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Installation, Operation and Maintenance Manual IOMM WHS

Group: Chiller

Part Number:746462

Effective: November 1998

Supersedes: IM 692-1

© 1997 McQuay International

Water-Cooled Screw Compressor Chiller

WHS 155A - WHS 200A, R-22WHS 220A, R-410A60 Hertz

2 WHS 155A- 220A IOMM WHS

Table of ContentsIntroduction.................................................................................................................3

Receiving and Handling...............................................................................................................................3Installation...................................................................................................................4

Location and Mounting....................................................................................................................................4Compressor Condensation...............................................................................................................................4Vibration Isolators..............................................................................................................................................4Evaporator and Condenser Water Piping.......................................................................................................7Water Treatment.................................................................................................................................................7Head Pressure Control, Tower System...........................................................................................................7Head Pressure Control, Well Water System...................................................................................................8Relief Valve Piping .............................................................................................................................................8Temperature and Water Flow Limitations.......................................................................................................9Startup With Cold Condenser Water..............................................................................................................9Evaporator Freeze Protection...........................................................................................................................9Condenser Protection and Design Considerations ......................................................................................9Chilled Water Thermostat.................................................................................................................................9Refrigerant Charge...........................................................................................................................................10Detection of Loss of Flow..............................................................................................................................10Glycol Solutions...............................................................................................................................................10Chilled Water Quantity....................................................................................................................................11

Evaporator and Condenser Water Flow and Pressure Drop...................................12

Physical Data.............................................................................................................16

Dimensional Data......................................................................................................18

Field Wiring ...............................................................................................................22

General Information.....................................................................................................................................22Pre-Start-up...............................................................................................................26

Sequence of Operation..............................................................................................26

Initial Conditions..............................................................................................................................................26Off Conditions..................................................................................................................................................27Alarm..................................................................................................................................................................27Initial Start-up...................................................................................................................................................27Load Recycle ....................................................................................................................................................28

Maintenance..............................................................................................................28

General..........................................................................................................................................................28Compressor Maintenance..........................................................................................................................28Lubrication ...................................................................................................................................................28Electrical Terminals ......................................................................................................................................29Condensers ..................................................................................................................................................29Refrigerant Sightglass ................................................................................................................................29Lead-Lag.......................................................................................................................................................29

Preventative Maintenance Schedule ............................................................................................................30"McQuay" is a registered trademark of McQuay International

1997 McQuay International"Illustrations cover the general appearance of McQuay International products at the time of publication and we reserve the right to

make changes in design and construction at anytime without notice"

IOMM WHS WHS 155A - 220A 3

Introduction

McQuay StarGate™ water-cooled chillers are completely assembled, factory wired, evacuated,charged, tested and ready for installation. Each unit consists of a water-cooled condenser withintegral subcooler, dual accessible semi-hermetic single screw compressors with suction anddischarge shutoff valves, replaceable tube shell-and-tube evaporator, and complete refrigerant piping.Liquid line components included are manual liquid line shutoff valves, charging valves, filter-dryers,liquid line solenoid valves, sightglass/moisture indicators, and electronic expansion valves. Otherfeatures include compressor heaters, and an advanced fully integrated microprocessor control system.

The electrical control center includes all safety and operating controls necessary for dependableautomatic operation, (the high and low pressure controls are external from the electrical controlcenter). Compressors are protected by solid-state overload protection and over temperatureprotection.

Receiving and HandlingInspect the unit immediately after receipt for possible damage. The unit is shipped FOB factory and allclaims for handling and shipping damage are the responsibility of the consignee. Leave the shippingskid in place until the unit is in final position. This will aid in handling the equipment. Use extremecare when rigging the equipment to prevent damage to the control center, or refrigerant piping. SeeDimensional Data for the center of gravity of the unit.

Lift the unit by fastening the rigging hooks to the four corners of the evaporator where the riggingeyes are located (see Figure 1). Use spreader bars between the rigging lines to prevent damage to thecontrol center.

