BULLETIN NO. IM 173JULY 1978

INSTALLATION ANDMAINTENANCE DATA

PACKAGED AIR COOLED CONDENSING UNITTYPE ALP-067A THRU 159A

G R O U P M c Q U A Y - P E R F E X Inc. 13600 Industrial Park Blvd., P.O. Box 1551, Minneapolis, Mn. 55440 @)

N O T I C E :

Installation and maintenance are to be performed only byqualified personnel who are familiar with local codes andregulations, and experienced with this type of equipment.CAUTION: Sharp edges and coil surfaces are a potentialinjury hazard. Avoid contact.

page 2

Nomenclature

PROPELLER FANS

LOW POWER CONSUMING

AIR COOLED CONDENSER

A L - 089 A D

REFRIGERANT CIRCUITS(D=Dual; S=Single)

DESIGN VINTAGE

NOMINAL CAPACITY (TONS)

Inspection

When the equipment is received, all items should be carefully checkedagainst the bill of lading to insure a complete shipment. All unitsshould be carefully inspected for damage upon arrival. All shippingdamage should be reported to the carrier and a claim should be filed.The unit serial plate should be checked before unloading the unit tobe sure that it agrees with the power supply available.

INSTALLATION

Handling

Care should be taken to avoid rough handling or shock due to droppingthe unit. Do not push or pull the unit from anything other than thebase, and block the pushing vehicle away from the unit to preventdamage to the sheet metal cabinet. (See Figure 1.)

FIGURE 1 SUGGESTED PUSHING ARRANGEMENT

GOOD PUSHING ARRANGEMENTCABINET DAMAGE UNLIKELY

POOR PUSHING ARRANGEMENTCABINET DAMAGE LIKELY

page 4

Never allow any part of the unit to fall during unloading or movingas this may result in serious damage.

To lift the unit, 2+" diameter lifting holes are provided in the baseof the unit. Spreader bars and cables should be arranged to preventdamage to the condenser coils or unit cabinet. (See Figure 2.)

FIGURE 2

TABLE 1

SUGGESTED LIFTING ARRANGEMENT

SPREADER BAR REQD.

-MUST USE THESE RIGGING HOLES( NO T E CONTROL 60x L~cATI~NI

SHIPPING WEIGHTS

ALP UNIT SIZE UNIT WEIGHT (Ibs)

067ASlD 4125

078ASlD 4308

089A 4963

106A 5134

ALP UNIT SIZE

126A

136A

149A

159A

UNIT WEIGHT (Ibs)

6021

6095

6873

7202

Location

Due to the vertical condenser design, it is recommended that certainprecautions be taken before installation to orient the unit so thatprevailing winds blow parallel to the unit length thus minimizingeffects on condensing pressure. If it is not practical to orientthe unit in this manner, a wind deflecting fence should be consi-dered.

It is also necessary to provide adequate clearance on all sides ofthe unit for service access and satisfactory performance. At least60 in. (1 fan diameter) should be allowed on each side of the unitfor condenser air inlet and compressor removal on units 067 & 078.If parallel units are installed side by side, 120 in. should be al-lowed between units. This will prevent excessive condensing temper-atures and enhance system performance and operating economy. Clear-ance for service access should be at least 78 in. at the control cen-ter end for compressor removal on units 089 through 159 and 42 in.on units 067 and 078. Allow 36 in. clearance at the end oppositethe control center for ease of access to bearings and drives. Theseclearances are illustrated in Figure 3.

page 5

FIGURE 3 CLEARANCE AROUND UNIT

t60” MINIMUM CLEARANCE (2)

60” M I N I M UM CLEARANCE (2)

NOTE: (I) Minimum vertical clearance above unit should be 10feet.

(2) Clearance to condenser coil must be increased if morethan one side is obstructed or between adjacent units.Consult your McQUAY sales representative.

Service Access

Each end of the unit must be accessible after installation for peri-odic service work. Compressors and manual liquid line shutoff valvesare accessible from the control center end of the unit through re-movable access panels on unit sizes 089 through 159 and hinged sideaccess doors on unit sizes 067 and 078. All operational, safety,and starting controls are located in the unit control center. Theyare protected by a keylocked, weatherproof enclosure which containsinternal "dead front" doors for protection of service personnel fromhigh voltage starting controls while servicing low voltage opera-tional controls. All resettable or adjustable controls are locatedjust below the main control center. There is one resettable controlenclosure on each side of the unit and each enclosure contains con-trols for compressors on that side of the unit. Capped connectionsfor field service gauges are also located inside these enclosures.In addition, each of these enclosures are removable to improve accessto compressors for field replacement.

The condenser fans, motors, and drives are accessible through a walk-in, keylocked access door. The access door is located at the end ofthe unit opposite the control center.

An internal fan guard is located below the condenser fans and driveson units 089 through 159. This guard must be removed to service thefan drives but MUST always be reinstalled when service work is com-plete.

On unit sizes 067 and 078, an interlock switch kills power to conden-ser fans whenever the door is opened for service work on fans ordrives.

CAUTION: Disconnect all power to the unit while servicing condenserfan drives.

page 6

Vibration Isolators

Vibration isolators are recommended for all roof mounted installa-tions or wherever vibration transmission is a consideration. Table2 lists spring isolators for all ALP unit sizes. Figure 4 showsisolator locations in relation to the unit control center. Figure 5gives dimensions that are required to secure each McQuay isolatorselection to the mounting surface.

Table 3 shows the isolator loads at each location shown in Figure 4and the maximum loads for each McQuay selection.

TABLE 2 VIBRATION ISOLATORS

216404B-27 2164046-26

TABLE 3 IS0 LATOR LOADS

page 7

REFRIGERANT PIPING

General

McQuay type ALP condensing units are adaptable to either chilledwater or air handling air conditioning applications. The only re-striction on applications is that the evaporator be selected for asystem using refrigerant 22.

