McQuay ALR-012A Installation Manual

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Page 1

BULLETIN NO. IM 207

MAY, 1980

INSTALLATION AND

MAINTENANCE DATA

GROUP

PACKAGED AIR COOLED WATER CHILLER

TYPE ALR-012A THRU 030A

McQuay-PERFEX Inc.

13500 Industrial Park Blvd., P.O. Box 1551, Minneapolis, Mn. 55440

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INTRODUCTION

McQUAY

automatic water cooling units that include the latest in engineered components arranged to provide a compact and efficient unit. Each unit is assembled before evacuation, charging and testing. Each unit consists of an air cooled condenser with integral subcooler section, unloading compressor and replaceable tube, shell-and-tube evaporator.

ALR SEASONPAK air cooled water chillers are

NOMENCLATURE

A L R-030 A-S

Air Cooled Condensing

Reciprocating Compressor

INSPECTION

When the equipment is received, all items should be

carefully checked against the bill of lading to insure a

complete shipment. All units should be carefully inspected

for damage upon arrival. All shipping damage should be

INSTALLATION

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

HANDLING Care should be taken to avoid rough handling or shock due to dropping the unit. Do not push or pull the unit from anything other than the base, and block the pushing vehicle away from the unit to prevent damage to the sheet metal cabinet (See Figure 1). Do not let the lifting fork damage the refrigerant piping within the cabinet.

To lift the unit, 2 provided in the base of the unit. Spreader bars and cables should be arranged to prevent damage to the condenser coils or unit cabinet (See Figure 2).

-1/2-inch

diameter lifting holes are

Liquid line components included are manual liquid line shutoff valve, replaceable core filter-drier, liquid line solenoid valve, sightglass/moisture indicator and double diaphragm hydraulic element thermal expansion valve. Other features include: compressor crankcase heater, an evaporator heater for chilled water freeze protection and recycling pumpdown during “on” or “off” seasons.

Nominal Capacity (Tons)

reported to the carrier and a claim should be filed. The unit

serial plate should be checked before unloading the unit to

be sure that it agrees with the power supply available.

FIGURE 1. SUGGESTED PUSHING ARRANGEMENT

BLOCKING

LOCATION

Due to vertical condenser design, it is recommended that

the unit be oriented so that prevailing winds blow parallel

to the unit length, thus minimizing effects on condensing pressure. manner, a wind deflector should be constructed.

mounted on a roof or concrete slab (ground level installation). Roof-mounted units should be installed level on steel channels or an l-beam frame to support the unit above the roof. Use of vibration pads or isolators is

recommended. The roof must be strong enough to support the weight of the unit. See Table 1 for unit weights. Concrete slabs used for unit mounting should be installed level and be properly supported to prevent settling. A one-piece concrete slab with footings extended below the frost line is recommended.

TABLE 1.

If it is not practical to orient the unit in this

Units are designed for outdoor application and may be

UNIT WEIGHTS

ALR MODEL

012 015 020 025 030

OPERATING WEIGHT

1364 1661 1883 2012 2330

(LBS.)

GOOD PUSHING ARRANGEMENT -CABINET DAMAGE UNLIKELY

FIGURE 2.

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WATER PIPING

PIPING PRACTICES

Due to the variety of piping practices; it is advisable to follow the recommendations of local authorities. They can supply the installer with the proper building and safety

codes required for a safe and proper installation.

Basically, the piping should be designed with a

minimum number of bends and changes in elevation to

keep system cost down and performance up. It should

contain:

Vibration eliminators to reduce vibration and noise transmission to the building.

Shut-off valves to isolate the unit from the piping system during unit servicing. prevent moisture condensation and possible damage to the

Manual or automatic air vent valves at the high points

of the system. Some means of maintaining adequate system water

pressure (e.g., expansion tank or regulating valve).

COOLER WATER CONNECTIONS

Temperature and pressure indicators located at the unit to aid in unit servicing.

A strainer or some means of removing foreign matter from the water before it enters the pump. It should be placed far enough upstream to prevent cavitation at the pump inlet (consult pump manufacturer for recommendations). The use of a strainer will prolong pump life and thus keep system performance up.

Prior to insulating the piping and filling the system, a

preliminary leak check should be made.

Piping. insulation should include a vapor barrier to

building structure. It is important to have the vapor barrier on the outside of the insulation to prevent condensation within the insulation on the cold surface of the pipe.

It is suggested that horizontal water piping connections to the cooler be made through the holes provided in the base frame. Two suggested arrangements that will align the

7. Vertical connections may be made to the cooler through

the open base using

2-inch

IPS

90-degree

elbows. Figure 10

gives the necessary dimensions for either piping method.

piping with the base frame holes are shown in Figures 6 and

FIGURE 6.

FIELD

P-

2” IPS WATER PIPE

NOTE: FOR INSTALLING A CHILLED WATER THERMOSTAT IN RETURN WATER LINE A REDUCING TEE SE USED INSTEAD OF A 2” IPS 90 ELBOW. SEE FIGURE 8.

COOLER WATER CONNECTIONS

INSTA

2”

IPS STREET ELBOW

BASE FRAME

”

IPS WATER CONNECTION

(2” x

1/2” x

2”)

MAY

CHILLED WATER THERMOSTAT

The chilled water thermostat is mounted inside the unit

FIGURE 7.

FIELD INSTALLED

FIGURE 8.

OOLER WITH 2” IPS CONNECTION

”

IPS

45’

ELBOW

BASE FRAME

2” IPS WATER PIPE

THERMOSTAT SENSOR INSTALLATION

control center. The sensor must be installed in the return water line as shown in Figure 8. The thermostat sensor should be insulated after installation.

REDUCING TEE

THERMOSTAT

12”~ l/Z” x 2”)

BULB

FIELD INSTALLED

CAUTION: Thermostats have maximum operating

temperature limits of

125OF on return water. Temperatures

exceeding these limits may damage the controls.

ETURN

WATER

THERMOSTAT SENSO EVAPORATOR

RETURN WATER

LINE

CONNECTION OF

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FLOW SWITCH

A water flow switch or pump starter interlock is required to insure that there will be adequate water flow and cooling load to the evaporator before the unit can start. This will safeguard against slugging the compressors on start-up. It also serves to shut down the unit in the event that water flow is interrupted to guard against evaporator freeze-up.

A flow switch is available from

ordering number 860-175033X-00. It is a “paddle” type switch and adaptable to any pipe size from l-inch to 6-inch nominal. Certain minimum flow rates are required to close

McQUAY

under

the switch and are listed in Table 4. Installation should be as shown in Figure 9.

Electrical connections in the unit control center should

be made at terminals 12 and 21. The normally open

contacts of the flow switch should be wired between these

two terminals. There is also a set of normally closed

contacts on the switch that could be used for an indicator

light or an alarm to indicate when a “no flow” condition

exists.

