Carrier GR-45, GR-60 Operation And Service

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Bus Air Conditioning Equipment

Models GR--45 GR--60

(N.A.O.)

T--295

AC Pressure Sensor

OPERATION AND

SERVICE MANUAL

BUS

AIR CONDITIONING

UNIT

Models

Carrier Refrigeration Operations Carrier Transicold Division, Carrier Corporation, P.O. Box 4805, Syracuse, N.Y. 13221 U. S. A.

Carrier Corporation 2000 D Printed in U. S. A. 0300

GR--45 GR--60

(N.A.O.)

AC Pressure Sensor

SAFETY SUMMARY

GENERAL SAFETY NOTICES

The following general safety notices supplement the specific warnings and cautions appearing elsewhere in this manual. They are recommended precautions that must be understood and applied during operation and maintenance of the equipment covered herein. A listing of the specific warnings and cautions appearing elsewhere in the manual follows the general safety notices.

FIRST AID

Aninjury,no matterhow slight, should nevergo unattended.Alwaysobtain firstaidormedicalattentionimmediately.

OPERATING PRECAUTIONS

Always wear safety glasses. Keep hands, clothing and tools clear of the evaporator and condenser fans. No work should be performed on the unit until all circuit breakers and start-stop switches are placed in the OFF

position, and power supply is disconnected. Always work in pairs. Never work on the equipment alone. In case of severe vibration or unusual noise, stop t he unit and investigate.

MAINTENANCE PRECAUTIONS

Beware of unannounced starting of the evaporator and condenser fans. Do not open the unit cover before turning power off.

Besurepoweristurnedoffbeforeworkingon motors, controllers, solenoid valves and electricalcontrols. Tagcircuit breaker and power supply to prevent accidental energizing of circuit.

Do not bypass any electrical safety devices, e.g. bridging an overload, or using any sort of jumper wires. Problems with the system should be diagnosed, and any necessary repairs performed, by qualified service personnel.

Whenperforming any arcweldingon the unit, disconnect allwireharnessconnectors from the modulesin the control box. Do not remove wire harnessfrom the modules unless you aregrounded to the unit frame with a static-safewrist strap.

In case of electrical fire, open circuit switch and extinguish with CO

SPECIFIC WARNINGS AND CAUTIONS

(never use water).

WARNING

DO NOT USE A NITROGEN CYLINDER WITHOUT A PRESSURE REGULATOR

WARNING

DO NOT USEOXYGEN IN OR NEAR A REFRIGERATION SYSTEM AS AN EXPLOSIONMAY OCCUR.

WARNING THE FILTER-DRIER MAY CONTAIN LIQUID REFRIGERANT. SLOWLY LOOSEN THE FLARE NUTS AND AVOID CONTACT WITH EXPOSED SKIN OR EYES.

CAUTION Donot under anycircumstancesattempt toservicethemicroprocessor. should aproblem developwith the microprocessor, replace it.

CAUTION If unit was recently operated, be careful of remaining hot coolant in the hoses when disassembling.

Safety-1

AC Pressure Sensor

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TABLE OF CONTENTS

PARAGRAPH NUMBER Page

SAFETY SUMMARY Safety-1.....................................................................

DESCRIPTION 1-1...............................................................................

1.1 INTRODUCTION 1-1..............................................................

1.2 GENERAL DESCRIPTION 1-2......................................................

1.2.1 Apex Unit 1-2..................................................................

1.2.2 Condensing S ection 1-2..........................................................

1.2.3 Evaporator Section 1-3...........................................................

1.2.4 Compressor Assembly 1-4........................................................

1.2.5 Fresh Air System 1-4............................................................

1.2.6 System Operating Controls And Components 1-4.....................................

1.3 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS 1-5........................

1.4 ELECTRICAL SPECIFICATIONS -- MOTORS 1-5......................................

1.5 ELECTRICAL SPECIFICATIONS -- SENSORS AND TRANSDUCERS 1-5..................

1.6 SAFETY DEVICES 1-5.............................................................

1.7 AIR FLOW 1-6....................................................................

1.8 AIR CONDITIONING REFRIGERATION CYCLE 1-6...................................

1.9 HEATING CYCLE 1-8.............................................................

1.10 RELAY BOARD 1-9...............................................................

1.10.1 Permanent Magnet Motors with 2 speed switching from series to parallel

connection (Option 1) 1-9........................................................

1.10.2 Electronically Communtated DC Motors with 2--speed Evaporator Input Signal (Option 2) 1-11.

1.11 LOGIC BOARD 1-12................................................................

1.12 CONTROL PANEL (Diagnostic Module) 1-13............................................

OPERATION 2-1.................................................................................

