Bulletin HP237a October, 1996 HANSEN TECHNOLOGIES CORPORATION CAM 2/3 (shown) HERMETIC LIQUID REFRIGERANT PUMPS Ideal for Liquid Overfeed and Liquid Re-Circulation (Also Usable for Liquid Transfer & Liquid Pressure Boost) OPERATOR INSTALLATION & INSTRUCTION MANUAL (For CAM and CNF Series Pumps) Hermetic pumps are superior to most other pumps for refrigeration systems because they are sealless, requiring no oil or grease lubricant , are very smooth and quiet, are not bothered by frost or moisture, and normally provide many years of reliable operation. Like many fine pieces of machinery, Hermetic pumps must be properly installed with regard to system layout, sizing, and controls so the pump receives adequate solid liquid which is free of gas bubbles and abrasive particles. Following these instructions helps guarantee a long and trouble-free pump life.
Transcript
Bulletin HP237aOctober, 1996
HANSEN TECHNOLOGIESCORPORATION
CAM 2/3 (shown)
HERMETIC LIQUIDREFRIGERANT PUMPS
Ideal for Liquid Overfeed and Liquid Re-Circulation(Also Usable for Liquid Transfer & Liquid Pressure Boost)
OPERATOR INSTALLATION& INSTRUCTION MANUAL
(For CAM and CNF Series Pumps)
Hermetic pumps are superior to most other pumpsfor refrigeration systems because they are sealless,requiring no oil or grease lubricant , are very smoothand quiet, are not bothered by frost or moisture, andnormally provide many years of reliable operation.
Like many fine pieces of machinery, Hermetic pumpsmust be properly installed with regard to systemlayout, sizing, and controls so the pump receivesadequate solid liquid which is free of gas bubbles andabrasive particles. Following these instructions helpsguarantee a long and trouble-free pump life.
2
MATERIAL SPECIFICATIONSCasing: Ductile Iron A356 (GGG-40.3)Stator casing: Steel A529 Grade 40Stator lining (Can): Stainless Steel A276 type 346TShaft: Chrome Steel A22C type 420Impeller: Cast Iron A48; CAM Class 30,
CNF Class 35Sleeves: Stainless Steel A276 type 346TBearings: Carbon type 23Maximum operating pressure: 362 PSIG (25 bar)Temperature range: -60F to 194F (-51°C to 90°C)Lower Temperature:
To -150F with stainless steel construction(contact Hansen)
Housing: NEMA 4 construction (IP64/IP67/IP55)CSA Listed: File No. LR75907-2
Figure 1
PUMP EQUIPMENTBelow is a drawing depicting a typical pump as wouldbe supplied by Hansen, see Figure 1. Pumps comecomplete and pretested. Please note the protectiondevices which are provided with pump. One shouldbecome familiar with each or these devices andunderstand how, when properly installed and utilized,they can help to ensure a long and trouble-free pumplife.
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Proper pump suction line sizing helps to minimizebubbling and vortexing of the liquid refrigerant whichcan cause cavitation or loss of prime. For ammonia,typical pump suction line sizing should deliver anoptimum 3 feet per second from the accumulator vessel(pump recirculator). For halocarbons, a flow rate of2.5 feet per second is optimum. The suction lineshould be sized for the maximum allowable pump flow,not the nominal design flow because pump demandcan vary widely due to system demands such asdefrost terminate and production start up. Undersizingthe suction line is not tolerable, while oversizing shouldnot exceed 1 or 2 pipe sizes. Suction line pipe sizingis listed in Table 2. Because the pump inlet is Venturishaped, the pump inlet flange connection is normallyone or two sizes smaller than the pump suction linepipe. Reducers on the pump inlet should be eccentricwith flat side on top to avoid bubble accumulation inthe suction line.
Adequate NPSH (Net Positive Suction Head) isnecessary to minimize the potential of cavitation duringnormal operating conditions. Typically, NPSH is definedas the static head of liquid (in feet) above the centerlineof the pump inlet; see Figure 3. Insufficient availableNPSH can cause the loss of pump pressure andlubrication; eventually leading to shortened pumpbearing life. The system required minimum NPSHvalues for each pump are specified in the StandardPump Specifications on page 20.
Avoid any unnecessary pressure drop in the pumpsuction line from valves, strainers, and fittings. Whereneeded, they should be of low pressure drop design.The pump suction line should be as short as possibleand ideally piped with a steady downward slope to thepump. Horizontal runs should not exceed 18 inches.Baffle plates should be installed in the accumulatorbefore the exit to the pump to eliminate vortexformation. The liquid level inside the vessel shouldbe a minimum of ten inches above the vessel internalinlet to the pump suction line and located away fromevaporator overfeed return, liquid makeup, hot gascondensate return and other piping arrangements.Some examples of correct and incorrect routing ofsuction piping are shown in Figure 2. The pump suctionline, vessel, level column, and float switches shouldbe insulated to minimize bubble formation.