TABLE 4. FLOW SWITCH MINIMUM FLOW RATES

NOMINAL

PIPE SIZE

(INCHES)

l/4

1/2 2

MINIMUM REQUIRED

FLOW TO ACTIVATE

SWITCH (GPM)

9.80

12.70

18.80

FIGURE 10. DIMENSIONAL DRAWING

68.60 OPENING (AIR

WATER CONN.

CLEARANCE HOLES

3.62 DIA.

(2)

OUTLET SCREEN NOT SHOWN)

FIGURE 9.

FLOW SWITCH

NO RESTRICTIONS 5

PIPE DIAMETERS MIN.

AFTER SWITCH

FLOW DIRECTION

MARKED ON SWITCH

NO RESTRICTIONS 5 PlPE DIAMETERS MlN BEFORE SWITCH

(FIELD MOUNTED)

OPTIONAL

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14.761

LIFTING HOLES

2.50 DIA.

EACH SIDE)

MOUNTING HOLES,

.750 DIA. (2 EACH

SIDE)

ALR

UNIT SIZE

012A-S 015A-S 020A-S 025AS 030A-S

POWER CONN.

46.00

MOUNTING HOLES

DIMENSIONS & CONNECTIONS

50.60

65.60

80.60

DIMENSIONS (INCHES)

48.88,

Inlet

36.88,

Inlet

36.88, Inlet

Outlet

14.02,

7.20,Outlet

7.20.

Outlet

7.20,

Outlet

7.20,Outlet

18.06, Inlet

WATER CONN. SIZE

2”I.P.S. 2”I.P.S.

.P.S.

2” 2”I.P.S. 2”

.P.S.

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REFRIGERANT

ADDING REFRIGERANT CHARGE

On systems that have been previously charged with

refrigerant, an insufficient charge is indicated by bubbling in the sightglass. On uncharged systems the system should be leak tested and evacuated before charging.

Upon charging a system the discharge and suction shut-off valves on the compressor should be open and there should be normal water flow through the cooler.

CAUTION: Do not make any safety controls

inoperative during the charging operation; cooler damage from freezing may result.

Back seat the liquid line shut-off valve and connect the

charging hose to the

Install pressure gauges and review start-up instructions.

Purge the charging hose and open the charging cylinder

to allow refrigerant into the system.

When removing the refrigerant on water chiller systems to

prevent freeze-up, either drain the water or circulate the

water. If water cannot be drained, make sure the cooler

heater is energized; do not remove refrigerant rapidly since this can cause freeze-ups. Have a sufficient number of refrigerant containers at hand and a scale for weighing them. The containers should be clean, dry and empty.

To transfer the refrigerant to a container connect the

gauge manifold from the compressor discharge valve service

port to the container and purge the lines. Note the capacity

l/4-inch

flare connection.

REMOVING REFRIGERANT CHARGE

Turn the liquid line shut-off valve in three turns to permit a back flow of refrigerant into the subcooler.

After refrigerant stops flowing into the system, close

5. the liquid line shut-off valve. Start the compressor to charge the system.

If the amount of refrigerant has been predetermined,

add this amount and check the sightglass afterward. If

the amount of charge is unknown, every five minutes close the charging cylinder valve, open the liquid line shut-off valve and check for proper charge by

examining the sightglass. Continue charging and checking the sightglass until it

NOTE: Fluorocarbon refrigerants should not be

released to the atmosphere. For a means

to the following section.

of the container. Place the container in ice to cool the container so the fusible plug does not melt as the condenser

condenses. Operate the compressor normally. Turn the

discharge service valve in three turns to open the service port. Open the container valve and the gauge manifold. Do not close off the discharge valve to the condenser; discharge gas can enter the container and condense. Frequently weigh the container so as not to overfill. When the container is filled use additional ones.

clears.

recovery, refer

FIELD WIRING

Wiring should be done in accordance with all applicable codes and ordinances. Warranty is voided if wiring is not in

accordance with specifications. An open fuse indicates a short, ground or overload. Before replacing a fuse or restarting a compressor or fan motor, the trouble must be found and corrected.

Copper wire is required for all power lead terminations

at the unit.

All unit sizes are set up as standard for separate 115

volt power supply circuits for the control circuit and cooler

heater. The control circuit only, or both the control circuit

and the cooler heater, can be powered off the main unit power supply if the optional control circuit transformer is ordered. It may be desirable, however, to have the unit

cooler heater on a separate disconnect switch from the

main unit power supply so that the unit may be shut down without defeating the freeze protection provided by the cooler heater.

A standard feature on all ALR units is COPS

(Controlled Override of Pump Shut-down), a system for

interlocking

chiller control system. Relay RI9 is wired into the unit

control circuit so that a time clock and/or ambient thermostat can be connected to a pair of terminals (14 and

15) inside the unit control center. The time clock can energize a pump starter. Once the pump starts, the flow switch and/or pump interlock will close and energize that part of the control circuit that will allow the unit to start.

This feature makes it possible to start the chilled water pump and the chiller simultaneously only when cooling is required. For recycling

cooling, a relay (energized by the low pressure control) is also wired into this circuit to start the pump, close the flow switch and pump down the unit.

NOTE: If a time clock, ambient thermostat and/or remote on-off switch are not used, terminals 14 and 15 must be

Figure 11 shows typical field wiring that is required for unit installation.

the field supplied chilled water pump into the

pumpdown without a demand for

jumpered together before the unit will start.

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TABLE 6.

COMPRESSOR & CONDENSER FAN MOTORS

ALR

UNIT SUPPLY

SIZE

012A

015A

020A

025A

030A

NOTES:

ELEC.

(1)

208 230

380 460

208 230

380 460

208 230

380 460

208

230 380

460

208 230

380 460

1. Voltage limits:

RATED LOAD AMPS (2)

COMP. FAN MOTORS

44.0 4.4

22.0 2.4

64.0 4.4

32.0 2.4

80.0 4.4

80.0

41.0 2.4 41 .o

98.0 4.4

53.0 2.4

121.0 4.4 121 .o

61 .O 61 .O

Nameplate 208-Max. Nameplate 230-Max. Nameplate 380-Max. Nameplate 460-Max.

FAN MOTOR

(EACH)

4.4

2.4

4.4

2.4

229V,

253V, Min. 418V, 506V.

NO.

MOTORS (EACH)

3 3

3 3 3

3 3

Min. 187V.

207V. Min. 342V. first winding. Min. 414V.

FAN

8.2

7.5

8.2

7.5

8.2

7.5

8.2

7.5

8.2

7.5

2. Compressor rated load amps are for wire sizing purposes only

3. Compressor locked rotor amps for part-winding start is for the

ACROSS-THE-LINE-START

do not reflect normal operating current draw.

LOCKED ROTOR AMPS

PART-WINDING-START

COMPRESSOR

228 _ 228

114 114

308 188 308 188

154 _ 154 _

428 250 428 250

214 _ 214

470 292 470 292 235

235 _ 565 340

565 340 283 _

283

COMPRESSOR

and

START-UP & SHUT-DOWN

PRE START-UP

With all electric disconnects open, check all screw or lug

type electrical connections to be sure they are tight for good electrical contact. Check all compressor valve con-

nections for tightness to avoid refrigerant loss at startup. Although all factory connections are tight before

shipment, some loosening may have resulted from ship-

ping vibration.

