packaged air-cooled water chiller -...

Installation, Operation and Maintenance Manual IOMM ALR2

Group: Chiller

Part Number: 629951

Effective: June 1999

Supersedes: IM 688

© 1997 McQuay International

Packaged Air-Cooled Water Chiller

Models ALR 020E Through ALR 030E60 Hertz

2 ALR 020E through 030E IOMM ALR2

Table of Contents

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

General Description................................................3Inspection................................................................3Installation...............................................................3Handling ..................................................................3Location...................................................................4Service Access........................................................5Vibration Isolators ..................................................6Water Piping............................................................6Flow Switch.............................................................8Water Connections ................................................9Refrigerant Charge .................................................9Glycol Solutions .....................................................9Evaporator Water Flow and Pressure Drop........9

Unit Layout and Operation............... 11

Control Center.......................................................11

Start-up and Shutdown...................... 11

Pre Start-up............................................................11Start-up ..................................................................11Sequence of Operation........................................12

Physical Data .................................... 13

Electrical Data ..................................14

Field Wiring...........................................................14

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

System Maintenance ........................18

General...................................................................18Fan Motor Bearings.............................................18Electrical Terminals ...............................................18Condensers ...........................................................18Refrigerant Sightglass .........................................19

Service ...............................................19

Thermostatic Expansion Valve ...........................19Filter-Driers............................................................19Liquid Line Solenoid ............................................20Standard Controls ................................................20Compressor Lockout............................................22Optional Controls .................................................23Control Settings....................................................26Troubleshooting Chart ........................................27

"McQuay" is a registered trademark of McQuay International1997 McQuay International

"Illustrations cover the general appearance of McQuay International products at the time of publication and we reserve the right to make changes indesign and construction at anytime without notice"

IOMM ALR2 ALR 020E through 030E 3

Introduction

General DescriptionMcQuay air-cooled water chillers are complete, self-contained automatic refrigerating units. Everyunit is completely assembled, factory wired, charged, and tested. Each unit consists of two air-cooledcondensers connected in parallel with integral subcooler sections, Copeland DISCUS semi-hermeticcompressor, single circuit brazed plate-to-plate evaporator, and complete refrigerant piping. Liquidline components include manual liquid line shutoff valve, sight-glass/moisture indicator, solenoidvalve, and double diaphragm hydraulic element thermal expansion valve. Other features include acompressor crankcase heater, an evaporator heater for chilled water freeze protection, and a hot gasmuffler.

The electrical control center includes all safety and operating controls necessary for dependableautomatic operation. Condenser fan motors are three phase (except single phase on No. 1 fan withFanTrol option) and started by their own contactors and have inherent overload protection. Thecompressor is not fused but has solid state motor protection for inherent thermal overload protection.

InspectionCheck all items carefully against the bill of lading. Inspect all units for damage upon arrival. Reportshipping damage and file a claim with the carrier. Check the unit name plate before unloading, makingcertain it agrees with the power supply available. Units are shipped fob factory and McQuay is notresponsible for physical damage after unit leaves the factory.

Note: Unit shipping and operating weights are listed on page 13, Table 3.

Installation

Note: Installation is to be performed by qualified personnel who are familiar with local codesand regulations especially concerning refrigerant release to the atmosphere.

WARNING

Sharp edges and coil surfaces are a potential hazard. Avoid contact with them.

HandlingBe careful to avoid rough handling of the unit. Do not push or pull the unit from anything other thanthe base. Block the pushing vehicle away from the unit to prevent damage to the sheet metal cabinetand end frame (see Figure 1).

To lift the unit, lifting slots are provided in the base of the unit. Arrange spreader bars and cables toprevent damage to the condenser coils or cabinet (see Figure 2).


Figure 1, Suggested pushing arrangement

Figure 2, Suggested lifting arrangement

Location

Unit PlacementALR units are for outdoor applications and can be mounted on a roof or ground level. Set units on asolid and level foundation. For roof mounted applications, install the unit on a steel channel or I-beamframe to support the unit above the roof. For ground level applications, install the unit on asubstantial base that will not settle. A one-piece concrete slab with footings extended below the frostline is recommended. Be sure the foundation is level (within 1/2” [13 mm] over its length and width).The foundation must support the operating weights listed in the Physical Data Table on page 13.

Unit operation is affected by wind and it should located so that length is parallel with the prevailingwind. If this is not practical, field fabricated wind deflectors should be employed.

ClearancesThe flow of air to and from the condenser coil must not be limited. Restricting airflow or allowing airrecirculation will result in a decrease in unit performance and efficiency. There must be no obstructionabove the unit that would deflect discharge air downward where it could be recirculated back to theinlet of the condenser coil. The condenser fans are propeller type and will not operate with ductworkon the fan outlet.

Blocking requiredacross full width


Install the unit with enough sideclearance for air entrance to the coil andfor servicing. Provide service access tothe evaporator, compressors, electricalcontrol panel and piping componentsas shown in Figure 3. Do not blockaccess to the unit with piping orconduit.

Do not allow debris to accumulate nearthe unit. Air movement may drawdebris into the condenser coil causingair starvation. Give specialconsideration to low ambient operationwhere snow can accumulate. Keepcondenser coils and fan discharge freeof snow or other obstructions to permitadequate airflow.

Sound IsolationThe low sound levels of the ALR chillerare suitable for most applications.When additional sound reduction isnecessary, locate the unit away fromsound sensitive areas. Avoid locationsbeneath windows or betweenstructures where normal operatingsounds may be objectionable. Reducestructurally transmitted sound byisolating water lines, electrical conduitand the unit itself. Use wall sleevesand rubber isolated piping hangers toreduce transmission of water or pumpnoise into occupied spaces. Useflexible electrical conduit to isolatesound through electrical conduit.Spring isolators are effective inreducing the low amplitude soundgenerated by the Discus semi-hermeticcompressors and for unit isolation insound sensitive areas.

Service AccessEach end of the unit must be accessibleafter installation for periodic service.Compressors, filter-driers, and manualliquid line shutoff valves are accessiblefrom the end of the unit. High pressure,low pressure, and motor protector controls are on the compressor. Most operational, safety andstarting controls are located in the unit control box.

The condenser fan and motors can be removed from the top of the unit.