Figure 1, Rigging Eyes

Rigging EyesRigging Eyes


Installation

CAUTION

Installation must be performed by qualified personnel who are familiar with local codes,regulations, and experienced with this type of equipment.

Start-up by McQuayService is included on all units sold for installation within North Americaexcluding Mexico. Two weeks prior notification of start-up is required. The contractor should obtaina copy of the Start-up Scheduled Request Form from the sales representative or from the nearestMcQuayService office.

Location and MountingMount the unit on level concrete or steel base. Service and tube pull clearance (at either end of theunit) is 14 feet (4.3 m). Evaporator and condenser tubes are rolled into the tube sheets to permitreplacement. Clearance at the sides and other end, including the top, is 3 feet (1 m).

Make certain the floor or structural support is adequate to support the full operating weight of thecomplete unit. Optional rubber-in-shear pads, or spring isolators can be ordered for use under eachcorner of the base members. It is not necessary to bolt the unit to the mounting slab or frame work;although mounting holes are provided in the unit support at the four corners.

Compressor CondensationCondensation occurs on the compressor surface when the temperature of the compressor surface islower than the ambient dew point temperature. Drain pans with drain connections are providedunderneath each compressor to collect the condensate. The compressor motor housing extends pastthe drain pans. Install a floor drain close to the unit to collect condensate from motor housing andcondensate pans.

Vibration IsolatorsWaffle type vibration isolator pads are shipped with the unit for field installation. These pads provideminimal isolation. Vibration isolators are recommended on all upper level installations where vibrationtransmission is a consideration. When vibration isolators are used, install springs under the main unitsupports. Adjust spring so the upper housing clears lower housing by at least 1/4” (6mm) and notmore than 1/2” (13mm). If hold-down bolts are not used, install a rubber anti-skid under isolators.Install vibration eliminators in water piping to reduce piping strain, vibration, and noise. Table 1 listsspring and rubber-in-shear isolators for all WHS unit sizes.


Table 1, Vibration Isolators (WHS 155A - 200A)

Isolator Isolator Per Location1 2 3 4

Rubber-in-Shear RP-4 RP-4 RP-4 RP-4Spring CP-4-28 CP-4-28 CP-4-28 CP-4-28

Figure 2, Isolator location

Table 2, Isolators (WHS 220A)

Color Recom.

Isolator Type Of McQuay Max Ld

Stripe Part No. Lb. (Kg)

Rubber-In-Shear RP-4 Green 0021639803 3300 (1497)Spring CP-4-28 Green 0058051328 3600 (1633)

Note: The spring is fully compressed at about 5400 lb (2449 Kg).

Figure 3 and Figure 4 give dimensions required to secure each McQuay isolator section to themounting surface. The maximum loads for each unit are shown in Table 3.

Figure 3 , Rubber-in-Shear Isolator


Figure 4, Spring Flex Isolator

Table 3, Corner Weights for Standard Shell Units lb (kg)

WHS Unit U X V W

155-200 2105 (953) 2475 (1121) 2477 (1122) 2913 (1320)

220 2564 (1161) 3060 (1386) 2935 (1330) 3501 (1586)

Figure 5, Corner Weight Locations


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

CAUTION

Remove 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.

CAUTION

Freeze Notice: The evaporator and condenser are not self-draining. Both must be blown out.

Include thermometers at the inlet and outlet connections and air vents at the high points of piping.The water heads can be interchanged (end for end) allowing water connections to be made at eitherend of the 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 unit is mounted on spring isolators, flexible piping connections arenecessary.

Water TreatmentIf unit is operating with a cooling tower, clean and flush cooling tower. Make sure tower "blowdown"or bleedoff is operating. Atmospheric air contains many contaminants which increases the need forwater treatment. The use of untreated water may result in corrosion, erosion, sliming, scaling, or algaeformation. A water treatment service is recommended. McQuay International is not responsible fordamage or faulty operation from untreated or improperly treated water.

