Single/Dual Compressor Centrifugal Chillers · 8 Centrifugal Chillers IOMM WSCWDC Oil Cooler Piping...

Installation, Operating and Maintenance Manual IOMM WSCWDC

Group: Chiller

Part Number: 736015417

Effective: October 1999

Supersedes: IOMM PEHPFH

© 1997 McQuay International

The McQuay DISTINCTION SERIES

Single/Dual Compressor Centrifugal Chillers

WSC/WDC 050, 063, 079, 087, 100, 126

2 Centrifugal Chillers IOMM WSCWDC

Table of Contents

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

General Description ...........................................................................................................................................3Application .........................................................................................................................................................3

Installation...................................................................................................................4

Receiving and Handling....................................................................................................................................4Location and Mounting....................................................................................................................................5Water Piping .......................................................................................................................................................6Oil Cooler Piping ................................................................................................................................................8Refrigerant Vent Piping .....................................................................................................................................9Electrical............................................................................................................................................................11Power Wiring ....................................................................................................................................................11Control Wiring..................................................................................................................................................12Prestart System Checklist ...............................................................................................................................14

Operation...................................................................................................................15

Operator Responsibilities ...............................................................................................................................15Nomenclature....................................................................................................................................................15MicroTech Control Panel................................................................................................................................16Capacity Control System................................................................................................................................16Lubrication System..........................................................................................................................................19Hot Gas Bypass................................................................................................................................................21

Maintenance..............................................................................................................22

Pressure/Temperature Chart ...........................................................................................................................22Routine Maintenance......................................................................................................................................22Annual Shutdown............................................................................................................................................25Annual Startup.................................................................................................................................................26Repair of System..............................................................................................................................................26

Maintenance Schedule..............................................................................................29

Service Programs ......................................................................................................32

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 to makechanges in design and construction at anytime without notice"

IOMM WSCWDC Centrifugal Chillers 3

Introduction

General DescriptionThe McQuay Centrifugal Water Chillers are complete, self-contained, automatically controlled fluidchilling units. Each unit is completely assembled and factory tested before shipment.

In the WSC series, each unit contains one compressor connected to a condenser and evaporator. TheWDC series are equipped with two compressors operating in parallel on a single evaporator andcondenser.

The chillers use refrigerant R-134a to reduce the size and weight of the package compared to negativepressure refrigerants and since R-134a operates at a positive pressure over the entire operation range,no purge system is required.

The controls are pre-wired, adjusted and tested. Only normal field connections such as piping,electrical and pump interlocks, etc. are required thereby simplifying installation and increasingreliability. All necessary safety and operating controls are factory installed in the control panel.

The basic sizes of units are the WSC/WDC 050, 063, 076, 079, 087, 100 and 126. They provide acapacity range from 80 tons to 2500 tons. In this manual all references to the WSC models will equallyapply to other models unless specifically referenced otherwise.

ApplicationThe operation and maintenance procedures presented in this manual apply to the standardWSC/WDC family of chillers. Reference to the Installation Manual, OM 125 for these units should bemade for details pertaining to operation of the MicroTech control.

All McQuay centrifugal chillers are factory tested prior to shipment and must be initially started at thejob site by a factory trained McQuay service technician. Failure to follow this startup procedure mayaffect the equipment warranty.

The standard warranty on this equipment covers parts which prove defective in material orworkmanship. Specific details of this warranty can be found in the warranty statement furnished withthe equipment.

Cooling towers used with McQuay centrifugal chillers are normally selected for maximum condenserinlet water temperatures between 75°F and 90°F (24°C and 32°C). Lower entering water temperaturesare desirable from the standpoint of energy reduction but a minimum does exist. For recommendationsfor optimum entering water temperature and cooling tower fan control, consult McQuay ProductManual PM WSC/WDC, Applications Section.


Installation

Receiving and HandlingThe unit should be inspected immediately after receipt for possible damage.

All McQuay centrifugal water chillers are shipped FOB factory and all claims for handling andshipping damage are the responsibility of the consignee.

Insulation corners from the evaporator's rigging hole locations is shipped loose and should be gluedin place after the unit is finally placed. Neoprene vibration pads are also shipped loose. Check to besure that these items are delivered with the unit.

Leave the shipping skid in place until the unit is in its final position. This will aid in handling theequipment.

Extreme care should be used when rigging the equipment to prevent damage to the control center, orrefrigerant piping. See certified dimension sheets for the center of gravity of the unit.

The unit can be lifted by fastening the rigging hooks to the four corners of the unit where the riggingeyes are located (see Figure 1). Spreader bars should be used between the rigging lines to preventdamage to the control center and motor terminal boxes on WDC dual compressor units.

Figure 1, Unit Components

Control Panel

EvaporatorRelief Valve

Evaporator

Condenser

Expansion Valve

Liquid LineShutoff Valve

Condenser DualRelief Valves


Figure 2, Major Component Location

NoteThe WDC126 Dual Compressor Chiller shown has the evaporator inlet in the bottom.

Consult unit certified drawings for connection locations on specific units.

Location and MountingThe unit should be mounted on a level concrete or steel base and should be located so as to provideservice clearance at one end of the unit for possible removal of evaporator tubes and/or condensertubes. Clearances required are 18 feet (5.5 meters) for units with 16 foot (4.9 meters) long shells, 16feet (4.9 meters) for units with 14-foot (4.3 meters) long shells, 14 feet (4.3 meters) for units with 12-foot (3.7 meters) long shells, and 10 feet (3 meters) for units with 8-foot (2.4 meters) long shells.Evaporator/condenser tubes are rolled into the tube sheets to permit replacement if necessary.Clearance at all other points, including the top, is 3 feet (1 meter).

The shipped loose neoprene vibration pads should be located under the corners of the unit (unlessthe job specifications state otherwise).

LubricationControl Box

DischargeCheck Valve

Condenser

Motor CoolingOutlet Filter-Drier

MotorCooling Inlet

RiggingEyes

(2) Dual ReliefValues

Lubricant Outlet to Cooler

Mounting Holes(2) Each Corner

CondenserInlet

CondenserOutlet

EvaporatorInlet (Note)

EvaporatorOutlet

RiggingEyes

SuctionShutoff Valve(Duals Only)

Oil Pressure Regulator

Vent Line from Oil Sump

Lubricant to Lub ControlBox for Unloader Oil Sump,

Pump, Heater

MotorTerminal Box


Units are shipped with refrigerant and oil valves closed to isolate these fluids forshipment. Valves must remain closed until start-up by McQuay technician.