SUCTION LINE PIPE SIZING (Ideal)
¾" thru 1½"= Schedule 80; 2" thru 6"= Schedule 40Basis: R717 at 3 ft/sec; Halocarbon at 2.5 ft/sec
The discharge line of a Hansen Hermetic pumpnormally must include a Q-max flow (capacity) controlorifice (see page 4) or Constant flow (capacity)regulator (see page 5) to limit maximum flow to preventcavitation and possible motor overload. Centrifugalpumps of all makes, whether canned or seal design,can operate inefficiently or at the higher NPSH thanrequired region on the pump performance curve ifcapacity is not controlled. Typical pump dischargeline sizing for ammonia should be based on a maximumof 7 feet per second and 5 feet per second forhalocarbons; see Table 3.
DISCHARGE LINE PIPE SIZING (minimum)
Basis: R717 at 7 ft/sec; Halocarbon at 5 ft/sec.Table 3
Normally, a check valve is located after the flowcontrol device to prevent back flow and reverse rotationof the pump when multiple pumps are in parallel. Ashut-off valve for servicing of the pump should beplaced after the check valve with a relief device thereinbetween. Alternately, a combination stop/check valvecan be used in place of both (see Hansen BulletinC519).
GENERAL INSTALLATIONA stable vessel pressure must be maintained to avoidthe spontaneous vaporization (boiling) of liquidrefrigerant inside the pump accumulator andassociated piping. The system designer must ensurethat compressor loading and loading sequences anddefrosting cycles do not change vessel pressurestoo rapidly. As general rule, vessel pressure changesdownward should be limited to 1 psi per minute tomaintain solid liquid flow to pump.
For pump servicing, a valved pump-out line from thebottom of the pump suction line, near the pump, shouldbe installed for the purpose of quickly evacuatingliquid refrigerant and system oil. This should be inaddition to properly sized, low pressure drop service/isolation valves in pump suction and discharge lines.
Pumps should be properly mounted to eliminatevibration damage and thermodynamic strains as thepump and piping are cooled to operating temperature.All pipe work should be flushed to clean out weldingslag and other foreign matter before operating pump.Unless the system is proven to be quite clean, asystem filter should be installed in pump dischargeline to remove silt, rust and particles which otherwisewould continue to recirculate throughout the system.This can improve overall system life by minimizingwear to other components and bearings. See HansenSystem Filter Bulletin HP782, available late 1996.
EZISEPIP MPG717R MPGnobracolaH"1 71 21
11/4" 72 91
11/2" 83 72
"2 36 94
21/2" 701 67
"3 661 011
"4 472 691
Figure 2
4
Q-min FLOW CONTROL ORIFICEThe supplied Q-min flow control orifice is required tovent gas from the pump and ensure proper pumpcooling. The Q-min flow control orifice should beinstalled in a horizontal part of vent/bypass line andabove the normal liquid level inside the vessel. Theline from the Q-min orifice to the vessel must freedrain into the vessel. For pump systems whereoperation at low flow rates is frequent, it isrecommended that a bypass differential regulator beinstalled parallel with the Q-min orifice. The differentialregulator opens at lower flow rates (and higherdifferential pressure) to maintain the pump nearer tothe smoothest low flow pump operation region.
The vent/bypass line should be piped from the dischargeline before the check valve, vertically back to theaccumulator above the high level limit. Any shut-offvalves in the vent line should be tagged and sealed inthe open position for closing only during pumpservicing. If multiple pumps in parallel are connectedto a common pump discharge line, each must have aseparate vent/bypass line with a Q-min orifice.
Q-max FLOW CONTROL ORIFICEThe Q-max flow control orifice limits the flow outputof the pump preventing it from developing cavitationand operating at higher than acceptable NPSHrequirements. It is normally installed between thepump flange and its companion outlet (discharge)flange. The Q-max orifice will help to preventoverloading of the motor during start up and varyingload conditions such as after defrost. If higherdischarge pumping head is desired, an optionalConstant Flow Regulator can be used instead of aQ-max orifice. See Constant Flow Regulator sectionand typical pump curve (Figure 4).
Figure 4
CONSTANT FLOW REGULATORConstant flow regulator can be used instead of the Q-max flow control orifice when higher pump dischargepressures at higher flow rates are necessary to meetdesign conditions (Figure 4). Constant flow regulatorcapacities are matched to the performance of a specificpump type. This protects the pump from motoroverload and provides a steady rate of flow to thesystem, and yet keeps the pump operating within therequired NPSH range.
