SEASONCON”Packaged air cooled condensing unit

Models ALP-O16A thru -033A

McQuayG R O U P McQuay-PERFEX Inc. 13600 Industrial Park Blvd., P.O. Box 1551, Minneapolis, Mn. 55440 @

.

INTRODUCTIONMcQUAY type ALP SEASONCON air cooled condensing consists of an air cooled condenser with integral subcoolerunits are designed for outdoor installations and are section, an unloading compressor, complete dischargecompatible with either air handling or chilled water piping and suction and liquid connections for connection tosystems. Each unit is completely assembled and factory any air or water cooling evaporator.wired before evacuation, charging and testing. Each unit

NOMENCLATUREA L P - 0 3 3 A - S

Nomtnal Capacity (Tons)

INSPECTION When the equipment is received, all items should be

carefully checked against the bill of lading to insure acomplete shipment. All units should be carefully inspectedfor damage upon arrival. All shipping damage should be

reported to the carrier and a claim should be filed. The unitserial plate should be checked before unloading the unit tobe sure that it agrees with the power supply available.

INSTALLATION

NOTE: Installation and maintenance are to be performed only by qualified personnel who are familiarwith local codes and regulations, and experienced with this type of equipment. CAUTION: Sharp edgesand coil surfaces are a potential injury hazard. Avoid contact with them.

HANDLING

Care should be taken to avoid rough handling or shock dueto dropping the unit. Do not push or pull the unit fromanything other than the base, and block the pushing vehicleaway from the unit to prevent damage to the sheet metalcabinet. (See Figure 1.)

FIGURE 1. SUGGESTED PUSHING ARRANGEMENT

To lift the unit, 2-1/2-inch diameter lifting holes areprovided in the base of the unit. Spreader bars and cablesshould be arranged to prevent damage to the condensercoils or unit cabinet. (See Figure 2.)

LOCATIONDue to vertical condenser design, it is recommended thatthe unit is oriented so that prevailing winds blow parallel tothe unit length, thus minimizing effects on condensingpressure. If it is not practical to orient the unit in thismanner, a wind deflector should be constructed.

Units are designed for outdoor application and may bemounted on a roof or concrete slab (ground levelinstallation). Roof-mounted units should be installed levelon steel channels or an l-beam frame to support the unitabove the roof. Use of vibration pads or isolators isrecommended. The roof must be strong enough to supportthe weight of the unit. See Table 1 for unit weights.Concrete slabs used for unit mounting should be installedlevel and be properly supported to prevent settling. Aone-piece concrete slab with footings extended below thefrost line is recommended.

GOOD PUSHING ARRANGEMENT -CABINET DAMAGE UNLIKELY

FIGURE 2.

TABLE 1. UNIT WEIGHTS-?

ALP MODEL OPERATING WEIGHT (LBS.)

016A 1122

019A 1383

023A 1471

027A 1600

033A 1866

PAGE 3

ACCESS VIBRATION ISOLATORS

It is necessary to provide adequate clearance on all sides ofthe unit for service access and satisfactory performance.Necessary clearances are shown in Figure 3.

FIGURE 3. CLEARANCE AROUND UNIT

Vibration isolators are recommended for all roof-mountedinstallations or wherever vibration transmission is apotential problem. Table 2 lists spring and rubber-in-shearisolators for all ALP unit sizes. Table 3 shows isolator loadsand the maximum allowable load for each isolator. Figure 4shows isolator locations in relation to the unit controlpanel. Figure 5 gives dimensions that are required to secureeach McQUAY isolator selection to the mounting surface.Each unit base frame is provided with the necessary holesto accept the 0.50-inch diameter positioning pin of eachisolator.

“A-‘MIN.CLEARANCE

FOR AIR INLET

-i%q Acc~~~~~N pQ%z-CONTROL PANEL

CLEARANCEFOR DISCHARGE

ALP DIMENSIONS (IN FEET)

M O D E L A 0 C D

016A 3 4 3 4

019A 3 4 3 4

023A 3 5 3 4

027A 3 5 3 4

0 3 3 A 3 6 3 4

By removing the access screens, access can be gained tothe compressor, refrigerant lines, refrigerant components,condenser fans and SPEEDTROL components. All othercontrols are located in the unit control panel. They areprotected by a keylocked, weatherproof enclosure whichcontains an internal “dead front” door for protection ofservice personnel from high voltage starting controls whileservicing low voltage operational controls.

TABLE 2. ISOLATOR SELECTIONS

’ ALP LOCATIONS 1,2.3 & 4

U N I T SPRING-FLEX RUBBER-IN-SHEAR

SIZE ORDERING NUMBER ORDERING NUMBER

016A 877-2164036-25 a77-216397Aal

019A 877-2164030-26 877-216397A-01

023A 877-2164030-26 877.216397AJJl

027A 877-2164030-26 877-216397Aal

033A 877-2164030-27 a77-216397A-03

FIGURE 4. ISOLATOR LOCATIONS

FIGURE 5. ISOLATOR DIMENSIONS (IN.)Spring-Flex Isolators

ADJUST MOUNTING SO UPPER0.50 DIA. HOUSING CLEARS LOWER HOUSING

” AND NOT MORE

ACOUSTkAL NONSKlDNEOPRENE PAD

TABLE 3. IS0 LATO R LOADS

Rubber-In-Shear Isolators

,600 Dia. Pin 2 Holes

L4.12--- 1

5.50 A

Mounting Moldedin Neoorene -\1’2.5”7

ALP ISOLATOR LOADS AT MAXIMUM LOADS ALLOWABLE

U N I T EACH MOUNTING LOCATION FOR EACH ISOLATOR SELECTION

SIZE LOCATION 1.2,3 & 4 SPRING-FLEX RUBBER-IN-SHEAR

016A 281 450 525

019A 346 600 525

023A 368 600 525

027A 400 600 525

033A 467 750 750

PAGE 4

REFRIGERANT PIPINGMcQUAY type ALP SEASONCON condensing units areadaptable to either chilled water or air handling airconditioning applications using refrigerant 22. Refrigerantpiping to and from the unit should be sized and installedaccording to the latest ASHRAE Guide. The following

EVAPORATOR ABOVE CONDENSING UNIT

Figure 6 shows an installation where the evaporator isinstalled above the condensing unit. It is shown for an airhandling installation, but all components shown arerecommended for chilled water installations except that arefrigerant distributor is not usually required forshell-and-tube evaporators.