Evaporator Above Condensing Unit

Figure 6 shows an installation where the evaporator is installedabove the condensing unit. It is shown for an air handling instal-lation but all components shown are recommended for chilled waterinstallations except that a refrigerant distributor is not usuallyrequired for shell-and-tube evaporators.

FIGURE 6 EVAPORATOR ABOVE CONDENSING UNIT

Legenda Filter-drierb Solenoid valve

:Sight-glass/moisture indicatorThermal expansion valve

e Suction line, pitched toward compressorf Liquid line9 Vibration absorber

Notes:1. Piping shown is for one circuit only, second circuit is similar.2. All piping & piping components are by others.

Evaporator Below Condensing Unit

Figure 7 shows an installation where the evaporator is installed be-low the condensing unit. It is shown for an air handling installa-tion but all components shown are recommended for chilled water in-stallations except that a refrigerant distributor is not usually re-quired for shell-and-tube evaporators. Mote that a double suctionriser is shown for this arrangement.

Risers "A + B" are sized so that their combined cross-sectional in-ternal area will allow full load unit operation without excessivepressure drop (see notes, Table 4). Riser "B" is sized to provideadequate suction gas velocity for proper oil return at minimum loadconditions. This riser becomes effective only when the trap shownin riser "A" fills itself with oil. It should be emphasized that

the trap shown in riser "A" should be designed to contain a minimuminternal volume to keep the total system oil requirements at a mini-mum. Table 4 gives recommended line sizes for both single and doublesuction lines and for liquid lines.

page 9

Figure 9 shows typical field wiring that is required for unit instal-lation. Items that require field wiring are: liquid line solenoids(SVl & SV2), optional hot gas bypass solenoid (SV5) and the coolingthermostat as well as the unit power supplies.

FIGURE 9 TYPICAL FIELD WIRING

PBlDISCONNECT UNIT MAINB Y O T H E R S - - \ , , < T E R M I N A L B L O C K

3pH ---_H _ _ _

POWER ___/-:__ CONI, llNlT COMPRESSORSc AND FAN MOTORS

;BKSuppLy _ _ __I’_ - -

WH I

\SEPARATE II?,“-IOA LEGENDPOWER FOR CONTROLS

I ‘,‘--DISCONNECT BY OTHERS OPTIONAL FdSEUi g_ ~~~SLT~OM~~~,~~NNECTION

01

8

ANOTEI

TRANSFORMER

FUSE-IO A

0 II- F L O W S W I T C H

(C.W. SYSTEMS)

irJH_WHlTt WlhlNG fNEUT1.

SVl,2-LIOUID ’ INESOL. VALVE

REFRIGERANT CIRCUIT ISAFETY AND OPERATING

SVS-HOT GAS BY PASS

CONTROLS SOL VALVER3,4-COMP. 3 8 4 S T A R T

TIME CLOCK;;- RELAYSR5,6,7,E -SAFETY RELAYSPSI.2 -PUMPDOWN

SWITCHESTDl1,12,13-COMP SEOUEN-

CING TIME DELAYSRx-EVAP. FAN INTERLOCK

PREVENTS OPENINGSV’S WITHOUT LOAD

RELAYS PROVIDERECYCLING PUMPDOWN DURING OFFSEASON

REFRIGERANT CIRCUIT 2SAFETY AND OPERATING

CONTROLS

UNIT CONDENSER FANSOPERATING CONTROLS

POWER SUPPLYFOR CONTROLS

’ I 1I I I

PUMP STARTER PUMP STARTER

CIRCUITR9 RIO NOTE; CIRCUIT SHOWN ASSUMES CONTINUOUS

6 6

T

-CPUMP OPERATIIN~FOR INTERMITTENT

CC. W. S Y S T E M S 1a0 __: I I 1 PUMP OPERATION CONSULT McOUAY

I I I

Thermostat Wiring

Since it is impossible for McQuay to anticipate the type of installa-tion that an ALP condensing unit may be used on, we do not factoryinstall a thermostat. We do, however, provide numbered terminals in-side the unit control center to which a thermostat may be connected.These terminals are shown and labeled "Terminals For Thermostat" onthe electrical schematics.

On a two circuit unit it is important to connect the thermostat sothat as successive stages of cooling are called for, the compressorsin the unit will be started to alternately increase the condenserload from refrigerant circuit 1 to circuit 2. This is illustratedin Table 9. Figure 10 shows how to install 2 independent four stagethermostats for controlling an 8 stage unit and Figure 11 shows typi-cal field wiring for an 8 stage thermostat.

page 14

Flow Switch for Chilled Water Applications

A WATER FLOW SWITCH MUST BE MOUNTED in either the entering or leav-ing water line to insure that there will be adequate water flow andcooling load to the evaporator before the unit can start. This willsafeguard against slugging the compressors on start up. It alsoserves to shut down the unit in the event that water flow is inter-rupted to guard against evaporator freeze up.

A flow switch is available from McQuay under ordering number 860-175033x-00. It is a "paddle"size from 1" to 6" nominal.

type switch and adaptable to any pipeCertain minimum flow rates are required

to close the switch and are listed in Table 11. Installation shouldbe as shown in Figure 13.

TABLE 11 FIGURE 13

FLOW SWITCH MINIMUM FLOW RATES

NOMINAL MINIMUM REQUIREDPIPE SIZE FLOW TO ACTIVATE(INCHES) SWITCH (GPM)

1 6.001 l/4 9.801 l/2 12.70

2 18.802 l/2 24.30

3 30.004 39.705 58.706 79,20

FLOW DIRECTIONMARKED ON SWITCH

1.00 NPT FLOW SWITCHCONNECTION

G% O:Nl.,.AFTER SWiTCH BEFORE SWITCH

Electrical connections in the unit control center should be made atterminals 11 and 12. The normally open contacts of the flow switchshould be wired between these two terminals. There is also a set ofnormally closed contacts on the switch that could be used for an in-dicator light or an alarm to indicate when a "no flow" conditionexists.