Water Piping

Water PumpsMake sure that the floor or structural support is adequate to support the full operating weight of thecomplete unit.

Rubber Shearflex pads, or "Isomode," are supplied with the unit for use under each corner of the basemembers. The unit must be level.

It will not be necessary to bolt the unit to the mounting slab or framework; but should this bedesirable, 1 1/8" (28.5 mm) mounting holes are provided in the unit support at the four corners andunder the compressor base on the side-mounted compressor units.

Note Avoid the use of 3600/3000 rpm (two-pole motor) pump motors.

It is not uncommon to find these pumps operate with objectionable noise and vibration.

It is also possible to build up a frequency beat due to the slight difference in the operating rpm of thepump motor and the McQuay centrifugal motor. McQuay encourages the use of 1750/1460 rpm orfour-pole pump motors whenever possible.

Evaporator and Condenser Water PipingAll WSC and WDC evaporators and condensers come equipped with groove-type nozzles forVictaulic couplings (also suitable for welding) or optional flange connections. The installingcontractor must provide matching mechanical connections of the sizes given in the system dimensionand capacity tables.

Important Notes on Welding

1. If welding is to be performed on the mechanical or flange connections, the solid-state temperaturesensor and thermostat bulbs must be removed from the wells to prevent damage to thosecomponents.

2. The unit must be properly grounded or severe damage to the MicroTech Controller may occur.

Small water pressure test valves or pipe plugs are provided at both the inlets and outlets of the vesselheads. The test valves permit the water flow pressure drops to be checked. The pressure drops andflow rates for the various evaporators and condensers are shown in McQuay Product Manual PMWSC/WDC. Refer to the nameplate on the vessel shell for identification.

Evaporator inlet and outlet water connections have been reversed over time with design changes inthe vessel. Be sure that water inlet and outlet connections match certified drawings and stencilednozzle markings. The condenser is connected with the coolest water entering at the bottom tomaximize subcooling.

NoteWhen common piping is used in connection with a heating system, care should be

taken to insure that water flowing through the evaporator cannot exceed 110°F whichcan cause the relief valve to discharge refrigerant or damage controls.

The piping should be supported to reduce the weight and strain on the fittings and connections.Piping should also be adequately insulated. A cleanable 20-mesh water strainer should be installed


at both inlets. Sufficient shutoff valves should be installed to permit draining the water from theevaporator or condenser without draining the complete system.

Flow SwitchA water flow switch must be mounted in either the entering or leaving water line to insure that therewill be adequate water flow to the evaporator before the unit can start. This will safeguard againstslugging the compressors on start-up. It also serves to shut down the unit in the event that waterflow is interrupted to guard against evaporator freeze-up.

A flow switch is available from McQuay under Part Number 017503300. It is a "paddle" type switchand adaptable to any pipe size from 1 inch to 8 inches.

Consult the manufacturer's data for the minimum flow rates required to close the switch. Installationshould be as shown in Figure 3.

Figure 3, Flow Switch Mounting

Electrical connections in the unit control center should be made at terminals 62 and 63. The normallyopen contacts of the flow switch should be wired between these two terminals. Flow switch contactquality must be suitable for 24 VAC, low current (16ma). Flow switch wire must be in separate conduitfrom any high voltage conductors (115 VAC and higher).

CAUTIONFreeze Notice: Neither the evaporator nor the condenser is self-draining;

both must be blown out.

The piping should also include thermometers at the inlet and outlet connections and air vents at thehigh points.

The water heads can be interchanged (end for end) so that the water connections can be made ateither end of the unit. If this is done, new head gaskets must be used and control sensors relocated.

In cases where the water pump noise may be objectionable, rubber isolation sections arerecommended at both the inlet and outlet of the pump. In most cases, it will not be necessary toprovide vibration eliminator sections in the condenser inlet and outlet water lines; but where noiseand vibration are critical (for example, where a pipe chase goes through walls adjoining living quartersin an apartment building), they may be required.

Where a cooling tower is used to supply condenser water, a flow balancing valve is required. Someform of temperature control is required if tower water becomes too cold.

Flow direction markedon switch

I in. (25mm) NPT flowswitch connection

Tee


Oil Cooler PipingFigure 4, Oil Cooler Water Piping Across Chilled Water Pump

Figure 5, Oil Cooler with City Water or Other Supply

WSC-048/050 and WDC-048/050 units are equipped with internal self-contained refrigerant-cooled oilcoolers and require no field piping for the coolers.

WSC 063, 079, 087, 100 and 126 single compressor units have a factory mounted water-cooled oilcooler, a solenoid valve, and a temperature controlled water regulating valve mounted inboard of thecompressor. Accessories must be installed as shown Figure 4 or 5.

WDC 063, 079, 087, and 126 dual compressor units are equipped as above but the solenoid valves andtemperature control valve are factory installed at each cooler as standard. The water piping for thetwo oil coolers cooling is factory piped to a common connection at the tube sheet.

Field water piping to the inlet and outlet connections must be installed according to good pipingpractices and should include stop valves to isolate the cooler for servicing. A 1" minimum cleanablefilter (40 mesh maximum), a solenoid stop valve wired in accordance with the field connection controldiagram (also available as a factory installed option,), and drain valve or plug should also be fieldinstalled. The water supply for the oil cooler may be either from the chilled water circuit (preferred andrecommended) or from an independent source such as city water (see Figure 5).


The use of condenser water for oil cooling is not recommended. When using chilled water it isimportant that the water pressure drop through the oil cooler be less than the drop across theevaporator or insufficient oil cooler flow will result. This is normally no problem except on single passevaporators in which case the oil cooler water should be piped across the chilled water pump toprovide the maximum possible head and flow.

The water flow through the oil cooler will be adjusted by the regulating valve so that the temperatureof oil supplied to the compressor bearings (leaving the oil cooler) is between 80°F (27°C) and 110°F(43°C).

When supplied with city water, the oil piping should discharge through a trap into an open drain toprevent draining the cooler by siphoning. The discharged city water may also be used for coolingtower makeup by discharging it into the tower sump above the highest possible water level.

Refrigerant Vent PipingAs a safety precaution, each system is equipped with pressure relief valves located on the condenser,evaporator, and oil sump vessel for the purpose of relieving excessive refrigerant pressure to theatmosphere. Most codes require that relief valves be vented to the outside, and this is desirableinstallation practice for all installations.

Note Remove plastic shipping plugs (if installed) from the inside of the valves prior to

making pipe connections. Whenever vent piping is installed, the lines should be runin accordance with local code requirements; where local codes do not apply, ANSI/ASHRAE Standard 15-1994 code recommendations should be followed.