Figure 3, Clearance requirements


Vibration IsolatorsVibration isolators are recommended for all roof mounted installations or wherever vibrationtransmission is a consideration. The isolators can be purchased from McQuay by the part numbersshown in the table. Install spring isolators under the main unit support according to the dimensiondrawing. Adjust springs to allow the upper housing to clear the lower housing by 1/4” to 1/2”. Ananti-skid pad should be used if hold-down bolts are not used.

Table 1, Recommended Vibration IsolatorsALR UNIT ISOLATOR

TYPEMcQUAYPART NO.

NUMBERREQUIRED

ISOLATORDESCRIPTION

MAX. LOADEACH (LBS)

020E-028E Rubber-in-shear 00-216397-01 4 RP-3 Red 525030E Rubber-in-shear 00-216397-01 2 RP-3 Red 525

00-216397-03 2 RP-3 Green 725020E-028E Spring Isolators 00-477927-26 4 CP-1-26 600

030E Spring Isolators 00-477927-26 2 CP-1-26 60000-447927-27 2 CP-1-27 750

Note: See dimension drawing for location of isolators

Water PipingLocal authorities can supply the installer with the proper building and safety codes required for safeand proper installation.

Install piping with minimum bends and changes in elevation to minimize pressure drop. Consider thefollowing when installing water piping:

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

2. Shutoff valves to isolate the unit from the piping system during unit servicing.

3. Manual or automatic air vent valves at the high points of the system. Install drains at the lowestpoints in the system.

4. A means of maintaining adequate system water pressure (expansion tank or regulating valve).

5. Temperature and pressure indicators located at the unit to aid in unit servicing. Pressure gaugetaps must be installed in the chilled water inlet and outlet piping or as shown in Figure 4.

6. A strainer or other means of removing foreign matter from the water before it enters the pump.Place the strainer far enough upstream to prevent cavitation at the pump inlet (consult pumpmanufacturer for recommendations). The use of a strainer will prolong pump life and keep systemperformance up.

7. Place a strainer in the water line just before the inlet of the evaporator. This will help preventforeign material from entering and decreasing the performance of the evaporator.

CAUTION

If separate disconnect is used for the 110V supply to the evaporator heating cable, mark thedisconnect clearly to ensure disconnect is not accidentally shut off during cold seasons.

8. The brazed plate evaporator has a thermostat and heating cable to prevent freeze-up down to -20°F (-29°C). It is suggested that the heating cable be wired to a separate 110V supply circuit. Asshipped from the factory, the heating cable is wired to the control circuit. All water piping to theunit must also be protected to prevent freezing.

9. If the unit is used as a replacement chiller on a previously existing piping system, flush thesystem thoroughly before unit installation. Regular water analysis and chemical water treatmenton the evaporator is recommended immediately at equipment start-up.


10. The total water volume in the system should be sufficient to prevent frequent “on-off” cycling.Turnover rate should not be less than 15 minutes for normal variable cooling loads. Turnoverrate for a constant load should not be less than 6 minutes.


11. When glycol is added to the water system for freeze protection, the refrigerant suction pressurewill be lower, cooling performance less, and water side pressure drop greater. If the percentage ofglycol is high, or if propylene is used instead of ethylene glycol, the added pressure drop andloss of performance could be substantial. Reset the freezestat and low leaving water alarmtemperatures. The freezestat is factory set to default at 36°F (2.2°C). Reset the freezestat settingto approximately 4 to 5 degrees F (2.3 to 2.8 degrees C) below the leaving chilled water setpointtemperature. See the section titled “Glycol Solutions” for additional information concerningglycol.

12. Perform a preliminary leak check before insulating the piping and filling the system.

13. Piping insulation should include a vapor barrier to prevent condensation and possible damage tothe building structure.

Figure 4, Typical Field Evaporator Water Piping

Note: the above piping is correct for both brazed plate and tube-in-shell evaporators

Flow SwitchMount a water flow switch in the leaving water line to shut down the unit when water flow isinterrupted.

A flow switch is available from McQuay (part number 0701804-04). It is a “paddle” type switch andadaptable to pipe sizes down to 1 1/4 ” (32mm) nominal. Certain minimum flow rates are required toclose the switch and are listed in Table 2. Installation should be as shown in Figure 5. Connect thenormally open contacts of the flow switch in the unit control center at terminals 4 and 5. There is alsoa set of normally closed contacts on the switch that can be used for an indicator light or an alarm toindicate when a “no flow” condition exists. Freeze protect any flow switch that is installed outdoors.

NOTE: Differential pressure switches are not recommended for outdoor installation.

Table 2, Flow Switch Settingsmm 32 38 51 63 76 102Pipe Sizeinch 1 1/4 1 1/2 2 2 1/2 3 4gpm 4.8 6.3 9.9 15.3 24.4 33.3FlowLpm 18.2 22.7 37.5 57.9 92.4 126.0gpm 3.0 3.6 5.9 9.5 15.4 21.1

MinimumAdjustment No

Flow Lpm 11.3 13.6 22.3 36.0 58.3 79.9gpm 7.7 10.0 15.8 23.7 35.5 61.4FlowLpm 29.1 37.9 59.8 89.7 134.4 232.4gpm 5.9 7.0 11.0 17.0 29.2 37.7

MaximumAdjustment No

Flow Lpm 22.3 26.5 41.6 64.3 110.5 142.7


Figure 5, Flow Switch Installation

Water ConnectionsBring water piping to the cooler from the end of the unit, in the top and out the bottom connection.

Refrigerant ChargeAll units are designed for use with HCFC-22 and other refrigerants. See nameplate for specificrefrigerant used. Units are shipped with an operating charge. The operating charge(using HCFC-22) for each unit is shown in the Physical Data Table on page 12.

Glycol SolutionsThe use of glycol anti-freeze solutions will decrease unit capacity, and increase the pressure dropthrough the cooler. See Product Manual 985 for specific ratings and correction factors.

CAUTION

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

Evaporator Water Flow and Pressure DropEvaporator flow rate must fall between the minimum and maximum values shown in the evaporatorpressure drop curve, Figure 6. Flow rates below the minimum values will result in laminar flow that willreduce efficiency, cause erratic operation of the expansion valve and could cause low temperaturecutouts. Flow rates exceeding the maximum values can cause erosion on the evaporator waterconnections and tubes.

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

Varying chilled water flow through the evaporator while the compressor are operating is notrecommended.