Head Pressure Control, Tower SystemThe minimum entering water temperature to the condenser must not be lower than 75°F (23.9°C) at fulltower water flow. If lower temperature water is used, the flow must be reduced proportionally. Use athree-way bypass valve around the tower to modulate the condenser water flow. Figure 6 shows athree-way pressure actuator water regulating valve used for cooling applications. This regulatingvalve will assure an adequate condensing pressure if the inlet condenser water temperature falls below75°F (23.9°C). An optional AOX-4 board located in the MicroTech panel will control a cooling towerbypass 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 (23.9°C). Thecondenser service valve provides a pressure tap for the regulating valve. The valve can modulate inresponse to head pressure. On shutdown, the valve closes, preventing water from siphoning out ofthe condenser. Siphoning causes condenser waterside drying and accelerates fouling. If a valve isnot used, Figure 7 illustrates the recommendation of a loop at the outlet. Size the loop height (H) tooffset the negative pressure caused by the siphoning effect. A vacuum breaker may be required.

Figure 6, Bypass valve

Figure 7, Well Water System

Relief Valve PipingFollow the requirements of ANSI/ASHRAE Standard 15-1994 for relief valve piping. The condenserrelief valve assembly consists of a tree valve and two relief valves. The tree valve must be fully frontor back seated to ensure only one relief valve is available for discharge.


Temperature and Water Flow LimitationsWHS units are designed to operate in conditions from 20°F (-6.7°C) to 50°F (10°C) leaving watertemperature on the evaporator side and 75°F (23.9°C) to 95°F (35°C) entering water temperature on thecondenser side.

Glycol in the evaporator is required on all applications below 40°F (4.4°C) leaving evaporator fluidtemperature. The maximum allowable water temperature to the cooler in a non-operating cycle is 105°F(40.6°C). The non-operating leaving condenser water temperature maximum is 115°F (46.1°C). Flowrates below the minimum values shown in the evaporator and condenser pressure drop curves maycause freeze-up problems, scaling and poor control. Flow rates above the maximum values shown inthe evaporator and condenser pressure drop curves will result in unacceptable pressure drops,excessive nozzle and tube erosion and possibly cause tube failure.

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 (21°C to 27°C)with a condenser water temperature of 55°F (13°C). Start up under these conditions is expected. If thecooling load is excessive, or condenser water temperatures substantially less, modification of alarmtimer settings by the McQuayService Technician may be required.

Evaporator Freeze ProtectionWhen freeze protection is a concern, do the following:

1. If the unit will not be operated during the winter, drain and flush the evaporator and chilled waterpiping with glycol. Drain and vent connections are provided on the evaporator.

2. When using a cooling tower, add glycol solution to the chilled water system. Freeze point shouldbe approximately 10°F (5.6°C) below minimum design ambient temperature.

Note: Freeze damage is not considered a warranty failure and is not the responsibility ofMcQuay International.

3. Insulate field water piping, especially on the chilled water side.

Condenser Protection and Design ConsiderationsIf pond or river water is used as a condensing medium and the water valves leak, the condenser andliquid line refrigerant temperature could drop below the equipment room temperature on the "off"cycle. This problem occurs when cold water continues to circulate through the condenser and theunit remains off due to satisfied cooling load. If this occurs:

1. Cycle the condenser pump off with the unit.

2. Verify the liquid line solenoid valves are operating properly.

Chilled Water ThermostatThe WHS water-cooled chiller is equipped with the MicroTech leaving water controller. Be carefulwhen working around the unit to avoid damaging lead wires and sensor cables. Check lead wiresbefore running the unit. Avoid rubbing the lead wires on the frame or other components. Verify thelead wires are firmly anchored. If the sensor is removed from the well for servicing, do not wipe off theheat conducting compound supplied in the well.


Refrigerant Charge All units are designed for use with R-22 or R-410A and are shipped with a full operating charge. Theoperating charge for each unit is shown in the Physical Data Table.