2.1 STARTING, STOPPING AND OPERATING INSTRUCTIONS 2-1..........................

2.1.1 Power to Logic Board 2-1........................................................

2.1.2 Starting 2-1....................................................................

2.1.3 Self-Test and Diagnostics (Check for Errors and/or Alarms) 2-1..........................

2.1.4 Stopping 2-1...................................................................

2.2 PRE--TRIP INSPECTION 2-1........................................................

2.3 MODES OF OPERATION 2-3.......................................................

2.3.1 Temperature Control 2-3.........................................................

2.3.2 Cooling Mode 2-3..............................................................

2.3.3 Heating Mode 2-3..............................................................

2.3.4 Boost Pump 2-3................................................................

2.3.5 Vent Mode 2-3.................................................................

2.3.6 Fresh Air System 2-3............................................................

2.3.7 Compressor Unloader Control 2-3..................................................

2.3.8 Evaporator Fan Speed Selection 2-4................................................

2.3.9 Condenser Fan Control 2-4.......................................................

2.3.10 Compressor Clutch Control 2-4....................................................

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TABLE OF CONTENTS (Continued)

PARAGRAPH NUMBER Page

2.3.11 Alarm Description 2-4...........................................................

2.3.12 Hour Meters 2-4................................................................

2.4 MICROPROCESSOR DIAGNOSTICS 2-4..........................................

2.4.1 Connecting 2-4.................................................................

2.4.2 Control 2-5....................................................................

2.4.3 Diagnostic Mode 2-5............................................................

2.4.4 System Parameters 2-5...........................................................

2.4.5 Test Mode 2-5.................................................................

TROUBLESHOOTING 3-1.........................................................................

3.1 SELF DIAGNOSTICS 3-1...........................................................

3.2 SYSTEM ALARMS 3-1............................................................

3.2.1 Alarm Codes 3-1...............................................................

3.2.2 Activation 3-1.................................................................

3.2.3 Alarm Queue 3-1...............................................................

3.2.4 Alarm Clear 3-1................................................................

3.3 TROUBLESHOOTING 3-1..........................................................

3.3.1 System Will Not Cool 3-4........................................................

3.3.2 System R uns But Has Insufficient C ooling 3-4........................................

3.3.3 Abnormal Pressures 3-4..........................................................

3.3.4 Abnormal Noise Or Vibrations 3-4.................................................

3.3.5 Control System Malfunction 3-5...................................................

3.3.6 No Evaporator Air Flow Or Restricted Air Flow 3-5...................................

3.3.7 Expansion Valve Malfunction 3-5..................................................

3.3.8 Heating Malfunction 3-5.........................................................

SERVICE 4-1....................................................................................

4.1 MAINTENANCE SCHEDULE 4-1....................................................

4.2 OPENING TOP COVER 4-1.........................................................

4.3 SUCTION AND DISCHARGE SERVICE VALVES 4-1...................................

4.4 INSTALLING MANIFOLD GAUGE SET 4-2...........................................

4.5 PUMPING THE SYSTEM DOWN OR REMOVING THE REFRIGERANT CHARGE 4-2.......

4.5.1 System Pump Down For Low Side Repair 4-2........................................

4.5.2 Refrigerant Removal From An Inoperative Compressor. 4-3.............................

4.5.3 Pump Down An Operable Compressor For Repair 4-3..................................

4.5.4. Removing Entire System Charge 4-4................................................

4.6 REFRIGERANT LEAK CHECK 4-4..................................................

4.7 EVACUATION AND DEHYDRATION 4-4.............................................

4.7.1 General 4-4....................................................................

4.7.2 Preparation 4-4.................................................................

4.7.3 Procedure for Evacuation and Dehydrating System 4-4.................................

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TABLE OF CONTENTS (Continued)

PARAGRAPH NUMBER Page

4.8 ADDING REFRIGERANT TO SYSTEM 4-5...........................................

4.8.1 Checking Refrigerant Charge 4-5..................................................

4.8.2 Adding Full Charge 4-5..........................................................

4.8.3 Adding Partial Charge 4-5........................................................

4.9 CHECKING FOR NONCONDENSIBLES 4-5...........................................

4.10 CHECKING AND REPLACING HIGH PRESSURE SWITCH 4-5..........................

4.11 FILTER-DRIER 4-6................................................................

4.11.1 To Check Filter--Drier 4-6.........................................................

4.11.2 To Replace Filter--Drier 4-6.......................................................

4.12 CONDENSER COIL REPLACEMENT 4-6.............................................

4.13 EVAPORATOR COIL REPLACEMENT 4-7............................................

4.14 SERVICING THE HEAT VALVE 4-7..................................................

4.14.1 COIL REPLACEMENT 4-7......................................................

4.14.2 INTERNAL PART REPLACEMENT 4-7............................................

4.14.3 REPLACE ENTIRE VALVE 4-7...................................................

4.15 SERVICING THE LIQUID LINE SOLENOID VALVE 4-8.................................

4.15.1 Coil Replacement 4-8............................................................

4.15.2 Internal Part Replacement 4-8.....................................................

4.15.3.Replace Entire Valve 4-8.........................................................

