception the temperature of the water leaving thecooling tower will be the temperature entering the condenser.

This temperature should be highest that the chiller will be exposed to during it’s operation. At lowercooling loads and at lower outside wet bulb temperatures the tower’s basin water temperature beingdelivered to the condenser should also be lower that 85°F.

This lower temperature should not be permitted to drop below 75°F (24°C) at full design water flow,In other words, if entering condenser water temperature can be expected to drop below 75°F (24°C).,bypass valves, or variable speed pumping is desirable to reduce the volume of water circulated throughthe condenser.

McQuay screw compressors, coupled with the electronic expansion valve, can operate satisfactorilywith saturated condensing pressures of 150 psig when leaving chilled water temperature is 46 degreesF.

For each 2 degrees F, reduction in chilled water temperature below 46°F, the minimum saturatedcondensing pressure can be reduced by 2 psig.

Startup with Cold Condenser WaterWHS screw compressor chillers are designed to permit startup with elevated chilled watertemperatures and cold condenser water. Following a weekend shutdown, for example, in relativelycool, low wet bulb ambient, the building chilled water temperature could be 70°F to 80°F with acondenser water temperature of 55°F. Start up under these conditions is expected. If the cooling loadis excessive, or condenser water temperatures substantially less, modification of alarm timer settingsby the McQuayService Technician may be required.

ClearanceService and tube pull clearance must be provided in accordance with the unit dimension drawings.Tubes can be pulled from either end.

VibrationUnit vibration levels are extremely low, less than 0.14 in/sec. However vibration isolation may bedesirable in sensitive installations.

Electrical

Voltage ToleranceThe standard tolerance is +/- 3% voltage variation between phases. If a voltage variation of 2.5%occurs, the motor temperature rise will increase by 12.5% (2.52 x 2) which is within compressorspecification. However, a 3.5% voltage unbalance would cause a 24.5% (3.52 x 2) increase in motortemperature that is outside of the allowable compressor motor tolerance. The connected voltagetolerance is +/- 10% of the motor nameplate rating.

Current UnbalanceCurrent unbalance is limited to 10% but will be influenced by or with voltage. The percent motorcurrent unbalance will be approximately 6 to 10 times the percent voltage unbalance.



Options

StartersAll units are furnished with a factory-mounted starter; either Delta-Delta or Solid-State . Delta-Deltastarters work on the same principal as part-winding start. The inrush current is reduced by using two-step starting of each compressor. When a further reduction in inrush current is preferred, a solid-statestarter may be used.

Solid-State starter consists of a power section rated for the given RLA and consists of six back-to-backsilicon controlled rectifiers (SCR’s) to provide smooth, stepless acceleration of the compressor motor.Once the motor reaches full speed, an bypass contactor is energized in parallel to the SCR’s to handlethe motors continuous duty load.

Vessel Options (Length and Pass Arrangement)Units are equipped with shell size and passes as noted in the Physical Data tables. Various evaporatorand condenser pass arrangements are available to accommodate specific applications. Standard unitshave vessels with a water side pressure rating of 150 psig. Special vessels can be ordered with waterside pressure ratings of 300 psig.

Flanged ConnectionsFlanges for evaporator and condenser are available. All companion flanges, nuts, bolts, and gasketsmust be field supplied. Standard unit has victaulic connections for evaporator and condenser.

Marine Water BoxesMarine Boxes with victaulic or flanged connections are available. These simplify removal andcleaning of evaporator and condenser tubes without disconnecting the water piping and can reducedowntime and labor costs.

InsulationStandard insulation on low temperature surfaces, including the evaporator is 3/4 inch closed cellinsulation. Optional 1-1/2 inch closed cell insulation for the evaporator and 3/4 inch closed cellinsulation for the condenser is available. All insulated surfaces are painted to match the unit color.