The condenser design incorporates two relief valves (one set) with a three-way shutoff valveseparating the two valves (see Figure 6). One valve remains/in the system at all times and the secondvalve acts as a standby.

If one relief valve of the two-valve set fails, the shutoff valve may be used to isolate the faulty reliefvalve, while the other valve provides pressure protection.

Figure 6, Condenser Relief Valve Set

When piping the vent line to a dual valve set, it may be sized for one relief valve and piped to bothvalves. On large capacity condenser designs, two separate sets of dual relief valves are used. Thevent line must be sized to the total of two valves but piped to all four.

Relief Valve # 1 Relief Valve # 2

3-Way ValveStem In: # 1 OpenStem Out: # 2 OpenAlways Front or Back Seat


Relief ValvesRelief valve connection sizes and quantityare shown to the right. Relief valves mustbe piped to the outside of the building inaccordance with ANSI/ASHRAE 15. Twinrelief valves mounted on a transfer valve areused on the condenser so that one reliefvalve can be shut off and removed leavingthe other in operation. Where 4 valves areshown, they consist of two valves mountedon two transfer valves. Only two reliefvalves of the four are active at any time.

Vent piping is sized for only one valve of the set since only one can be in operation at a time. In nocase would a combination of evaporator and condenser sizes require more refrigerant than thepumpdown capacity of the condenser. Condenser pumpdown capacities are based uponANSI/ASHRAE Standard 15 recommendations of 90% full at 90°F (32°C).

Relief Valve Pipe SizingRelief valve pipe sizing is based on the discharge capacity for the given evaporator or condenser andthe length of piping to be run. Discharge capacity for HFC-134a vessels is calculated as follows:

C xDxL= 0 133.

Where: C=Minimum discharge capacity, lbs of air/min

D=Vessel diameter, in.

L=Vessel length, ft.

Example: E3016 Evaporator, HFC-134a Refrigerant, 75 equivalent feet of piping

C x x Lbs of air= =0133 30 16 63 8. . / min

From the table below, 75 feet of piping for 63.8 lb. of air/min. at 180 psig valve setting requires a 2"diameter pipe.

Discharge Capacity, lbs of Air/MinEQUIVALENT DIAMETER STANDARD WALL IRON PIPELENGTH OF 1” (25mm) 1.25” (32mm) 1.5” (38mm) 2” (50mm) 2.5” (64mm) 3” (76mm)DISCHARGE RELIEF VALVE PRESSURE SETTNG

PIPING, FT. (m) 180 225 180 225 180 225 180 225 180 225 180 22550 (15.2) 21.4 26.8 42.8 53.6 62.7 78.4 117.0 146.3 182.2 227.7 315.4 393.775 (22.9) 17.5 21.9 35.0 43.8 51.5 64.4 95.4 119.3 150.5 188.1 257.4 321.8100 (30.5) 15.2 19.1 30.2 27.8 44.3 55.4 82.6 103.3 129.6 162.0 222.5 278.1150 (45.7) 12.4 15.6 24.7 30.9 36.0 45.0 67.3 84.2 105.1 131.9 182.2 227.7200 (61.0) 10.6 13.6 21.4 26.8 31.4 39.3 58.4 73.1 91.1 113.9 157.7 197.1300 (91.4) 8.8 11.1 17.5 21.9 25.5 32.0 47.6 59.6 75.6 94.5 128.5 160.7

Note: Standard relief valve settings; R-134a, evaporator=180 psig, condenser=225 psig

Note: Per ASHRAE Standard 15, the pipe size may not be less than the relief device, meaning aminimum 1" diameter pipe is required. The discharge from more than one relief valve may be run into acommon header, the area of which shall not be less than the sum of the areas of the connected pipes.For further details, refer to ASHRAE Standard 15. The common header can be calculated by theformula:

DCommon D D Dn= +

1

222 2 0 5

. .. ..

Relief ValveEvaporator Code Connection Number

E1608 Thru E2616 1” FPT 1E3016 Thru E4216 1” FPT 2E4820 Thru E4824 1” FPT 2Condenser CodeC1608 thru C3016 1” FPT 2C3616 Thru C4216 1” FPT 4C4820 Thru C4824 1” FPT 4


ElectricalWiring, fuse and wire size must be in accordance with information located in the electrical data.Standard NEMA motor starters require modification to meet McQuay specifications. Refer to electricaldata supplied with the unit or McQuay Product Manual PM WSC/WDC.

Important: The voltage to these units should be within the limitation of +10%, and the voltageunbalance between phases must not exceed 3%. Since a 3 1/2% voltage unbalance will cause anapproximate 25% increase in motor temperature, it is most important that the unbalance betweenphases be kept at a minimum.

Power Wiring

CAUTIONQualified and licensed electricians must perform wiring. Shock hazard exists.

Power wiring to compressors must be in proper phase sequence. Motor rotation is set up forclockwise rotation facing lead end with phase sequence of 1-2-3. Care should be taken that properphase sequence is carried through the starter to compressor. With the phase sequence of 1-2-3 andL1 connected to T1 and T6, L2 connected to T2 and T4, and L3 connected to T3 and T5, rotation isproper. See diagram in terminal box cover.

Proper phase sequence will be determined by the McQuay start-up technician.

CAUTIONConnections to terminals must be made with copper lugs and copper wire.

Care should be taken when attaching leads to compressor terminals.

NoteDo not make final connections to motor terminals until wiring has been checked and

approved by a McQuay technician.

Under no circumstances should a compressor be brought up to speed unless proper sequence androtation have been established. Serious damage may result if compressor starts in wrong direction.

It is the installing contractor's responsibility to insulate the compressor motor terminals when the unitvoltage is 600 volts or greater. This is to be done after the McQuay start-up technician has checkedfor proper phase sequence and motor rotation.

Following this verification by the McQuay technician, the contractor should apply the followingfurnished items.

Materials required:

1. Locktite brand safety solvent (12 oz. package available as McQuay part number 350A263H72)

2. 3M Co. Scotchfil brand electrical insulation putty (available in a 60-inch roll as McQuay partnumber 350A263H81)

3. 3M Co. Scotchkote brand electrical coating (available in a 15 oz. can with brush as McQuay PartNumber 350A263H16)

4. Vinyl plastic electrical tape

The above items are also available at most electrical supply outlets.


Application procedure:

1. Disconnect and lock out the power source to the compressor motor.

2. Using the safety solvent, clean the motor terminals, motor barrel adjacent to the terminals, leadlugs, and electrical cables within the terminal 4OX to remove all dirt, grime, moisture and oil.