Constant flow regulators are not a check valves andwill not prevent reverse flow. A detailed bulletin whichdescribes specifications, applications and serviceinstructions for these Constant Flow Regulators isavailable; Hansen Bulletin HP421. Spare factorycalibrated, pre-assembled regulators may be orderedfor Hansen or other pumps; specify GPM andrefrigerant. Consult factory for proper sizing as notto exceed pump safe operating range.
LOW LEVEL CUTOUTA low level float switch or level control (such as theHansen Vari-level Adjustable Level Controls) mustbe installed to prevent liquid level in the vessel fromdropping below system required minimum NPSH forthe pump under the design conditions.
PRESSURE GAUGESIt is strongly recommended that a pressure gauge beinstalled at the ¼" NPT fitting (discharge port adapter)located just below pump discharge flange, see figure3. This gauge can be an important tool when checkingproper pump performance and rotation. It is alsorecommended that gauges be installed to sense pumpsuction pressure and discharge pressure after theQ-max or constant flow regulator to monitor pressureto system.
TYPICAL PUMP CURVE
5
PUMP CONTROLLERA newly developed optional pump controller, the PumpGuardian, is available from Hansen. This pumpcontroller is designed to safeguard refrigerant liquidpumps and to alert operators of harmful operatingconditions as they occur. When properly connected,the Pump Guardian will provide excess-recyclingprotection to a pump thus preventing unnecessarydamage before cause of reoccurring problem can bediscovered and fixed. Pump Guardian also providesan integrated means of protection against cavitation,low liquid level, insufficient or loss of pump pressure,and motor-overtemperature. See wiring diagram onpage 13 and Hansen Bulletin HP519.
Typical schematic piping provided to help assist system designers in applying and selecting pumps, valves, andcontrols. The designer is ultimately responsible for safe and satisfactory operation of the pumping system.
Figure 3
DIFFERENTIAL PRESSURESTATThis control provides a dependable and economicalpressure cutout for liquid refrigerant pumps. It candisable the pump when a loss of pressure is detectedthus preventing pump from running dry. The standard,supplied pressurestat has a built-in 30 second timedelay which enables pressure to build up at start-upand also avoids nuisance shutdowns when pressurebriefly drops during the run cycle. Pressure is sensedacross the inlet and outlet of the pump (See Figure 3).Pump outlet pressure should be sensed at the ¼"NPT fitting (discharge port adapter) located just belowpump discharge flange. Pump inlet pressure shouldbe sensed near the pump inlet on top of the suctionline. The factory differential pressure setting is 10psid.
To reset pressurestat after it trips, simply push buttonlocated on front face of pressurestat. To avoidmanually resetting pressurestat, contact factory foradditional control requirements or consider using thePump Guardian Pump Controller, see right.
TYPICAL PUMP INSTALLATION
INSTALLED IN PUMP OUTLET FLANGE
6
Table 4
Service factor of 1.0 is for all pump models listed.
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00.0200.5301.3302.5100.02
05.106.006.054.205.1
ELECTRICAL SPECIFICATIONS
OVER-TEMPERATURE CONTROLThe CNF series pumps are provided with miniaturethermistors which are imbedded in the windings ofthe electric motor stator. With an increase intemperature, these thermistors change theirresistance value exponentially within their maximumallowed temperature range. Typically, a rise inresistance is caused by excess current draw due tolow or high voltage, worn bearings, oil in pump or lackof refrigerant to pump. At a resistance value of about4.5 k ohm, the INT-69 cuts off the motor by openingthe motor contactor. This stopping of the pump shoulddraw operator's attention to the possible causes ofelevated winding temperatures. Note: INT-69 will allowpump to restart automatically after motor cools tonormal temperature.
The thermistors are connected in series and are marked5 & 6 (grey and white wires) in the main power cord(or a separate adjacent cord for model CNF 50-160AGX 8.5). They are to be wired directly to terminals 1and 2 of the INT-69 control in the motor control circuit,per wiring diagram (Figure 6). An alarm may be addedusing relay terminal "L". The INT-69 will not protectagainst single phasing of a 3-phase motor. Thermistorsare sensitive electronic sensors and therefore shouldnever be connected directly to motor poweror even the contactor pilot circuit� Voltages of115V, 230V or 440V will destroy the thermistors andpossibly burn out one or more of the motor windings.