Evaporator Fan Interlock for Air Handler Coil Installations

It is important to interlock the air handler evaporator fan with thecondensing unit control center to insure that there will be a coolingload on the evaporator before the unit can start, to prevent com-pressor slugging. A pair of terminals for each refrigerant circuitis available in the unit control center for this purpose. Theseterminal numbers are shown in Figure 12.

page 18

Control Center

All electrical controls are enclosed in a weatherproof control cen-

UNIT LAYOUT AND PRINCIPLES OF OPERATION

ter with keylocked, hinged access doors. The control center is com-posed of three separate enclosures. The upper enclosure is thelargest and contains all of the 208, 230, or 460 volt compressor andfan motor starting controls. Also included in this enclosure butpartitioned separately are the exposed terminal type - 115 volt oper-ational controls. A "dead front" cover over the high voltage sectionprotects service personnel from high voltage starting controls whileservicing low voltage operational controls.

Below the upper enclosure are two smaller, separate enclosures thatcontain 115 volt adjustable or resettable controls. There is one ofthese enclosures on each side of the unit, and each contains controlsfor the compressors on that side.

Power supply conduits are intended to come into the bottom of theupper enclosure and between the two lower enclosures. It is recom-mended that the unit disconnect switch be mounted away from the unitbut Figure 14 recommends a unit mounting arrangement if the discon-nect must be unit mounted.

FIGURE 14 POWER CONDUIT ENTRY

CONTROL ~CENTER

DISCONNECT

Powerintounit

ALP-089A THRU 159A ALP - 067A THR U 078A

page 19

Sequence of Operation

The following sequence of operation is typical for ALP Seasoncon aircooled condensing unit operation. It is written for a 4 compressorunit, but where components that apply to the fourth compressor arereferred to, the equivalent components for the third and second com-pressors are indicated in parentheses.

With the control circuit power on, control stop switch Sl closed,and manual pumpdown switches PSl and PS2 closed ("Auto." position),115 volt power is applied through control circuit fuse Fl to the com-pressor crankcase heaters HTRl through HTR4, (HTR3, HTR2), and alsoto the contacts of low pressure switches LPl and LP2.

When the remote time clock, ambient thermostat, manual shutdownswitch and/or evaporator fan interlocks energize the thermostaticcircuit, and provided that high pressure controls HP1 and 2 and com-pressor motor protectors MPl through PIP4 (MP3, MP2) do not sense analarm condition, safety relays R5 through R8 (R7, R6) are energizedclosed applying power to the temperature control thermostat. At thispoint the unit will operate automatically in response to the thermo-stat.

On a call for cooling, the temperature control thermostat TCl ener-gizes liquid line solenoid valve SVl, opening the valve and allowingrefrigerant to flow into the evaporator. As refrigerant pressurebuilds up, low pressure control LPl closes, energizing low pressurerelay R9 which closes to energize compressor contactor Ml, startingcompressor number 1. Closing relay R9 contacts also energizes con-denser fan relay R17. Closing its contacts and providing power tocondenser fan motor contactors Mll, 12 & 13 on 3 & 4 compressor units,or Mll, & 12 on 2 compressor units.

If additional stages of cooling are required, temperature controlthermostat TCl energizes liquid line solenoid valve SV2 after timedelay relay TDll has sequenced closed, to initiate the same startingsequence in refrigerant circuit number 2.

On 3 and 4 compressor units, if additional cooling is still required,the third and fourth stages of temperature control thermostat TClenergize the third and fourth compressors after time delay relaysTD12 and TD13 have sequenced closed.

Pumpdown Cycle

As the temperature control thermostat is satisfied, it opens its con-tacts, de-energizing liquid line solenoid valve SVl, causing thevalve to close. When the compressor has pumped most of the refrig-erant from the evaporator to the condenser, the low pressure controlLPl opens, shutting down the compressor and condenser fan motors.

Should a closed solenoid valve allow refrigerant to leak to the lowside of the refrigerant circuit during unit "off" time, the buildupin pressure will cause the low pressure control to close, energizingthe low pressure relay and starting the compressor for pumpdown.

NOTE: Models ALP-067AS and 078AS have single refrigerant circuitsbut dual pumpdown switches (PSl & PS2). To manually pumpthese units down, it is recommended that both pumpdownswitches be moved to the "man.pumpdown" position simultane-ously.

page 22

START-UP AND SHUT-DOWN

Pre Start--Up

1.

2 .

3 .

4 .

5 .

6.

7 .

8 .

With all electric disconnects open, check all screw or lug typeelectrical connections to be sure they are tight for good elec-trical contact.fore shipment,

Although all factory connections are tight be-

vibration.some loosening may have resulted from shipping

a) On chilled water installations, check to see that all waterpiping is properly connected.b) Open all water flow valves and start the chilled water pump.Check all piping for leaks and vent the air from the evaporatorand system piping to obtain clean, non-corrosive water in theevaporator circuit.Check the compressor oil level. Prior to start-up, the oil levelshould cover at least l/2 of the oil sight glass.Remove the (8) compressor shipping blocks that are attached to thecompressor rails and the base of the unit. The ALP 067 and 078do not have shipping blocks.Check the voltage of the unit power supply and see that it iswithin the + 10% tolerance that is allowed. Phase voltage unbal-ance must be within t 2%.Check the unit power supply wiring for adequte ampacity and aminimum insulation temperature rating of 75C.Verify that all mechanical and electrical inspections have beencompleted per local codes.See that all auxiliary control equipment is operative and thatan adequate cooling load is available for initial start up.

Initial Start-Up

1. Open the compressor suction and discharge shutoff valves untilback seated.

2.Always replace valve seal caps.

Open the manual liquid line shutoff valve at the outlet of thesubcooler.