FIGURE 6. Evaporator Above Condensing Unit

-G-AIR FLOW

LEGEND

a Fil terdrierb Solenoid valvec Sightglasslmoisture indicatord Thermal expansion valvee Suction line, pitched toward compressorf Liquid lineg Vibration absorber

NOTES: All piping and piping components are by others.

TABLE 4.

ALP RECOMMENDED LINE SIZEUNIT DOUBLE

SIZE +y;.?lSINGLE

SUCTIONLIQUID

016A-S 1 118-l l/8 1 518 718

019A-S 1 318-l 318 2 118 718

023A-S 1 518-l 318 2 118 1 l/8

027A-S 1 518-l 318 2 118 1 l/8

033A-S 1 518-l 518 2 118 1 118

Note: Liquid and suction lines based on a recommended pressuredrop of 3 PSIG 12OF) per 100 ft. equrvalent length.

discussion is for use as a general guide to sound, economicaland trouble-free piping. The correct application of theprinciples discussed here is the responsibility of theinstaller.

EVAPORATOR BELOW CONDENSING UNIT

Figure 7 shows an installation where the evaporator isinstalled below the condensing unit. It is shown for an airhandling installation, but all components shown arerecommended for chilled water installations except that arefrigerant distributor is not usually required forshell-and-tube evaporators. Note that a double suction riseris shown for this arrangement.

Risers “A + B” are sized so that their combinedcross-sectional internal area will allow full load unitoperation without excessive pressure drop (see notes, Table4). Riser “B” is sized to provide adequate suction gasvelocity for proper oil return at minimum load conditions.This riser becomes effective only when the trap shown inriser “A” fills itself with oil. It should be emphasized thatthe trap shown in riser “A” should be designed to contain aminimum internal volume to keep the total system oilrequirements at a minimum. Table 4 gives recommendedline sizes for both single and double suction lines and forliquid lines.

FIGURE 7. Evaporator Below Condensing Unit

e-AIR FLOW

LEGEND

a Fil terdrierb Solenoid valvec Sightglass/moisture indicatord Thermal expansion valvee Suction line, pitched toward compressorf Liquid lineg Vibration absorber

A+8 - Double suction riser (see note 2)

NOTES:1. All piping and piping components are by others.2. Trap for double suction riser should be as small in the

horizontal direction as fittings will allow.

REFRIGERANT PIPING CONNECTIONS

Refrigerant piping connections should be made through theholes provided in the base frame on access screen side ofthe unit.

PAGE 5

LIQUID LINE COMPONENTS

McQUAY has available a “Liquid Line Accessory Kit” foreach ALP unit size. Table 5 shows the ordering number tobe used for each ALP unit size. The components includedin these kits are:

TABLE 5. LIQUID LINE ACCESSORY KITS

1.2.3

4:5.

Replaceable core type filter-drier.Filter-drier core element.Refrigerant solenoid valve.Refrigerant sightglass/moisture indicator.Expansion valve.

ALP LIQUID LINE CONNECTION SIZES O.D. (IN.1

U N I T ACCESSORY KIT FILTER- SOLENOID SIGHT- EXPANSION VALVE

SIZE ORDERING NUMBER DRIER V A L V E GLASS IN OUT

016A-S 886-368903641 718 718 7ta 718 I 318

019A-S 886366903641 718 7/a 7/a 7/a i 3/a

023A-S 8863689039-01 718 718 718 718 I 3/a

027A-S 886-368903841 7/a 7/a 7/a 718 i 318

033A-S aa6-36890384x2 7ta 718 718 718 i 3/a,

FIGURE 8. DIMENSIONAL DRAWING

REFRIGERANT CHARGE ADDING REFRIGERANT CHARGE

Each ALP condensing unit is designed for operation usingrefrigerant 22. Table 6 lists refrigerant charge required for acondensing unit/cooler combination.

On systems that have been previously charged wi threfrigerant, an insufficient charge is indicated by bubblingin the sightglass. On uncharged systems, the system shouldbe leak tested and evacuated before charging. Uponcharging a system, the discharge and suction shut-off valveson the compressor should be open and there should benormal water flow through the cooler.

TABLE 6. APPROXIMATE REFRIGERANT CHARGE

ALP ‘R-22 REFRIGERANT

MODEL CHARGE (LBS.)

016A-S 17

019A-S 23

023A-S 32

0 2 7 A S 37

033A-S 53

l Refrigerant charge is for a close-coupled system. A remote coolerwill require an additional charge.

CAUTION: Do not make any safety controls inoperativeduring the charging operation: cooler damage from freezingmay result.

1. Back seat the liquid line shut-off valve and connect thecharging hose to the 1/4-inch flare connectron.

2. Install pressure gauges and review start-up instructions.

3. Purge the charging hose and open the charging cylinderto allow refrigerant into the system.

PAGE 6

‘4.

5.

6.

Turn the liquid l ine shut-off valve in three turns topermit a back flow of refrigerant into the subcooler.

After refrigerant stops flowing into the system, close theliquid line shut-off valve. Start the compressor to chargethe system.

If the amount of refrigerant has been predetermined,add this amount and check the sightglass afterward.

If the amount of charge is unknown, close the chargingcylinder valve every five minutes, open the liquid lineshut-off valve and check for proper charge by examiningthe sightglass. Continue charging and checking thesightglass until it is clear.

NOTE: Fluorocarbon refrigerants should not be released tothe atmosphere. For a means of recovery, refer to thefollowing section.