Detection of Loss of Flow

NOTE: Water pressure differential switches are not recommended for outdoor applications.

The preferred means for detecting loss of flow is the use of factory-mounted pressure differentialswitches for the evaporator and condenser.

A flow switch is available from McQuay (part number 00175033-00). It is a “paddle” type switch andadaptable to any pipe size from 3” (76mm) to 8” (203mm) nominal. Two flow switches are required.Mount the flow switch in either the entering or leaving water line of the evaporator and condenser.Certain minimum flow rates are required to close the switch and are listed in Table 4. Installationshould be as shown in Figure 8.

Figure 8, Flow Switch

Connect the normally open contacts of the flow switch in the unit control center at terminals 62 and63. Flow switch contact must be suitable for 24 VAC, low current (16ma).

Table 4, Flow Switch Minimum Flow Rates

Nominal Pipe Size Min. Required Flow to

(inches) Activate Switch - GPM (L/s)

5 58.7 (3.7)6 79.2 (5)

Glycol SolutionsA glycol anti-freeze solution is required for operation below 40°F leaving chilled fluid temperature.The introduction of a glycol solution reduces the capacity of the chiller and any air handlingequipment. Contact the local McQuay sales office for determination of the affect of glycol on thechiller capacity, power input and pressure drop.

CAUTION

Use industrial grade glycols only. Do not use an automotive grade antifreeze. Automotiveantifreeze contains inhibitors that will cause plating on the copper tubes within the chillerevaporator. The type and handling of glycol used must be consistent with local codes.


Chilled Water QuantityAll chillers need adequate time to recognize a load change, respond to the load change and stabilizewithout short-cycling the compressor. There is a distinct relationship between the minimum capacityof the chiller plant, the system minimum expected capacity, system water volume, the desired intervalbetween starts, and the dead band of the chiller controller-the number of degrees between shut offand turn on. McQuay centrifugal chillers unload to 10% (5% for dual compressor units), have as littleas 20 minutes between starts (adjustable from 60 to 20 minutes), and a factory default value of 6degrees F of chilled water temperature between shut off and restart (adjustable 2 to 20°F). There mustbe sufficient time/volume when the compressor is running with more capacity than system load, plussufficient time/volume for the compressor to be off during the required anti-cycle time. Theserelationships are expressed in the following formula:

VTS

TD

H H

TD

H

=

−

+

720

1 2 2

Where: V = Total system U.S. gallons TS = Time between starts (min)

TD = Dead band range of controller (°F)

H2 = Minimum system capacity (btu/hr) H1 = Chiller minimum capacity (btu/hr)


Evaporator and Condenser Water Flow and Pressure Drop

Important Note

Flow rates must fall between the minimum and maximum values shown on the appropriate evaporatorand condenser curves. Flow rates below the minimum values shown will result in laminar flow that willreduce efficiency, cause erratic operation of the electronic expansion valve and could cause lowtemperature cutouts. Flow rates exceeding the maximum values shown can cause erosion on theevaporator water connections and tubes.

Measure the chilled water pressure drop through the evaporator at field installed pressure taps. It isimportant not to include the effect of valves or strainers in these readings.

Do not vary the water flow through the evaporator while the compressor(s) are operating. MicroTechcontrol setpoints are based on constant flow.

Figure 9, Evaporator 2-Pass


Figure 10, Evaporator, 3-Pass


Figure 11, Condenser 2-Pass


Figure 12, Condenser, 3-Pass


Physical Data

Table 5, Physical Data, WHS 155A - WHS 180A

Data 155A 170A 180A

BASIC DATA

Unit 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 (withstarters),lb.(kg)

9970 (4522) 9970 (4522) 9970 (4522)

Shipping Weight, (withstarters),lb.(kg)

9567 (4339) 9567 (4339) 9567 (4339)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Tons, (kW) 70 (250) 70 (250) 70 (250) 85 (300) 85 (300) 85 (300)FLOODED EVAPORATOR