3 . Check to see that pumpdown switches (PSl & PS2) are in the Isman.pumpdown" position and the control stop switch (Sl) is in theIIon" position.

4. Adjust the dial on the temperature controller to the desiredchilled water or leaving air temperature.

5 . Throw the main power and control circuit disconnects to the "on"position.

CAUTION: Most relays and terminals in the unit control center arehot with Sl and the control circuit disconnect on.

6 . Allow the crankcase heaters to operate for at least 8 hours priorto start-up.

7 . Start the auxiliary equipment for the installation.8. Start the system by moving pumpdown switches (PSl & PS2) to the

"auto. pumpdown" position.9. After system performance has stabilized, it is necessary that the

"Compressorized Equipment Warranty Form" (form no. 206036A) becompleted to obtain full warranty benefits. This form is shippedwith the unit and after completion should be returned to McQuay'sService Department through your sales representative.

page 37

Temporary Shut-Down

Move pumpdown switches (PSl & PS2) to the "man. pumpdown" position.After the compressors have pumped down, turn off the chilled waterpump or evaporator fan. It is especially important on chilled waterinstallations that the compressors pump down before the water flowto the evaporator is interrupted to avoid freeze up.

Start-Up After Temporary Shut-Down

1. Start the chilled water pump or evaporator fan.2. With control stop switch (Sl) in the "on" position, move pumpdown

3.switches (PSl & PS2) to the '"auto. pumpdown" position.Observe the unit operation for a short time to be sure that thecompressors do not cut out on low oil pressure.

Extended Shut-Down

1. Close the manual liquid line shutoff valves.2. After the compressors have pumped down, turn off the chilled

water pump or evaporator fan.3.4.

Turn off all power to the unit and to the auxiliary equipment.Move the control stop switch (Sl) to the "off" position.

5. Close the compressor suction and discharge valves.6. Tag all opened disconnect switches to warn against start up be-

fore opening the compressor suction and discharge valves.

Start-Up After Extended Shut-Down

1.

2.

3.4.5.

6.

7.

8.

9.

Inspect all auxiliary equipment (pumps, fans, etc.) to see thateach device is in satisfactory operating condition.Remove all debris that has collected on the surface of the con-denser coils.Open the compressor suction and discharge valves.Open the manual liquid line shutoff valves.Check to see that pumpdown switches (PSl 6; PS2) are in the "man.pumpdown" position.Turn on the electric power to the unit and other parts of thesystem.Allow the crankcase heaters to operate for at least 8 hours priorto start-up.On chilled water installations, start the chilled water pump andpurge the water piping as well as the evaporator.Check to see that the control stop switch (Sl) is in the "on"position.

CAUTION: Most relays and terminals in the unit control center arehot with Sl and the control circuit disconnect on.

10. Start the unit by moving pumpdown switches (PSl & PS2) to the"auto. pumpdown" position.

11. After running the unit for a short time, check the oil level ineach compressor crankcase and check for flashing in the refri-gerant sight glass.

page 38

SYSTEM MAINTENANCE

General

On initial start up and periodically during operation it will benecessary to perform certain routine service checks. Among theseare checking the compressor oil level and taking condensing, suc-tion and oil pressure readings. During operation, the oil levelshould be visible in the oil sight glass with the compressor run-ning. On units ordered with gauges, condensing,suction and oilpressures can be read from the unit control center. The gaugesare factory installed with a manual shutoff valve on each gaugeline. The valves should be closed at all times except when gaugereadings are being taken. On units ordered without gauges, thegauge shutoff valves come factory installed inside the unit controlcenter for convenient connection of service gauges form outside theunit.

Fan Shaft Bearings

The fan shaft bearings do not require lubrication at the time theunit is put into service. The fan shaft bearings should be greasedonce a year using STANDARD OIL COMPANY AMCO Multi-Purpose LithiumGrease. DO NOT OVERLUBRICATE.

Fan Motor Bearings

All fan motors are ball bearing, pre-lubricated and do not requirethe addition of grease at the time of installation. Periodically,the ball bearings should be cleaned and the grease renewed, to gainthe ultimate in service from the motor bearings.

Extreme care must be exercised to prevent foreign matter from enter-ing the ball bearings. It is also important to avoid overgreasing.Only a high grade clean mineral grease having the following charac-teristics should be used. Consistency: A little stiffer than thatof Vaseline, maintained over the operating temperature range; meltingpoint preferably over 150C (302OF); freedom from separation of oiland soap under operating and storage conditions and freedom from a-brasive matter, acid, alkali and moisture.

Specific greasing instructions are to be found on the label attachedto the unit and should be generally followed.

Electrical Terminals

CAUTION: ELECTRIC SHOCK HAZARD, TURN OFF ALL POWER BEFORE CONTINU-ING WITH FOLLOWING SERVICE.

All power electrical terminals should be retightened every 6 months,as they tend to loosen in service due to normal heating and coolingat the wire.

Compressor Oil Level

Because of the large refrigerant charge required in an air cooledcondensing unit it is usually necessary to put additional oil intothe system. The oil level should be watched carefully upon initialstart up and for sometime thereafter.

page 39

At the present time, Suniso #3GS oil is the only oil approved byCopeland for use in these compressors. The oil level should be main-tained at about the midpoint of the sight glass on the compressorbody.

Condensers

Condensers are air cooled and constructed with 3/8 0-D. copper tubesbonded in a staggered pattern into rippled aluminum fins. No main-tenance is ordinarily required except the occasional removal of dirtand debris from the outside surface of the fins. Care should betaken not to damage the fins during cleaning. Periodic use of thepurge valve on the condenser will prevent the buildup of non-conden-sables.