REMOVING REFRIGERANT CHARGETo prevent freeze-up when removing the refrigerant for

ALP installations on water chiller systems, either drain thewater or circulate the water. If water cannot be drained,make sure the cooler heater is energized. Do not removerefrigerant rapidly since this can cause freeze-ups. Have asufficient number of refrigerant containers and a scale forweighing them. The containers should be clean, dry andempty.

To transfer the refrigerant to a container, connect thegauge manifold from the compressor discharge valve serviceport to the container and purge the iines. Note the capacityof the container. Place the container in ice to cool theconta iner so the fus ib le p lug does not mel t as therefrigerant condenses. Operate the compressor normally.Turn the discharge service valve in three turns to open thegauge manifold. Do not close off the discharge valve to thecondenser. Discharge gas can enter the container andcondense. Frequently weigh the container so as not tooverfill. When the container is filled use additional ones.

FIELD WIRINGWARNING: USE ONLY COPPER CONDUCTORS IN MAIN TERMINAL BLOCK.

Wiring should be done in accordance with all applicable transformer is ordered, the control circuit is powered offcodes and ordinances. Warranty is voided if wiring is not in the main power supply.accordance with specifications. An open fuse indicates a Figure 9 shows typical field wiring that is required forshort, ground or overload. Before replacing a fuse or unit installation. Items that require field wiring are liquidrestarting a compressor or fan motor, the trouble must be line solenoid SV1, optional hot gas bypass solenoid SV5found and corrected. and the cooling thermostat, as well as the unit power

All standard units require a 115 volt power supply for supplies.t h e c o n t r o l c i r c u i t . I f t h e o p t i o n a l c o n t r o l c i r c u i t

FIGURE 9. TYPICAL FIELD WIRINGPB1

““ll Ml,”

THERMOSTAT WIRING,

Since it is impossible for McQUAY to anticipate the type of to which a thermostat may be connected. These terminalsinstallation that an ALP condensing unit may be used on, are shown and labeled “Terminals For Thermostat” on thewe do not factory install a thermostat. We do, however, electrical schematics. Figure 9 shows typical field wiring forprovide numbered terminals inside the unit control center a thermostat with temperature controlled unloading.

PAGE 7

FLOW SWITCH FOR CHILLED WATER APPLICATIONS

A water flow switch or pump starter interlock is requiredon chilled water applications to insure that there will be

switch and adaptable to any pipe size from l-inch to 6-inch

adequate water flow and cooling load to the evaporatornominal. Certain minimum flow rates are required to closethe switch and are listed in Table 9. Installation should be

before the unit can start. This will safeguard against as shown in Figure 10.slugging the compressors on start-up. It also serves to shutdown the unit in the event that water flow is interrupted toguard against evaporator freeze-up.

A flow switch is available from McQUAY underordering number 860-175033X-00. It is a “paddle” type

FIGURE 10.

,/ - FLOW DIRECTIONHARKED ON SWITCH

TABLE 9. FLOW SWITCH MINIMUM FLOW RATES SWITCH UPRIGHTIN A HORIZONTALRUN OF PIPE

rJ /

NO RESTRICTIONS NO RESTRICTIONS5 PIPE DIAMETERS MIN. 5 PIPE DIAMETERS MINAFTER SWITCH BEFORE SWITCH

Electrical connections in the unit control center shouldbe made at terminals 12 and 21. The normally opencontacts of the flow switch should be wired between thesetwo terminals. There is also a set of normally closedcontacts on the switch that could be used for an indicatorlight 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 start to prevent compressor slugging. A pair of terminals iswith the condensing unit control center to insure that there available in the unit control center for this purpose. Thesewill be a cooling load on the evaporator before the unit can terminal numbers are shown in Figure 9.

ELECTRICAL

CONTROL CENTER FIGURE 11.

All electrical controls are enclosed in a weatherproofcontrol center with a keylocked, hinged access door (seeFigure 11). The control center is composed of two sections.The left section is the largest and contains all of the 208,230, 380 or 460 volt compressor and fan motor startingcontrols. Also included in this section, but partitionedseparately, are the exposed terminal type, 115 voltoperational controls. A “dead front” cover over the leftsection protects service personnel from high voltage startingcontrols and exposed terminal operational controls.

The right section, not covered by the “dead front”panel, contains 115 volt adjustable or resettable controls.

Power supply conduits are intended to come into thebottom of the control center. Figure 11 shows arecommendation for unit mounting arrangements if thedisconnect is to be unit mounted.

IT DISCONNECT

CONTROL CENTER’

SkUENCE OF OPERATION PUMPDOWN CYCLE

As the temperature control thermostat is satisfied, it opensits contacts, de-energizing liquid line solenoid valve SV1,causing the valve to close. When the compressor haspumped most of the refrigerant from the evaporator to thecondenser, the low pressure control LP1 opens, shuttingdown the compressor and condenser fan motors.

Should a closed solenoid valve allow refrigerant to leakto the low side of the refrigerant circuit during unit “off”time, the buildup in pressure will cause the low pressurecontrol to close, energizing the low pressure relay andstarting the compressor for pumpdown.

The following sequence of operation is for an ALPSEASONCON air cooled condensing unit. With controlcircuit power on, control stop switch S1 closed and manualpumpdown switch PS1 closed (“auto” position), 115 voltpower is applied through control circuit fuse F1 to thecompressor crankcase heater HTR1 and also to the contactsof low pressure switch LPI.

When the remote time clock, ambient thermostat,manual shutdown switch and/or evaporator fan interlocksenergize the thermostatic circuit and, provided that highpressure control HP1, oil pressure control OP1 (not onALP-016A) and compressor motor protector MP1 do notsense an alarm condition, safety relay R5 is energizedclosed, applying power to temperature control thermostat.At this point the unit will operate automatically in responseto the thermostat.