ELECTRICALBefore attempting to connect pump electrical, verifythat line voltage and pump name plate motor voltageare the same. Normally, motors are 3-phase, dualvoltage but factory wired to name plate voltage. Referto typical wiring diagrams on page 7. Standard controlvoltage is usually 110V ( optionally 220V). To ensuremotor and bearing protection, the differentialpressurestat and INT-69 must always be part of theelectrical control circuit; even in the "manual" pumpstart switch position. Pressurestat should be wiredso that when pump is turned off, the power to thepressurestat is also off. This will prevent thepressurestat from de-energizing the control circuit.Pump Guardian pump controller is available to simplifywiring and integrate pump protective devices, seepage 5.
Either "quick trip" or "electronic" overload relaysmust be installed for pump motor protection. Heaterson the motor starter "quick trip" or overloads shouldbe sized to rated motor current or less. Pump shouldbe separately fused at no more than three times themotor rated current (non-delay type fuses). Singlephasing protection devices for these hermetic motorsis recommended.
Test all safety devices before putting pump into fullservice (see Start-up Procedure section on page 8and as supplied with pump).
7
The typical wiring diagram control logics shown inthe two diagrams below will shut the pump off whenthe differential pressurestat trips ( senses loss ofpressure difference across the pump for more than30 seconds). The pump must then be manually restartedby pressing the reset button on the standardpressurrestat. Other safety controls such as lowlevel float switch, latching relays, etc., located in thecontrol circuit, as shown, also stop the pump.
but will automatically restart the pump when the safetycontrol is re-engaged. If other control logic is required,it is the control designer's responsibility to ensurethe pump is protected from running "dry" by includingthe differential pressurestat and low level float switchin the pump control wiring circuit and that suchprotection occurs in manual (if any) as well asautomatic mode. Warranty is void if the differentialpressurestat is not installed properly.
TYPICAL WIRING
FOR CAM SERIES
FOR CNF SERIES
Figure 6
Figure 5
* On older INT-69 controllers these terminals, N and L,are designated Mp and R respectfully.
Note: Above diagrams depict 110v control circuit only.INT-69 motor over-temperature controllers for 200V areavailable.
8
START-UP PROCEDUREThe following is a general start-up procedure forcommissioning Hansen Hermetic liquid refrigerantpumps. After the pump is properly installed and allthe electrical work has been completed, but notpowered, this procedure should be followed.
1. Leak check. If not already done, check for leaksby pressurizing the pump and associated piping.Opening the vent/bypass line is a good way to allowrefrigerant gas into the pump. If the recirculator isoperating in a vacuum, allow a small amount of liquidrefrigerant from the accumulator into the pump byopening the pump inlet valve and then closing it. Allowliquid to vaporize and build up pressure to check forleaks at flange gaskets, welds, and pump gaskets.Three pressures should be sensed for monitoringpump performance (Figure 3): the recirculator vesselpressure, the pressure sensed by the pressurestatat pump discharge, and the line pressure to the systemsensed after the Q-max flow control orifice or constantflow regulator.
2. Cool down pump. Open the pump inlet valveand the valve in vent/bypass line. Allow pump to coolto near the recirculator temperature. This may take5 to 10 minutes to develop frost or sweat on the pumpcasing surface. Gas developed as a result of coolingthe pump and associated piping will vent through thevent/bypass line.
3. Check for pump rotation. With the pumpdischarge shut-off valve ½ turn open and the Q-minvent/bypass line open, start pump and observedischarge pressure. Pressure should fluctuate for afew seconds and then remain steady as liquid entersthe pump. (See Table 5 for approximate pressuredifferential between discharge and suction.) Stoppump and reverse two of the three power leads to themotor. Start pump again and observe the dischargepressure. Wire the pump leads to the position thatproduces the highest discharge pressure. Thisensures proper rotation. Measure motor amp drawand compare to Table 4.
4. With pump operating, slowly open pump dischargevalve and allow discharge line and system to fill withliquid.
5. Check differential pressurestat operation.Cavitate the pump by gradually closing the pumpinlet valve with the pump running. Cavitating thepump in this manner will not harm the pump. This willstarve the pump for liquid. Discharge pressure ofpump should fall to nearly inlet pressure. Thedifferential pressurestat should shut the pump offafter 30 seconds. If not, stop the pump at once andthe check wiring of differential pressurestat(Figure 5 and 6). Repeat the procedure to ensure thatthe differential pressurestat stops the pump afterabout 30 seconds of cavitation.
6. After the pump has “tripped off” on differentialpressurestat shutdown, continue to observe differentialpressurestat for a minimum of one minute for anyoverheating of the differential pressurestat time delayrelay circuit. Shut off control circuit and rewire ifnecessary.