Refrigerant Sight Glass

The refrigerant sight glasses should be observed periodically. (Amonthly observation should be adequate.) A clear glass of liquid in-dicates that there is adequate refrigerant charge in the system toinsure proper feed through the expansion valve. Bubbling refriger-ant in the sight glass indicates that the system is short of refri-gerant charge. On sight glasses ordered from XcQuay as part of the"Liquid Line Accessory Kits" listed on page 12, an element insidethe sight glass indicates what moisture condition corresponds to agiven element color. If the sight glass does not indicate a dry con-dition after a few hours of operation, the unit should be pumped downand the cores in the filter-driers changed.

SERVICE

SERVICE ON THIS EQUIPMENT TO BE PERFORMED BY QUALIFIED REFRIGERATION SERVICE PER-SONNEL. CAUSES FOR REPEATED TRIPPING OF SAFETY CONTROLS MUST BE INVESTIGATED ANDCORRECTED.

Filter-Driers

To change the filter drier core(s) , pump the unit down by movingpumpdown switches (PSl & PS2) to the "man. pumpdown" position. Turnoff all power to the unit and install jumpers from terminals 21 to24 and 41 to 44. Turn power to the unit back on and re-start theunit by moving pumpdown switches (PSl & PS2) to the "auto. pumpdown"position. Close the manual liquid line shutoff valve(s) and whenevaporator pressure reaches 0 PSIG,(Sl) to the "off" position.

move the control stop switchThis will close the liquid line sole-

noid valve(s) and isolate the short section of refrigerant pipingcontaining the filter-drier(s). Remove the cover plate from thefilter-drier shell and replace the core(s).

After core replacement, replace the cover plate. A leak check a-round the flange of the filter-drier shell is recommended after thecores have been changed.

page 40

Liquid Line Solenoid Valve

The liquid line solenoid valves, which are responsible for automaticpumpdown during normal unit operation,maintenance.

do not normally require anyThey may, however, require replacement of the solenoid

coil or of the entire valve assembly.

The solenoid coil may be removed from the valve body without openingthe refrigerant piping by moving pumpdown switches (PSl & PS2) tothe 1'man. pumpdown" position. The coil can then be removed from thevalve body by simply removing a nut or snap ring located at the topof the coil. The coil can then be slipped off its mounting stud forreplacement. Be sure to replace the coil on its mounting stud beforereturning pumpdown switches (PSl & PS2) to the "auto. pumpdown" po-sition.

To replace the entire solenoid valve, the unit must be pumped downby use of the manual liquid line shutoff valve.

Thermostatic Expansion Valve

The expansion valve is responsible for allowing the proper amount ofrefrigerant to enter the evaporator regardless of cooling load. Itdoes this by maintaining a constant superheat. (Superheat is thedifference between refrigerant temperature as it leaves the evapor-ator and the saturation temperature corresponding to the evaporatorpressure.) Typically,15F.

superheat should run in the range of 10F toOn valves purchased through McQuay, the superheat setting can

be adjusted by removing a cap at the bottom of the valve to exposethe adjustment screw. Turn the screw clockwise (when viewed from theadjustment screw end) to increase the superheat setting and counter-clockwise to reduce superheat. Allow time for system rebalance af-ter each superheat adjustment.

INLET

POWER ELEMENT(CONTAINS DIAPHRAGM)

OUTLET

SPRING

ADJUSTMENT SCREW

CAP

page 41

Trouble Shooting Chart

PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS

1. Main switch open. 1. Close switch.2. Fuse blown. Circuit breakers open. 2. Check electrical circuits and motor winding for shorts

or grounds. Investigate for possible overloading. Re-place fuse or reset breakers after fault is corrected.

3. Thermal overloads tripped. 3. Overloads are auto. reset. Check unit closely when

Compressor will unit comes back on line.

not run 4. Defective contactor or coil. 4. Repair or replace.5. System shut down by safety devices. 5. Determine type and cause of shutdown and correct it

before resetting safety switch.6. No cooling required. 6. None. Wait until unit calls for cooling.7. Liquid line solenoid will not open. 7. Repair or replace coil.8. Motor electrical trouble 8. Check motor for opens, short circuit, or burn out.9. Loose wiring. 9. Check all wire junctions, Tighten all terminal screws.I. Flooding of refrrgerant Into crankcase. 1. Check setting of expansion valve.

Compressor noisy 2. Improper piping support on suction or 2. Relocate, add or remove hangers.or vibrating liquid line.

3. Worn compressor 3. Replace.1. Non-condensibles in system. I. Purge the non-condensibles.

High Discharge 2. System overcharged with refrigerant. 2. Remove excess.

Pressure 3. Discharge shut off valve partially closed. 3. Open valve.4. Seasontrol out of adjustment 4. Adjust Seasontrot valves.5. Fan not running. 5. Check belts and electrical crrcuit.I. Faulty condenser temperature regulation. I. Check condenser control operation.2. Suction shut-off valve partially closed. 2. Open valve.

Low Discharge 3. insufficient refrrgerant in system. 3. Check for leaks. Repair and add charge.Pressure 4. Low suction pressure. 4. See Corrective Steps for low suction pressure below.

5. Compressor operating unloaded. 5. See Corrective Steps for failure of compressor to loadup below.

1. Excessive load. 1. Reduce load or add additional equipment.High Suction 2. Expansron valve overfeedrng. 2. Check remote bulb. Regulate superheat.Pressure 3. Compressor unloaders open. 3. See Corrective Steps below for failure of compressor

to load up.1. Lack of refrigerant. 1. Check for leaks. Repair and add charge.2. Evaporator dirty. Plugged acr filters. 2. Clean chemrcally.3. Clogged liqurd lrne filterdrier. 3. Replace cartridge(s).

Low Suction 4. Clogged suction line or compressor suction. 4. Clean strarners.

Pressure gas strainers.5. Expansion valve malfunctioning. 5. Check and reset for proper superheat.6. Condensing temperature too low. 6. Check means for regulating condensing temperature.7. Compressor will not unload. 7. See Correctrve Steps for failure of compressor to

unload.Compressor will not 1. Defective capacrty control. I. Replace.unload or load up. 2. Pressurestat not set for application. 2. Reset pressurestat setting to fit applicatron.