For ALP416 - On a call for cooling, temperaturecontrol thermostat TC1 energizes liquid line solenoid valveSV1, opening the valve and allowing refrigerant to flow intothe evaporator. As refrigerant pressure builds up, lowpressure control LP1 closes, energizing low pressure relayR9 which closes to energize time delay TD14. The closingof TD14 energizes fan motor relay Ml 1, closing its contactsand providing power to condenser fan motor contactorsM l l , Ml 2 and M13. At reduced load conditions,thermostat TC1, stage 2, is closed, relay R21 is energizedand normally open contact R21 is closed. Relay Ml isenergized and normally closed Ml AUX. contacts are open.Compressor contactor Ml is closed and the compressor isrunning at slow speed.

At full load conditions, thermostat TC1, stage 2, isopen, relay R21 is de-energized and normally closedcontact R21 is closed. On 208 volt and 230 volt units, relayM9 is energized and normally open contacts M9 are closed.Compressor contactors M9 (on 208 volt and 230 volt only)

and M5 are closed and the compressor is running at fastspeed.

F o r ALP-019, 023, 027 and 033 - On a call forcooling, temperature control thermostat TC1 energizesliquid line solenoid valve SV1, opening the valve andallowing refrigerant to flow into the evaporator. A srefrigerant pressure builds up, low pressure control LP1closes, energizing low pressure relay R9 which closes toenergize compressor contactor Ml, starting the compressor.Closing relay R9 contacts also energizes condenser fan relayMl 1, closing its contacts and providing power to condenserfan motor contactors Ml 1, Ml2 and M13. At reduced loadconditions, thermostat TC1, stage 2, is closed, unloader U1is energized and the compressor is unloaded. At full loadconditions, thermostat TC1, stage 2, is open, unloader U1 isde-energized and the compressor is loaded.

MAJOR COMPONENT LOCATIONS

REAR VIEW OF UNIT

COIL ON OPPOSITE SIDE

TABLE 10.

I MODEL

ICOh4PRESSOR

NUMBER SIZE

NOTE: Condenser Fan 11 is location of optionalSPEEDTROL motor.

PAGE 11

START-UP & SHUT-DOWNPRE START-UP

1.

2.

3.

4.

5.

6.

7.

With electrical disconnects open, check all screw or lugtype electrical connections to be sure they are tight forgood electrical contact. Check all compressor valve con-nections for tightness to avoid refrigerant loss at start-up. Although all factory connections are tight beforeshipment, some loosening may have resulted from ship-ping vibration.

A. On chilled water installations, check to see that allwater piping is properly connected.

B. Open all water flow valves and start the chilledwater pump. Check all piping for leaks and vent theair from the evaporator and system piping. Flushthe evaporator and system piping to obtain clean,non-corrosive water in the evaporator circuit.

Check the compressor oil level. Prior to start-up, the oillevel should cover at least 1/2 of the oil sightglass.

Check the voltage of the unit power supply and see thatit is within the RIO% tolerance that is allowed. Phasevoltage unbalance must be within &2%.

Check the unit power supply wiring for adequateampacity and a minimum insulation temperature ratingof 75c.

Verify that all mechanical and electrical inspectionshave been completed per local codes.

See that all auxiliary control equipment is operative andthat an adequate cooling load is available for initialstart-up.

INITIAL START-UP

1. Open the compressor suction and discharge shut-offvalves until back seated. Always replace valve seal caps.

2. Open the manual liquid line shut-off valve at the outletof the subcooler.

3. Allow the crankcase heater to operate for at least eighthours prior to start-up.

4. Check to see that pumpdown switch PS1 is in the“manual pumpdown” position and the control switchS1 is in the “on” position.

5. Adjust the dial on the temperature controller to thedesired chilled water or leaving air temperature.

CAUTION: Most relays and terminals in the unit controlcanter are hot with S1 and the control circuit disconnecton.

6.

7.

8.

9.

Throw the main power and control circuit disconnectsto the “on” position.

Start the auxiliary equipment for the installation.

Start the system by moving pumpdown switch PS1 tothe “auto. pumpdown” position.

After system performance has stabilized, it is necessarythat the “Compressorized Equipment Warranty Form”(Form No. 206036A) be completed to obtain fullwarranty benefits. This form is shipped with the unitand after completion should be returned to McQUAY’sService Department through your sales representative.

TEMPORARY SHUT-DOWN

Move pumpdown switch PS1 to the “manual pumpdown”position. After the compressors have pumped down, turn

off the chilled water pump or evaporator fan.NOTE: With the unit left in this condition, it is capable

of recycling pumpdown operation. To defeat this mode ofoperation, move the control stop switch S1 to the “off”position.

It is especially important on chilled water installationsthat the compressors pump down before the water flow tothe evaporator is interrupted to avoid freeze-up.

START-UP AFTER TEMPORARY SHUT-DOWN

Start the chilled water pump or evaporator fan.

With control stop switch S1 in the “on” position, movepumpdown switch PS1 to the “auto. pumpdown”position.

Observe the unit operation for a short time to be surethat the compressors do not cut out on low oil pressure.

EXTENDED SHUT-DOWN

1.

2.

3.

4.

5.

6.

Close the manual liquid line shut-off valve.

After the compressor has pumped down, turn off thechilled water pump or evaporator fan.

Turn off all power to the unit and to the auxiliaryequipment.

Move the control stop switch S1 to the “off” position.

Close the compressor suction and discharge valves.

Tag all opened disconnect switches to warn againststart-up before opening the compressor suction anddischarge valves.

START-UP AFTER EXTENDED SHUT-DOWN

1.

2.

3.

4.

5.

6.

inspect all auxiliary equipment (pumps, fans, etc.) tosee that each device is in satisfactory operatingcondition.

Remove all debris that has collected on the surface ofthe condenser coils.

Open the compressor suction and discharge valves.

Open the manual liquid line shut-off valve.

Check to see that pumpdown switch PS1 is in the“manual pumpdown” position.

Turn on the electric power to the unit and other partsof the system.

Allow the crankcase heaters to operate for at least eighthours prior to start-up.

On chilled water installations, start the chilled waterpump and purge the water piping as well as theevaporator.