Figure 6, Evaporator Water Pressure Drop Curve


Unit Layout and Operation

Control CenterAll electrical controls are enclosed in a weatherproof control center with keylocked, hinged accessdoors. The control center has two separate compartments, high voltage and low voltage. All highvoltage components are located in the compartment on the right side of the unit.

The low voltage components are located on the left side with the live terminals behind the deadfrontpanel. This protects service personnel from live terminals when accessing the adjustable andresettable controls.

Start-up and Shutdown

Pre Start-up1. Open all electric disconnects and check all electric connections for tightness. Check all

compressor valve connections for tightness.

2. Inspect all water piping for flow direction and correct connections at the evaporator.

3. Verify thermostat water temperature sensor is installed in the leaving water line (supply tobuilding). On all ALR units the sensor well and sensor are factory mounted.

4. Check compressor oil level. The oil level should be visible in the oil sightglass.

5. Check voltage of the unit power supply and make certain voltage is within ±10% of nameplaterating. Check unit power supply wiring for proper ampacity and a minimum insulationtemperature of 75°C.

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

7. Open compressor suction and discharge shutoff valves until backseated. Always replace valveseal caps.

8. Open control stop switch S1(off). Turn on the main power and control disconnect switches. Thiswill energize crankcase heaters. Wait at least 24 hours before starting up unit.

9. Open all water flow valves and start the chilled water pump. Check all piping for leaks and ventthe air from the evaporator as well as from the system piping. Flush the evaporator and systempiping to obtain clean, noncorrosive water in the evaporator.

CAUTION

Most relays and terminals in the unit control center are energized with S1 and the controlcircuit disconnect on. Do not close S1 until start-up.

Start-up1. Verify compressor suction and discharge shutoff valves are backseated. Always replace valve

seal caps.

2. Open manual liquid line shutoff valve at the outlet of the condenser subcooler.

3. Set temperature controller CP1 to the desired chilled water temperature. Set the control band.

4. Start auxiliary equipment by turning on the following: time clock (if present), ambient thermostatand/or remote on/off switch, chilled water pump.


5. If the controller calls for cooling, the unit will begin the start-up sequence.

6. After running the unit for a short time, check the oil level in the compressor crankcase, rotation offans, and flashing in refrigerant sightglass.

7. Verify superheat temperature is at the factory setting of 8 to 12 degrees F (4.4 to 6.7 degrees C).

8. After system performance has stabilized, complete the “Compressorized Equipment WarrantyForm” (Form No. 415415Y) to obtain full warranty benefits. Return the form to McQuayInternational through your sales representative.

Sequence of OperationThe following sequence of operation is typical for Models ALR 020E through ALR 030E. Thesequence can vary depending upon options.

Start-UpWith the control circuit power on and the control stop switch S1 closed, 115V power is appliedthrough the control circuit fuse F1 to the compressor crankcase heater HTR1, the compressor motorprotections MP1 and the primary of the 24V control circuit transformer. The 24V transformer providespower to the contacts of the low pressure controls LP1 and the compressor lockout timer TD1.

When the remote time clock (optional) or manual shutdown switch turns on the chilled water pump,the flow switch closes and 115V power is applied to the relay contacts on the return water controlCP1. The unit will operate in response to TC 10 if:

1. The compressor lockout time delays are closed

2. The compressor motor protection and high pressure control (HP1) do not sense a failure.

On a call for cooling, the return water control CP1 completes the circuit to the liquid line solenoidvalve SV1 in circuit #1, opening the valve and allowing refrigerant to flow through the expansionvalve and into the evaporator. As the evaporator refrigerant pressure increases, the low pressurecontrol LP1 closes. This energizes the compressor starting relay R9, starting the compressor via thecompressor contactors M1. Closing the R9 contacts also energizes the condenser fan motor contactsM11, M12, and M13, starting the fan motors.

ShutdownAs the leaving water control is satisfied, it will unload the compressor and then de-energize the liquidline solenoid valve SV1, causing the valve to close. The compressor will stop and the compressorcrankcase heater will energize, keeping the small amount of refrigerant in the plate heat exchanger frommigrating to the compressor.


Physical Data

Table 3, Physical Data ALR 020E through 030EPHYSICAL DATA ALR MODEL NUMBER

020E 025E 028E 030E

BASIC DATA

Unit Capacity @ ARI Conditions (1), Tons (kW) 21.0 (73.8 ) 24.2 (85.1) 27.1 (95.3 ) 31.7 (111.5 )Number Of Refrigerant Circuits 1 1 1 1Unit Operating Charge, R-22, Lbs. (kg) 30 (13.6) 30 (13.6) 30 (13.6) 35 (15.9)Cabinet Dimensions, LxWxH, In. 96 x 58 x 46 96 x 58 x 46 96 x 58 x 46 96 x 58 x 46Cabinet Dimensions, LxWxH, (mm) (2426 x 1461 x

1168)(2426 x 1461 x

1168)(2426 x 1461 x

1168)(2426 x 1461 x

1168)Unit Operating Weight, Lbs. (kg) 1595 (724) 1610 (730) 1610 (730) 1720 (780)Unit Shipping Weight, Lbs. (kg) 1578 (716) 1590 (721) 1590 (721) 1698 (770)Add'l Weight If Copper Finned Coils, Lbs. (kg) 350 (159) 350 (159) 350 (159) 530 (240)COMPRESSORS

Type Semi-Hermetic Semi-Hermetic Semi-Hermetic Semi-HermeticNominal Horsepower 25 30 30 35Number Of Cylinders Per Compressor 4 4 6 6Oil Charge Per Compressor, Oz. (g) 130 (3686) 140 (3969) 140 (3969) 140 (3969)CAPACITY REDUCTION STEPS - PERCENT OF COMPRESSOR DISPLACEMENT

Standard Staging 0-50-100 0-50-100 0-67-100 0-67-100Optional Staging NA NA 0-33-67-100 0-33-67-100CONDENSERS - HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLING

Coil Face Area, Sq. Ft. (M2) 49.0 (4.6) 49.0 (4.6) 49.0 (4.6) 49.0 (4.6)Finned Height x Finned Length, In. 84 x 84 84 x 84 84 x 84 84 x 84Finned Height x Finned Length, (mm) (2134 x 2134) (2134 x 2134) (2134 x 2134) (2134 x 2134)Fins Per Inch x Rows Deep 16 x 2 16 x 2 16 x 2 16 x 3CONDENSER FANS - DIRECT DRIVE PROPELLER TYPE