1. Clogged suction oil strainer. 1. Clean.2. Excessive liquid rn crankcase. 2. Check crankcase heater. Reset expansion valve for

higher superheat. Check liquid line solenoid valveoperation.

3. Oil pressure gauge defective. 3. Repair or replace. Keep valve closed except whentaking readings.

Little or no oil 4. Low oil pressure safety switch defective. 4. Replace.

pressure 5. Worn 011 pump. 5. Replace.6. Oil pump reversing gear stuck in wrong 6. Reverse drrectron of compressor rotation.

position.7. Worn bearrngs. 7. Replace compressor.8. Low oil level. 8. Add oil.9. Loose fitting on oil lines. 9. Check and tighten system.

10. Pump housing gasket leaks. 10. Replace gasket.11. Flooding of refrigerant into crankcase. 11. Adjust thermal expansion valve.

Compressor loses 1. Lack of refrrgerant. 1. Check for leaks and repair Add refrigerant.oil 2. Excessive compression ring blow-by. 2. Replace compressor.

1. Low voltage during high load conditions. 1. Check supply voltage for excessive lrne drip.2. Defective or grounded wring in motor. 2. Replace compressor motor.3. Loose power wiring.

Motor overload3. Check all connections and tighten.

4. High condensrng temperature. 4. See Corrective Steps for high discharge pressure.relays or circuit 5. Power line fault causing unbalanced voltage. 5. Check supply voltage. Notify power compnay. Do notbreakers open start until fault is corrected.

6. High ambient temperature around the over- 6. Provide ventilation to reduce heat.load relay.

7. Failure of second starter to pull in on part- 7. Repair or replace starter or time delay mechanism.winding start systems.

Compressor thermalprotector switchopen.

1. Operating beyond design conditions.

2. Discharge valve partially shut.3. Blown valve plate gasket.

I. Add facilities so that conditions are within allowablelimits.

2. Open valve.3. Replace gasket.

page 42

IN-WARRANTY RETURN MATERIAL PROCEDURE

Compressor

Copeland Refrigeration Corporation has stocking wholesalers who main-tain a stock of replacement compressors and service parts to serverefrigeration contractors and servicemen.

When a compressor fails in warranty, contact your local sales represen-tative, or McQuay Warranty Claims Department at the address on thecover of this bulletin. You will be authorized to exchange the de-fective compressor at a Copeland Wholesaler, or an advance replace-ment can be obtained. A salvage credit is issued to you by the whole-saler on the returned compressor after Copeland factory inspection ofthe inoperative compressor. Provide McQuay with full details and in-voices and we will reimburse the difference. In this transaction, becertain that the compressor is definitely defective. If a compressoris received from the field that tests satisfactorily, a service chargeplus a transportation charge will be charged against its original cre-dit value.

On all out-of-warranty compressor failures, Copeland offers the samefield facilities for service and/or replacement as described above.The credit issued by Copeland on the returned compressor will be deter-mined by the repair charge established for that particular unit.

Components Other Than Compressors

Material may not be returned except by permission of authorized fac-tory service personnel of McQuay, Inc., at Mpls., MN. A "ReturnGoods" tag will be sent to be included with the returned material.Enter the information as called for on the tag in order to expeditehandling at our factories and prompt issuance of credits.

The return of the part does not constitute an order for replacement.Therefore, a purchase order must be entered through your nearestMcQUAY Representative. The order should include part name, part num-ber, model number and serial number of the unit involved.

Following our personal inspection of the returned part, and if it isdetermined that the failure is due to faulty material or workmanship,and in warranty,credit will be issued on customer's purchase order.

All parts shall be returned to the pre-designated McQUAY factory,transportation charges prepaid.

APPENDIX

STANDARD CONTROLS

Oil Pressure Safety Control

The oil pressure safety control is a manually resettable device whichsenses the differential between oil pressure at the discharge of thecompressor oil pump and suction pressure inside the compressor crank-case. When the oil pressure reaches approximately 15 PSI above thecrankcase suction pressure, the pressure actuated contact of the con-trol opens from its normally closed position. If this pressure dif-ferential cannot be developed, the contact will remain closed andenergize a heater element within the control. The heater elementwarms a normally closed bimetallic contact and causes the contact toopen de-energizing a safety relay and breaking power to the compres-sor.

page 43

It takes about 120 seconds to warm the heater element enough to openthe bimetallic contact thus allowing time for the pressure differen-tial to develop.

If during operation, the differential drops below 10 PSI, the heaterelement will be energized and the compressor will stop. The controlcan be reset by pushing the reset button on the control. If the com-pressor does not re-start, allow a few minutes for the heater elementand bimetallic contacts to cool and reset the control again.

To check the control, pump down and shutoff all power to the unit.Remove the compressor fuses, and install a voltmeter between termin-als "L" and "M" of the oil pressure control. Turn on power to theunit control circuit (separate disconnect or main unit disconnect de-pending on the type of installation). Check to see that the controlstop switch (Sl) is in the "on" position. The control circuitshould now be energized but with the absence of the compressor fuses, __

no oil pressure differential can develop and thus the pressure actu-ated contacts of the control will energize the heater element andopen the bimetallic contacts of the control within 120 seconds. Whenthis happens, the safety relay is de-energized, the voltmeter read-ing will rise to 115V, and the compressor contactor should open. Re-peated operations of the control will cause a slight heat buildupin the bimetallic contacts resulting in a slightly longer time forreset with each successive operation.

LINE (SEE NOTE 1) NEUTRAL

- HEATER ELEMENTCONTACT

L M

LINE (SEE NOTE 2) 41 NEUTRAL

BIMETALLIC CONTACTS SAFETY RELAY

NOTES: 1. Hot only when the unit thermostat calls for compressorto run.