Check to see that the control stop switch S1 is in the“on” position.

CAUTION: Most relays and terminals in the unit controlcenter are hot with S1 and the control circuit disconnecton.

10.

11.

Start the unit by moving pumpdown switch PS1 to the“auto. pumpdown” position.

After running the unit tor a short time, check the oillevel in the compressor crankcase and check forflashing in the refrigerant sightglass.

PAGE 17

CONTROLS

OIL PRESSURE SAFETY CONTROLALP-OlSA, 023A, 027A, 033A (NOT ON ALP-OlGAI

The oil pressure safety control is a manually resettabledevice which senses the differential between oil pressure atthe discharge of the compressor oil pump and suctionpressure inside the compressor crankcase. When the oilpressure reaches approximately 15 PSI above the crankcasesuction pressure, the pressure actuated contact of thecontrol opens from its normally closed position. If thispressure differential cannot be developed, the contact willremain closed and energize a heater element within thecontrol. The heater element warms a normally closedbimetallic contact and causes the contact to open,de-energizing a safety relay and breaking power to thecompressor.

It takes about 120 seconds to warm the heater elementenough to open the bimetallic contact, thus allowing timefor the pressure differential to develop.

If during operation the differential drops below 10 PSI,the heater element will be energized and the compressorwill stop. The control can be reset by pushing the resetbutton on the control. If the compressor does not restart,

allow a few minutes for the heater element and bimetalliccontacts to cool and reset the control again.

To check the control, pump down and shut off allpower to the unit. Remove the compressor relay wiring atterminals 2 and 8, and install a voltmeter between terminalsL and M of the oil pressure control. Turn on power to theunit control circuit (separate disconnect or main unitdisconnect, depending on the type of installation). Checkto see that the control stop switch S1 is in the “on”position. The control circuit should now be energized, butwith the absence of the compressor running, no oil pressuredifferential can develop and thus the pressure actuatedcontacts of the control will energize the heater element andopen the bimetallic contacts of the control within 120seconds. When this happens the safety relay is de-energized,the voltmeter reading will rise to 115V and the compressorcontactor should open. Repeated operations of the controlwill cause a slight heat build-up in the bimetallic contactsresulting in a slightly longer time for reset with eachsuccessive operation.

I I 120LINE (SEE NOTE 1)

1 tm NEUTRAL

y HEATER ELEMENT

CONTACTL M

LINE (SEE NOTE 2) 41I

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.

NOTE: PERFORM AN OPERATIONAL CHECK ON ALL UNIT SAFETY CONTROLS ONCE PER YEAR.

SOLID STATE COMPRESSOR MOTOR PROTECTION

All air cooled condensing units have compressors with solidstate motor protection. Both Robertshaw and TexasInstruments systems are used and their components are notinterchangeable.

There are two major components in a protectionsystem. First, the protector sensors are mounted internallyin the motor windings. The sensors monitor windingtemperature. A change in temperature causes a change insensor resistance. Sensor resistance is monitored by thesecond component of the system - the control module -which is a sealed enclosure containing a relay, transformerand other electronic components. Leads from the sensorsare connected to the module. Sensor resistance triggers thecontrol module relay at definite opening and closingsettings.

The module voltage will always be 120V and will be somarked. When the control module needs repair no attemptshould be made to repair it. It should be returned intact forreplacement . If the module is opened or physicallydamaged the warranty is void.

The control module and solid state sensor can bedamaged by high voltage. A high potential test should neverbe made to the module or sensors.

If the compressor motor is not operating properly, thefollowing procedure may be used to check the solid statemotor control circuit.

PAGE 18

1.

2.

If the compressor has been operating and has beenstopped by the motor protector, allow one hour for thecompressor to cool and the motor protector to reset.

If reset does not occur, connect a jumper wire acrossthe motor protector from terminal 30 to 36. If thecompressor does not operate with the jumper installed,the problem is not within the solid state protectorsystem. If the compressor operates with the jumperinstalled and does not operate without the jumper, thecontrol circuit relay in the module is open for somereason.

CAUTION: Only check compressor operation with jumperinstalled. Do not continue operation.

A possible cause of the open relay is the motor sensors.They may be checked by first removing the connections tothe terminal board. Use an ohmmeter of 3 volt maximumvoltage to check resistance from each sensor terminal to thecommon terminal. No voltage or current should be appliedto the sensors to check continuity. The resistance acrosseach motor sensor should be approximately 500 to 2400ohms with a motor temperature below 1400F. If theresistance is zero, there is a short. If the resistance isinfinity, there is an open connection.

O n reset the resistance of the sensors must be below thereset point before the relay contacts will close. The resetresistance is 2700 to 4500 ohms.

If the sensor resistance has been checked and found to besatisfactory and the compressor will run with the controlbypassed but will not run with the control wired properly,the control module is defective and must be replaced.

In case the resistance across a sensor is infinity, themodule will prevent compressor operation. As anemergency means of obtaining compressor operation untilthe compressor can be replaced, a resistor may be addedbetween the terminal of the open sensor and the commonterminal in the terminal box. The control module then“sees” an acceptable resistance and compressor operationwill be restored. The emergency resistor should be 1 watt,2200 ohms L 10% resistor. The emergency resistor will notprovide the same degree of protection, but it provides areasonable measure of safety.

RESIS

OPEN

L--L- L-J

SENSORS

l SOLID STATE MODULE 1

HIGH PRESSURE CONTROL

The high pressure control is a single pole pressure activated condenser pressure rise. The highest point reached beforeswitch that opens on a pressure rise to de-energize the cut-out is the cut-out setting of the control.entire control circuit except for compressor crankcaseheater. It senses condenser pressure and is factory set to CAUTION: Although there is an additional pressureopen at 380 PSIG and can be manually reset closed at 315 relief device in the system set at 425 PSIG, it is highlyPSIG. To check the control, block off condenser surface recommended that the control stop switch S1 be close atand observe the cut-out point of the control by watching hand in case the high pressure control should malfunction.