Number Of Fans - Fan Diameter, In. (mm) 3 - 26 (660) 3 - 26 (660) 3 - 26 (660) 3 - 26 (660)Number Of Motors - HP (kW) 3 - 1.0 (.7) 3 - 1.0 (.7) 3 - 1.0 (.7) 3 - 1.5 (1.1)Fan And Motor RPM, 60 1100 1100 1100 110060 Hz Fan Tip Speed, FPM 7760 7760 7760 776060 Hz Total Unit Airflow, CFM 20925 20925 20925 18000DIRECT EXPANSION EVAPORATOR - BRAZED PLATE-TO-PLATE

LxWxH, In. 5.9 x 9.4 x 20.5 6.8 x 9.4 x 20.5 7.8 x 9.4 x 20.5 7.8 x 9.4 x 20.5LxWxH, (mm) (149.9 x 238.8 x

520.7)(172.7 x 238.8 x

520.7)(198.1 x 238.8 x

520.7)(198.1 x 238.8 x

520.7)Water Volume, Gallons (L) 2.0 (7.6) 2.3 (8.7) 2.7 (10.2) 2.7 (10.2)Maximum Water Pressure, psig (kPa) 430 (2966) 430 (2966) 430 (2966) 430 (2966)NOTE:Nominal capacity based on 95°F ambient air and 54°F/44°F water range.


Electrical Data

Field Wiring

CAUTION

Internal power wiring to the compressors for single and multiple point option are different.Field wiring must be installed according to unit wiring diagram.

Wiring must comply with all applicable codes and ordinances. Warranty is void if wiring is not inaccordance with specifications. Copper wire is required for all power lead terminations at the unit.Aluminum or copper can be used for all other wiring.

ALR 020E through ALR 030E units have single point power connection. A single field supplied fuseddisconnect is required. An optional factory mounted transformer may be installed.

If the evaporator heater is on a separate disconnect switch from the main unit power supply, the unitmay be shut down without defeating the freeze protection provided by the evaporator heater.

Table 4. ALR 020E - ALR 030E Electrical Data, Single PointMinimum POWER SUPPLY FIELD FUSE SIZECircuit Field Wire Hub

Ampacity Wire Nominal Max.

ALRUnitSize

Volts

(MCA)Quantity

GaugeQuantity

Size

Recom-mended

208 105 3 2 1 1.25 (32) 150 175230 105 3 2 1 1.25 (32) 150 175460 52 3 6 1 1.00 (25) 70 80

020E

575 45 3 8 1 0.75 (19) 70 70208 118 3 1 1 1.25 (32) 150 200230 118 3 1 1 1.25 (32) 150 200460 59 3 6 1 1.00 (25) 80 100

025E

575 52 3 6 1 1.00 (25) 70 80208 131 3 1/0 1 1.50 (38) 175 225230 131 3 1/0 1 1.50 (38) 175 225460 65 3 6 1 1.00 (25) 90 110

028E

575 52 3 6 1 1.00 (25) 70 80208 169 3 2/0 1 1.50 (38) 225 250230 157 3 2/0 1 1.50 (38) 200 250460 83 3 4 1 1.00 (25) 110 125

030E

575 59 3 6 1 1.00 (25) 80 100


Table 5, ALR 020E - ALR 030E Compressor and Condenser Fan Motor Amp DrawRated Load Amps Locked Rotor Amps

Compressors Compressors

Across-The-Line Reduced Inrush

ALRUnitSize

VoltsNo.1

No.2

No.3

No.4

FanMotors(Each)

No. OfFan

Motors

FanMotors(Each) No. 1 No. 2 No. 3 No. 4 No. 1 No. 2 No. 3 No. 4

208 74 ---- ---- ---- 4.0 3 17.0 428 ---- ---- ---- 250 ---- ---- ----230 74 ---- ---- ---- 4.0 3 17.0 428 ---- ---- ---- 250 ---- ---- ----

020E 460 37 ---- ---- ---- 2.0 3 8.5 214 ---- ---- ---- 132 ---- ---- ----575 31 ---- ---- ---- 2.2 3 10.3 172 ---- ---- ---- 103 ---- ---- ----

208 85 ---- ---- ---- 4.0 3 17.0 470 ---- ---- ---- 292 ---- ---- ----230 85 ---- ---- ---- 4.0 3 17.0 470 ---- ---- ---- 292 ---- ---- ----

025E 460 42 ---- ---- ---- 2.0 3 8.5 235 ---- ---- ---- 141 ---- ---- ----

575 36 ---- ---- ---- 2.2 3 10.3 200 ---- ---- ---- 130 ---- ---- ----

208 95 ---- ---- ---- 4.0 3 17.0 565 ---- ---- ---- 340 ---- ---- ----230 95 ---- ---- ---- 4.0 3 17.0 565 ---- ---- ---- 340 ---- ---- ----

028E 460 47 ---- ---- ---- 2.0 3 8.5 283 ---- ---- ---- 156 ---- ---- ----575 36 ---- ---- ---- 2.2 3 10.3 230 ---- ---- ---- 138 ---- ---- ----

208 121 ---- ---- ---- 5.8 3 23.7 650 ---- ---- ---- 400 ---- ---- ----230 112 ---- ---- ---- 5.8 3 21.4 594 ---- ---- ---- 340 ---- ---- ----

030E 460 60 ---- ---- ---- 2.8 3 10.7 297 ---- ---- ---- 195 ---- ---- ----575 42 ---- ---- ---- 2.3 3 11.5 245 ---- ---- ---- 152 ---- ---- ----

Table 6, 010E - 016E Field Wiring Data, Single Point PowerWiring to Standard Power Block

ALRUnitSize

Volts TerminalAmps

Connector Wire Range(Copper Wire Only)

208 175 (1 qty.) #12 - 2/0

230 175 (1 qty.) #12 - 2/0

460 175 (1 qty.) #12 - 2/0020E

575 175 (1 qty.) #12 - 2/0

208 175 (1 qty.) #12 - 2/0

230 175 (1 qty.) #12 - 2/0

460 175 (1 qty.) #12 - 2/0025E

575 175 (1 qty.) #12 - 2/0

208 175 (1 qty.) #12 - 2/0

230 175 (1 qty.) #12 - 2/0

460 175 (1 qty.) #12 - 2/0028E

575 175 (1 qty.) #12 - 2/0

208 175 (1 qty.) #12 - 2/0

230 175 (1 qty.) #12 - 2/0

460 175 (1 qty.) #12 - 2/0030E

575 175 (1 qty.) #12 - 2/0


Notes for “Electrical Data Single Point

1. Unit wire size ampacity (MCA) is equal to 125% of the largest compressor-motor RLA plus 100%of RLA of all other loads in the circuit including the control transformer.