3. Wrap the terminal with Scotchfil filling in all irregularities. The final result should be smooth andcylindrical.

4. Doing one terminal at a time, brush the Scotchkote on the motor barrel to a distance of up to '/2"around the terminal and, on the wrapped terminal, the rubber insulation next to the terminal andthe lug and cable for approximately 10". Wrap additional Scotchfil insulation over theScotchkote.

5. Tape the entire wrapped length with electrical tape to form a protective jacket.

6. Finally, brush on one more coat of Scotchkote to provide an extra moisture barrier.

Unit Mounted Starter Power WiringSome units are supplied with a factory wired and mounted starter equipped with ambient compensatedquick trip overloads. Wiring, fuse and wire size must be in accordance with information located in theelectrical data supplied with the unit or the electrical data pertaining to your unit.

Important: See reference above to maximum voltage unbalance limitation of 3%.

The transition timer in the starter is factory set to disconnect the star winding connection and connectthe delta winding, when the motor comes up to speed and before any speed reduction occurs.

Control WiringThe control circuit on the McQuay WSC/WDC packaged chiller is designed for 115 volts. Power canbe supplied from a separate circuit and fused at 20 amps inductive load. If the unit is supplied with afactory-mounted starter then the control circuit power supply is provided through a transformerlocated in the starter. A free-standing starter furnished by McQuay will have a control transformerand requires field wiring.

The disconnect switch should be tagged to prevent current interruption. Switch is to remain on at alltimes in order to keep oil heaters operative and prevent refrigerant from diluting in oil.

The control center off-on switch should be turned to the "off" position at any time compressoroperation is not desired.

In the event control voltage is supplied by a transformer, the transformer should be rated at 2 KVA,with an inrush rating of 12 KVA minimum at 80% power factor and 95% secondary voltage. Forcontrol wire sizing, refer to N.E.C. Articles 215 and 310. In the absence of complete information topermit calculations, the voltage drop should be physically measured. Again, the disconnect switchshould be marked to prevent control circuit from being de-energized. Water flow interlock terminalsare provided on the control center terminal strip. See field connection diagram in the Electrical DataSection or in the cover of control center for proper connections.

The purpose of the water flow interlocks is to prevent compressor operation until such time as boththe evaporator water and condenser water pumps are running. If flow or pressure differential switchesare not furnished factory installed and wired, they must be furnished and installed by others beforethe unit can be started.

WARNING

On older style units severe damage to the compressor can result if the anti-recycletimer is turned to the "off" position and the flow switches operate intermittently.


Operation of the chilled water pump may be to cycle the pump with the compressor, operatecontinuously, or start automatically by a remote source. The cooling tower pump must cycle with themachine. The holding coil of the cooling tower pump motor starter must be rated at 115 volts, 60 Hzwith a maximum volt-amperage rating of 100. If the voltage-amperage rating is exceeded, a controlrelay is required.

All interlock contacts must be rated for no less than 10 inductive amps. The alarm circuit provided inthe control center utilizes 115 volts AC. The alarm used should not draw more than 10 volt amperes.

See OM 125 for MicroTech control details.

Testing Control CircuitMcQuay will test the circuits upon completion of power and control wiring during unit's initial start-up.

Surge CapacitorsAll units (except those supplied with solid state starters) are supplied with surge capacitors to protectcompressor motors from electrical damage resulting from high voltage spikes. The capacitors may ormay not be wired depending upon whether or not the starter was furnished by McQuay or whether ornot it was factory mounted. Surge capacitors should be enclosed, either inside the starter (on terminalbox mounted starters) or in the compressor motor terminal box, and should be connected on the motorterminals with leads less than 18 inches (460 mm).


Prestart System ChecklistYes No N/A

Chilled Water

Piping complete ............................................................................................................................... o o o

Water system filled, vented ........................................................................................................... o o o

Pumps installed, (rotation checked), strainers cleaned ............................................................. o o o

Controls (3-way, face and bypass dampers, bypass valves, etc.) operable ........................... o o o

Water system operated and flow balanced to meet unit design requirements ...................... o o o

Condenser Water

Cooling tower flushed, filled and vented .................................................................................... o o o

Pumps installed, (rotation checked), strainers cleaned ............................................................ o o o

Controls (3-way, bypass valves, etc.) operable ......................................................................... o o o

Water system operated and flow balanced to meet unit requirements .................................. o o o

Electrical

115 volt service completed, but not connected to control panel ............................................ o o o

Power leads connected to starter; load leads run to compressor ready for connection when service engineer is on hand for start-up ................................................... o o o

(Do not connect starter or compressor terminals)

All interlock wiring complete between control panel and complies with specifications ..... o o o

Starter complies with specifications ............................................................................................ o o o

*Oil cooler solenoid wired to control panel as shown on wiring diagram Pump starter and interlock wired .............................................................................................. o o o

Cooling tower fans and controls wired ...................................................................................... o o o

Wiring complies with National Electrical Code and local codes ............................................. o o o

Condenser pump starting relay (CWR) installed and wired ................................................... o o o

Miscellaneous

Oil cooler water piping complete (units with water cooled oil coolers only) ........................ o o o

Relief valve piping complete ......................................................................................................... o o o

Thermometer wells, thermometers, gauges, control wells, controls, etc., installed .............. o o o

Minimum system load of 25% of machine capacity available for testing and adjusting controls ................................................................................................................. o o o

NoteThis checklist must be completed and sent to the local McQuay service location

two weeks prior to start-up.


Operation

Operator ResponsibilitiesIt is important that the operator become familiar with the equipment and the system before attemptingto operate the chiller. In addition to reading this manual the operator should study operation manualOM 125 and the control diagram furnished with the unit so that he understands the starting, operatingand shutdown sequences as well as the safety shutdown modes.

During the initial startup of the chiller the McQuay technician will be available to answer anyquestions and instruct in the proper operating procedures.

It is recommended that the operator maintain an operating log for each individual chiller unit. Inaddition, a separate maintenance log should be kept of the periodic maintenance and servicingactivities.

This McQuay centrifugal chiller represents a substantial investment and deserves the attention andcare normally given to keep this equipment in good working order. If the operator should encounterabnormal or unusual operating conditions, it is recommended that a McQuay service technician beconsulted.

McQuay International conducts training for centrifugal operators at its factory Training Centerseveral times a year. These sessions are structured to provide basic classroom instruction andinclude hands-on operating and troubleshooting exercises. For further information, contact yourMcQuay representative.

NomenclatureEach centrifugal chiller is assigned a set of identifying numbers that are used to describe the unitfeatures and to identify each individual unit. These number groups are stamped on each unitnameplate.