Water Flow Switch/Pressure Differential SwitchWater flow switches are available for field installation in the chilled water and condenser water pipingto prevent evaporator freeze-up under low or no flow conditions. Terminals are provided in the unitcontrol center for field connection of the water flow safety switch.

Factory mounted pressure differential switches are available to detect evaporator or condenser loss offlow. Pressure drop across the evaporator or condenser is used to determine a loss of flow in thevessels. A positive method of proving flow is required before units can be started up.

Main Circuit BreakerA factory installed panel mounted main circuit breaker is available on all units. The circuit breaker isproperly sized for model and voltage required (not available with Compressor Circuit Breaker option).The circuit breaker serves as a disconnecting means when servicing the unit. The breaker qualifies as adisconnecting device specified by the National Electrical Code Section 440-21, "Branch Circuit Short-Circuit and Ground Fault Protection".


Compressor Circuit BreakerFactory installed compressor circuit breakers are available on all units (not available with MainCircuit Breaker option).

Ammeter and VoltmeterAmmeters and voltmeter are available. One voltmeter with phase selection switch and two ammeters(one for each compressor) with phase selection switch.

Ground Fault ProtectionA ground fault interrupter provides protection from damaging line-to-ground fault currents by openingall ungrounded conductors of the faulted circuit and shutting down the entire unit.

Vibration IsolatorsSpring or rubber-in-shear vibration isolators are available for field installation under the unit baseframe. Unit vibration levels are extremely low, however vibration isolators are recommended on allupper level installations where vibration transmission is a concern.

Chiller System ControllerA Chiller System Controller (CSC) panel provides monitoring and control of up to four chillers, eachchiller connected by a single twisted pair of wires. The CSC panel allows the user to accessinformation regarding the chiller status, such as temperatures, pressures, control setpoints, alarmconditions, time and date of alarms, and the ability to clear alarms remotely.

Phone ModemA 9600 baud modem is available allowing the operator to control (or monitor) all chiller operationsfrom a remote location using standard telephone lines. This feature avoids frequent trips to the jobsiteto read the display panel and provides easy access to system data from a remote location.

Open ProtocolOpen Protocol provides an interface between one or multiple MicroTech controllers and the buildingautomation system. Reduced installation costs, greater reliability and a continuous operator interfacewith all equipment in the building is the result when using open protocol. The MicroTech OpenProtocol Master (OPM) panel provides the temperature control company a single-point connectionwhen two or more MicroTech controllers are being networked with the temperature control company'ssystem.

Personal Computer MonitoringMicroTech Monitor software may be used on the customers personal computer to communicate withthe MicroTech controller. The controller connects directly or remotely over phone lines with anoptional modem.

Network Master PanelThe MicroTech Network Master Panel (NMP) allows incorporation of multiple screw chillercontrollers into a building-wide network with other MicroTech units and auxiliary controllers. Inconjunction with a personal computer, the building operator has the capability to perform advancedequipment control and monitoring from a central or remote location.

Chiller TestingAll units are run tested extensively before shipment to assure a trouble free start-up. An optionalwitness or certified test is also available. Certified test allows capacity verification at full and partload conditions.



Product Specification

NOTE: These specifications are available on disk in an editable MSWord format fromthe local McQuay sales office.

SECTION 15XXXWATER-COOLED ROTARY SCREW CHILLERS

PART 1 - GENERAL

1.01 SUMMARY

Section includes design, performance criteria, refrigerants, controls, and installation

requirements for water-cooled rotary screw chillers.

1.02 REFERENCES

Comply with applicable Standards/Codes of ASHRAE 90.1, ARI 590, ANSI/ASHRAE 15,

ASME Section VIII, NEC, and OSHA as adopted by the State.

1.03 SUBMITTALS

A. Submit shop drawings and product data in accordance with specification

requirements

B. Submittals shall include the following:

1. Dimensioned plan and elevation view drawings, required clearances, and

location of all field connections.