. .

LOW PRESSURE CONTROL

The low pressure control is a single pole pressure switchthat closes on a pressure rise. It senses evaporator pressureand is factory set to close at 60 PSIG and automaticallyopen at 25 PSIG. The control has an adjustable range of 20rn. of Hg. to 100 PSIG and an adjustable differential of 6 to40 PSIG. To check the control (unit must be running),m o v e t h e pumpdown s w i t c h PS1 t o t h e “ m a n u a lpumpdown” position. As the compressor pumps down,

FANTROL - HEAD

FANTROL is a system for progressively turning on or offcondenser fans when they are no longer required. This isdone to reduce condenser capacity (typically in lowoutdoor ambient temperatures) and is accomplished by acombination of pressure and temperature actuated controls.The first fan (No. 11) is started by its contactor when thecompressor in the unit starts. The second fan (No. 12) iscontrolled by a pressure switch which senses condenserpressure. The third fan (No. 13) is controlled by atemperature switch which senses condenser air inlettemperature. Pressure and temperature control setpoints areindicated below.

To check the cut-in points of the controls, the unit

condenser pressure will rise and evaporator pressure willdrop. The lowest evaporator pressure reached beforecut-out is the cut-out setting of the control. By moving thepumpdown switch PS1 to the “auto. pumpdown” position,evaporator pressure will rise. The highest evaporatorpressure reached before compressor restart is the cut-insetting of the control.

PRESSURE CONTROL

must initially be off. With the unit prepared for start-upaccording to the procedures outlined in this bulletin, movepumpdown switch PS1 to the “auto. pumpdown” position.Evaporator pressure will begin to rise and the compressorshould start with Fan 11 starting immediately. After thecompressor starts, observe condenser pressure as it rises.When the condenser pressure reaches approximately 270PSIG, contactor Ml2 should pull in to start Fan 12. Onthree-fan units Fan 13 should start via contactor Ml3whenever the ambient air at the condenser inlet reaches8OF.

It may be difficult to check the cut-out point of Fan 13(on three-fan units) at the instant it happens, but it shouldbe off whenever the ambient air at the condenser inlet isbelow 70F. To check the cut-out point of Fan 12, somemeans of reducing the load on the unit must be available orthe fan operation and condenser pressure must be observedas the load drops off naturally. When the condenserpressure drops to approximately 170 PSIG, contactor Ml2should drop out to turn off Fan 12.

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OPTIONAL CONTROLS

SPEEDTROL (OPTIONAL)

McQUAY’s solid state SPEEDTROL, located on the back-side of the control center, continuously varies No. 11 con-denser fan motor speed on air cooled condensers by sensingchanges in refrigerant head pressure. SPEEDTROL makespossible unit operation in lower ambient temperatures.

With an increase in refrigerant head pressure SPEED-TROL increases fan motor speed. With a decrease in pres-sure fan motor speed is decreased.

The pressure connection of the transducer is made to thehigh pressure side of the refrigeration system at the purgevalve connection on the condenser coil header. This trans-ducer coupled with a solid stage unit modulates the phase

conduction angle of the AC sine wave supplied to the fanmotor. The fan motor is a special 208/230V SPEEDTAOLmotor. For 460 volt units a transformer is supplied todecrease line voltage to 230 volt motor voltage. TheSPEEDTROL controller is calibrated to deliver 90% of linevoltage at the setpoint pressure of 230 PSIG. It has aneffective throttling range of 60 PSIG which is the decreasein pressure below the calibration setpoint where 45% ofsupply voltage is transmitted to the motor. When 45% ofsupply voltage is transmitted to the motor, minimum motorspeed is reached; below this point there is no change inspeed.

PART WINDING START (OPTIONAL)Part winding start consists of a solid state time delay wired is energized instantly, while that for the second motorin series with the contactor that energizes the second winding is delayed for one second.winding of each compressor motor. Its purpose is to limit Control checkout is best accomplished by observationcurrent in-rush to the compressors upon start-up. As each as each contactor is pulled in to see that the one-secondcompressor starts, the contactor for the first motor winding delay occurs before the second contactor pulls in.

LINE NEUTRAL

PART WINDINGTIME DELAY 1

COMPRESSOR CONTACTOR(1st MOTOR WINDING)

LINE + NEUTRAL

COMPRESSOR CONTACTOR(2nd MOTOR WINDING)

LOW AMBIENT START (OPTIONAL)

Low ambient start is available on all units as an option withF ANTROL and included automatically with optionalSPEEDTROL. It consists of a solid state normally closedtime delay wired in series with a relay. These are both wiredin parallel to the liquid line solenoid valve so that when thesolenoid valve is energized by the unit thermostat, the lowambient start relay is also energized through the time delay.The relay has contacts that essentially short circuit the lowpressure control and allow the compressor to start with thelow pressure control open.

After about 2-3/4 minutes, the time delay will open andde-energize the relay. If the system has not built up enoughevaporator pressure to close the low pressure control, thecompressor will stop. The time delay can be reset to itsoriginal normally closed position by moving the pumpdown

switch PS1 to the “manual pumpdown” position. Movingthe pumpdown switch PS1 back to the “auto. pumpdown”position will again energize the relay for another attempt atstart-up. If the system has built up enough evaporatorpressure, the compressor will continue to run.

To check the control, turn off all power to the unit andremove the wire leading to the low pressure control LP1from terminal 11 in the unit control center. Remove thewires leading from the contactors to the compressor andjumper across terminals L and M of the oil pressure safetycontrol. Energize the control circuit by turning on thecontrol circuit disconnect or main power disconnect(depending on the installation) and the control stop switchS1. The compressor contactors should pull in instantly.

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

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COMPRESSOR LOCKOUT (OPTIONAL)Compressor lockout consists of a solid state time delaywired in series with the compressor contactor( Itspurpose is to prevent rapid compressor cycling whencooling demands are erratic.