All inquiries pertaining to operating and servicing of this unit should include all identificationnumbers.

Each of the major individual components also have nameplates to provide certain necessaryinformation to the installer and the operator.

Compressors are designated as model CE. For example a model CE050 compressor is used on a modelWSC050 chiller unit. The compressor nameplate identifies the compressor model, style and serialnumber and includes the electrical characteristics of the compressor motor. The CE050 compressornameplate also shows the oil pump electrical characteristics.

The condenser and evaporator vessels have nameplates stamped with the maximum working pressureof the vessel, the National Board Number, and the vessel style number. It should be noted that thevessel relief valve maximum settings coincides with the maximum refrigerant side vessel workingpressure.


MicroTech Control PanelThe MicroTech unit controller is a microprocessor based control panel designed to initiate the step-by-step start functions of its host centrifugal compressor unit, monitor and regulate the compressorscapacity, protect it, and sequence the compressor shutdown on lack of load or in response to a presettime. On dual compressor units, each compressor has its own controller. They are interconnected toprovide lead-lag and load-balance functions.

The full information on the features, installation, operation and problem analysis of the McQuaymicroprocessor control for Centrifugal chillers, see Operators Manual OM 125. The MicroTech panelprovides a wide range of control options and data reporting and recording capability. Familiarity withthe control system is important for optimum unit operation.

Figure 7, MicroTech Control Panel

Capacity Control SystemThe movement of the inlet vanes, opening or closing to permit the correct quantity of refrigerant toenter the impeller, controls the compressor capacity. The vane movement occurs in response to oilflow from the SA or SB solenoid valves which, in turn, respond to a control module signal. This oilflow activates a piston to rotate the vanes.

Vane OperationThe hydraulic system for the inlet guide vane capacity control operation consists of a 4-way normallyopen solenoid valve located in the oil management control panel. Oil under pressure from the oil filteris directed by the 4-way valve to either or both sides of the piston depending on whether the controlsignal is to load, unload, or hold.

To open the vanes (or load the compressor) solenoid SA is de-energized and solenoid SB isenergized, allowing oil flow from port SA to one side of the piston then drain through port SB.

To close the vanes (unload compressor) valve SB is de-energized and valve SA is energized to movethe piston and vanes toward the unload position.

When both solenoid valves SA and SB are de-energized, full oil pressure is directed to both sides ofthe piston through ports SA and SB, thus the vanes are held in that position. Refer to Figure 9 andFigure 10 for solenoid action. Note that both solenoids cannot be energized simultaneously.


Metering ValvesThe speed at which the capacity control vanes are opened or closed can be adjusted to suit systemoperating requirements. Adjustable needle valves in the oil drain lines are used to control the rate ofbleed-off and consequently the “vane speed”. These needle valves are part of the 4-way solenoidvalve assembly located in the compressor lube box (Figure 8).

The valves are normally factory set so the vanes will move from fully closed to fully opened inapproximately 3 minutes and from fully open to fully closed in 1 minute (except CE126). The speedshould be slow enough to prevent over-controlling and hunting.

Vane Speed AdjustmentThe vane speed at which the capacity control vanes open or close is controlled by the rate of oilbleed-off from the vane actuating position. This bleed-off rate is adjustable by positioning the needlevalves on SA and SB solenoid valves located in the lube box.

Screwdriver openings in the left side of the lube box permit access. The upper opening accesses theSB needle valve for adjusting the vane OPENING speed for loading the compressor (refer to Figure 8).Turn this screw clockwise to decrease the vane opening and counterclockwise to increase theopening speed.

The lower opening accesses the SA needle valve for adjusting the CLOSING speed for unloading thecompressor. The same adjustment applies . . . clockwise to decrease closing, counterclockwise toincrease vane closing.

The vane speed is factory set and varies by compressor size:

Compressor Model Opening Time Closing TimeCE048 - CE050 2 - 2 1/2 min. 3/4 - 1 min.CE063 - CE100 3 - 5 min. 1 - 2 min

CE126 5 - 8 min. 1 - 2 min.

Figure 8, Lube Box


Figure 9, Vane Control Solenoid Operation


Figure 10, Vane Control Solenoid Operation, Continued

Lubrication SystemThe lubrication system for the WSC family of units provides lubrication and heat removal forcompressor bearings and internal parts. In addition, the system provides oil under pressure tohydraulically operate the unloading piston for positioning the inlet guide vanes for capacity control.WDC dual compressor chillers have completely independent lubrication systems for each compressor.

Proper operation of the hydraulic system and bearing lubrication system can be assured only ifrecommended oil is used, recommended oils are shown in Table 1. Each unit is factory charged withthe correct amount of the recommended oil. Under normal operation, no additional should be needed.Oil should be visible in the oil sump sight glass at all times.

The oil pump for the CE048/050 compressor is completely self-contained within the compressorhousing. The assembly includes the pump, pump motor, oil heater and oil separator. The oil ispumped through the oil discharge line to the oil filter in the compressor casting and then to theinternal refrigerant-cooled oil cooler.

The other compressor sizes-CE063, through CE126-utilize a separate oil pump contained in the oilreservoir. This assembly includes pump, motor, heater and oil separator system. Oil is pumpedthrough the external oil cooler and then to the oil filter located inside the compressor housing.WSC/WDC 063-126 units, single or dual compressor, utilize a water-cooled oil cooler.

The oil coolers maintain the proper oil temperature under normal operating conditions. The coolantflow control valve should maintain 90°F-100°F (32°C-38°C). Lubrication protection for coast down inthe event of a power failure is accomplished by a spring loaded piston in models CE050 through 100.When the oil pump is started, the piston is forced back by the oil pressure, compressing the spring


and filling the piston cavity with oil. When the pump stops, the spring pressure on the piston forcesthe oil out to the bearings.

In model CE126 the compressor coast down lubrication is supplied from a gravity feed oil reservoir.

A typical flow diagram is shown in Figure 11.

Table 1, Approved Polyolester Oils For R-134a Units

Compressor Models CE050 - 126

Lubricant Designation Mobil Artic EAL 46;

ICI Emkarate RL32H(2)

McQuay Part Number

55 Gal. Drum

5 Gal. Drum

1 Gal. Can

735030432, Rev 47

735030433, Rev 47

735030435, Rev 47

Compressor Oil Label 070200106, Rev OB

1. Approved oil from two suppliers can be mixed.


Figure 11, Typical Oil Flow Diagram

1. Does not apply to CE 048,050 compressors2. Connections not necessarily in correct relative location

Hot Gas BypassWSC and WDC units can be equipped with an optional hot gas bypass system used to feeddischarge gas directly into the evaporator when the system load falls below 10% compressor capacity.