2. Summary of all auxiliary utility requirements such as electricity, water,

compressed air, etc. Summary shall indicate quality and quantity of each

required utility.

3. Single line schematic drawing of the power and ancillary utility field

hookup requirements, indicating all items which are furnished.

4. Schematic diagram of control system indicating points for field

interface/connection. Diagram shall fully delineate field and factory

wiring.

5. Certification of factory run test of chiller unit signed by company officer.

6. Installation Manuals

1.04 QUALITY ASSURANCE

A. Qualifications; Equipment manufacturer must specialize in the manufacture of the

products specified and have five years experience with the equipment and

refrigerant offered.

B Regulatory Requirements: Comply with the codes and standards specified

C Chiller manufacturer must be ISO 9002 registered.


1.05 DELIVERY AND HANDLING

A. Chillers shall be delivered to the job site completely assembled and charged with

refrigerant and oil by the manufacturer

B. Comply with the manufacturers instructions for rigging and handling equipment.

1.06 WARRANTY

The refrigeration equipment manufacturer’s warranty shall be for a period of one

year from date of equipment start but not more than 18 months from shipment. The

warranty shall cover defects in material and workmanship and include labor to

replace or repair the defective part and shall include replacement of refrigerant loss

due to defects.

PART 2--PRODUCTS

2.01 ACCEPTABLE MANUFACTURERSA. McQuay InternationalB. (Approved Equal)

2.02 UNIT DESCRIPTIONProvide and install as shown on the plans factory assembled, factory charged, and factory run

tested water-cooled rotary screw packaged chillers in the quantity specified. Each chillershall consist of accessible semi-hermetic rotary screw compressors, flooded evaporator,water-cooled condenser, microprocessor based control system and all components necessaryfor safe and controlled unit operation.

2.03 DESIGN REQUIREMENTSA. General: Provide a complete rotary screw packaged chiller as specified herein and as

shown on the drawings . The unit shall be in accordance with the standards referenced insection 1.02 and any local codes in effect.

B. Performance: Refer to the schedule of performance on the drawings. The chiller shall becapable of stable operation to a minimum of 12.5 percent of full load without hot gasbypass . Performance shall be in accordance with ARI Standard 590, and ASHRAE 90.1.

C. Acoustics: Sound pressure levels for the units shall not exceed the following specifiedlevels. The manufacturer shall provide the necessary sound treatment to meet theselevels if required. sound data shall be provided with the quotation. Test shall be inaccordance with ARI Standard 575.

Octave Band

63 125 250 500 1000 2000 4000 8000 dBA


2.04 CHILLER COMPONENTSA. Compressors: The compressors shall be field serviceable, semi-hermetic, single-screw

type with one main helical rotor meshing with two opposed gaterotors. If a twin-screwcompressor is used, the manufacturer shall provide an extended 5-year parts and laborwarranty covering all moving parts, due to the large bearing loads inherent with thisdesign. The gaterotors’ contact elements shall be constructed of a carbon impregnatedcomposite material designed for extended life. Liquid refrigerant shall be used forcooling and sealing the rotor interfaces.Compressor motors shall be two pole, squirrel cage induction type and cooled bycirculating liquid refrigerant. Suction gas cooled designs shall include an extended 5-year compressor warranty including parts and labor. Full load power factor shall be aminimum of 0.92.

B. Evaporator: The evaporator shall be of the flooded shell and tube type with refrigerant inthe shell and chilled fluid in the tubes. Enhanced high efficiency copper tubes shall bereplaceable and rolled into steel tube sheets. Water heads shall be removable. Theevaporator shall be insulated with 3/4 inch (19mm) closed cell polyurethane insulationand painted with resilient paint to resist cracking. The evaporator shall be designed for arefrigerant side working pressure of 250 psig (1725 kPa) for R-22 and 400 psig (2760kPa) for R-410A and water side working pressure of 150 psig (1035 kPa). Theevaporator shall be designed, inspected, and stamped in accordance with ASME SectionVIII requirements.