Inspect all water piping for flow direction and correct

connections at the evaporator.

Open all water flow valves and start the chilled water

pump. Check all piping for leaks and vent the air from the evaporator as well as from the system piping. Flush the evaporator and system piping to obtain clean,

non-corrosive water in the evaporator circuit.

Check to see that the thermostat water temperature sensor is installed in the return water line (return to chiller). The sensor well should be full of heat conducting compound and the sensor should be secured

in the well with the retaining clip provided.

Check the compressor oil level. Prior to start-up, the oil

level should cover at least

Check the voltage of the unit power supply and see that

it is within the

*IO%

voltage unbalance must be within 42%.

Check the unit power supply wiring for adequate ampacity and a minimum insulation temperature rating of 75c.

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

1/2

of the oil sightglass.

tolerance that is allowed. Phase

See that all auxiliary control equipment is operative and that an adequate cooling load is available for initial start-up.

10. Making sure control stop switch pumpdown pumpdown,”

switches PSI and PS2 are on “manual

throw the main power and control discon-

is open (off) and

nect switches to “on.” This will energize the crankcase heaters. Wait a minimum of 12 hours before starting unit.

CAUTION: Most relays and terminals in the unit control center are hot with connect on.

S1 and the control circuit dis-

START-UP

Double check that the compressor suction and dis-

charge shut-off valves are back seated. Always replace valve seal caps.

Open the manual liquid line shut-off valve at the outlet

2. of the subcooler.

Allow the crankcase heater to operate for at least eight

3. hout

prior to start-up.

Check to see that the

4. “manual pumpdown”

switch

Adjust the dial on temperature controller

(S1)

is in the “on” position.

pumpdown

position and the control stop

desired chilled water temperature. Start the auxiliary equipment for the installation by

6. turning

on the time clock, ambient thermostat and/or

switch PSI is in the

TC1

to the

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remote on/off switch if the unit and chilled water pump are electrically interlocked by using the COPS method discussed in “Field Wiring.”

Start the system by moving pumpdown switch PSI to the “auto. pumpdown” position.

After running the unit for a short time, check the oil level in each compressor crankcase and check for flashing in the refrigerant sightglass (see “Maintenance”).

After system performance has stabilized, it is necessary that the “Compressorized Equipment Warranty Form” (Form No. 206036A) be completed to obtain full warranty benefits. This form is shipped with the unit and after completion should be returned to Service Department through your sales representative.

TEMPORARY SHUTDOWN

If the unit is equipped with COPS switching devices (see

Typical Field Wiring Diagrams, page IO), open the switch.

If not, proceed as follows:

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

NOTE: With the unit left in this condition, it is capable of recycling operation, move control stop switch tion.

It is important that the compressors pump down before the water flow to the unit is interrupted to avoid freeze-up in the evaporator.

pumpdown

operation. To defeat this mode of

to the “off” posi-

McQuay’s

START-UP AFTER TEMPORARY SHUTDOWN

If the unit is equipped with COPS switching devices (see Typical Field Wiring, page IO), open the switch. If not proceed as follows:

1. Start the chilled water pump.

2. With control stop switch

pumpdown switch PSI to the “auto. pumpdown” position.

3. Observe the unit operation for a short time to be sure

that the compressor does not cut out on low oil pressure.

EXTENDED SHUT-DOWN

Close the manual liquid line shut-off valve.

After the compressor has pumped down, turn off the chilled water pump.

Turn off all power to the unit and to the chilled water

pump.

Move the control stop switch

Close the compressor suction and discharge valves.

Tag all opened disconnect switches to warn against start-up before opening the compressor suction and discharge valves.

Drain all water from the unit evaporator and chilled water piping if the unit is to be shut down during freezing temperatures.

If water is not drained during freezing temperatures leave power to cooler heater on.

in the “on” position, move

to the “off” position.

ELECTRICAL

CONTROL CENTER All electrical controls are enclosed in a weatherproof

control center

Figure

12). The The left section is the largest and contains all of the 208, 230, 380 or 460 volt compressor and fan motor starting controls. Also included in this section but partitioned separately are the exposed terminal type, 115 volt operational controls. A “dead front” cover over the left section protects service personnel from high voltage starting controls 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 the bottom of the control center. It is recommended that the unit disconnect switch be mounted away from the unit.

However, Figure 12 shows a recommendation for unit mounting arrangements if the disconnect must be unit mounted.

with

a keylocked, hinged access door (see

control center is composed of two sections.

FIGURE 12.

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SEQUENCE OF OPERATION

The following sequence of operation is typical for the single compressor ALR SEASONPAK air cooled water chiller.

With control circuit power on, control stop switch

closed and manual

pumpdown

switch

PS1

closed (“auto” position), 115 volt power is applied through control circuit fuse

to the compressor crankcase heater

HTR1

to the contacts of low pressure switch LPI.

When the remote time clock or manual shut-down

switch turns “on”,

COPS pump starter relay RI9 is energized, closing contacts 1 and 3 to start the chilled water pump. Relay

R19

contacts 4 and 6 in the thermostatic circuit also close. With the flow switch closed and if freeze control

FS1

high pressure control

OP1

(not on

MP1

do not sense an alarm condition, safety relay R5 is energized, controller response to

For ALR-012

control thermostat SV1

opening the valve and allowing refrigerant to flow into

ALR-012A),

and compressor motor protector

applying power to the water temperature

TC1

The unit will operate automatically in

TC1.

On a call for cooling, temperature

TC1

energizes liquid line solenoid valve

HP1

oil pressure control

the evaporator. As refrigerant pressure builds up, low pressure control

LP1

closes, energizing low pressure relay

R9 which closes to energize time delay TD14. TD14 closes

to energize fan motor relay Ml 1, closing its contacts and providing power to condenser fan motor contacts Ml 1,

Ml2 and M13. On a drop in return water temperature, stage

2 of thermostat

TC1

closes, relay R21 is energized and normally open contact R21 is closed. Relay Ml is energized and normally closed Ml AUX contacts are open.

Compressor contactor Ml is closed and the compressor is running at slow speed. On a rise in return water

temperature, stage 2 of thermostat

TC1

opens, relay R21 is

de-energized and normally closed contact R21 is closed.

Relay

is energized and normally open contact M9 is closed. Compressor contactors M5 and M9 are closed and the compressor is running at fast speed.

For ALR-015, 020, 025, 030

temperature control thermostat solenoid valve

SV1

opening the valve and allowing

On a call for cooling,

TC1

energizes liquid line

refrigerant to flow into the evaporator. As refrigerant pressure builds up, low pressure control LPI closes,

energizing low pressure relay R9 which closes to energize

and also

compressor contactor M 1, starting the compressor. Closing relay R9 contacts also energizes condenser fan relay Ml 1, closing its contacts and providing power to condenser fan motor contactors Ml 1, Ml2 and M13. On a drop in return water temperature,

stage 2 of thermostat

TC1

closes.