2. Hot only when other safety control contacts are closed.

High Pressure Control

The high pressure control is a single pole pressure activated switchthat opens on a pressure rise to de-energize the entire control cir-cuit except for compressor crankcase heaters. It senses condenserpressure and is factory set to open at 380 PSIG and can be manuallyreset closed at 315 PSIG. To check the control, either block offcondenser surface or start the unit with fuses in only one fan fuseblock (FBll) and observe the cut-out point of the control by watch-ing condenser pressure rise. The highest point reached before cut-out is the cut-out setting of the control.CAUTION: Although there is an additional pressure relief device in

the system set at 425 PSIG, it is highly recommended thatthe "control stop" switch (Sl) be close at hand in casethe high pressure control should malfunction.

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Low Pressure Control

The low pressure control is a single pole pressure switch that closeson a pressure rise. It senses evaporator pressure and is factory setto close at 60 PSIG and automatically open at 25 PSIG. The controlhas an adjustable range of 20 in. of Hg. to 100 PSIG and an adjusta-ble differential of 6 to 40 PSIG. To check the control (unit mustbe running), move the pumpdown switch(es) (PSl and PS2) to the "man.pumpdown" position. As the compressor pumps down condenser pressurewill rise and evaporator pressure will drop. The lowest evaporatorpressure reached before cut-out is the cut-out setting of the control.By moving the pumpdown switch(es) (PSl and PS2) to the "auto. pump-down" position, evaporator pressure will rise. The highest evapora-tor pressure reached before compressor re-start is the cut in settingof the control.

Fantrol - Head Pressure Control--

Fantrol is a system for progressively turning on or off condenserfans when they are no longer required. This is done to reduce con-denser capacity (typically in low outdoor ambient temperatures) andis accomplished by a combination of pressure and temperature actuatedcontrols. The first fan (No. 11) is started by its contactor whenthe first compressor in the unit starts. The second fan (No. 12) iscontrolled by a pair of parallel wired pressure switches, one ofwhich senses condenser pressure in refrigerant circuit No. 1, andone which senses pressure in refrigerant circuit No. 2. The thirdfan (No. 13-3 fan units only) is controlled by a pair of parallelwired temperature switches, one of which senses condenser air inlettemperature for refrigerant circuit No. 1 and one for circuit No. 2.Pressure temperature control set points are indicated below.

j:::_llWITH COMPRESSOR WITH COMPRESSOR

To check the cut-in points of the controls, the unit must initiallybe off. With the unit prepared for start up according to the proce-dures outlined in this bulletin, move pumpdown switches (PSl & PS2)to the "auto. pumpdown" position. Evaporator pressure will begin torise and the compressor(s) should start with fan No. 11 starting im-mediately. After the compressor(s) starts, observe condenser pres-sure as it rises. When the condenser pressure reaches approximately270 PSIG, contactor Ml2 should pull in to start fan No. 12. On 3fan units, fan No. 13 should start via contactor Ml3 whenever theambient air at the condenser inlet reaches 80F.

It may be difficult to check the cut-out point of fan No. 13 (on 3fan units) at the instant it happens, but it should be off wheneverthe ambient air at the condenser inlet is below 70F. To check thecut-out point of fan No. 12, some means of reducing the load on theunit must be available or the fan operation and condenser pressure(s)must be observed as the load drops off naturally. When the condenserpressure drops to approximately 170 PSIG, contactor Ml2 should dropout to turn off fan No. 12.

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OPTIONAL CONTROLS

Dampertrol - Optional Head Pressure Control

Dampertrol is an optional system for reducing condenser capacity. Itconsists of an assembly of damper blades, linkages and blade operatorsinstalled over the first fan turned on by Fantrol (Fan No. 11) andarranged to operate as shown. The blade operators sense condenserpressure and extend or contract in response to the pressure to openor close the damper blades as required to maintain adequate conden-ser pressure. The operators are factory set to begin opening thedamper blades at 170 + 5 PSIG and to be fully open at 250 2 10 PSIG.

To check the damper blade operator pressure settings, the unit shouldbe started with the fuses removed from fans 11 and 13 (on 3 fan unitsonly). At condenser pressures below 170 & 5 PSIG, the damper bladesshould be completely closed. As pressure rises above 170 & 5 PSIG,the damper blades should begin opening and be fully open at 250 +_10 PSIG. Leaving the fuses in on fan 12 will prevent head pressurefrom becoming excessive since this fan will start after the fullyopen setting of the damper operators has been observed.

DAMPERTROL IN OPEN POSITION

/DAMPER SECTION

1

/-UNIT CONDENSER

DAMPER SECTION

-rtz3qf

UNIT CONDENSER

DAMPERTROL IN CLOSED POSITION

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Part Winding Start - Optional

Part winding start is available on all voltage units and consists ofa solid state time delay wired in series with the contactor that ener-gizes the 2nd winding of each compressor motor. Its purpose is tolimit current in-rush to the compressors upon start up. As each com-pressor starts, the contactor for the first motor winding is energizedinstantly while that for the second motor winding is delayed for 1second.

Control checkout is best accomplished by observation as each contac-tor is pulled in to see that the 1 second delay occurs before thesecond contactor pulls in.

LINE NEUTRAL

PART WINDINGTIME DELAY 1

COMPRESSOR CONTACTOR(1st MOTOR WINDING)

LINE .-%.., NEUTRAL

A- COMPRESSOR CONTACTOR(2nd MOTOR WINDING)

Low Ambient Start - Optional

Low ambient start is available on all units as an option with Fantroland included automatically with optional Dampertrol. It consists ofa solid state normally closed time delay wired in series with a relay.These are both wired in parallel to the liquid line solenoid valve sothat when the solenoid valve is energized by the unit thermostat, thelow ambient start relay is also energized through the time delay.The relay has contacts that essentially short circuit the low pres-sure control and allow the compressor to start with the low pressurecontrol open.