When the unit thermostat no longer calls for coolingand the compressor contactor(s) have opened, the lockouttime delay breaks open the circuit preventing compressorrestart.

The circuit remains open for a period of five minutes sothat if the unit thermostat should call for cooling beforethe delay period has expired, the compressor will notrestart. After five minutes, the time delay will close itscontacts to complete the circuit and be ready for start-up.The time delay opens its contacts whenever there is powerto the terminals of the compressor relay and resets closedautomatically after the time delay period.

initially. Move the pumpdown switch PS1 to the “manualpumpdown” position. immediately after the compressorhas stopped running, move the pumpdown switch back tothe “auto. pumpdown” position. The compressor shouldnot restart for five minutes.

LINE(SEE NOTE)

To check the control, the compressor must be running NOTE: Hot whenever freeze cc,n,r~, and hqh ,xessure contrd permt safe ~,xtatcr

AL ARM BE L L (O P TI O N A L)It is expected that the customer will want to locate thealarm bell where it will be heard in the event of a safetyfailure. After mounting, the bell should be wired totransformer T4. When the bell is wired into the control

circuit it will sound whenever there is a failure due to low

oil pressure (not on ALP-OlGAI, motor overload, orexcessive condenser pressure.

HOT GAS BYPASS (OPTIONAL)Hot gas bypass is a system for maintaining evaporatorpressure at or above a minimum value. The purpose fordoing this is to keep the velocity of the refrigerant as itpasses through the evaporator high enough for proper oilreturn to the compressor when cooling load conditions arelight.

The system usually consists of a solenoid valve piped inseries with a pressure regulating valve as shown. Provisionsare provided for installing the hot gas bypass kit.

The solenoid valve should be wired to operate as close tothe unit’s maximum unloaded state as possible. Thepressure regulating valve that McQuay offers is factory setto being opening at 58 PSIG (32F for R-22) when the aircharged bulb is in an 80F ambient temperature. The bulbcan be mounted anywhere as long as it senses a fairlyconstant temperature at various load conditions. Thecompressor suction line is one such mounting location. It isgenerally in the 50F to 60F range. The chart belowindicates that when the bulb is sensing 50F to 60Ftemperatures, the valve will begin opening at 54 to 56PSIG. This setting can be changed, as indicated above, bychanging the pressure of the air charge in the adjustablebulb. To raise the pressure setting, remove the cap on thebulb and turn the adjustment screw clockwise. To lower thesetting, turn the screw counter-clockwise. Do not force theadjustment beyond the range it is designed for as this willdamage the adjustment assembly.

The regulating valve opening point can be determinedby slowly reducing the system load while observing thesuction pressure. When the bypass valve starts to open, therefrigerant line on the evaporator side of the valve willbegin to feel warm to the touch.

CAUTION: The hot gas line may become hot enough tocause injury in a very short time, so care should be takenduring valve checkout.

On installations where the condensing unit is remotefrom the evaporator, it is recommended that the hot gasbypass valve be mounted near the condensing unit tominimize the amounts of refrigerant that will condense inthe hot gas line during periods when hot gas bypass is notrequired.

HOT GAS BYPASS PIPING DIAGRAM

rHot Gas BypassSolenoid Valve y- Surt1on Line

External Equalizer

in ALP Unit Bypass Valve Expansion Valvewith Factory (On DX Coil withCapped Tee for Distributor, useConnection. A Sporlan Auxiliarymanual shut-off Sideport Connectorvalve between the or Equivalent.)bypass tee andsolenoid valve isrecommended.

HOT GAS BYPASS ADJUSTMENT RANGE

REMOTE BULB ADJUSTMENT RANGE

80

3030 40 52 60 70 80 90 100 1,:

TEuP f0F1 AT BULB LOCATION

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MAINTENANCE PROCEDURESNOTE: Service on this equipment is to he performed by qualified refrigeration service personnel. Causes for repeated tripping of Safety controlsmust be investigated and corrected. CAUTION: Disconnect all power before doing any service inside the unit.

On Initial start-up and periodically during operation it willbe necessary to perform certain routine service checks,Among these are checking the compressor o i l level andtaking condensing, suction and oil pressure readings. Duringoperation the oil level should be visible in the oil sightglasswith the compressor running. On units ordered with gauges,

condensing, suction and o i l pressures can be read from thegauges. Oil pressure gauge is not available on ALP-OIGA.The gauges are installed with a manual shut-off valve oneach gauge line. The valves should be closed at all timesexcept when gauge readings are being taken.

REFRIGERANT SIGHTGLASSThe refrigerant sightglass should be observed periodically. o r d e r e d f r o m McQUAY as part of the "Liquid L i n e(A monthly observation should be adequate.) A clear glass Accessory Kits”, an element Inside the sightglass indicatesof liquid indicates that there is adequate refrigerant charge what moisture condition corresponds to a given elementin the system to insure proper feed through the expansion color. If the sightglass does not indicate a dry conditionvalve. Bubbling refrigerant in the srghtglass indicates that after a few hours of operation, the unit should be pumpedthe system is short of refrigerant charge. On sightglasses down and the cores in the filter-driers changed.

FILTER-DRIERSTo change the filter-drier core, pump the unit down by position. Th is will close the liquid line solenoid valve andmoving pumpdown switch PS1 to the “manual pumpdown” isolate the short section of refrigerant piping containing theposition. Turn off all power to the unit and install a jumper filter-drier. Remove the cover plate from the filter-drierfrom terminal 31 to 34. Turn power to the unit back on shell and replace the core.and restart the unit by moving pumpdown switch PS1 to After core replacement, replace the cover plate. A leakthe “auto. pumpdown” position. Close the manual liquid check around the f lange of the f i l ter -dr ier shel l isline shut-off valve and when evaporator pressure reaches 0 recommended after the core has been changed.PSIG. move t he con t ro l s t op sw i t ch S1 to the “o f f ”

LIQUID LINE SOLENOID VALVE

T h e liquid line solenoid valve, which is responsible for by simply removing a nut or snap ring located at the top ofautomatic pumpdown during normal unit operation, does the coil. The coil can then be slipped off its mounting studnot normally require any maintenance. It may, however, for replacement. Be sure to replace the c o i l on its mountingrequire replacement of the solenoid coil or of the entire stud before returning pumpdown switch PS1 to the “auto.valve assembly. pumpdown” position.