7. With the pump running, pull the low level floatswitch magnet away from the tube by lifting the switchhousing or raise the low level set point on a probetype level control. The pump should shut off. If not,wire correctly.
8. Measure the current draw on each motor leg. Thevalues should be equal or less than the running ampsshown in Table 4.
9. Repeat this procedure with any standby pump.
Pumps under normal operation makepractically no noise or vibration. Do not runthe pump if it makes unusual noise orvibration. Check for bearing wear every 5years or sooner.
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Note: The greatest danger to a pump at initial start-up is “trying” it before the system and pump areproperly supplied with liquid. This can only happen ifthe pressurestat and low level switch are bypassedor incorrectly wired, especially for “manual” starterswitch position.
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Differential pressures are based on refrigerant liquidtemperature at 0°F (–17.8°C)
The three most common reasons why refrigerantpumps fail prematurely are cavitation, running dry,and excessive dirt in the system. This is true whetherthe pump is a centrifugal, turbine, or positivedisplacement pump and whether it is an open pumpwith shaft seal or a canned sealless pump. The greatestdanger from cavitation for a pump is the loss of inletliquid flow causing it to run dry. Cavitation for anextended period will greatly reduce the seal life of anopen pump and the bearing life of a sealless pump. Inmany instances, cavitation can be avoided by properlyinstalling pump suction lines, flow control devices,having sufficient NPSH available, and controlling radicalchanges in vessel pressure.
1. New System Start-Up. Cavitation is oftenexperienced on new system start-up because theplant suction is being brought down to operatingtemperature. Bringing suction pressure down slowlyover several hours will generally minimize the problem.In each step of pull down, the system pressure shouldbe stabilized before operating the pump. This includeswhen pumps are turned off during times of peakelectrical rates, and then restarted.
2. New System Start-Up—No Load. Sometimesplants are started where only a small portion of thenormal load is operating. At this condition thecompressor may be too large for the load. Select thesmallest compressor available to handle the loadand adjust the compressor loading and unloadingrate to eliminate or minimize pressure variations.Also, the liquid makeup expansion valve should beadjusted to match the small initial system load. Extendfeeding time of the liquid makeup solenoid valve to atleast 50% to 75% open by further closing the handexpansion valve.
3. Liquid Makeup Expansion Valve Open TooFar. An expansion valve set too far open will feedonly a short time. The flash gas generated will causepressure to build up in the recirculator vessel andmay load up a compressor. When the liquid makeupsolenoid valve closes, the unnecessarily loadedcompressor will quickly pull the vessel pressure downcausing flashing in the liquid and potential pumpcavitation. Set the expansion valve at a point wherethe liquid makeup solenoid valve is open at least50%, and preferably 75%, of the time. This will minimizethe increase in pressure in the recirculator and theunnecessary loading and unloading of thecompressors.
4. Large Liquid Makeup Controls. On recirculatorvessels where the liquid makeup line is 1½� or larger,the condition stated in reason 3 is more severe anddifficult to overcome. Therefore, the use of a dualliquid makeup control is recommended. The level atwhich each makeup valve is controlled should beoffset. The amount of offset is dependent on thedifferential of each valve control device beingincorporated. Typically 4� to 6� (0.10 m 0.15 m) isappropriate. A review of the system load profile
should be analyzed to determine the sizing of eachcontrol valve. The upper level control valve or handexpansion valve should be sized for lighter or weekendload conditions. It will serve as a fixed bypass. Shouldthe loading exceed the upper control valve’s capacity,then the lower level control will cycle for the fullsystem load capacity. Two liquid makeup controlswill even out and slow the compressor loading andunloading sequence, thereby reducing fluctuation ofthe pressure and minimizing cavitation.
5. Defrosting Coils. The defrost scheme used inthe plant can affect the recirculator vessel pressure.With today's larger coils, the amount of hot gasreturning to the recirculator vessel can cause abnormalincreases in pressure. The compressor tends to befully loaded during defrosting. At the end of defrost,the suction pressures can drop quickly, therebyencouraging cavitation unless the unloaders are setto respond quickly. The use of pump out, bleed down,and liquid drainers can minimize the recirculator vesselpressure build up during defrost. Defrosting at onetime only a small portion of the total number of coilswill also minimize pressure fluctuation.
6. Compressor Computer Controls. Duringcompressor loading, fast reductions in vessel pressureat a rate of more than 1 psi/minute(0.07 bar/minute) will likely cause pumps to cavitate.This is because a portion of the liquid in the vesseland pump suction line flashes to gas and is pulledinto the pump inlet. Occasionally software logic maytry to optimize something other than maintaining astable recirculator vessel pressure. Softwareprogramming adjustments may be necessary toaccomplish the goal of a stable recirculator pressure.