2. If the control transformer option is furnished, no separate 115v power is required.

If a separate 115V power supply is used for the control circuit, then the wire sizing amps is 2amps for unit sizes ALR 020E through ALR 030E.

3. Recommended power lead wire sizes for 3 conductors per conduit are based on 100% conductorampacity in accordance with NEC. Wire sizes for 6 conductors per conduit are based on 80%conductor ampacity in accordance with NEC. Voltage drop has not been included. Therefore, it isrecommended that power leads be kept short. All terminal block connections must be made withcopper (type THW) wire.

4. The unit power terminal block may have 2 lugs per phase. Single or parallel conductors should beused for power connections as listed under “Recommended Power Lead Wire Size.”

5. “Recommended Fuse Sizes” are selected at approximately 150% of the largest compressor RLA,plus 100% of all other loads in the circuit.

6. “Maximum Fuse Sizes” are selected at approximately 225% of the largest compressor RLA, plus100% of all other loads in the circuit.

7. The recommended power lead wire sizes are based on an ambient temperature of 86° F. Ampacitycorrection factors must be applied for other ambient temperatures. Refer to the National ElectricalCode Handbook.

Voltage Limitations:

Within ± 10% of nameplate rating

Notes for “Compressor and Condenser Fan Amp Draw”:

1. Compressor RLA values are for wiring sizing purposes only but do not reflect normal operatingcurrent draw at rated capacity. If unit is equipped with SpeedTrol condenser fan motors, the firstmotor on each refrigerant circuit is a single phase, 1hp motor, with a FLA of 2.8 amps at 460 volts,5.6 amps at 208, 230, and 575 volts.

2. Single point power supply requires a single disconnect to supply electrical power to the unit.This power must be fused.

3. All field wiring to unit power block or optional non-fused disconnect switch must be copper.

4. All field wire size values given in table apply to 75° C rated wire per NEC.


Figure 7, ALR 020E through ALR 030E, Typical Field Wiring Diagram

SEENOTE

1

WH

16

NB

BK

TOCOMPRESSOR(S)

ANDFANMOTORS.

OPTIONAL FUSED

CONTROL CIRCUIT

TRANSFORMER

3PHASE

POWER

SUPPLY

DISCONNECT

BYOTHERS

UNITMAIN

TERMINALBLOCK

540

13 F2

COOLERHEATER

THEMOSTATTC2. COOLERHEATER

545

WH

4

S1

2

F1

SEPARTE115V

POWERFORCOOLER

HEATER(SEENOTE A)

24 V

T217

18

2 7

28

120 V

5

CONTACT

CHILLERCONTROL

(CIRCUIT 1)

6

7

CHILLER CONTROL

TI MECLOCK

AUTOON

OFF

15

CHI LLER

FLOWSWI TCH

CONTACT

8

LEGEND

FIELDCONNECTIONTERMINAL

FACTORY WIRING

FIELDWIRING

NOTE:

IT MAY BE DESIRABLE TOHAVE THE UNIT

COOLERHEATERON A SEPARATE DISCONNECT

SWITCHFROM THE MAIN UNIT POWERSUPPLY

SOTHAT THE UNIT MAYBE SHUT DOWNWITH-

OUT DEFEATING THE FREEZE PROTECTION

PROVIDEDBY THE COOLERHEATER. TOAC-

COMPLISH THIS, REMOVE WIRES 540 AND 545

ANDFIELD WIRE TERMINALS 13 AND 16 TO A

SEPARATE 115V CIRCUIT.

Note: See control and power wiring diagrams on unit control panel for specific unit information.


Dimensional Data

Figure 8, 020E through ALR 030E Dimensions

System Maintenance

GeneralOn initial startup and periodically during operation, it will be necessary to perform certain routineservice checks. Among these are taking condensing and suction pressures. On units ordered withgauges, condensing and suction pressures can be read from the vertical support on the side of theunit adjacent to the compressors.

The gauges are factory installed with a manual shutoff valve on each gauge line. The valves shouldbe closed at all times except when gauge readings are being taken.

Fan Motor BearingsThe fan motor bearings are of the permanently lubricated type. No lubrication is required.

Electrical Terminals

WARNING

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

Normal heating and cooling of the wire will cause terminals to loosen. Retightened all power electricalterminals every six months.

CondensersCondensers are air cooled and constructed with 3/8” (9.5mm) O.D. internally finned copper tubesbonded in a staggered pattern into slit aluminum fins. No maintenance is ordinarily required exceptthe occasional removal of dirt and debris from the outside surface of the fins. Use locally purchasedfoaming condenser coil cleaners for periodic cleaning of the coil. Condenser cleaners may containharmful chemicals, be careful when using cleaners. Care should be taken not to damage the finsduring cleaning.


Refrigerant SightglassObserve the refrigerant sightglass monthly. A clear glass of liquid indicates adequate refrigerantcharge in the system to ensure proper feed through the expansion valve. Bubbling refrigerant in thesightglass indicates the system is short of refrigerant charge. Refrigerant gas flashing in thesightglass could also indicate an excessive pressure drop in the line, possible due to a clogged filter-drier or a restriction elsewhere in the system. The sightglass indicates what moisture conditioncorresponds to a given element color. If the sightglass does not indicate a dry condition after about12 hours of operation, the unit should be pumped down and the filter-driers changed.

Service

WARNING

Disconnect all power before doing any service inside the unit.

CAUTION

Service on this equipment is to be performed by qualified service personnel with special regardto regulations concerning release of refrigerant to the atmosphere.

Note: Repeated tripping of safety controls must be investigated and corrected.

Thermostatic Expansion ValveThe expansion valve is responsible for allowing the proper amount of refrigerant to enter theevaporator regardless of cooling load. It does this by maintaining a constant superheat. (Superheatis the difference between refrigerant temperature as it leaves the evaporator and the saturationtemperature corresponding to the evaporator pressure.) Typically, superheat should run in the rangeof 10°F to 15°F.