4.16 CONDENSER FAN/MOTOR ASSEMBLY 4-8..........................................

4.16.1 Removal 4-8...................................................................

4.16.2 Inspection And Cleaning 4-9......................................................

4.16.3 Brush Replacement 4-9..........................................................

4.17 REPLACING EVAPORATOR FAN 4-9................................................

4.18 REPLACING RETURN AIR FILTERS 4-9.............................................

4.19 THERMOSTATIC EXPANSION VALVE 4-9............................................

4.19.1 Valve Replacement 4-9..........................................................

4.19.2 Superheat Measurement 4-10.......................................................

4.20 COMPRESSOR MAINTENANCE 4-10.................................................

4.20.1 Removing the Compressor 4-10....................................................

4.20.2 Transferring Compressor Clutch 4-11................................................

4.20.3 Compressor Oil Level 4-12........................................................

4.20.4 Checking Unloader Operation 4-12..................................................

4.21 TEMPERATURE SENSOR CHECKOUT 4-13...........................................

4.22 PRESSURE TRANSDUCER CHECKOUT 4-13..........................................

4.23 REPLACING SENSORS AND TRANSDUCERS 4-13.....................................

4.24 LOGIC BOARD CONFIGURATION 4-13...............................................

ELECTRICAL 5-1................................................................................

5--1 INTRODUCTION 5-1...............................................................

INDEX Index-1..................................................................................

iii T--295

LIST OF ILLUSTRATIONS

FIGURE NUMBER Page

Figure 1-1. A/C Component Identification 1-1..................................................

Figure 1-2. Apex Unit Components 1-2........................................................

Figure 1-3. Condensing Section Components 1-3................................................

Figure 1-4. Evaporator Section Components 1-4.................................................

Figure 1-5. Air Flow Paths 1-6..............................................................

Figure 1-6. Refrigerant Flow Diagram 1-7.....................................................

Figure 1-7. Heating Cycle Flow Diagram 1-8...................................................

Figure 1-8 Relay Board (Option 1) 1-9........................................................

Figure 1-9 Relay Board (Option 2) 1-11........................................................

Figure 1-10 Logic Board 1-12................................................................

Figure 1-11. Micromate Control Panel 1-13.....................................................

Figure 2-1 Capacity Control Diagram 2-2......................................................

Figure 4-1. Opening Top Cover 4-1...........................................................

Figure 4-2.Suction or Discharge Service Valve 4-2...............................................

Figure 4-3. Manifold Gauge Set 4-2..........................................................

Figure 4-4. Low Side Pump Down Connections 4-3..............................................

Figure 4-5. Compressor Service Connections 4-3................................................

Figure 4-6. S ystem Charge Removal Connections 4-4............................................

Figure 4-7. Checking High Pressure Switch 4-6.................................................

Figure 4-8. Filter--Drier Removal 4-6.........................................................

Figure 4-9. Heat Valve 4-7..................................................................

Figure 4-10. Liquid Line Solenoid Valve 4-8...................................................

Figure 4-11. Condenser Fan/Motor Assembly 4-8................................................

Figure 4-12. Evaporator Fan Removal 4-9.....................................................

Figure 4-13. Thermostatic Expansion Valve 4-9.................................................

Figure 4-14.Thermostatic Expansion Valve Bulb and Thermocouple 4-10..............................

Figure 4-15.Removing Bypass Piston Plug 4-11..................................................

Figure 4-16. Compressor C lutch 4-11..........................................................

Figure 4-17. Compressors 4-12...............................................................

Figure 4-18 Transducer Terminal Location 4-13..................................................

Figure 5--1. Electrical Wiring Schematic Diagram - Legend 5-2.....................................

Figure 5--2. Wiring Schematic, Permanent Magnet Motors - Interconnection 5-3.......................

Figure 5--3. Wiring Schematic, Permanent Magnet Motors - Relays to External Components 5-4..........

Figure 5--4. Wiring Schematic, Electronically Communtated Motors - Interconnection 5-5...............