7. Other Reasons for Cavitation. Dirt, weld slagand foreign objects sometimes are pulled into thepump and block the entrance or lodge in the impeller.If a fine mesh strainer is needed, these should beinstalled in the pump discharge. In either case, pressuredrop across the strainer must be monitored to maintaingood system performance. Hansen manufactures apump discharge system filter, contact factory fordetails. Excessive oil at cold operating temperaturescan cause reduced flow and pressure in the pump,eventually causing cavitation. Improper inlet pipe size,routing, or length may cause gas bubbles to enter thepump or result in insufficient NPSH.
Note: The Pump Guardian works with simple non-time delay, non-manual restart differential pressure cutoutshaving no integral time delay switch and also directly connects to any Hansen pump motor winding temperaturesensor circuit with need of the INT-69 controller.
PUMP CONTROLLER TYPICAL WIRING(See also Pump Guardian Instruction Bulletin HP519)
SERVICE AND MAINTENANCEWhen properly installed, these pumps with theirsealless design and hydrodynamic bearings generallyexperience very little wear on parts. Pumps shouldrun vibration free and without noise. Noise or vibrationindicates a fault, DO NOT RUN PUMP. Regardless, itis recommended that after five years the bearings bechecked for wear (sooner if there is any unusualrotation noise or repeated safety device cutouts) thatbearings be checked for wear.
Only qualified refrigeration technicians using suitabletools should dismantle and repair Hansen HermeticPumps. Follow refrigeration system safe proceduresand read and understand the Caution section of thisbulletin. Before attempting to remove or dismantlethe pump, be sure it is completely isolated from therefrigeration system and all refrigerant is removed(pumped out to zero pressure).
AXIAL SHAFT PLAYLeave the pump intact and through the pump inletopening push the shaft completely back. Using calipersor other accurate measuring device, measure fromthe end of the shaft to the pump flange face. Next, pullthe shaft completely forward and take a secondmeasurement. The difference between the twomeasurements is the axial shaft play. If the differenceis greater than the appropriate Maximum Axial BearingClearance (SA MAX) in Table 11, replace the bearings.
BEARING REPLACEMENTThe item numbers in parenthesis and replacementparts referenced below are described on page 12 forCAM pumps and page 14 for CNF pumps.
CAM SERIES PUMPS1. Loosen the 8 hexagon nuts (920.1), remove the
suction cover (162.2).2. Bend down the tab washer (931.1), unscrew the
impeller screw (906) and take off the firstimpeller.
3. Remove the impeller key from the shaft, removethe stage casing (108) and take out the secondimpeller.
4. Remove any additional impellers.5. Loosen the 4 hexagon nuts (920.2) and
completely remove the motor from the pumpcasing (101). Take off the front bearingassembly (381).
6. Remove the rear carbon bearing (545.2) with thehelp of the stator stud bolts (900.4); see Figure11. To prevent bearing and stator lining damage,pull the bearing gently, pushing the bearing backif necessary to wipe dirt particles from thestator lining. Lightly oil the stator lining tofacilitate removal of the carbon bearing.
7. Measure the front and rear carbon bearing andbearing sleeve diameters (529.1/2). If thedifference between diameters DN and dN
exceeds the appropriate Maximum BearingClearance (SN MAX) in Table 11, then replace thebearings and sleeves.
8. Check the stator electrical resistance per StatorWinding Inspection section (page 18).
9. Visually check stator lining “CAN” (816) forscratches, gouges, and dents. If the stator liningis damaged, return it to the factory or qualifiedmotor repair shop for replacement.
CNF SERIES PUMPS1. Loosen 8 socket (10 mm) screws (914) and
withdraw the motor from the pump. Check thestator resistance per Stator Winding Inspectionsection.
2. To remove the rotor assembly, tap on theinducer to push the bearing insert (381), rotor,and impeller from the pump housing.
3. Bend up the tab washer (931.1) and remove theinducer (235) and the retaining plate (552.1).Withdraw the impeller (230) from the motor shaft(819). Take off the front bearing assembly (381).
4. To remove the auxiliary impeller and rearbearing and sleeve, loosen the countersunkhexagon (8 mm) screw (917) and withdraw thebearing sleeve (529.2) from the shaft.
5. Remove the carbon bearing (545.2) on the motorside with the help of the stator stud bolts (900.3);see Figure 10. To prevent bearing and statorlining damage, pull the bearing gently, pushingback if necessary to wipe dirt particles from thestator lining. Lightly oil the stator lining tofacilitate removal of the carbon bearing.