Quantity, (Number of WaterPasses)

1 (1,2,3) 1 (1,2,3) 1 (1,2,3)

Shell Diameter – Tube Length 18 - 12 18 - 12 18 - 12in. - ft. (mm - 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)

CONDENSER


1 (2,3) 1 (2,3) 1 (2,3)

Shell Diameter -- Tube Length 18 - 12 18 - 12 18 - 12 in. - ft. (mm - 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)


6 (152) 6 (152) 6 (152)


Table 6, Physical Data, WHS 190A - WHS 220A

DAta 190A 200A 220A

BASIC DATA

Unit Capacity @ ARI Conditions,tons (kW)

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

Refrigerant HCFC-22 HCFC-22 HFC-410AUnit 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 (withstarters),lb.(kg)

9970 (4522) 9970 (4522) 12060 (5469)

Shipping Weight, (withstarters),lb.(kg)

9567 (4339) 9567 (4339) 11300 (5125)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Tons, (kW) 85 (300) 100 (350)) 100 (350) 100 (350) 105 (365 105 (365FLOODED EVAPORATOR


1 (1,2,3) 1 (1,2,3) 1 (1,2,3)

Shell Diameter – Tube Length 18 - 12 18 - 12 22 - 12in. - ft. (mm - 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)


6 (152) 6 (152) 8 (204)

CONDENSER


1 (2,3) 1 (2,3) 1 (2,3)

Shell Diameter -- Tube Length 18 - 12 18 - 12 20 - 12in. - ft. (mm - 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)


6 (152) 6 (152) 6 (152)


Dimensional Data

Figure 13, WHS 155 - 200

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 Weights

X 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 155 - 200 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)

Notes1. 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. 168 inches (4267) 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. f 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. These values are for units with standard wall thickness copper tubing only.13. The shipping skid adds 4 inches (102) to the overall unit height.


Figure 14, WHS 220

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 1/4 47 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 220 Continued

Vessel Code Head Connection U.S. PipeSize

AA BB

Evap. Cond. 1P 2P 3PE2212 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 table6. 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.


Field Wiring

CAUTION

WHS unit compressors are single direction rotation compressors. For this reason properphasing of electrical power is essential. Electrical phasing must be A, B, C clockwise forelectrical phases 1, 2 and 3 (A=L1 ,B=L2,C=L3). The unit is supplied with single point factorypower connection and includes one MotorSaver phase failure, phase reversal protective devicethat will prevent operation of the unit with incorrect power phasing. The MotorSaver is factorywired and tested. Do not alter the wiring to the MotorSaver.

General InformationWiring must comply with all applicable codes and ordinances. Warranty is void if wiring is not inaccordance with specifications. Copper wire must be used for all wiring.

The WHS is typically supplied with the main power wiring for single point power connection. Asingle large power terminal block is provided. Wiring within the unit is sized according to the NationalElectrical Code. A single field-mounted disconnect (supplied by others) is required. An optionalfactory mounted transformer for the 115 volt control circuit may have been provided.

Main power must enter the control panel at the location indicated on the unit illustration.

Table 7, Compressor Amp Draw

WHS Compressor Rated Compressor Locked Rotor AmpsUnit Load Amps Delta-Delta StartSize Volts Hz Comp. 1 Comp. 2 Comp. 1 Comp. 2

208 179 179 934 934230 162 162 1042 1042

155A 380 60 98 98 604 604460 81 81 489 489575 65 65 377 377208 179 223 934 934230 162 202 1042 1042

170A 380 60 98 122 604 604460 81 101 489 489575 65 81 377 377208 223 223 934 934230 202 202 1042 1042

180A 380 60 122 122 604 604460 101 101 489 489575 81 81 377 377208 223 254 934 934230 202 230 1042 1042

190A 380 60 122 139 604 604460 101 115 489 489575 81 92 377 377208 254 254 934 934230 230 230 1042 1042

200A 380 60 139 139 604 604460 115 115 489 489575 92 92 377 377208 286 286 934 934230 259 259 1042 1042

220A 380 60 157 157 604 604460 130 130 489 489575 104 104 377 377

NOTES: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 8, Customer Wiring Information, WHS 155A - 200A