Light load conditions are signaled by measurement of a set percentage of RLA amps by theMicroTech control panel. When the RLA drops to the setpoint the hot gas bypass solenoid isenergized making hot gas bypass available for use. This introduction of hot gas provides a stablerefrigerant flow and keeps the chiller from short cycling under light load conditions. It also preventssurge during heat recovery operation.

The factory setpoint for bringing on hot gas bypass is 40% of RLA.


Maintenance

Pressure/Temperature ChartHFC-134a Temperature Pressure Chart

°F PSIG °F PSIG °F PSIG °F PSIG

6 9.7 46 41.1 86 97.0 126 187.3

8 10.8 48 43.2 88 100.6 128 192.9

10 12.0 50 45.4 90 104.3 130 198.7

12 13.2 52 47.7 92 108.1 132 204.5

14 14.4 54 50.0 94 112.0 134 210.5

16 15.7 56 52.4 96 115.9 136 216.6

18 17.1 58 54.9 98 120.0 138 222.8

20 18.4 60 57.4 100 124.1 140 229.2

22 19.9 62 60.0 102 128.4 142 235.6

24 21.3 64 62.7 104 132.7 144 242.2

26 22.9 66 65.4 106 137.2 146 249.0

28 24.5 68 68.2 108 141.7 148 255.8

30 26.1 70 71.1 110 146.3 150 262.8

32 27.8 72 74.0 112 151.1 152 270.0

34 29.5 74 77.1 114 155.9 154 277.3

36 31.3 76 80.2 116 160.9 156 284.7

38 33.1 78 83.4 118 166.0 158 292.2

40 35.0 80 86.7 120 171.1 160 299.9

42 37.0 82 90.0 122 176.4 162 307.8

44 39.0 84 93.5 124 181.8 164 315.8

Routine Maintenance

Lubrication (See Caution)After the system is once placed into operation, no other additional oil is required except in the eventthat repair work becomes necessary to the oil pump or unless a large amount of oil is lost from thesystem due to a leak.

If oil must be added with the system under pressure, use a hand pump with its discharge lineconnected to the service valve at the bottom of the oil pump. (The CE050 compressor with its internaloil pump is equipped with an oil service valve on the compressor.) The POE oils used with R-134a arehygoscopic and care should be exercised to avoid exposure to moisture (air).

Changing Oil Filters (See Caution)McQuay chillers are at positive pressure at all times and do not leak contaminated moist air into therefrigerant circuit eliminating the need for annual oil changes. An annual laboratory oil check isrecommended to check overall compressor condition.


CE050 Compressors - If the unit is equipped with a suction line service valve (dual compressor unitsare so equipped as standard), close this valve and close the valve on the motor cooling liquid line toisolate the compressor. Remove the refrigerant from the compressor using approved procedures.Remove the filter cover and the old filter and install the new filter, open end first. Replace the coverusing a new gasket. Reopen the suction and liquid line valves.

If the unit is not equipped with a suction line service valve, the unit will have to be pumped down inorder to remove the pressure in the compressor before removing the cover and changing the filter.Refer to later section for pumpdown procedure.

CE063 and Larger Compressors - The oil filter in each of these machines can be changed by simplyisolating the filter cavities. Close the oil discharge line service valve at the oil pump (at the filter onCE126). Remove the filter cover; some foaming may occur but the check valve should limit leakagefrom other compressor cavities. Remove the filter, replace with new element and replace filter coverusing new gasket. Reopen the valve in pump discharge line and purge air from the oil filter cavity.

When machine is operated again, the oil level should be checked to determine if oil needs to be addedto maintain the proper operating level.

CAUTION

Improper servicing of the lubrication system,including the addition of excessive or incorrect oil, substitute quality oil filter,

or mishandling of the equipment under pressure is hazardous.Only authorized and trained service personnel should attempt this service.

For qualified assistance, contact your local McQuay service location.

Refrigerant CycleMaintenance of the refrigerant cycle consists of maintaining a log of the operating conditions, andassuring the unit has the proper oil and refrigerant charge. (See the maintenance schedule and theappropriate operating log at the end of this bulletin).

At every inspection, the oil, suction and discharge pressures should be noted and recorded, as wellas condenser and chiller water temperatures.

The suction line temperature at the compressor should be taken at least once a month. Subtractingfrom this, the saturated temperature equivalent of the suction pressure will give the superheat.Extreme changes in subcooling and/or superheat over a period of time will indicate losses ofrefrigerant or possible deterioration of the expansion valves. Proper superheat setting is 0 to 1 degreeF (0.5 degree C) at full load. Such a small temperature difference can be hard to measure accurately.Another method is to measure the compressor discharge superheat, the difference between the actualdischarge temperature and the saturated discharge temperature. The discharge superheat should bebetween 14 and 16 degrees F (8 to 9 degrees C) at full load with R-134a refrigerant. The liquid injectionshould be deactivated (remove relay #10) when taking the discharge temperature. The superheat willincrease linearly to 55 degrees F (30 degrees C) at 10% load. The Series 200 MicroTech Control candisplay all superheat and subcooling temperatures.


Figure 8. Typical Refrigerant Flow Diagram

1. Connection not necessarily in correct relative location.2. Filter on dual compressor units only.3. Liquid injection does not apply to CE 048, 050, compressors.4. The evaporator chilled water connections are correct for WDC 126 dual compressor units only. All other models have the

chilled water inlet in the top connection.

Electrical SystemMaintenance of the electrical system involves the general requirement of keeping contacts clean andconnections tight and checking on specific items as follows:

1. The compressor current draw should be checked and compared to nameplate RLA value.Normally the actual current will be lower since the nameplate rating represents full load operation.Also check all pump and fan motor amperages and compare with nameplate ratings.

2. Inspection should verify that the oil heaters are operative. The heaters are insert cartridge typeand can be checked by ammeter reading. They should be energized whenever power is availableto the control circuit and when the compressor is inoperative). When the compressor starts theheaters are de-energized.

3. At least once a quarter, all safety controls except compressor overloads should be made tooperate and their operating points checked. Any control may shift its operating point as it ages,and this must be detected so the controls can be adjusted or replaced. Pump interlocks and flowswitches should be checked to be sure they interrupt the control circuit when tripped.

4. The contactors in the motor starter should be inspected and cleaned quarterly. Tighten allterminal connections.

5. The compressor motor resistance to ground should be checked and logged semi-annually. Thislog will track insulation deterioration. A reading of 50 megohms or less indicates a possibleinsulation defect or moisture and should be further checked.