Figure 5--5. Wiring Schematic, Electronically Communtated Motors - Relays To External Components 5-6..

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LIST OF TABLES

TABLE NUMBER Page

Table 2-1. Evaporator Fan Speed Relay Operation 2-4.............................................

Table 2-2. C ontroller Test List 2-5.............................................................

Table 2-3. Parameter Codes 2-6...............................................................

Table 3-2 Alarm Codes 3-2..................................................................

Table 3-3 General System Troubleshooting Procedures 3-4.........................................

Table 4-1. Temperature Sensor Resistance 4-13...................................................

Table 4-2. PressureTransducer Voltage 4-14......................................................

Table 4-3. Logic Board Configuration 4-14.......................................................

v T--295

SECTION 1

DESCRIPTION

1.1 INTRODUCTION

This manual contains Operating Instructions, Service Instructions and Electrical Data for the Model GR Air Conditioning and Heating equipment furnished by Carrier Transicold Division as shown in Table 1-1.

ModelGR systems consistsofan ApexUnit,containing the condenser and evaporator and an engine compartment mounted compressor. To complete the

Table 1-1. Model

MODEL

GR45 ROOF MOUNTED 05K 4 4

SERIES COMPRESSOR CONDENSER

GR60 ROOF MOUNTED 05G 6 6

Table 1-2. Additional Support Manuals

MANUAL/FORM NUMBER

EQUIPMENT COVERED TYPE OF MANUAL

62--02491 O5K Compressor Operation and Service 62--02460 O5K Compressor Parts List 62--02756 O5G Compressor Operation and Service

T--200 O5G Compressor Parts List

system, the air conditioning and heating equipment interfaces with electrical cabling, refrigerant piping, enginecoolant piping (forheating), duct work andother components furnished by the bus manufacturer.

Operation of the units is controlled automatically by a microprocessor based Micromax Controller which maintains the vehicle’s interior temperature at the desired set point.

FANS

EVAPORATOR

FANS

1. Compressor

2. Refrigerant Lines

3. Compressor Harness

4. Heat Valve

5. Electronics Boards

6. Apex Unit

7. Main Harness

Figure 1-1. A/C Component Identification

12 10 9

8. Driver Control

9. Power Harness

10. Power Relay

11. Battery

12. Alternator

13. Discharge Check Valve

1-1

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1.2 GENERAL DESCRIPTION

1.2.1 Apex Unit

The apex unit (see Figure 1-2) includes the condensing

section, evaporator section, Micromax electronics, and theFresh AirSystem.All components are accessibleby lifting the top cover. Descriptions of the systems are provided in the following sub paragraphs.

1. Top Cover

2. Gas Spring (2)

3. Condenser Section (See Figure 1-3)

4. Evaporator Section (See Figure 1-4)

5. Base

6. Fresh Air System

7. Gas Spring Support (2)

8. Lock (2)

9. Serial Plate

Figure 1-2. Apex Unit Components

(GR-60 Shown)

1.2.2 Condensing Section

The condensing section (Figure 1-3) includes the condenser coils, fan and motor assemblies, filter-drier, receiver, liquid line solenoid valve, service valves, and an ambient temperature sensor.

The condenser coils provide heat transfer surface for condensing refrigerant gas at a high temperature and

10. Hinge 1 1. Condenser Fan Grille (4-GR45,

6-GR60)

12. Front Drain (2)*

13. Intermediate Drain (2)*

14. Evaporator Rear Drain (2)*

15. Condenser Rear Drain (2)* * Not Shown

pressure into a liquid at high temperature and pressure. The condenser fans circulate ambient air across the outside of the condenser tubes at a temperature lower than refrigerant circulating inside the tubes; this results in condensation of the refrigerant into a liquid. The filter-drier removes m oisture and debris from the liquid refrigerant before it enters the thermostatic expansion valve in the evaporator assembly.

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1-2

The receiver collects and stores liquid refrigerant. The receiver is fitted with upperand lowerliquid level sight glasses to enable determining refrigerant liquid level. The receiver is also fitted with a fusible plug which protects the system from unsafe high pressure conditions. The liquid line solenoid valve closes when system is shut down to prevent flooding of coils with liquidrefrigerant.The servicevalvesenable isolationof the filter-drier for service. The ambient temperature

sensor measures ambient temperature and sends an electrical signal to the controller.

The dischargecheck valve is a spring loaded, normally closedvalve that opens withthe flowofrefrigerantfrom the compressor. When the compressor clutch is disengaged, the discharge check valve will close, preventing the flow of high pressure liquid from the condenser back into the compressor.