WHS Wiring to Unit Power Block Wiring to Disconnect SwitchUnit Volts Hz Power Block Optional Disconnect SwitchSize 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 MCM230 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 MCM460 335 (1) #6-400 MCM 250 (1) #4-350 MCM575 335 (1) #6-400 MCM 250 (1) #4-350 MCM208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM230 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 MCM460 335 (1) #6-400 MCM 250 (1) #4-350 MCM575 335 (1) #6-400 MCM 250 (1) #4-350 MCM208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM230 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 MCM460 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

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

Table 9, Customer Wiring Information, WHS 220

WHS Wiring to unit Power Block Wiring to Main Circuit BreakerUnit Volts Hz Power Block Optional Main Circuit BreakerSize Terminal Size

AmpsConnector 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 NA220A 60 (1) # 6-350 MCM & (1) # 4-500 MCM

380 665 (1) # 6-350 MCM & (1) # 4-500 MCM 400 (2) 3/0-250 MCM460 335 (1) # 6-400 MCM 400 (1) 2/0-500 MCM575 335 (1) # 6-400 MCM 250 (1) #4-350 MCM

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


Table 10, Electrical Data, WHS 155A - 200A

WHS Minimum Power Supply Field Fuse Size

Unit Volts Hz Circuit Field Wire Recom-

Size Ampacity (MCA) Qty. Wire Gauge mended Maximum208 403 6 250 450 500230 365 6 3/0 450 500

155A 380 60 221 3 4/0 250 300460 183 3 3/0 225 250575 147 3 1/0 175 200208 458 6 250 600 600230 415 6 250 500 600

170A 380 60 251 3 250 300 350460 208 3 4/0 250 300575 167 3 2/0 200 225208 502 6 250 600 700230 455 6 250 600 600

180A 380 60 275 3 300 350 350460 228 3 4/0 300 300575 183 3 3/0 225 250208 541 6 300 700 700230 490 6 250 600 700

190A 380 60 296 3 350 350 400460 245 3 250 300 350575 196 3 3/0 225 250208 572 6 350 700 800230 518 6 300 600 700

200A 380 60 313 3 400 400 450460 259 3 300 300 350575 207 3 4/0 250 250

Table 11, Electrical Data, WHS 220A

WHS 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 is reduced by 20%. Consult the National Electrical 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 thelargest compressor-motor RLA plus 100% of all other loads on the circuit.

6. 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 15, Typical Field Wiring


Pre-Start-up

1. Open all electrical disconnects and check electrical connections are tight.

2. Verify water piping flow directions are correct and properly connected at the evaporator andcondenser.

3. Using a phase tester, verify electrical phasing is A-B-C clockwise (A=L1, B=L2, C=L3).

4. Verify unit power supply is within 10% of nameplate rating.

5. Verify power supply wiring is the correct size and has a minimum temperature insulation rating of75°C.

6. Verify all mechanical and electrical inspections have been completed according to local code.

7. Make certain all auxiliary control equipment is operative and an adequate cooling load isavailable.

8. Check all compressor valve connections for tightness.

9. Open compressor suction valve until backseated.

10. Open discharge shutoff valve until backseated.

11. Vent air from the evaporator and condenser water system piping.

12. Open all water flow valves and start chilled water pump.

13. Check all piping for leaks.

14. Flush the evaporator and condenser system piping.

Sequence of Operation

The following sequence of operation is typical for McQuay models WHS 155A through WHS 220Arotary screw water chillers. The sequence may vary depending on the software revision or variousoptions that maybe installed on the chiller.