WARNING

Never Megger a motor while in a vacuum. Severe damage can result.

6. The centrifugal compressor must rotate in the direction indicated by the arrow on the casting nearthe rotation sightglass. If the operator has any reason to suspect that the power systemconnections may have been altered, (phases reversed) the compressor should be jogged to checkrotation. For assistance, call the McQuay service location.

Cleaning and PreservingA common cause of service calls and equipment malfunction is dirt. This can be prevented withnormal maintenance. The system components most subject to dirt are:

1. Permanent or cleanable filters in the air handling equipment must be washed in accordance withthe manufacturer’s instructions; throwaway filters should be replaced. The frequency of thisservice will vary with each installation.

2. Remove and clean strainers in chilled water system, oil cooler line and condenser water system atevery inspection.

Seasonal ServicingPrior to shutdown periods and before starting up again, the following service procedures should becompleted.

Annual Shutdown1. Where the chiller may be subject to freezing temperatures, the condenser and chiller water piping

should be disconnected and drained of all water. Dry air blown through the condenser will aid inforcing all water out. Removal of condenser heads is also recommended. The condenser andevaporator are not self-draining. Water permitted to remain in the piping and vessels will rupturethese parts if subjected to freezing temperature.

Forced circulation of antifreeze through the water circuits is a sure method of avoiding freezeup.

2. Take measures to prevent the shutoff valve in the water supply line from being accidentallyturned on.

3. If a cooling tower is used and if the water pump will be exposed to freezing temperatures, be sureto remove the pump drain plug and leave it out so any water that may accumulate will drain away.

4. Open the compressor disconnect switch, and remove the Fusetrons. If the transformer is usedfor control voltage, the disconnect must remain on to provide power to the oil heater. Set themanual stop/auto switch (SWI) to the stop position. To insure against the possibility of anaccidental start, remove the fault relay from the left side of the MicroTech panel.

5. Check for corrosion and clean and paint rusted surfaces.

6. Clean and flush water tower for all units operating on a water tower. Make sure tower“blowdown” or bleed-off is operating. Set up and use a good maintenance program to prevent“liming up” of both tower and condenser. It should be recognized that atmospheric air containsmany contaminants that increase the need for proper water treatment. The use of untreated watermay result in corrosion, erosion, sliming, scaling or algae formation. It is recommended that theservice of a reliable water treatment company be used. McQuay International assumes noresponsibility for the results of untreated or improperly treated water.

7. Remove condenser heads at least once a year to inspect the condenser tubes and clean ifrequired.


Annual StartupA dangerous condition can exist if power is applied to a faulty compressor motor starter that has beenburned out. This condition can exist without the knowledge of the person starting the equipment.

This is a good time to check all the motor winding resistance to ground. Semi-annual checking andrecording of this resistance will provide a record of any deterioration of the winding insulation. Allnew units have well over 100 megohms resistance between any motor terminal and ground.

Whenever great discrepancies in readings occur or uniform readings of less than 50 megohms areobtained, the motor cover should be removed for inspection of the winding prior to starting the unit.Uniform readings of less than 5 megohms indicate motor failure is imminent and motor should bereplaced or repaired. Repair before failure occurs can save a great deal of time and labor expended inthe cleanup of a system after motor burnout.

1. The control circuit should be energized at all times. If the control circuit has been off and oil iscool, energize oil heaters and allow 24 hours for heater to remove refrigerant from the oil beforestarting.

2. Check and tighten all electrical connections.

3. Replace the drain plug in cooling tower pump if it was removed at shutdown time the previousseason.

4. Install Fusetrons in main disconnect switch (if removed).

5. Reconnect water lines and turn on supply water. Flush out condenser and check for leaks.

6. Refer to Manual OM 125 before energizing the compressor circuit.

Repair of System

Pressure Relief Valve ReplacementCurrent condenser designs use two relief valves (1 set) separated by a three way shutoff valve. Thisvalve allows either relief valve to be shut off, but at no time can both be shut off. In the event one ofthe relief valves are leaking in the two valve set, these procedures should be followed:

• If the valve closest to the valve stem is leaking, back seat the three-way valve all the way, closingthe port to the leaking pressure relief valve. Remove and replace the faulty relief valve. Thethree-way shutoff valve should remain either fully back seated or fully forward to normaloperation. If the relief valve farthest from the valve stem is leaking, front seat the three-way valveand replace the relief valve as stated above.

• The refrigerant in the evaporator must be pumped down to the condenser to replace its reliefvalve.

Pumping DownIf it becomes necessary to pump the system down, extreme care should be used to avoid damage tothe evaporator from freezing. Always make sure that full water flow is maintained through the chillerand condenser while pumping down. To pump the system down, close all liquid line valves. With allliquid line valves closed and water flowing, start the compressor. Set the MicroTech panel to themanual load. The vanes must be open while pumping down to avoid a surge or other damagingcondition. Pump the unit down until the MicroTech cuts out at approximately 20 psig. It is possiblethat the unit might experience a mild surge condition prior to cutout. If this should occur, immediatelyshut off the compressor. Use a portable condensing unit to complete the pump down, condense therefrigerant, and pump it into the condenser or pumpout vessel using approved procedures.


A pressure regulating valve should always be used on the drum being used to build the systempressure. Also, do not exceed the test pressure given above. When the test pressure is reacheddisconnect the gas cylinder.

Pressure TestingNo pressure testing is necessary unless some damage was incurred during shipment. Damage may bedetermined upon a visual inspection of the exterior piping assuring no breakage occurred or fittingsloosened. Service gauges should show a positive pressure. If no pressure is evident on the gauges,a leak may have occurred discharging the entire refrigerant charge. In this case, the unit should beleak tested to determine the location of the leak.

Leak TestingIn the case of loss of the entire refrigerant charge, the unit should be checked for leaks prior tocharging the complete system. This can be done by charging enough refrigerant into the system tobuild the pressure up to approximately 10 psig (69 kPa) and adding sufficient dry nitrogen to bring thepressure up to a maximum of 125 psig (860 kPa) and then leak test with an electronic leak detector.Halide leak detectors do not function with R-134a. Water flow through the vessels should bemaintained anytime refrigerant is added or removed from the system.

CAUTIONDo not use oxygen or a mixture of R-22 and air to build up pressure as a serious

explosion can result.

A pressure regulating valve should always be used on the drum used to build up the system pressure.Also, do not exceed the test pressure given above. When the test pressure is reached, disconnect thegas cylinder.