The superheat setting can be adjusted by removing the cap at the bottom of the valve to expose theadjustment screw. Turn the screw clockwise (when viewed from the adjustment screw end) toincrease the superheat setting and counterclockwise to reduce superheat. Allow time for systemrebalance after each superheat adjustment.

The expansion valve, like the solenoid valve, should not normally require replacement, but if it doesthe unit must be pumped down by following the steps involved when changing a filter-drier.

If the problem can be traced to the power element only, it can be unscrewed from the valve bodywithout removing the valve, but only after pumping the unit down.

Filter-DriersTo change the liquid line filter-drier, close the field supplied manual liquid line shutoff valve (seeFigure 4). By jumping out the low pressure control allow the unit to pump down to 0-5 PSIG(0-34 kPa). When the evaporator pressure reaches 0-5 PSIG (0-34kPa), shut the unit off at thedisconnect. Front seat the suction service valve, remove and replace the filter-drier, evacuate andremove the jumper.

After the filter-drier has been changed, a leak check is recommended before returning unit tooperation.


Liquid Line SolenoidThe liquid line solenoid valve does not normally require any maintenance. It may, however, requirereplacement of the solenoid coil. The solenoid coil may be removed from the valve body withoutopening the system by disconnecting power to the unit. The coil can then be removed from the valvebody by simply removing the nut or snap ring located at the top of the coil.

Standard Controls

Note: Perform an operational check on all unit safety controls once per year.

ThermostatThe thermostat provided as standard on ALR 020E through 030E is the Johnson Controls System 350.It is factory calibrated for use as a return water control, with the sensor strapped to the heat exchangerwater inlet. The A350 module provides a single stage of cooling. Additional staging can be obtainedby adding S350 stage modules, one stage per module. Modules are connected via five pinmale/female connectors with no interconnecting wiring required.

A350 Electronic Temperature ControlThe A350 temperature module has a visible control range scale and a knob-adjusted control point. AnLED indicator located on the face of the control will be illuminated when the relay is energized.

As shown in Figure 9, the A350 module’s two adjustment potentiometers are set per“Recommended Settings” below. To adjust the A350 differential setting, remove the four cornerscrews and adjust to the desired differential. The control point setting can be adjusted with the coverin place and is also set per “Recommended Settings’. Important: The control point does not reflecteither the desired return or leaving water temperature, but rather a control point that will allow the unitto deliver the desired average leaving water temperature specified. Step unloading systems willalways fluctuate around a desired control point.

S350 Stage Adder ModuleThe S350 module receives its power, control point and sensor input from the A350 module. As shownin Figure 9, the S350 module has both offset and differential potentiometers set per “RecommendedSettings”. Offset is the number of degrees above the A350 control point at which the S350 will stageoff. “Differential” is the number of degrees above offset at which the S50 will stage on. Both offsetand differential adjustments require cover removal.


Recommended SettingsControl has been factory set for a 44°F (6.7°C) leaving water temperature. The dial shows leavingwater temperature based on a 10 degree F (12.2 degree C) built in offset from the dial setting. Thecontrol settings are as follows:

• 1 Stage: A350 (CP1 Relay 1) dial setpoint 44°F (6.7°C)Control differential 4°F (2.2°C)

• 2 Stage: A350 (CP1 Relay 1) dial setpoint 44°F (6.7°C)Control differential 4°F (2.2°C)S350 (CP1 Relay 2) control differential 4°F (2.2°C)Offset 5°F (2.8°C)

• 3 Stage: A350 (CP1 Relay 1) dial setpoint 44°F (6.7°C)Control differential 4°F (2.2°C)S350 (CP1 Relay 2) control differential 4°F (2.2°C)Offset 3°F (1.7°C)S350 (CP1 Relay 2) control differential 4°F (2.2°C)Offset 6°F (3.3°C)

If a different leaving water temperature is needed, set the dial on the CP1 to the desired leaving watersetting. If the Delta-T between the entering and the leaving water is not 10 degrees F, follow the rulesset below.

12°° F Delta-T: Set the dial setting 1 degree F (0.6 degrees C) above the desired leaving watertemperature.

8°° F Delta-T: Set the dial setting 1 degree F (0.6 degrees C) below the desired leaving watertemperature.

Control Checkout1. Be sure the heat/cool switch is set for cooling

2. Set all offset and differential potentiometers per Figure 9 or job specifications

3. After necessary adjustments have been made, apply power to the control, put the system inoperation, and observe at least one complete operating cycle.

Figure 9, Temperature control details

Repairs and ReplacementField repairs or calibration must not be made. Sensors and replacement modules are available throughMcQuay parts distributors. Sensor resistance is 1005 ohms at 70°F (21.1°C), with 4.4 ohms per 1degree F (0.6 degrees C).


High Pressure ControlThe high pressure control is a single pole pressure activated switch that closes on a rise in pressure.When the switch closes, it de-energizes the compressor circuit preventing unit operation until thehigh pressure control is reset. The control is factory set to close at 400 PSIG and open at 300 PSIG.The control is attached to a Schrader fitting on the discharge line located in the compressorcompartment.

To check the control, either block off the condenser surface or start the unit with condenser fanmotors off and observe the cutout point of the control on the high side of the system. Resetting isaccomplished by opening and closing control stop switch S1.

CAUTION

The control stop switch S1 should be near at hand in case the high pressure controlmalfunctions. After testing the high pressure control, leak check the pressure relief device.

Low Pressure ControlThe low pressure control is a single pole pressure switch that closes on a pressure rise. It sensesevaporator pressure and is factory set to close at 60 PSI and automatically opens at 35 PSIG. To checkthe low pressure control (unit must be running), remove wire to de-energizing R-3 relay which in turnwill de-energize the liquid line solenoid. As the compressor pumps down, condenser pressure will riseand evaporator pressure will drop. The lowest evaporator pressure reached before cut-out is the cut-out setting of the control. Reconnecting the wire will energize the liquid line solenoid allowingevaporator pressure to rise. The highest evaporator pressure reached before compressor restart is thecut-in setting of the control.

Compressor LockoutCompressor lockout consists of a 5-minute time delay TD1. It is wired in series with the R5 safetyrelay that energizes after 5 minutes, enabling the compressor to start. Its purpose is to prevent rapidcompressor cycling when cooling demands are erratic.