6. Measure the front and rear carbon bearing andbearing sleeve diameters (529.1/2). If thedifference between diameters DN and dN
exceeds the appropriate Maximum BearingClearance (SN MAX) in Table 11, then replace thebearings and sleeves.
7. Check the stator electrical resistance per StatorWinding Inspection section (page 18).
8. Visually check stator lining “CAN” (816) forscratches, gouges, and dents. If the stator liningis damaged, return it to the factory or qualifiedmotor repair shop for replacement.
RE-ASSEMBLYCheck the impellers, wear rings, and bearings forwear traces and the stator lining for friction traces.Replace damaged parts; part numbers are listed onpages 13 and 15. Check for debris lodged in thepassageway of the enclosed impeller. Clean all partsbefore assembly. If new impellers or rotors areinstalled, the complete assembly must be rebalanced.
To install rear bearing, first clean and lightly oil thestator lining. Install the bearing using the stator studbolts (CAM 900.4, CNF 900.3) per Figure 11. Gentlypush bearing in to the can, lining up the notch in thebearing with the notch in the can. Careful do not tobend the stud bolts or twist the bearing. The remainingsteps in reassembling the pump should be performedin the reverse order of disassembly. Whenreassembling the pump, use new gaskets. The impellerscrew must be secured with a tab washer (931.1) ingood condition. Torque bolts (914, 920.3) on CNF andnuts (920.1/2) on CAM to 40 ft-lbs. After assembly iscomplete, rotate the shaft by hand through pump inletopening to make sure the rotor spins freely and recheckaxial shaft play. Pressure test the pump for leaksbefore putting it back into service.
17
BEARING REMOVAL
BEARING AND SLEEVE WEARAt the point of most wear, measure both the outsidediameter of the bearing sleeve (dN) and the insidediameter of the carbon bearing (DN), see below. Subtractthe two measurements to determine the bearing
clearance (SN). Compare measurements to the valuesin Table 11. If the measured values exceed maximumvalues given, then replace the bearings and sleeves.
S XAMN ecnaraelCgniraeBmumixaM "310. "310. "610. "310.
SA ecnaraelCgniraeBlaixAlanimoN "130. "130. "130.
S XAMA ecnaraelCgniraeBlaixAmumixaM "950. "950. "950.
*SN = DN – dN
Figure 11
Table 11
18
STATOR WINDING INSPECTIONA multimeter and insulation tester are needed to checkstator winding resistances. To test for ground fault,connect one test lead of the multimeter to the pumpground wire and the other test lead to the motor housing.The reading should be 0.1 ohm or less. With one testlead connected to the ground wire, check for electricshort to ground by individually connecting each pumplead wire with the other test lead (also, checkthermistor lead wires if pump is CNF series). Readingshould be infinite, if not stator may need rewinding ordry baking to remove moisture.
retseTtcennoCot1daeL
retseTtcennoCot2daeL gnidaeR
1-U 1-V 1-U
1-U 1-W 1-V
1-V 1-W 1-W
Table 12
Next, verify motor winding by checking electricalresistance between pump lead wires by connectingthe two test leads to the lead wires per Table 12.Compare the three reading taken to those in Table 4(page 6). If CNF series, test thermistor resistance byconnecting one lead to each thermistor wire, aconstant, steady ohm reading should appear. If noreading or the reading is erratic, then thermistorsneed replacing.
Use installation tester (Megger) to test the electricalinsulation by connecting one test lead to the groundwire and the other test lead individually to each of thepump lead wires. Readings should be 750 M ohms ormore. If not, stator may need to be rewound or bakedto remove moisture. Consult the factory or qualifiedmotor shop.
CAUTIONWhenever a pump filled with cold liquid refrigerant isisolated from a system by closing valves in pumpsuction and discharge lines, the vent/bypass valvemust be open. Otherwise, ambient heat may causeexcessive hydrostatic pressure due to solid liquidthermal expansion in the pump leading to casing failureand possible serious injury.
Hermetic Pumps are for refrigeration systems only.These instructions and related safety precautionsmust be read completely and understood beforeselecting, using, or servicing these pumps. Onlyknowledgeable, trained refrigeration techniciansshould install, operate, or service these pumps. Statedtemperature and pressure limits should not beexceeded. Pumps should not be removed ordisassembled unless the system has been evacuatedto zero pressure. See also Safety Precautions in thecurrent List Price Bulletin and the Safety PrecautionsSheet supplied with the product. Escaping refrigerantcan cause injury, especially to the eyes and lungs.
WARRANTYThese pumps must never be operated without amplerefrigerant liquid flowing through the pump for motorcooling and bearing lubrication. To help ensure liquidrefrigerant flow, the following protective controls mustbe properly installed.