If any leaks are found in welded or brazed joints or it is necessary to replace a gasket, relieve the testpressure in the system before proceeding. For copper joints, brazing is required.

After making any necessary repair, the system should be evacuated as described in the sectionfollowing.

EvacuationAfter it has been determined that there are no refrigerant leaks the system should be evacuated usinga vacuum pump with a capacity that will reduce the vacuum to at least 1000 microns of mercury.

A mercury manometer, electronic or other type of micron gauge should be connected at the farthestpoint from the vacuum pump. For readings below 1000 microns, an electronic or other micron gaugeshould be used.

The triple evacuation method is recommended and is particularly helpful if the vacuum pump is unableto obtain the desired 1 millimeter of vacuum. The system is first evacuated to approximately 29 inchesof mercury. Dry nitrogen is then added to the system to bring the pressure up to zero pounds.

Then the system is once again evacuated to approximately 29 inches of mercury. This is repeatedthree times. The first pulldown will remove about 90% of the noncondensables, the second about90% of that remaining from the first pulldown and, after the third, only 1/10-1% noncondensables willremain.


Charging the SystemWSC and WDC water chillers are leak tested at the factory and shipped with the correct charge ofrefrigerant as indicated on the unit nameplate. In the event the refrigerant charge was lost due toshipping damage, the system should be charged as follows after first repairing the leaks andevacuating the system.

a. Connect the refrigerant drum to the gauge port on the liquid line shutoff valve and purge thecharging line between the refrigerant cylinder and the valve. Then open the valve to the mid-position.

b. Turn on both the cooling tower water pump and chilled water pump and allow water to circulatethrough the condenser and the chiller. (It will be necessary to manually close the condenserpump starter.)

c. If the system is under a vacuum, stand the refrigerant drum with the connection up and open thedrum and break the vacuum with refrigerant gas to a saturated pressure above freezing.

d. With a system gas pressure higher than the equivalent of a freezing temperature, invert thecharging cylinder and elevate the drum above the condenser. With the drum in this position,valves open, water pumps operating, liquid refrigerant will flow into the condenser.Approximately 75% of the total requirement estimated for the unit can be charged in this manner.

e. After 75% of the required charge has entered the condenser, reconnect the refrigerant drum andcharging line to the service valve on the bottom of the evaporator. Again purge the connectingline, stand the drum with the connection up, and place the service valve in the open position.

IMPORTANT: At this point the charging position should be interrupted and prestart checks madebefore attempting to complete refrigerant charge. The compressor must not be started at this time.(Preliminary check must first be completed.)

Operation and maintenance manuals pertaining to the individual WSC or WDC unit are available fromyour local McQuay representative.

Caution

It is of utmost importance that all local, national, and international regulationsconcerning the handling and emission of refrigerants are observed.


Maintenance Schedule

I. Compressor A. Performance Evaluation (Log & Analysis) * O B. Motor • Meg. Windings X • Ampere Balance (within 10%) X • Terminal Check (tight conn., porcelain clean) X • Motor Cooling (check temperature) X C. Lubrication System • Oil Lines Temperatures O • Water (Refrigerant) Coolant Temperature O • Oil Cooler Strainer (water) X • Oil Cooler Solenoid Operation X • Oil Analysis X • Oil Appearance (clear color, quantity) O • Oil Filter Change X

• Oil change if indicated by oil analysis X D. Vane Operation • Compressor Loads: Operate Manual Switch X Record Motor Amps X • Compressor Unloads: Operate manual Switch X Record Motor Amps X • Vanes Will Hold (place manual switch in "hold") Observe Water Temp and Record Amps X E. Internal Compressor Check XII. Controls A. Operating Controls • Check Settings and Operation X • Check Vane Control Setting and Operation X • Verify Motor Load Limit Control X • Verify Load Balance Operation X • Check Oil Pump Contactor X B. Protective Controls • Test Operation of: Alarm Relay X Pump Interlocks X Hot and Cold Oil Temperature Cutouts X Guardistor and Surgeguard Relays X High and Low Pressure Cutouts X High Suction Temperature Cutout X High Discharge Temperature Cutout X Low Pressure Override Switch X Oil Pump Pressure Differential Cutout X Oil Pump Safety Timer X Oil Pump Time Delay X Vane Closed Switch X


Key: O = Performed by in-house personnel X = Performed by McQuay Service personnel


Maintenance Schedule, Cont.

III. Condenser A. Performance Evaluation O B. Test Water Quality X C. Clean Condenser Tubes X D. Eddycurrent Test - Tube Wall Thickness X E. Seasonal Protection XIV. Evaporator A. Performance Evaluation (Log Conditions And Analysis O B. Test Water Quality X C. Clean Evaporator Tubes (as required) X D. Eddycurrent Test - Tube Wall thickness (as required) X E. Seasonal Protection XV. Expansion Valves A. Performance Evaluation (Superheat Control) XVI. Compressor - Chiller Unit A. Performance Evaluation O B. Leak Test: • Compressor Fittings and Terminal X • Piping Fittings X • Oil Pump Joints and Fittings X • Vessel Relief Valves X C. Vibration Isolation Test X D. General Appearance: • Paint X • Insulation XVII. Starter(s) A. Examine Contactors (hardware and operation) X B. Verify Overload Setting and Trip X C. Test Electrical Connections XVIII. Optional Controls A. Hot Gas Bypass (verify operation) X B. Liquid Injections Controls (verify operation) X

Key: O = Performed by in-house personnel X = Performed by McQuay Service personnel

Note

Some compressors use power factory correction capacitors and all have a surgecapacitor (excepting units with solid state starters). The surge capacitor may be installed

out of sight in the compressor motor terminal box. In all cases, capacitors must bedisconnected from the circuit to obtain a useful Megger reading. Failure to do so will

produce a low reading. In handling electrical components, only fully qualifiedtechnicians should attempt service.


Service Programs

It is important that an air conditioning system receive adequate maintenance if the full equipment lifeand full system benefits are to be realized.

Maintenance should be an ongoing program from the time the system is initially started. A fullinspection should be made after 3 to 4 weeks of normal operation on a new installation and on aregular basis thereafter.

McQuay offers a variety of maintenance services through the local McQuay service office, itsworldwide service organization, and can tailor these services to suit the needs of the building owner.Most popular among these services is the McQuay Comprehensive Maintenance Contract.

For further information concerning the many services available, contact your local McQuay serviceoffice.

Post Office Box 2510, Staunton, Virginia 24402-2510 (540) 248-0711 www.mcquay.com

Single/Dual Compressor Centrifugal Chillers · 8 Centrifugal Chillers IOMM WSCWDC Oil Cooler Piping...

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