When the unit thermostat no longer calls for cooling and the compressor contactors have opened, thelockout time delay breaks open the circuit, preventing compressor restart.

The circuit remains open for a period of 5 minutes so that the unit thermostat should call for coolingbefore the delay period has expired, the compressor will not restart. After 5 minutes the time delay willclose its contacts to complete the circuit to R5, enabling the compressor to start. When R9 isenergized with the compressor, another set of contacts will shunt around TD1, allowing TD1 to resetopen for timing out the next compressor cycle.

To check the time delay, the compressor must be running initially. Allow the unit to pump down byadjusting the temperature control to simulate no call for cooling. Immediately after the compressorhas stopped running adjust the temperature control to call for cooling. The compressor should notrestart for 5 minutes.


Compressor Motor ProtectorThe solid-state compressor motor protector module incorporates a 2-minute “time off” relay utilizingthe bleed down capacitor principle. Any time the protection system opens or power to the module isinterrupted, the 2-minute “time off” delay is triggered and the module will not reset for two minutes.Once the 2-minute period is passed the motor protector contacts M1 and M2 reset, provided theprotection system is satisfied and power is applied to the module.

Note: If the power circuit is broken once the 2-minute period is passed the pilot circuit willreset without delay when power is reapplied.

Fantrol Head Pressure ControlFanTrol is the standard method of head pressure control (PC 12) that automatically cycles thecondenser fan motor in response to condenser pressure. This maintains head pressure and allows theunit to run at low ambient air temperatures down to 40°F (4.4°C).

FanTrol is a nonadjustable control set to open at 150 psig and close at 225 psig. The control isattached to a Schrader fitting on the discharge line inside the compressor compartment.

Optional Controls

SpeedTrol Head Pressure ControlThe SpeedTrol method of head pressure control operates in conjunction with FanTrol by modulatingthe motor speed on one fan in response to condenser pressure. By reducing the speed of the last fanas the condensing pressure falls, the unit can operate to 0°F (-18°C) ambient air temperature.

The SpeedTrol fan motor is a single phase, 230/460 volt, thermally protected motor specially designedfor variable speed operation. The solid-state speed control SC11 is mounted in the unit control paneland is connected to a Schrader fitting on the liquid line. The control is factory set to start modulatingfan speed at 230 psig, and will maintain a minimum condensing pressure of 170 to 180 psig. Minimumstarting voltage for SpeedTrol motors is 120 volts.

A low ambient timer is included with the optional SpeedTrol. It consists of a solid-state, normallyclosed time delay wired in series with a relay. These are both wired in parallel to the liquid linesolenoid valve so that when the solenoid valve is energized by the unit thermostat the low ambientstart 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 2-3/4 minutes, the time delay will open and de-energize the relay. If the system has notbuilt up enough evaporator pressure to close the low pressure control, the compressor will stop. Thetime delay can be reset to its original normally closed position by de-energizing relay R3 in thethermostat circuit.

Due to the vertical condenser design, it is recommended that the unit be oriented so that prevailingwinds blow parallel to the unit length, thus minimizing effects on minimum ambient operation. If it isnot practical to orient the unit in this manner, a wind deflector should be constructed.


Figure 10, Low Ambient Start Time Delay/Relay R13)

Hot Gas BypassHot gas bypass is a system for maintaining evaporator pressure at or above a minimum value. Thepurpose for doing this is to keep the velocity of the refrigerant as it passes through the evaporatorhigh enough for proper oil return to the compressor when cooling load conditions are light. It alsomaintains continuous operation of the chiller at light load conditions.

The solenoid valve should be wired to open whenever the liquid line solenoid valve is energized.This can be accomplished by wiring the hot gas solenoid (SV5) in parallel with the liquid line solenoidat terminals 3 and 5. The pressure regulating valve is factory set to begin opening at 58 PSIG (32°F forR-22) when the air charged bulb is in an 80°F ambient temperature. The bulb can be mountedanywhere as long as it senses a fairly constant temperature at various load conditions. Thecompressor suction line is one such mounting location. It is generally in the 50°F to 60°F range.

The chart below indicates that when the bulb is sensing 50°F to 60°F temperatures, the valve willbegin opening at 54 PSIG. This setting can be changed as indicated above, by changing the pressuresetting, remove the cap on the bulb and turn the adjustment screw clockwise. To lower the setting,turn the screw counterclockwise. Do not force the adjustment beyond the range it is designed for, asthis will damage the adjustment assembly.

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

WARNING

The hot gas line may become hot enough to cause injury in a very short time, be carefulduring valve checkout.

On installations where the condensing unit is remote from the evaporator, it is recommended that thehot gas bypass valve be mounted near the condensing unit to minimize the amount of refrigerant thatwill condense in the hot gas line during periods when hot gas bypass is not required.


Figure 11, Hot Gas Bypass Piping

Figure 12, Hot Gas Bypass Adjustment


Control SettingsTable 7, ALR Controls, Settings And Functions

DESCRIPTION FUNCTION SYMBOL

SETTING RESET LCATION DIFFERENTIAL

HIGH PRESSURECONTROL

Stops compressor athigh discharge

HP1 Closes at 400PSIG

Opens at 300PSIG

Auto Oncompressor

100 PSIG fixed

LOW PRESSURECONTROL

Stops compressor atlow suction

LP1 Closes at 60 PSIGOpens at 35 PSIG

Auto Oncompressor

25 PSIG fixed

MOTORPROTECTOR

High motortemperature

MP1 500 ohms cold to20,000 ohms hot

Auto 2700 to4500 ohms

Compressorjunction box

15,000 ohms

OIL PRESSURECONTROL

Stops compressor atlow oil pressure with120 second delay

OP1 Opens at 14 psig.If pressure drops

below 10 psig,closes energizing120 second delay

Manual Control box 5 psig

HIGH PRESSUREUNLOADER

Unloads compressor athigh discharge

pressure

PC5 Closes at 375 psigOpens at 300 psig

Auto Top ofcontrol box

75 psig

FANTROLCONTROL

Cycles fans bycondensing pressure

PC12TC13

See FanTroldescription

Auto Control box See FanTroldescription

PHASE/VOLTAGEMONITOR

Protects against powerloss, phase loss,phase reversal

PVM N/A At normalcondition

Control box N/A

SPEEDTROLCONTROL

Modulates fan speedby condensing press.