The solenoid c o i l may be removed from the valve bodywithout open ing t he re f r i ge ran t piping b y m o v i n gpumpdown s w i t c h PS1 t o t h e “ m a n u a l p u m p d o w n ”position. The c o i l can then be removed from the valve bodv

To replace the entire solenoid valve, the unit must bepumped down by use of the manual liquid line shut-offvalve.

CONDENSERS

Condensers are air cooled and constructed with 3/8 O.D.copper tubes bonded in a staggered pattern into rippledaluminum f ins. No maintenance IS ordinarily requiredexcept the occasional removal of dirt and debris from the

outside surface of the fins. Care should be taken not todamage the fins during cleaning. Periodic use of the Purgevalve on the condenser will prevent the build-up ofnon-condensables.

COMPRESSOR OIL LEVELBecause of the large refrigerant charge required in an air At the present time, Suniso 3GS o i l is the only oilcooled condensing unit it IS usual ly necessary to put approved by Copeland and Sundstrand for use in theseaddi t ional o i l into the system. The oil level should be compressors. The oil level should be maintained at aboutwatched carefully upon initial start-up and for sometime the midpoint of the sightglass on the compressor body. Thethereafter. use of a light may be required for proper o i l level reading.

ADDING OIL TO COMPRESSOROil may be added to the Copeland compressor through the Stop the compressor and close the discharge valve.011 1111 hole in the crankcase and t o t h e S u n d s t r a n d Add the requrred amount of 011. Durirrg the perrod thecompressor through the 3/8-Inch process tube on the side compressor IS exposed to the atmosphere the refrigerantof the compressor. To add 011, Isolate the crankcase and wi l l qeneratc a vapor pressure, retarding the entrance Ofpour or pump the necessary 011 in. If the system contains contamrnants. Before resealing the compressor purge theno rcfrrgerant. no special precautrons are necessary other crdnkcasr! by openrnq the suctrorr valve slightly for 1 or 2than keeping the o i l clean and dry. seconds. Close the o i l port, open the compressor valves and

If the system contains a refrigerant charge, close the restore the system to operation.suction valve and reduce crankcase pressure to 1 to 2 PSIG.

PAGE 22 .I.

I

ELECTRICAL TERMINALS

CAUTION: ELECTRIC SHOCK HAZARD -TURN OFF ALL POWER BEFORE CONTINUING WITHFOLLOWING SERVICE.

All power electrical terminals should be retightened every six months, as they tend to loosen in servicedue to normal heating and cooling of the wire.

FAN MOTOR BEARINGS

All fan motors are pre-lubricated and do not require the addition of grease.

THERMOSTATIC EXPANSION VALVE

The expansion valve is responsible for allowing the properamount of refrigerant to enter the evaporator, regardless ofcooling load. It does this by maintaining a constantsuperheat. (Superheat is the difference between refrigeranttemperature as it leaves the evaporator and the saturationtemperature corresponding to the evaporator pressure.)Typically, superheat should run in the range of 10F to 15F.

On valves purchased through McQUAY, the superheatsetting can be adjusted by removing a cap at the bottom ofthe valve to expose the adjustment screw. Turn the screwclockwise (when viewed from the adjustment screw end) toincrease the superheat setting and counter-clockwise toreduce superheat. Allow time for system rebalance aftereach superheat adjustment.

The expansion valve, like the solenoid valve, should notnormally require replacement, but if it does, the unit mustbe pumped down by using the manual liquid line shut-offvalve. If the problem can be traced to the power elementonly, it can be unscrewed from the valve body withoutremoving the valve, but only after pumping the unit downwith the manual liquid line shut-off valve.

IN1.ET

‘POWER ELEMENT(CONTAINS DIAPHRAGM)

OUTLET

SPRING

ADJUSTMENT SCREW

CAP

IN-WARRANTY RETURN MATERIAL PROCEDURE

COMPRESSOR

Bristol Corporation [compressor used in the ALP-0161, andCopeland Corporation [all other units], have stockingwholesalers who maintain a stock of replacement compres-sors and service parts to service refrigeration contractorsand servicemen.

When a compressor fails in warranty, contact your localsales representative or McQuay Warranty Claims Depart-ment at the address on the cover of this bulletin. You willbe authorized to exchange the defective compressor locally(an advance replacement can be obtained), or we will shipyou a replacement from our stock. A salvage credit is issuedto you by the wholesaler on the returned compressor after

Bristol or Copeland factory inspection of the inoperativecompressor. Provide McQuay with full details and invoicesand we will reimburse the difference. In this transaction, becertain that the compressor is definitely defective. If acompressor is received from the field that tests satisfactor-ily, a service charge plus a transportation charge will becharged against its original credit value.

On all out-of-warranty compressor failures, Bristol andCopeland offer the same field facilities for service and/orreplacement as described above. The credit issued by Bristolor Copeland on the returned compressor will be determinedby the repair charge established for that particular unit.

COMPONENTS OTHER THAN COMPRESSORS

Material may not be returned except by permission of should include part name, part number, model number andauthorized factory service personnel of McQUAY Inc. at serial number of the unit involved.Minneapolis, Minnesota. A “Return Goods” tag will be sent Following our personal inspection of the returned part,to be included with the returned material. Enter the and if it is determined that the failure is due to faultyinformation as called for on the tag in order to expedite material or workmanship and in warranty, credit will behandling at our factories and prompt issuance of credits. Issued on customer’s purchase order.

The return of the part does not constitute an order for All parts shall be returned to the pre-designatedreplacement. Therefore, a purchase order must be entered McQUAY factory, transportation charges prepaid.through your nearest McQUAY Representative. The order

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