Unloader U1 is then energized and the compressor unloads. On a rise in return-water temperature, stage 2 of thermostat

TC1

opens. Unloader U1 is de-energized and the

compressor is loaded.

PUMPDOWN CYCLE

As temperature control thermostat

its contacts, de-energizing liquid line solenoid valve

TC1

is satisfied, it opens

SV1 causing the valve to close. When the compressor has pumped most of the refrigerant from the evaporator to the condenser, the low pressure control LPI opens, shutting down the compressor and condenser fan motors.

Should a closed solenoid valve allow refrigerant to leak to the low side of the refrigerant circuit during unit “off” time, the build-up in pressure will cause the low pressure control to close, energizing the low pressure relay and starting the compressor for pumpdown.

MAJOR COMPONENT LOCATIONS ALR-012A-S, 015A-S, 020A-S, 025A-S

REAR VIEW OF UNIT

COIL ON OPPOSITE SIDE

NOTE

CONDENSER FAN 11 IS LOCATION OF OPTIONAL

SPEEDTROL MOTOR.

030A-S

PAGE 12

MODEL

NUMBER SIZE ALR-012A-S 12 Ton ALR-015A-S ALR-OPOA-S 25 ALR-025A-S 30 ALR-030A-S 35HP

COMPRESSOR

HP 3/4 3/4 3/4 HP HP 3/4

MAJOR COMPONENTS

FAN HP

3/4

3/4 3/4 3/4

3/4

3/4 3/4

13 DIA. xLENGTH

3/4

3/4 8”x 3/4

COOLER SIZE

6”x 48” 6”x60”

60” 8”x60” 8”x72”

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CONTROLS

OIL PRESSURE SAFETY CONTROL

ALR-015A, 020A, 025A, 030A (NOT ALR-012A)

The oil pressure safety control is a manually resettable device which senses the differential between oil pressure at the discharge of the compressor oil pump and suction pressure inside the compressor crankcase. When the oil pressure reaches approximately 15 PSI above the crankcase suction pressure, the pressure actuated contact of the control opens from its normally closed position. If this pressure differential cannot be developed, the contact will remain closed and energize a heater element within the control. The heater element warms a normally closed bimetallic contact and causes the contact to open, de-energizing a safety relay and breaking power to the compressor.

It takes about 120 seconds to warm the heater element enough to open the bimetallic contact, thus allowing time for the pressure differential to develop.

If during operation the differential drops below the heater element will be energized and the compressor will stop. The control can be reset by pushing the reset button on the control. If the compressor does not restart, allow a few minutes for the heater element and bimetallic

PSI,

contacts to cool and reset the control again.

To check the control, pump down and shut off all power to the unit. Remove the compressor relay wiring at terminals 2 and 8, jumper across terminals L and M of the freeze control and install a voltmeter between terminals L and M of the oil pressure control. Turn on power to the unit control circuit (separate disconnect or main unit disconnect, depending on the type of installation). Check to see that the emergency stop switch

is in the “on”

position. The control circuit should now be energized, but with the absence of the compressor running no oil pressure differential can develop and thus the pressure actuated contacts of the control will energize the heater element and open the bimetallic contacts of the control within 120 seconds. When this happens the safety relay is de-energized, the voltmeter reading will rise to 115V and the compressor contactor should open. Repeated operations of the control will cause a slight heat build-up in the bimetallic contacts

resulting in a slightly longer time for reset with each successive operation.

LINE (SEE NOTE 1)

CONTACT

LINE (SEE NOTE

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

to run.

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

T2 120

L M

BIMETALLIC CONTACTS

HEATER ELEMENT

SAFETYRELAY

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

SOLID STATE COMPRESSOR MOTOR PROTECTION

If the compressor has been operating and has been

All air cooled water chillers have compressors with solid state motor protection. Both Robertshaw and Texas

Instruments systems are used and their components are not interchangeable.

There are two major components in a protection

system. First, the protector sensors are mounted internally

in the motor windings. The sensors monitor winding temperature. A change in temperature causes a change in sensor resistance. Sensor resistance is monitored by the second component of the system

the control module

which is a sealed enclosure containing a relay, transformer

and other electronic components. Leads from the sensors

are connected to the module. Sensor resistance triggers the

control module relay at definite opening and closing

settings.

The module voltage will always be 120V and will be so marked. When the control module needs repair no attempt should be made to repair it. It should be returned intact for

replacement. If the module is opened or physically

damaged the warranty is void.

The control module and solid state sensor can be damaged by high voltage. A high potential test should never

be made to the module or sensors.

If the compressor motor is not operating properly the following procedure may be used to check the solid state motor control circuit.

PAGE 18

stopped by the motor protector, allow one hour for the compressor to cool and the motor protector to reset.

2. If reset does not occur connect a jumper wire across the motor protector from terminal 30 to 36. If the

compressor does not operate with the jumper installed

the problem is not within the solid state protector

system. If the compressor operates with the jumper

installed and does not operate without the jumper the

control circuit relay in the module is open for some

reason. CAUTION: Only check compressor operation with

jumper installed. Do not continue operation.

A possible cause of the open relay is the motor sensors.

They may be checked by first removing the connections to the terminal board. Use an ohmmeter of 3 volt maximum voltage to check resistance from each sensor terminal to the common terminal. No voltage or current should be applied

to the sensors to check continuity. The resistance across

each motor sensor should be approximately 500 to 2400

ohms with a motor temperature below

Instruments system. For the Robertshaw protector the

resistance across each sensor should be 75 ohms (cold) to

125 ohms (hot). If the resistance is zero there is a short.

the resistance is infinity there is an open connection.

NEUTRAL

140°F

for the Texas

Page 19

On reset the resistance of the sensors must be below the

reset point before the relay contacts will close. The reset resistances are 90 ohms for Robertshaw and 2700 to 4500 ohms with Texas Instruments.

If the sensor resistance has been checked and found to be satisfactory and the compressor will run with the control bypassed 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 the module will prevent compressor operation. As an emergency means of obtaining compressor operation until the compressor can be replaced, a resistor may be added between the terminal of the open sensor and the common terminal in the terminal box. The control module then “sees” an acceptable resistance and compressor operation will be restored. The emergency resistor should be as follows:

Robertshaw

Texas Instruments - 1 watt, 2200 ohm

The emergency resistor will not provide the same degree of protection, but it provides a reasonable measure of safety.

The high pressure control is a single pole pressure activated switch that opens on a pressure rise to de-energize the entire control circuit except for compressor crankcase heater and the cooler heater. It senses condenser pressure and is factory set to open at 380 reset closed at 315 PSIG. To check the control block off

condenser surface and observe the cut-out point of the

2 watt, 82 ohm

15%

resistor.

ItlO%

resistor.