12 3

1. Condenser Coil (2)

2. Receiver

3. Protection Plate

4. Service Valve

5. Discharge Line

6. Precharge Valve

7. Liquid Line Solenoid Valve

8. Filter Drier Upper Support

Figure 1-3. Condensing Section Components

(GR-60 Shown)

1.2.3 Evaporator Section

The evaporator section (Figure 1-4) includes the evaporator coils, six fan and motor assemblies, evaporator/heater coil assemblies, a thermostatic expansion valve and condensate drain connections.

The evaporator coils provide heat transfer surface for transferring heat from air circulating over the outside the coil to refrigerant circulating inside the tubes; thus providing cooling. The heating coils provide heat transfer surface for transferring heat from engine coolant water circulating inside the tubes to air

9. Filter Drier

10. Filter Drier Lower Support 1 1 Condenser Fan and Motor Assembly

(4-GR45, 6-GR60)

12. Condenser Coil Fastener (4)

13. Condenser Motor Support (4-GR45, 6-GR60)

circulating over the outside surface of the tubes, thus providing heating. The fans circulate the air over the coils. The air filters remove dirt particles from the air before it passes over the coils. The thermostatic expansion valve meters flow of refrigerant entering the evaporator coils. The heat valve controls the flow of enginecoolant water to the heatingcoils upon receipt of a signal from the controller. The condensate drain connections provide a means for connecting tubing for disposing of condensate collected on the evaporator coils during cooling operation.

1-3

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1. Evaporator Coil With Integrated Heating Coil (2)

2. Protection Plate

3. Expansion V alve

4. Evaporator Motor Fastening Clamps (4-GR45, 6-GR60)

Figure 1-4. Evaporator Section Components

(GR-60 Shown)

1.2.4 Compressor Assembly

The compressor assembly includes the refrigerant compressor, clutch assembly, suction and discharge service valves, high pressure switch, low pressure switch,suctionanddischargeservicing(charging) ports and electric solenoid unloaders.

The compressor raises the pressure and temperature of the refrigerant and forces it into the condenser tubes. The clutch assembly provides a means of belt driving the compressor by the bus engine. The suction and discharge service valves enable servicing of the compressor. Suction and discharge servicing(charging) ports mounted on the service valves enable connection of charging hoses for servicing of the compressor, as well as other parts of the refrigerant circuit. The high pressureswitch contacts open on a pressure rise to shut down the system when abnormally high refrigerant pressuresoccur. The electricunloaders provide a means of controlling compressor capacity, which enables controlof temperatureinside the bus. For more detailed informationon the compressor, referto manual number 62-02756.

1.2.5 Fresh Air System

The Fresh Air System (6, Figure 1-2) consists of a damperand damper operator. Thedamperoperatormay becontrolled bythe driver,if aswitchisprovided.Inthe automatic mode, it is controlled by the Micromax to open and close thedamper to allow addition of fresh air

5. Evaporator Motor (4-GR45, 6-GR60)

6. Suction Line

7. Heating Lines

8. Service Valve

9. Evaporator Harness

into the air entering the evaporator coil. For additional information on air flow, refer to paragraph 1.7.

1.2.6 System Operating Controls And Components

The system is operated by a Carrier Transicold Micromaxmicroprocessorcontrollerwhichconsist of a logic board (Figure 1-10), relay board (Figure 1-8 or Figure 1-9), and manualoperator switches. The manual operatingswitchesarelocatedon the driverscontroland may consist of a single OEM supplied ON/OFF switch, additional OEM supplied switches or a Carrier Transicold supplied Micromate control panel (Figure 1-11).The logic boardregulates the operational cycles of the system by energizing or de--energizing relays on the relay board in response to deviations in interior temperature. Modes of operation include Cooling, Heat andVent. On systems fitted with only an ON/OFF switchand on systems withthe Micromateset in the AUTO mode, the logic board will cycle the system between the operating modes as required to maintain desired set point temperature.

In the vent mode the evaporator fans are operated to circulate air in the bus interior.

Intheheatmodetheheatvalve is opened to allow aflow of engine coolant through the heat section of the evaporatorcoil. The evaporatorfansoperateto circulate air over the evaporator coil in the same manner as the vent mode.

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1-4

In the cooling mode the compressor is energized while

the evaporator and condenser fans are operated to provide refrigeration as required. The compressor is fitted with cylinder unloaders to match compressor capacity to the bus requirements. Once interior temperature reaches the desired set point, the system may operate in the clutch cycle or reheat mode. A controller programmed for clutch cycle will de--energizethecompressorclutchandallowthesystem to operate in the vent mode until further cooling is required. A controller programmed for reheat will maintain compressor operation and open the heatvalve to allow reheating of the return air. In the reheat mode interior temperature is maintained at the desired set point while additional dehumidification takes place.