C. Condenser: The condenser shall be of the shell and tube type with refrigerant in the shelland water in the tubes. Replaceable high efficiency copper tubes shall be rolled into steeltube sheets. The condenser shall have steel intermediate tube supports and be equippedwith removable water heads. It shall be constructed and stamped in accordance with therequirements of ASME Section VIII Unfired Pressure Vessel Code. Condenser shallhave a refrigerant side working pressure of 300 psig (2070 kPa) for R-22 and 475 psig(3275 kPa) for R-410A and water side working pressure of 150 psig (1035 kPa) and beprovided with ASME, ANSI B9.1 pressure relief valves.

D. Refrigerant circuit: Each compressor shall operate in parallel on a common refrigerantcircuit. Sufficient valving shall be included to allow a compressor to be removed forservice while the balance of the unit remains operable and also to allow the refrigerant tobe pumped into and contained in the condenser. The unit shall be equipped with a liquidline shut-off valve, filter-drier, liquid line sight glass, and solenoid valve and insulationwhere required to prevent condensation forming.

E. Control System: The microprocessor based controls shall be housed in a NEMA 1enclosure which will also include terminal points for power and control interlock wiring,starting contactors, circuit breakers, three-phase overload protection, and controltransformer and control fusing. Panel doors shall be lockable. The enclosure shall havea barrier panel to segregate line voltage components. A digital display and keypad shallbe mounted on the front panel.1. The following displays shall be furnished:

a) Entering and leaving chilled fluid temperatureb) Entering an leaving condenser water temperaturesc) Suction and discharge pressure and saturated temperature for each compressord) Suction temperature and calculated superheat for each compressore) Liquid line temperature and calculated subcooling temperaturef) Electronic expansion valve positiong) Programmed setpointsh) Alarm and failure messagesi) Run hours and starts for each compressor


2. The following features shall be included:a) Current limiting for each compressor, locally or from a remote 4-20mA signalb) Control of chilled fluid leaving temperaturec) Remote alarm contactd) Pro-active pre-alarm logic providing control adjustments to avert shutdowne) Fault messages including readout of all critical parameters at time of faultf) Fault history of 5 previous fault conditionsg) Adjustable soft load function to limit load during pulldown periodsh) Chilled fluid reset from a 4-20mA signal or by control of entering fluid

temperaturei) Manual or an automatic lead-lag control equalizing starts and run hoursj) Time clock for daily start and stop with weekend and holiday differentiationk) Auto-restart after a power interruption without battery backupl) Capability to add a modem for PC monitoringm) Capability to add open protocol communication to a BMS

3. The following safeties shall be included:a) High discharge and low suction pressure unloading for each compressorb) High discharge and low evaporator pressure cutoutc) Chilled water freeze protectiond) Loss of evaporator or condenser water flowe) Loss of evaporator or condensing pressure sensorsf) Loss of leaving chilled fluid temperature sensorg) Phase loss, phase reversal, phase imbalance, and under and over voltage

protectionh) Motor protection for each compressor

2.05 OPTIONS AND ACCESSORIES• Delta-Delta compressor starters• Solid-state compressor starters• Factory installed compressor motor circuit breakers• Ground fault protection

PART 3 - EXECUTION

3.01 INSTALLATION

A. Install in strict accordance with manufacturer’s requirements, shop drawings, and

contract documents.

B. Adjust and level chiller in alignment on supports.

C. Coordinate electrical installation and controls with the designated contractors.

D. Provide all appurtenances required to ensure a fully operational and functional chiller.

3.02 START-UP

A. Ensure proper charge of refrigerant and oil.

B. Provide Authorized Factory starting of machine, and instruction to the Owner in its

proper operation and maintenance.

END OF SECTION

Post Office 2510, Staunton, Virginia USA 24402-2510 (540) 248-0711

Date post:	29-Mar-2021
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