HIGH PRESSURE CONTROL

PSIG and can be manually

SENSOR CIRCUIT

r----

L-I- L-J

i/r---t”-

I---

r--l

SENSORS

SOLID STATE MODULE

I-J

control by watching 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 that the control stop switch

hand in case the high pressure control should malfunction.

be close at

LOW PRESSURE CONTROL

The low pressure control is a single pole pressure switch that closes on a pressure rise. It senses evaporator pressure and is factory set to close at 60 PSIG and automatically open at 35 PSIG. To check the control (unit must be running), move the pumpdown” position.As the compressor pumps down

condenser pressure will rise and evaporator pressure will

The thermostats supplied on all packaged chillers are factory calibrated for use in the return water line to the cooler inlet. The thermostat bulb is installed in a well in the return water line in order to be more stable under temperature changes due to load conditions. The return water does not change temperature as rapidly as the outlet because of the “flywheel effect” of the total water system. This results in stable control of the outlet water temperature. Normally the thermostat requires no adjustment in the field other than the dial setting for the

required control point. The control is preset at the factory to maintain a 44F average leaving water temperature throughout the loading and unloading sequence of the unit, based on a full load cooling range of

realized, however, that there will be a fluctuation in the

leaving water temperature as the unit cycles, unloads and

loads. The thermostat will provide satisfactory control over a chilled water range of 8 special controls will be required to provide best system

performance.

On a two-stage thermostat, the dial setting indicates the These settings may be checked by operating the unit average leaving water temperature that the control will and slowly reducing the load. The four-stage thermostat has maintain. At a 44F setting, the high stage should open at a fixed switch differential and fixed differential between approximately 51 F return water. The low stage will open at switches. DO NOT make any adjustments other than the 46F return. As the water warms up, the low stage should dial as this is a preset precision control.

pumpdown

- 12’F.

switch PSI to the “manual

THERMOSTAT

10F.

It should be

Beyond these extremes

drop. The lowest evaporator pressure reached before cut-out is the cut-out setting of the control. By moving the pumpdown evaporator pressure will rise. The highest evaporator pressure reached before compressor restart is the cut-in setting of the control.

cut in at approximately 49F which is the inlet and outlet temperature with the unit off; the high stage should close at 54F return.

These settings may be checked by operaing the unit and slowly regulating the load from full to minimum and return. It may then be necessary to adjust the dial and/or differential between switches to obtain these values.

is slow; consequently, approximately 5 minutes must be allowed for bulb response (after attaining system steady-state operation) before any or each adjustment to thermostat is made.

the cut-in point of the first stage. With the dial set at

46-1/2’F,

second stage at fourth stage at stage will open at a return water temperature of the third stage at the unit will shut off at

switch PSI to the “auto. pumpdown” position,

CAUTION: Response time on the two-stage thermostat

On the four-stage thermostat the dial setting indicates

the first stage will actuate at

49’F,

the third stage at

54’F.

On a temperature drop the fourth

49’F,

the second stage at

44’F

return water.

46-1/2’F,

51-1/2’F

46-1/2’F

the

and the

51-1/2’F,

and

PAGE 19

Page 20

FREEZE CONTROL

The freeze control is very similar to the oil pressure control in operation except that it senses evaporator pressure only

rather than a pressure differential. It contains a pressure activated contact that upon a fall in evaporator pressure energizes a heater element that in turn opens a normally closed bimetallic contact. When the bimetallic contact opens, it de-energizes the entire control circuit except for the compressor crankcase heaters and cooler heater. The control is factory set to close at 52 PSIG and open at 54 to

PSI to the pressure will zero, the pressure activated contacts of the control will

have closed. Note the evaporator pressure at which this

happens. Because the unit will have pumped down before the 60 second delay period, bimetallic contacts L and M will not open before the unit shuts down. This part of the control operation may be checked after the pumpdown

cycle is complete by connecting a jumper from terminal 13

“manual pumpdown” position. Evaporator begin

to drop. When the voltmeter goes to

57 PSIG. It takes approximately 60 seconds to warm the in the control center to terminal T2 of the control. This heater element enough to open the bimetallic contact. This

will energize the heater element of the control provided

time delay period prevents nuisance cut-outs due to a that evaporator pressure is sufficiently low. Within about

momentary drop in suction pressure, but since the control 60 seconds, the bimetallic contacts of the control should senses pressure rather than temperature it still provides quicker response for protection than a temperature sensing

open.

Should the control cause the unit to shut down during

control. normal operation, a period of about 2 minutes will be

To check the control, the system must be operating. A required before the bimetallic contacts of the control will

voltmeter should be connected across terminals of the have cooled enough to allow the control to be manually

pressure activated contact. With the unit running, there

reset. Similar to the oil pressure safety control, repeated

should be a 115 volt potential across these terminals. successive operations of the freeze control will prolong the

Observing evaporator pressure, move the pumpdown switch

LINE (SEE NOTE

LINE

(SEE NOTE 2)

PRESSURE ACTUATED CONTACT

L M

time required before reset.

120

HEATER ELEMENT

BIMETALLIC CDNTACT

NEUTRAL

LINE (SEE NOTE

NOTES: 1. Hot whenever unit compressor is running.

2. Hot whenever control circuit flow switch and control stop switch

(S1)

3. Provides power to energize compressor contactors through low pressure relay

are closed.

(R9).

FANTROL - HEAD PRESSURE CONTROL

FANTROL is a system for progressively turning on or off condenser fans when they are no longer required. This is done to reduce condenser capacity (typically in low outdoor ambient temperatures) and is accomplished by a combination of pressure and temperature actuated controls. The first fan (No. 11) is started by its contactor when the compressor in the unit starts. The second fan (No. 12) is controlled by a pressure switch which senses condenser pressure.

The third fan (No. 13) is controlled by a temperature switch which senses condenser air inlet temperature. Pressure and temperature control set points are indicated below.

CONDENSER

FAN NUMBER

11 12 270 PSIG 170 PSIG 13

CUT-IN

WITH COMPRESSOR WITH COMPRESSOR

8OF

CUT-OUT

70F

To check the cut-in points of the controls, the unit must initially be off. With the unit prepared for start-up according to the procedures outlined in this bulletin, move pumpdown switch PSI to the “auto. pumpdown” position.

Evaporator pressura will begin to rise and the compressor should start with Fan 11 starting immediately. After the compressor starts, observe condenser pressure as it rises.

When the condenser pressure reaches approximately 270

PSIG, contactor Ml2 should pull in to start Fan 12. Fan 13 should start via contactor Ml3 whenever the ambient air at the condenser inlet reaches 80F.

It may be difficult to check the cut-out point of Fan 13 at the instant it happens, but it should be off whenever the ambient air at the condenser inlet is below 70F. To check the cut-out point of Fan 12, some means of reducing the

load on the unit must be available or the fan operation and

condenser pressure must be observed as the load drops off

naturally. When the condenser pressure drops to approximately 170 PSIG, contactor Ml2 should drop out to turn off Fan 12.

PAGE 20

Page 21

OPTIONAL CONTROLS

SPEEDTROL (OPTIONAL)

McQUAY’s backside of the control center, continuously varies No. 11

condenser fan motor speed on air cooled condensers by

sensing changes in refrigerant head pressure. SPEEDTROL makes possible unit operation temperatures.