SC11 Maintains min. of170 to 180 PSIG

N/A Top ofControl box

N/AN/A

LIQUID LINESOLENOID

Close liquid line forpumpdown

SV1 N/A N/A Fieldinstalled

N/A

PUMPDOWNSWITCH

To manually pumpdown the unit

PS1 Auto/manual N/A Control box N/A

CONTROL STOPSWITCH

Shuts down the entireunit

S1 On/Off N/A Control box N/A

HGBP SOLENOIDVALVE

Close HGBP forpumpdown

SV5 N/A N/A Condensersection

N/A

LOCKOUT TIMEDELAY

Prevents compressorshort cycling

TD1 Fixed 5 minutes Auto Control box N/A

PART WINDINGSTART DELAY

Reduces inrush atstartup

TD5 1 second N/A Control box N/A

LOW AMBIENTSTART DELAY

Bypass LP control forcold starts

TD9 2 3/4 minutes Auto Control box N/A

COMPRESSORUNLOADERCONTROL

Energize to unload ,de-energize to load

compressor

U1, 2 N/A N/A Oncompressor

N/A

UNIT MASTERTHERMOSTAT

Stages compressor byreturn water

CP1 Adjustable from30°F to 60°F

N/A Control boxSensor in

return waterline

Adjustable from1°F to 3°F per

stage

FREEZECONTROL

Prevents evaporatorfreeze-up. Time delayto prevent nuisance

trips

FS1,2TD

15,16

Closes at 52 psigOpens at 56 psig

30 second TD

Manual thruRS1, 2

Suction linenear cooler

4 psig fixed

COOLER HEATERTHERMOSTAT

Energizes chiller heaterto prevent freeze-up

TC2 38°F Auto On cooler N/A

HIGH RETURNWATER

THERMOSTAT

Unloads compressor athigh return water

temperature

TC11 Adjustable 0°F to100°F, 70°Frecommended

Auto Control Box 3°F fixed


Troubleshooting ChartTable 8, Troubleshooting Chart

PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPSCOMPRESSOR WILLNOT RUN

1. Main switch open2. Fuse blown, breakers open

3. Thermal overloads tripped4. Defective contactor or coil5. System off by safety device6. No cooling required7. Liquid line solenoid will not open8. Motor electrical problem9. Loose wiring

1. Close switch2. Check electrical circuits and motor windings for

shorts. Check for overloads and loose connections.Replace fuse or reset breaker.

3. Check unit when back on line, auto reset4. Repair or replace5. Determine cause and correct6. None, should start on call for cooling7. Repair or replace coil8. Check motor for open or short circuit, or burnout9. Check all wire junctions. Tighten all terminals.

COMPRESSOR NOISYOR VIBRATING

1. Refrigerant flooding compressor2. Improper line support3. Worn compressor

1. Check expansion valve setting2. Relocate or add supports3. Replace

HIGH DISCHARGEPRESSURE

1. Noncondensables in system2. Refrigerant overcharge3. Discharge valve partially closed4. Fan not running5. Dirty condenser coils6. FanTrol out of adjustment

1. Remove with authorized procedures2. Remove excess3. Open valve4. Check electrical circuit5. Clean coil6. Adjust FanTrol setting

LOW DISCHARGEPRESSURE

1. Faulty condenser control2. Low refrigerant charge3. Low suction pressure

1. Check condenser control operation2. Check for leaks. Add refrigerant3. See low suction pressure steps below

HIGH SUCTIONPRESSURE

1. Excessive load2. Expansion valve overfeeding

1. Reduce load or add capacity2. Check remote bulb. Regulate superheat

LOW SUCTIONPRESSURE

1. Lack of refrigerant2. Evaporator dirty3. Clogged filter-drier4. Clogged suction strainer5. Expansion valve malfunctioning6. Low condensing temperature7. Compressor will not load8. Low evaporator air flow

1. Check for leaks. Repair and replace refrigerant.2. Clean chemically3. Replace4. Clean strainers5. Check and adjust for proper superheat6. Check discharge pressure control devices7. See steps below for correcting failure to unload8. Adjust airflow

COMPRESSOR WILLNOT LOAD ORUNLOAD

1. Defective capacity control2. Unloader mechanism defective3. Faulty thermostat stage/broken wire4. Stages not set for application

1. Replace2. Replace3. Replace4. Adjust thermostat setting

LOAD/UNLOADINTERVAL TOOSHORT

1. Erratic water thermostat2. Insufficient water flow

1. Replace2. Adjust flow

LOSS OF OILPRESSURE ORNUISANCE TRIPS

1. Clogged suction oil strainer2. Excessive liquid in crankcase

3. Oil pressure gauge defective

4. Oil pressure switch defective5. Worn oil pump6. Oil pump reversing gear stuck in wrong

position7. Worn bearings8. Low oil level9. Loose fitting on oil lines10. Pump housing gasket leaks11. Flooding of refrigerant to into crankcase.12. Insufficient water flow

1. Clean2. Check crankcase heater. Reset TXV for higher

superheat, Check liquid line solenoid valve operation.3. Repair or replace. Keep valve closed except when

taking readings4. Replace5. Replace6. Reverse compressor rotation

7. Replace compressor8. Add oil9. Check and tighten system10. Replace gasket11. Adjust TXV

12. Adjust water flow.COMPRESSOR LOSESOIL

1. Lack of refrigerant2. Excessive compression ring blowby3. Suction superheat too high4. Crankcase heater burned out

1. Check for leaks and repair2. Replace compressor3. Adjust superheat4. Replace crankcase heater

MOTOR OVERLOADRELAYS OPEN ORBLOWN FUSES

1. Low voltage during high loads2. Defective or grounded motor wiring3. Loose power wiring4. High condensing temperature5. Unbalanced voltage6. High ambient at overload relay

1. Check supply voltage2. Replace compressor3. Check all connections and tighten4. See steps for high discharge pressure5. Check voltage. Contact power company6. Provide ventilation to reduce heat

COMPRESSORTHERMAL SWITCH

1. Operating beyond design conditions 1. Add facilities so conditions are within allowable limits


OPEN

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Post Office Box 2510, Staunton, Virginia USA (540) 248-0711

packaged air-cooled water chiller -...

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