Controls may also be provided to allow manual operation of the evaporator fans in low or high speed andmanual controlofthefreshairdamper in the open or closed position.

1.3 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS

a. Refrigerant Charge

R--134a 14.3 lb (6.5 kg)

b. Compressor

UNIT MODEL

GR45 GR60

Compressor 05K 05G No of Cylinders 4 6 Weight - Dry 108 lbs

(49 kg)

Oil Charge 5.5 pints

(2.6 liters)

137 lbs (62 kg)

6.75 pints

(3.2 liters)

Oil Level:

Levelin sightglass betweenMin.--Max marks on compressor crankcase (curbside)

Approved Compressor Oils - R-134a:

Castrol: Icematic SW68C Mobil: EAL Arctic 68 ICI: Emkarate RL68H

c. Thermostatic Expansion Valve:

Superheat Setting (Non-externally adjustable): 10 to 12F MOP Setting (Nonadjustable): 55 ±4 psig (3.74 ±2.27 bar)

d. High Pressure Switch (HPS):

Opens at: 300 ±10 psig (20.41 ±0.68bar) Closes at: 200 ±10 psig (13.61 ±0.68bar)

e. Low Pressure Switch (LPS)

Opens at: 6 ±3psig (0.41 ±0.20 bar) Closes at: 25 ±3psig(1.7±0.20 bar)

1.4 ELECTRICAL SPECIFICATIONS -- MOTORS

a. Evaporator Fan Motor

ECDC* Permanent

Evaporator Motor

27.5

VDC

Magnet

24 VDC 12 VDC

Horsepower (kW) 0.34(.25) 1/8 (.09) Full Load Amps

8.4 9.5 19

(FLA) Operating Speed

High/Low (RPM)

4252/

3165

4200/

1850

Bearing Lubrication Factory Lubricated (addi-

tional grease not required)

b. Condenser Fan Motor

ECDC* Permanent

Condenser Motor

24 VDC 24 VDC 12 VDC

Magnet

Horsepower (kW) 0.15(.11) 1/8 (.09) Full Load Amps

7 9 18

(FLA) Operating Speed

High/Low (RPM)

4252/

4200/

1850

Bearing Lubrication Factory Lubricated (addi-

tional grease not required)

* Electronically Communicated Direct Current

1.5 ELECTRICAL SPECIFICATIONS -- SENSORS AND TRANSDUCERS

a. Suction and Discharge Pressure Transducer

Supply Voltage: 4.5 to 5.5 vdc (5 vdc nominal) Supply current: 8 mA maximum Output Range: 8K ohms minimum Input Range: --6.7 to 450 psig (--0.46 to 30.62 bar) Output Current: -1.5 mA minimum t o

1.5 mA maximum

Output Voltage: vdc = 0.0098 x psig + 0.4659

(See Table 4-2 for calculations.)

b. Temperature Sensors

Input Range: --52.6 to 158F (--47 to 70C) Output: NTC 10K ohms at 77F(25C) (See Table 4-1 for calculations.)

1.6 SAFETY DEVICES

System components are protectedfrom damage caused by unsafe operating conditions with safety devices. Safety devices with Carrier Transicold supplied equipment include high pressure switch (HPS), low pressure switch (LPS), circuit breakers and fuses.

a. Pressure Switches

High Pressure Switch (HPS)

During the A/C mode, compressor operation will automaticallystop if the HPS switch contacts open due toan unsafeoperatingcondition.OpeningHPScontacts de-energizes, through the controller, the compressor clutchshutting downthecompressor. The high pressure switch (HPS) is installed in the center head of the compressor.

1-5

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Low Pressure Sw itch (LPS)

The low pressure switch is installed in the compressor and opens on a pressure drop to shut down the system whena lowpressurecondition occurs. Inaddition, ifthe control monitors a pressure less than 10 psig (0.68 bar)by the suction pressure transducer mounted in the evaporator section, the system will be shut down for at least one minute.

b. Fuses and Circuit Breakers

The Relay Board is protected against high current by an OEM supplied 150 amp fuse. Independent 15 amp circuit breakers protect each motor while the output circuits are protected by an additional 15 amp circuit breaker.Duringahigh currentcondition,the breaker(or OEM fuse) may open. When power is removed from a device, a breaker alarm will be generated.

c. Ambient Lockout

The ambient temperature sensor located in the condenser section measures the condenser inlet air temperature. When the temperatureis below the cut out set point the compressor is locked out until the temperaturerisesabovethecutin setting. The set points maybe programmedto cutoutat45F7.2C)andcutin at 50F10C) or cut out at 25 F--3.9C) and cut in at 45F7.2C) in accordance with bus purchase specification.This setting protects the compressorfrom damage caused by operation at low pressures.