With an increase

SPEEDTROL increases fan motor speed. With a decrease in

pressure fan motor speed is decreased.

The pressure connection of the transducer is made to the high pressure side of the refrigeration system at the purge valve connection on the condenser coil header. This transducer coupled with a solid state unit modulates the

solid state SPEEDTROL, located on the

in lower ambient

in refrigerant head pressure

PART WINDING START (OPTIONAL)

Part winding start consists of a solid state time delay wired in series with the contactor that energizes the second winding of each compressor motor. Its purpose is to limit current in-rush to the compressors upon start-up. As each

compressor starts, the contactor for the first motor winding

LINE

PART WINDING

phase conduction angle of the AC sine wave supplied to the fan motor. The fan motor is a special SPEEDTROL motor. For 460 volt units a transformer is supplied to decrease line voltage to 230 volt motor voltage. The SPEEDTROL controller is calibrated to deliver 90% of line voltage at the effective throttling range of 60 PSIG which is the decrease in pressure below the calibration supply voltage is transmitted to the motor. When 45% of supply voltage is transmitted to the motor, minimum motor speed is reached; below this point there is no change in

speed.

is energized instantly, while that for the second motor

winding is delayed for one second.

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

setpoint

pressure of 230 PSIG. It has an

setpoint

208/230V

where 45% of

LOW AMBIENT START (OPTIONAL)

Low ambient start is available on all units as an option with

FANTROL and included automatically with optional SPEEDTROL. It consists of a solid state normally closed time delay wired in series with a relay. These are both wired

in parallel to the liquid line solenoid valve so that when the solenoid valve is energized by the unit thermostat, the low ambient start relay is also energized through the time delay. The relay has contacts that essentially short circuit the low

pressure control and allow the compressor to start with the

low pressure control open.

After about de-energize the relay. If the system has not built up enough evaporator pressure to close the low pressure control, the compressor original normally closed position by moving the switch PSI to the “manual pumpdown” position. Moving

2-3/4

minutes, the time delay will open and

will stop. The time delay can be reset to its

pumpdown

(2nd MOTOR WINDING)

the

pumpdown

position will again energize the relay for another attempt at start-up. pressure, the compressor will continue to run.

To check the control, turn off all power to the unit and

remove the wire leading to the low pressure control LPI

from terminal 11 in the unit control center. Remove the wires leading from the contactors to the compressor and jumper across terminals L and M of the freeze control and

oil pressure safety control. Energize the control circuit by

turning on the control circuit disconnect or main power

disconnect (depending on the installation) and the control

stop switch

instantly. After about

again.

switch back to the “auto. pumpdown”

If the system has built up enough evaporator

The compressor confactors should pull in

2-3/4

minutes they should drop out

NOTE:

Line is only hot when the unit thermostat calls for

compressor to run.

PAGE 21

Page 22

COMPRESSOR LOCKOUT (OPTIONAL)

Compressor lockout consists of a solid state time delay pumpdown” wired in series with the compressor purpose is to prevent rapid compressor cycling when cooling demands are erratic.

contactor(s)

its

has stopped running, move the the “auto. pumpdown” position. The compressor should not restart for five minutes.

When the unit thermostat no longer calls for cooling

and the compressor

contactor(s)

have opened, the lockout time delay breaks open the circuit preventing compressor restart.

The circuit remains open for a period of five minutes so that if the unit thermostat should call for cooling before the delay period has expired, the compressor will not restart. After five minutes the time delay will close its contacts to complete the circuit and be ready for start-up. The time delay opens its contacts whenever there is power to the terminals of the compressor relay and resets closed automatically after the time delay period.

To check the control, the compressor must be running initially. Move the

In most cases, the customer will want to locate the alarm

bell where it will be heard in the event of a safety failure. After mounting the bell should be wired to the transformer T4.

pumpdown

switch PSI to the “manual

ALARM BELL (OPTIONAL)

When the bell is wired into the control circuit, it will

sound whenever there is a failure due to low oil pressure

(not on

ALR-012A),

condition, or excessive condenser pressure.

HOT GAS BYPASS (OPTIONAL)

Hot gas bypass is a system for maintaining evaporator pressure at or above a minimum value. The purpose for

doing this is to keep the velocity of the refrigerant as it

passes through the evaporator high enough for proper oil return to the compressor when cooling load conditions are light.

The system consists of a solenoid valve piped in series with a pressure regulating valve as shown above. The solenoid valve is factory wired to open whenever the unit thermostat calls for the first stage of cooling. The pressure regulating valve is factory set to begin opening at 58 PSIG

(32F

for R-22) when the air charged bulb is in an 80F ambient temperature. Since the bulb is factory mounted on the suction line and suction line temperatures are usually in the 50F to 60F range, the chart above indicates that for ALR chillers the valve is factory set to begin opening at 54 to 56 PSIG. This setting can be changed as indicated above

by changing the pressure of the air charge in the adjustable bulb. To raise the pressure setting, remove the cap on the bulb and turn the adjustment screw clockwise. To lower the setting, turn the screw counter-clockwise. Do not force the adjustment beyond the range it is designed for as this will damage the adjustment assembly.

The regulating valve opening point can be determined by slowly reducing the system load (or increasing the required chilled water temperature setting indicated on the unit thermostat) while observing the suction pressure. When the bypass valve starts to open, the refrigerant line on the evaporator side of the valve will begin to feel warm to the touch.

CAUTION: cause injury in a very short time so care should be taken during valve checkout.

position. Immediately after the compressor

pumpdown

1’

COMP.

TIME DELAY

TO UNIT THERMOSTAT

switch back to

LOCKOUl

motor overload, and evaporator freeze

The hot gas line may become hot enough to

HOT GAS BYPASS PIPING DIAGRAM

Hot Gas Bypass Solenoid Valve

Discharge Line

PAGE 22

.&lot

Gas

Bypass Valve

I~- Suction Line

Remote Bulb

k-To

Evaporator Inlet After Expansion Valve

HOT GAS BYPASS ADJUSTMENT RANGE

REMOTE

BULB ADJUSTMENT RANGE

311

30 40

TEMP IOFI

AT BULB LOCATION

80 90

100

110

:’

I L_

:; 5<

Page 23

UNIT MAINTENANCE

GENERAL

CAUTION: Disconnect all power before doing any service inside the unit.

On initial start-up and periodically during operation after ordered with gauges, condensing, suction and oil pressures

installation, it will be necessary to perform certain routine service checks. Among these are checking the compressor oil level and taking condensing, suction and oil pressure

readings. During operation the oil level should be visible in the oil sightglass with the compressor running. On units taken.