1. The supplied Differential Pressurestat must beconnected to the pump suction or accumulator andthe pump discharge to stop the pump if the pressuredifference is less than 10 psi after the time delayperiod indicating inadequate flow.
2. A low level float switch or control must be installedto stop the pump if the liquid level above the pumpinlet drops below stated system required minimumNPSH.
3. All CNF series pumps are supplied with thermistormotor over-temperature sensor (not standard for CAM).These MUST BE connected to the appropriateelectronic circuit of the supplied INT-69 motor controlmodule (or the optional Pump Guardian pumpcontroller). The INT-69 must be wired to interrupt themotor control circuit if high motor temperature occurs.The thermistor must never be wired directly to linevoltage or control voltage.
4. The supplied Q-max flow control orifice or constantflow regulator must be installed in the discharge line.See Q-max Flow Control Orifice or Constant FlowRegulator sections and Figure 3.
5. The supplied Q-min flow control orifice must beproperly installed in the vent/bypass line. See the Q-min Flow Control Orifice section and Figure 3.
If the above precautions are followed and the pump isinstalled on a clean, properly-designed system,mechanical parts are guaranteed for one year fromdate of shipment and electrical parts for 90 daysfrom date of shipment, F.O.B. the factory. The pumpshould normally operate for many years withoutservicing.
DISCLAIMER: This warranty does not pertain to anypump connected to a Differential Pressurestat havingauto-reset or any different controls instead of theHansen supplied Differential Pressurestat with manualreset. Differential Pressurestat or controls withoutmanual reset must be used in conjunction with adevice to alarm if more that (5) losses of differentialpressure across the pump occur within an hour suchas Pump Guardian. Failure to observe the aboverequirements can greatly shorten the life of the pumpbeing with potentially pump destroying consequences.
19
PRESSURE/TEMPERATURE GPM/TON RATIO
tnaregirfeRerutarepmeT
)F°(717R 22R a431R
001 352.0 594.0 105.0
- 09 752.0 505.0 115.0
- 08 062.0 515.0 815.0
- 07 462.0 425.0 135.0
- 06 762.0 335.0 045.0
- 05 172.0 245.0 945.0
- 04 472.0 055.0 755.0
- 03 872.0 955.0 665.0
- 02 182.0 765.0 375.0
- 01 382.0 475.0 875.0
2- 0 782.0 285.0 885.0
01- 092.0 095.0 395.0
02- 392.0 795.0 206.0
03- 692.0 406.0 606.0
04- 992.0 116.0 416.0
05- 303.0 816.0 026.0
06- 503.0 526.0 726.0
tnaregirfeRerutarepmeT
)F°(717R 22R a431R
- 06 570.0 632.0 242.0
- 05 370.0 622.0 332.0
- 04 070.0 712.0 322.0
- 03 860.0 802.0 512.0
- 02 760.0 402.0 802.0
- 01 560.0 691.0 302.0
2- 0 460.0 981.0 591.0
01- 260.0 481.0 091.0
02- 160.0 871.0 481.0
03- 950.0 471.0 971.0
04- 850.0 961.0 471.0
05- 750.0 561.0 071.0
06- 650.0 161.0 661.0
07- 550.0 851.0 261.0
08- 350.0 451.0 851.0
PRESSURE/HEAD (FT) RATIO
To convert head (in feet) to psi, multiply the head by thefactor in the above table at the required temperature.
Table 15
To determine the GPM required, multiply the systemtonnage by the factor in the above table at the requiredtemperature. Multiply the resultant GPM by the systemrecirculation rate (i.e. 3:1, 4:1, etc.) to determine therequired GPM of the pump.
Above nominal ratings are based on 60Hz. Larger capacityand higher pressure boost pumps are available.Standard voltages: 440V/3/60Hz, 220V/3/60Hz, 575V/3/60Hz,380V/3/50 Hz. Consult factory for 50 Hz applications andother voltages.
Weld neck flanges are standard, however flangesbored to accept ODS coupling are available for CAMseries pumps.† Includes 1.5 ft. reserve for inlet piping losses.Pump curves are available from factory.
�
TYPICAL SPECIFICATIONS"Liquid refrigerant pump shall be centrifugal type,sealless hermetic design with rotor inside a stainlesssteel containment envelope (can) and internally cooledand lubricated by the pumped refrigerant. Isolatedstator inside secondary containment chamber, assupplied by Hansen Technologies Corporation orapproved equal."
*
HANSEN TECHNOLOGIESCORPORATION6827 High Grove BoulevardBurr Ridge, Illinois 60527 U.S.A.Telephone: (630) 325-1565Toll-free: 1-800-426-7368FAX: (630) 325-1572