After about 2 3/4 minutes, the time delay will open and de-energizethe relay. If the system has not built up enough evaporator pressureto close the low pressure control, the compressor will stop. Thetime delay can be reset to its original normally closed position bymoving the pumpdown switch(es) (PSl or PS2) to the "man. pumpdown"position. Moving the pumpdown switch back to the "auto. pumpdown"position will again energize the relay for another attempt at startup . If the system has built up enough evaporator pressure, the com-pressor will continue to run.

To check the control, turn off all power to the unit and remove thewire(s) (No. 113 & 213) leading to the low pressure control(s) (LPl& LP2) from terminal 4 in the unit control center. Remove the com-pressor fuses and jumper across terminals L & M of the freeze con-trols(s) and oil pressure safety control(s). Energize the controlcircuit by turning on the control circuit disconnect or main powerdisconnect (depending on the installation) and the control stopswitch Sl. The compressor contactors should pull in instantly.

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NOTE: Line is only hot when the unit thermostat calls for compressor to run.

Compressor Lockout - Optional

Compressor lockout consists of a solid state time delay wired inseries with the compressor contactor( Its purpose is to preventrapid compressor cycling when cooling demands are erratic. The cir-cuit illustrated above is for the lead compressor in each refriger-and circuit. The circuit for the second compressor(s) performs thesame function but is wired differently (see unit wiring diagram).

When the unit thermostat no longer calls for cooling and the com-pressor contactor have opened, the lockout time delay breaks openthe circuit preventing compressore re-start.

The circuit remains open for a period of 5 minutes so that if theunit thermostat should call for cooling before the delay period hasexpired, the compressor will not re-start. After 5 minutes, thetime delay will close its contacts to complete the circuit and beready for start up. The time delay opens its contacts whenever pow-er to terminal 4 is interrupted and resets closed automatically af-ter the time delay period.

To check the control, the compressor(s) must be running initially.Move the pumpdown switch (PSl or PS2) to the "man. pumpdown" posi-tion. Immediately after the compressor(s) have stopped running,move the pumpdown switch back to the "auto. pumpdown" position. Thelead compressor should not re-start for 5 minutes. The second com-pressor in the refrigerant circuit should start approximately 20seconds after the lead compressor,high enough to require it.

provided that the cooling load is

the same way.Each refrigerant circuit can be checked

LINE(SEE NOTE) - ’ ’

COMF! LOCKOUTTIME DELAY

x-k-TO UNIT THERMOSTAT

NOTE: Hot whenever freeze control and highpressure control permit safe operation.

page 48

Alarm Bell - Optional

The 24 volt alarm bell is mounted inside the control center but notwired to the control circuit. It is expected that in most cases,the customer will want to relocate the bell where it will be moreeasily heard in the event of a safety failure. There are leads forconnection of the bell inside a junction box which is located in theunit control center. All that is necessary is that the bell bemounted in a preferred location and wired to the leads in the junc-tion box.

The bell is wired into the control circuit so that it will soundwhenever there is a failure due to low oil pressure, motor overload,or excessive condenser pressure.

Hot Gas Bypass - Optional

Hot gas bypass is a system for maintaining evaporator pressure at orabove a minimum value. The purpose for doing this is to keep the ve-locity of the refrigerant as it passes through the evaporator highenough for proper oil return to the compressor when cooling load con-ditions are light.

The system usually consists of a solenoid valve piped in series witha pressure regulating valve as shown. Units are available with op-tional hot gas connection with a manual shutoff valve and capped stub.A hot gas bypass kit consisting of a 115 volt solenoid valve and apressure regulating valve is available from McQuay under orderingnumber 886-321262B-02 for ALP units 067AS/D through 159AD.

The solenoid valve should be wired to open whenever the unit thermo-stat calls for the first stage of cooling (see Figure 10). The pres-sure regulating valve that McQuay offers is factory set to beginopening at 58 PSIG (32F for R-22) when the air charged bulb is inan 80F ambient temperature. The bulb can be mounted anywhere aslong as it senses a fairly constant temperature at various load con-ditions. The compressor suction line is one such mounting location.It is generally in the 50F to 60F range. The chart on page 50 indicatesthat when the bulb is sensing 50F to 60F temperatures, the valve willbegin opening at 54 to 56 PSIG. This setting can be changed as in-dicated above, by changing the pressure of the air charge in theadjustable bulb. To raise the pressure setting, remove the cap onthe bulb and turn the adjustment screw clockwise. To lower the set-ting, turn the screw counter-clockwise. Do not force the adjustmentbeyond the range it is designed for as this will damage the adjust-ment assembly.

The regulating valve opening point can be determined by slowly reduc-ing the system load while observing the suction pressure. When thebypass valve starts to open, the refrigerant line on the evaporatorside of the valve will begin to feel warm to the touch.

CAUTION: The hot gas line may become hot enough to cause injury ina very short time so care should be taken during valvecheckout.

page 49

On installations where the condensing unit is remote from the evapor-ator, it is recommended that the hot gas bypass valve be mounted nearthe condensing unit to minimize the amount of refrigerant that willcondense in the hot gas line during periods when hot gas bypass isnot required.

The expansion valve, like the solenoid valve, should not normally re-quire replacement, but if it does, the unit must be pumped down byusing the manual liquid line shutoff valve. If the problem can betraced to the power element only, it can be unscrewed from the valvebody without removing the valve but only after pumping the unit downwith the manual liquid line shutoff valves.

HOT GAS BYPASS PIPING

Hot Gas BypassSolenoid Valve

DIAGRAM HOT GAS BYPASS ADJUSTMENT RANGE

R EM OTE BULB A D J U S T M E N T R A N G E

a0 I I I I I I Ir Suction

sLine ;,

L Discharge Line

Remote Bulb

External EqualizerConnection to SuctionSide of Evapoator

Bypass ValveInlet AfterExpansion Valve

T E M P ioFI A T B U L B L O C A T I O N

p a g e 5 0