Initial ConditionsBefore energizing the control box, do the following:

1. Verify the two control circuits are powered through the primary fuses FU1, FU2 and thesecondary fuse FU3.

2. Verify power is developed through the transformer CPT in the starter and is 120 VAC on thesecondary.

3. Make certain the S1 switch is in the off position.

When applying power to the control for the first time do the following:

1. Open left door and the top door to each control box.

2. Apply power and observe the following:

§ Display lights up

§ Unit Status screen appears

§ EXV board lights rapidly sequence closed.

3. Listen for stepper motors closing with a racheting sound.

4. Verify Unit Status Screen on the display indicates Off: Front Panel Sw.


Off ConditionsWith power on the controller there are several "off" states possible:

Off: Manual: when the setpoint in menu “11 Control Mode” is set to the Mode= Manual Off. Tochange, simply set the Mode= Auto: Network (or any other running mode).

Off: Front Panel Sw: when the panel switch is in the “Stop” position. To change move the switch to“Auto” position.

Off Alarm remove the alarm state then clear the alarm to remove this off state.

Off Compressor 1 or Off Compressor 2 is the on / off switch inside the top right control box door.Turn to ‘on’ to clear.

AlarmThe alarm light on the front panel illuminates when the particular control receives an active alarm state.The unit or a particular compressor will be locked out. The other compressor will start if only one islocked out by a compressor fault.

Initial Start-up

CAUTION

Initial Start-up must be performed by authorized McQuay Service personnel.

1. Set up control as described in Initial Conditions.

2. Turn front panel switch to Auto position (chilled water pump relay will energize).

3. If the field installed flow indicator does not indicated chilled water flow after 30 seconds, then thealarm output will be energized.

Note: The unit starts the compressor with the least starts and run hours while in auto lead lagsetting.

4. When the Active Setpoint is 3°F lower than the actual leaving water temperature, the chillerstarts.

5. When the chiller starts the following occurs:

§ Crank case heaters de-energize

§ Compressor starts

§ Liquid injection solenoid is energized

§ Motor cooling solenoid is energized

§ Suction injection solenoids are energized

6. Suction injection will turn off when the following conditions have been met:

§ Discharge superheat drops below 3°F

§ Liquid Presence sensor shows liquid

§ Absolute Pressure ratio is greater than 1.2 ( Condenser psia / Evaporator psia)


7. The unit status changes:

FROM TOEvapOn-Recirc **Sec All Systems Off

All Systems Off MCR StartedMCR Started Pre-purgePre-purge Open Solenoid

Open Solenoid Running Min Amp LimRunning Min Amp Lim Running: % Cap 50

8. The following occurs if additional cooling capacity is required:

§ Controllers add capacity by changing the capacity control solenoids outputs 6, 7, and 8.

§ As capacity increases the second compressor is started.

§ After both compressors are running, the unit continues to load by changing the capacitycontrol solenoids outputs 12, 13, and 14.

Load RecycleAs chilled water requirements lessen, the controls unload the compressors until the chilled waterdrops below the lag cutoff point for the delay time required. The control will shut off the lagcompressor and reduced load will cause the leaving water temperature to drop 3°F below the activesetpoint. The compressor de-energizes on Load Recycle and the display will show Waiting For Load.The chilled water pump will remain on.

Maintenance

GeneralOn initial start-up and periodically during operation, it will be necessary to perform certain routineservice checks. Among these are checking the liquid line sightglasses and taking condensing andsection pressure readings. Through the MicroTech keypad, check to see that the unit has normalsuperheat and subcooling readings. A recommended maintenance schedule is located at the end ofthis section.

Compressor MaintenanceSince the compressor is semi-hermetic requiring no oil separator, oil heaters and pumps, no yearlymaintenance is normally required. However, vibration is an excellent check for proper mechanicaloperation. Compressor vibration is an indicator of the requirement for maintenance and contributes toa decrease in unit performance and efficiency. It is recommended that the compressor be checked witha vibration analyzer at or shortly after start-up and again on an annual basis. When performing thetest the load should be maintained as closely as possible to the load of the original test. The initialvibration analyzer test provides a benchmark of the compressor and when performed routinely cangive a warning of impending problems. The compressor is checked at the factory for maximumvibration of 0.14 IPS (3.56 mm/s) at 3600 rpm.