1.7 AIR FLOW

The paths for ambient air through the condenser and coach air through the evaporator are illustrated in Figure 1-5.

1.8 AIR CONDITIONING REFRIGERATION CYCLE

When air conditioning (cooling) is selected by the controller, the unit operates as a vapor compression system using R-134a as a refrigerant (see Figure 1-6). The main components of the system are the reciprocating compressor, air-cooled condenser coils, receiver, filter-drier, thermostatic expansion valve, liquid line solenoid valve and evaporator coils.

The compressor raises thepressureand thetemperature of the refrigerant and forcesit into the condenser tubes. The condenser fan circulates surrounding air (which is at a temperature lower than the refrigerant) over the outside of the condenser tubes. Heat transfer is establishedfrom the refrigerant (inside the tubes) to the condenser air (flowing over the tubes). The condenser tubes have fins designed to improve the transfer ofheat from the refrigerant gas to the air; this removal of heat causes the refrigerant to liquefy, thus liquid refrigerant leaves the condenser and flows to the receiver.

The receiver serves as a liquid refrigerant reservoir so that a constant supply of liquid is available to the evaporators as needed, and acts as a storage space when pumping down the system. The receiver is equipped with sight glasses to observe the refrigerant for restricted flow and correct charge level.

The refrigerant leaves the receiver and passes through the receiver outlet/service valve, through a filter-drier where an absorbent keeps the refrigerantclean and dry.

From the filter-drier, the liquid refrigerant then flows through the liquid line solenoid valve to the thermostatic expansion valve. the thermal expansion valve reduce pressure and temperatureof the liquid and metersthe flow of liquid refrigerant tothe evaporatorto obtain maximum use of the evaporator heat transfer surface.

Thelow pressure,lowtemperatureliquidthatflowsinto the evaporator tubes is colder than the air that is circulated over the evaporator tubes by the evaporator fans (fans). Heat transfer is established from the evaporatorair (flowing over the tubes)to the refrigerant (flowing inside the tubes). The evaporator tubes have aluminum fins to increase heat transfer from the air to the refrigerant; therefore the cooler air is circulated to the interior of thebus. Liquidline solenoid valvecloses during shutdown to prevent refrigerant flow.

The transfer of heat from the air to the low temperature liquid refrigerant in the evaporator causes the liquid to vaporize. This low temperature, low pressure vapor passes through the suction line and returns to the compressor where the cycle repeats.

CONDENSER AIR FLOW

3. THROUGH FAN

2. THROUGH CONDENSER

1. FROM AMBIENT

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4. RETURN TO AMBIENT

1. FROM DAMPER

3. THROUGH EVAPORAT OR

4. THROUGH FAN

5. RETURN TO COACH

Figure 1-5. Air Flow Paths

1-6

(IF ACTIVE)

2. FROM COACH

EVAPORATOR AIR FLOW

7 8 9

DISCHARGE LIQUID SUCTION

RECEIVER

VIEW A-A

MAIN ENGINE

RADIATOR

10 11

12 13

SUCTION

DISCHARGE

1. Condenser Fan Assembly

2. Evaporator Fan Assembly

3. Expansion V alve

4. Expansion V alve Equalizer Line

5. Liquid Line

6. Precharge Valve

7. Expansion V alve Bulb

8. Pressure Transducer, Low Side

9. Service Port, Low Side

10. Pressure Transducer, High Side

11. Service Valve With Port

12. Liquid Line Solenoid Valve

13. Filter Drier

14. Service Port, High Side

15. Discharge Check Valve

16. Receiver

17. Refrigerant Sight Glass

18. Moisture Indicator

Figure 1-6. Refrigerant Flow Diagram

(GR60 Shown)

1-7

COMPRESSOR

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SUPPLY RETURN

Figure 1-7. Heating Cycle Flow Diagram

(GR60 Shown)

1.9 HEATING CYCLE

Heating circuit (Figure 1-7) components furnished by Carrier Transicold include the integral evaporator coil heater cores and a solenoid operated heat valve. Componentsfurnishedby the bus manufacturerinclude auxiliary heater and boost water pump. The controller automaticallycontrols theheat valveduring theheating and reheat modes to maintain required temperatures

HEAT VALVE

BOOST PUMP

MAIN ENGINE

RADIATOR

COMPRESSOR

inside the bus. Engine coolant (glycol solution) is circulatedthrough the heating circuitby the engine and an auxiliary boost water pump. When the heat valve solenoid i s energized, the valve will open to allow enginecoolanttoflowthrough theheatercoil. Thevalve is normally closed so that if a failureoccurs, the system will be able to cool.