REFRIGERANT SIGHTGLASS

The refrigerant sightglass should be observed periodically.

monthly observation should be adequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the unit to insure proper feed through the expansion valve. Bubbling refrigerant in the sightglass indicates that the unit is short of refrigerant charge. An element inside the

FILTER-DRIERS

To change the filter-drier core, pump the unit down by moving pumpdown switch PSI to the “man. pumpdown” position. Turn off all power to the unit and install a jumper the filter-drier. Remove the cover plate from the filter-drier from terminal 31 to 34. Turn power to the unit back on and restart the unit by moving pumpdown switch PSI to the “auto. pumpdown” position. Close the manual liquid check around the flange of the filter-drier shell is line shut-off valve and when evaporator pressure reaches 0 PSIG, move the control stop switch

to the “off”

can be read from the gauges. Oil pressure gauge is not available on unit ALR-012A. The gauges are installed with a manual shut-off valve on each gauge line. The valves should

be closed at all times except when gauge readings are being

sightglass is sensitive to moisture and a color key on the face of the sightglass indicates what moisture condition corresponds to a given element color. If the sightglass does not indicate a dry condition after a few hours of operation, the unit should be pumped down and the cores in the filter-driers changed.

position. This will close the liquid line solenoid valve and

isolate the short section of refrigeration piping containing

shell and replace the core.

After core replacement, replace the cover plate. A leak

recommended after the core has been changed.

LlQUID

The liquid line solenoid valve, which is responsible for automatic

not normally require any maintenance. It may, however, require replacement of the solenoid coil or of the entire

valve assembly.

without opening the refrigerant piping by moving

pumpdown

Condensers are air cooled and constructed with copper tubes bonded in a staggered pattern into rippled aluminum fins. No maintenance is ordinarily required except the occasional removal of dirt and debris from the

The oil level should be watched carefully upon initial start-up and for sometime thereafter. At the present time, Suniso 3GS oil is the only oil approved by Copeland and Sundstrand for use in these compressors. The oil level

Oil may be added to the Copeland compressor through the oil fill hole in the crankcase and to the Sundstrand compressor through the of the compressor. To add oil isolate the crankcase and

pour or pump the necessary oil in. If the system contains no refrigerant, no special precautions are necessary other

than keeping the oil clean and dry.

suction valve and reduce crankcase pressure to 1 to 2 PSIG.

pumpdown

The solenoid coil may be removed from the valve body

switch PSI to the “manual pumpdown”

If the system contains a refrigerant charge, close the

during normal unit operation, does

3/8-inch

process tube on the side

LINE SOLENOID VALVE

CONDENSERS

3/8

O.D.

COMPRESSOR

ADDING OIL TO COMPRESSOR

position. The coil can then be removed from the valve body by simply removing a nut or snap ring located at the top of the coil. The coil can then be slipped off its mounting stud for replacement. Be sure to replace the coil on its mounting stud before returning pumpdown switch PSI to the “auto. pumpdown” position.

To replace the entire solenoid valve, the unit must be

pumped down by use of the manual liquid line valve.

outside surface of the fins. Care should be taken not to damage the fins during cleaning. Periodic use of the purge valve on the condenser will prevent the build-up of non-condensables.

OI L LEVEL

should be maintained at about the midpoint of the sightglass on the compressor body. The use of a light may

be required for proper oil level reading.

Stop the compressor and close the discharge valve.

Add the required amount of oil. During the period the compressor is exposed to the atmosphere the refrigerant will generate a vapor pressure, retarding the entrance of contaminants. Before resealing the compressor, purge the crankcase by opening the suction valve slightly for one or two seconds. Next, close the oil port, open the compressor valves and restore the system to operation.

PAGE 23

Page 24

ELECTRICAL TERMINALS

CAUTION: ELECTRIC SHOCK HAZARD

TURN OFF ALL POWER BEFORE CONTINUING WITH

FOLLOWING SERVICE.

All power electrical terminals should be retightened every six months, as they tend to loosen in service

due 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 proper amount of refrigerant to enter the evaporator regardless of cooling load. It does this by maintaining a constant superheat. (Superheat is the difference between refrigerant temperature as it leaves the evaporator and the saturation temperature corresponding to the evaporator pressure.) All

ALR chillers are factory set for between 8F and 12F superheat. If it is necessary to increase the superheat setting of the valve, remove the cap at the bottom of the valve to expose the adjustment screw. Turn the screw clockwise

(when viewed from the adjustment screw end) to increase

the superheat setting and counter-clockwise to reduce superheat. Allow time for system rebalance after each superheat adjustment.

The expansion valve, like the solenoid valve, should not

normally require replacement, but if it does, the unit must

be pumped down by using the manual liquid line shut-off valve. If the problem can be traced to the power element only, it can be unscrewed from the valve body without

removing the valve, but only after pumping the unit down with the manual liquid line shut-off valve.

INLET

?v/AP7K

-A-----

POWER ELEMENT

(CONTAINS DIAPHRAGM)

t OUTLET

ADJUSTMENT SCREW

HYDRAULIC FILL BETWEEN

DIAPHRAMS

PAGE 24

Page 25

EVAPORATOR

The evaporator is of the direct expansion, shell-and-tube type with refrigerant flowing through the tubes and water flowing through the shell over the tubes. The tubes are

internally finned to provide extended surface as well as

turbulent flow of refrigerant through the tubes. Normally

no service work is required on the evaporator. In the rare case of freeze-up, a tube may leak refrigerant into the water side of the system. In the cases where only one or two tubes leak, the problem can best be solved by plugging the tube at both ends. When the tube must be replaced, the old tube can be removed and replaced.

To remove a tube, the unit should be temporarily

pumped down by moving

pumpdown

switch PSI to the

“man. pumpdown” position. Power to the unit should be shut off to install a jumper from terminal 31 to 34. Turn power to the unit back on. Pump down the refrigerant circuit until evaporator pressure is at or near 0 PSIG by closing the manual liquid line shut-off valve at the outlet of the condenser. Close the compressor suction valve by turning the valve stem clockwise. These steps will insure a minimum amount of refrigerant loss when the

evaporator is opened up. The tubes are mechanically expanded into the tube sheets (see sketch above) at each end of the cooler. In

TOP VIEW OF TYPICAL SHELL-AND-TUBE EVAPORATOR

order to remove the tubes it is necessary to break this bond by collapsing the tube. After doing this at both ends of the shell, the tube can be removed for replacement. The new tube can then be inserted and re-expanded into the tube sheet.

NOTE: The bond produced by expansion must be

refrigerant tight. This bond must be produced by rolling the

tube into the tube sheet.

After re-assembling the evaporator, a small amount of

refrigerant should be introduced by momentarily opening

the manual liquid line valve. A leak check should then be

performed on the evaporator.

Tube removal can only take place after the leaking tube is located. This aspect depends on the ingenuity of the serviceman. One method that would work would be to

subject each tube to air pressure by plugging each end, and with a pressure gauge attached to one of the end plugs,

observe to see if there is a loss of air pressure over a period of a minute or two.

NOTE: The evaporator should always be supplied with clean water to minimize scale build-up on the refrigerant tubes.