The compressor is supplied with a lifetime oil filter under normal operating conditions. However, it is agood policy to replace this filter anytime the compressor is opened for servicing.

LubricationNo routine lubrication is required on WHS units.

Compressor oil must be Planetelf ACD68AW. This is a polar synthetic oil with anti-wear additivesand is highly hygroscopic. Care must be taken to minimize exposure of the oil to air and moisturewhen charging oil into the system.


Electrical Terminals

WARNING

Electric shock hazard. Turn off all power before continuing with following service.

Disconnect power from unit and check electrical terminals for tightness annually.

CondensersThe condensers are water-cooled and subject to tube fouling depending on the level of watertreatment to the cooling water. Under normal conditions the condenser tubes should be examinedannually to check for fouling.

If the service technician has reason to believe that the refrigerant circuit contains noncondensables,purging of the condenser may be required strictly following regulations governing refrigerantdischarge to the atmosphere. Purge with the unit off, after shutdown of 15 minutes or longer, to allowair to collect at the top of the coil. Restart and run the unit for a brief period. If necessary, shut unitoff and repeat the procedure. Follow all refrigerant discharge regulations and sound service practiceswhen purging non-condensables or removing refrigerant from the unit.

Refrigerant SightglassThe refrigerant sightglass should be observed periodically. (A weekly observation should beadequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the system toinsure proper feed through the expansion valve. Bubbling refrigerant in the sightglass, during stablerun conditions, indicates that the system may be short of refrigerant charge. Refrigerant gas flashingin the sightglass could also indicate an excessive pressure drop in the liquid line, possibly due to aclogged filter-drier or a restriction elsewhere in the liquid line. If subcooling is low add charge to clearthe sightglass. If subcooling is normal (10°-15°F) and flashing is visible in the sightglass check thepressure drop across the filter-drier.

An element inside the sightglass indicates the moisture condition corresponding to a given elementcolor. If the sightglass does not indicate a dry condition after about 12 hours of operation, the circuitshould be pumped down and the filter-drier changed.

Lead-LagA feature on all McQuay WHS water-cooled chillers is a system for alternating the sequence in whichthe compressors start to balance the number of starts and run hours. Lead-Lag of the refrigerantcircuits is accomplished automatically through the MicroTech Controller. When in the auto mode thecircuit with the fewest number of starts will be started first. If all circuits are operating and a stagedown in the number of operating compressors is required, the circuit with the most operating hourswill cycle off first. The operator may override the MicroTech controller, and manually select circuit#1or #2 as the lead circuit.


Preventative Maintenance SchedulePREVENTATIVE MAINTENANCE SCHEDULE

OPERATION WEEKLY MONTHLY(Note 1)

ANNUAL(Note 2)

General Complete unit log and review (Note 3) X Visually inspect unit for loose or damaged components X Inspect thermal insulation for integrity X Clean and paint as required X

Electrical Check terminals for looseness X Clean control panel interior X Visually inspect components for signs of overheating X Verify compressor heater operation X Megger compressor motor every five years (Note 5)

Refrigeration Leak test X Check sight glasses for clear flow X Check filter-drier pressure drop (see manual for spec) X Perform compressor vibration test X

Condenser Check and clean tubes (Note 4) X

Notes:

1. Monthly operations include all weekly operations.

2. Annual (or spring start-up) operations includes all weekly and monthly operations.

3. Log readings may be taken daily for a higher level of unit observation.

4. Tube cleaning may be required more frequently in areas with poor water quality or marginal water treatment.

5. Do not Megger motor while in a vacuum.

13600 Industrial Park Boulevard, P.O. Box 1551, Minneapolis, MN 55440 USA (612) 553-5330