LIQUID CONNECTION

SUCTION CONNECTION

REFRIGERANT TUBES

WATER BAFFLES

WATER NOZZLES

TUBE SHEETS

PAGE 25

Page 26

IN-WARRANTY RETURN MATERIAL PROCEDURE

COMPRESSOR

Bristol Corporation [compressor used in the Copeland Corporation [all other units] have stocking wholesalers who maintain a stock of replacement compressors and service parts to service refrigeration contractors and servicemen,

When a compressor fails in warranty, contact your local

sales representative or McQuay Warranty Claims Depart-

ment at the address on the cover of this bulletin. You will be authorized to exchange the defective compressor locally

(an advance replacement can be obtained), or we will ship you a replacement from our stock. A salvage credit is issued to you by the wholesaler on the returned compressor after

Material may not be returned except by permission of authorized factory service personnel of McQUAY Inc. at

Minneapolis, Minnesota. A “Return Goods” tag will be sent to be included with the returned material. Enter the

information as called for on the tag in order to expedite

handling 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 nearest McQUAY Representative. The order

ALR-012],

COMPONENTS OTHER THAN COMPRESSORS

and

Bristol or Copeland factory inspection of the inoperative compressor. Provide McQuay with full details and invoices and we will reimburse the difference. In this transaction, be certain that the compressor is definitely defective. If a compressor is received from the field that tests satisfactorily, a service charge plus a transportation charge will be charged against the original credit value.

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

should include part name, part number, model number and serial number of the unit involved.

Following our personal inspection of the returned part,

and if it is determined that the failure is due to faulty

material or workmanship, credit will be issued on

customer’s purchase order.

All parts shall be returned to the pre-designated

McQUAY factory, transportation charges prepaid.

PAGE 26

Page 27

TROUBLE SHOOTING CHART

PROBLEM

Compressor will not run.

Compressor noisy

vibrating.

High Discharge Pressure

Low Discharge Pressure.

High Suction Pressure

Suction

Low

Pressure

Compressor not unload or load up.

Compressor

Loading -

Intervals too short

Little

oil pressure.

Compressor

loses

Motor overload relays open or

fuses blown.

Compressor thermal Protector Switch open.

Freeze protection opens.

Unloading

or no

oil.

POSSIBLE CAUSES

Main switch

2. Fuse blown.

3. Thermal overloads

Defective

5. System shut down by safety devices.

6. No

7. Liquid line solenoid

8. Motor electrical trouble.

9. Loose wring

1. Flooding of refrigerant into crankcase.

2. Worn compressor.

1. Dirty tube and fin surface.

Non-condensables

3. System overcharged

4. Discharge shut off valve partially closed.

1. Faulty condenser temperature regulation. Suction shutoff

Insufficient

4. Low suction pressure.

5. Compressor operating unloaded.

6. Low

1. Excessive load.

2. Expansion valve

3. Compressor unloaders open.

1. Lack of

2. Evaporator

3. Clogged liquid line filter-drw.

4. Clogged gas strainers.

5. Expansion valve

6. condensing temperature too low.

7. Compressor will not unload.

8. Insufficient water flow.

1. Defective capacity control.

2. Unloader mechanism defectwe.

3. Faulty thermostat stage or broken capillary tube.

4. Stages not set for

1. Erratic water thermostat.

InsufficIent water

1. Clogged

2. Excessive liquid in crankcase.

Oil

4. Low

5. Worn

Oil position

7. Worn bearings.

8. Low oil level.

9. Loose

10. Pump housing gasket leaks.

11.

Flooding

Lack

2. Excessive

1. Low voltage during high load

Defective

power

3. Loose power

4. High condensing temperature.

5. Power line fault causing unbalanced voltage.

6. High ambient temperature around the overload relay.

7. Failure of second starter to pull in on winding start systems.

1. Operating beyond design conditions.

2. Discharge valve partially shut.

3. Blown valve plate gasket.

1. Thermostat sat too low.

2. Low water flow.

3. Low

open.

tripped

or fuses blown.

contactor or coil.

cooling

required.

refrigerant in system.

ambient

refrigerant.

suction line

suction oil strainer.

pressure gauge defectwe.

oil

pressure safety switch defectwe.

oil

pump.

pump

reversing

fitting

of refrigerant into crankcase.

of refrigerant.

compression

or grounded wiring in motor or

circuits.

suction pressure.

will

not open.

in system.

with

refrigerant.

valve partially closed.

controls not set properly.

overfeedlng.

dirty.

or compressor suction

malfunctioning.

application.

flow.

gear stuck in wrong

on oil lines.

ring blow-by.

conditions.

wiring.

part-

POSSIBLE CORRECTIVE STEPS

1. Close switch.

2. Check electrical circuits and motor winding for shorts or grounds. Investigate for possible overloading. Replace fuse after fault is corrected.

3. Overloads are auto. reset. Check unit closely when unit comes back on line.

4. Repair or replace.

5. Determine type and cause of shutdown and correct it. before resetting safety switch.

6. None. Wait until unit calls for cooling.

7. Repair or replace coil.

8. Check motor for opens. short circuit or burn-out.

9. Check all wire junctions. Tighten all terminal screws.

1 Check setting of expansion valve.

2. Replace.

1. Clean.

2. Purge the

3. Remove excess.

4. Open valve.

1. Check condenser control operation.

2. Open valve.

3. Check for leaks. Repair and add charge.

4. See

5. See below for Corrective Steps for failure of compressor to load up.

6. Reset controls.

Reduce load or add

2. Check remote bulb. Regulate superheat.

3 See Corrective Steps below for failure of compressor

to load up.

Check for leaks. Repair and add charge.

2. Clean chemically.

3. Replace cartridge(s).

4. Clean

5. Check and reset for proper superheat. Replace if necessary.

6. Check means for regulating condensing temperature.

7. See Corrective Steps for

8. Adjust gpm.

1. Replace.

2. Replace.

3. Replace.

4. Reset thermostat setting to fit application.

1. Replace.

2. Adjust gpm.

Clean.

Check

superheat. Check liquid line solenoid valve operation.

3. Repair or replace. Keep valve closed except when taking readings.

4. Replace.

5. Replace.

6. Reverse

7. Replace compressor.

8. Add oil.

9. Check and tighten system.

10. Replace gasket.

11. Adjust thermal expansion valve.

1. Check for leaks and repair. Add refrigerant.

2. Replace compressor.

1. Check supply voltage for excessive line drop.

2. Replace compressor-motor.

3. Check all connections and tighten.

4. See Correctwe Steps for high discharge pressure.

5. Check supply voltage. Notify power company. Do not

Provide

7. Repair or replace starter or time

1. Add facilities so that conditions are within allowable limits.

2. Open valve.

3. Replace gasket.

Reset to 400F or above.

2. Adjust gpm.

3. See “Low

non-condensables.

below for

Corrective Steps for low suction pressure.

additional

strainers

crankcase heater. Reset expansion valve for higher

direction

of compressor rotation.

start until fault is corrected.

ventilation to reduce heat.

suction

pressure”.

equipment.

failure of

compressor to unload.

delay

mechanism.

PAGE 27