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1-8

1.10 RELAY BOARD

1.10.1 Permanent Magnet Motors with 2 speed switching from series to parallel connection (Option 1)

JP6

D2 D6

CB 1

CB 2

CB 3

CB 4

EF1

EF2

EF4EF3

D14

D17

EF6

CB 5

CB 6

D26 D30

EF5

CB 7

CB 8

CB 9

CB 10

CF1

CF3

CF2

K11

CF4

K10

D38 D41

K22K24

CB 13

CB 11

CB 12

K12

CF6 CF5

K23K21

K15K14

K17K16

K20K18

D85

K13K19

JP1

D57

D54

JP5

D63

D60

JP4

D72

5 6

D66

D51

JP3

D69

JP2

Figure 1-8 Relay Board (Option 1)

a. Relays

K1 Energizes evaporator fans 1 & 2 in high speed

or evaporator fans 1,2,3 & 4 in low speed.

K2 Energizes evaporator fans 3 & 4 in high speed

(not energized in low speed).

K3 Energizes evaporator fan 5 in high speed or

evaporator fans 5 & 6 in low speed.

K4 Energizes evaporator fan 6 in high speed (not

energized in low speed).

K5 Connects the negative side of evaporator fans

1 & 2 to ground in high speed. Connects the negative side of evaporator fans 1 & 2 to positive side of evaporator fans 3 & 4 in low speed

K6 Connects the negative side of evaporator fan

5 to ground in high speed. Connects the negative side of evaporator fan 5 to positive side of evaporator fan 6 in low speed

K 7 Energizes condenser fans 1 & 2 in high speed

or condenser fans 1,2,3 & 4 in low speed

K 8 Energizes condenser fans 3 & 4 in high speed

(not energized in low speed).

K 9 Energizes condenser fan 5 in high speed or

condenser fans 5 & 6 in low speed.

K10 Energizes condenser fan 6 in high speed

(not energized in low speed).

K11 Connects the negative side of condenser fans

1 & 2 to ground in high speed. Connects the negative side of condenser fans 1 & 2 to the positive side of condenser fans 3 & 4 in

low speed.

K12 Connects the negative side of condenser fan

5 to ground in high speed. Connects the negative side of condenser fan 5 to the positive side of condenser fan 6 in

low speed. K13 Energizes the A/C clutch. K14 Energizes unloader 1. K15 Energizes unloader 2. K16 Energizes the fresh air damper. K17 Energizes the heat valve. K18 Energizes the fault light output. K19 Energizes the Boost Pump. K20 Energizes the spare output. K21 Is energized by the logic board to turn the

evaporator fans on high. The contacts of this

relay energize the coils of relays K1, K2,

K3 & K4. K22 Is energized by the logic board to turn the

evaporator fans on low. The contacts of this

relay energize the coils of relays K1, K3,

K5 & K6. K23 Is energized by the logic board to turn the

condenser fans on high. The contacts of this

relay energize the coils of relays K7, K8,

K9 & K10. K24 Is energized by the logic board to turn the

condenser fans on low. The contacts of this

relay energize the coils of relays K7, K9,

K11 & K12.

1-9

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b. Thermal Circuit Breakers

CB 1 Evaporator Fan #1. 15 Amp. CB 2 Evaporator Fan #2. 15 Amp. CB 3 Evaporator Fan #3. 15 Amp. CB 4 Evaporator Fan #4. 15 Amp. CB 5 Evaporator Fan #5. 15 Amp. CB 6 Evaporator Fan #6. 15 Amp. CB 7 Condenser Fan #1. 15 Amp. CB 8 Condenser Fan #2. 15 Amp. CB 9 Condenser Fan #3. 15 Amp. CB10 Condenser Fan #4. 15 Amp. CB11 Condenser Fan #5. 15 Amp. CB12 Condenser Fan #6. 15 Amp. CB13 A/C clutch, Unloaders 1&2,

Fresh Air Damper, Heat Valve, Fault Output and Spare output. 15 Amp

c. Connectors

EF1-EF6 Evaporator fans. CF1-CF4 Condenser fans. JP1 External evaporator & condenser fan

thermal overload connections. JP2 Logic board connector. JP3 Boost pump. JP4 A/C clutch, fault output, compressor high

pressure switch. JP5 Spare output, fresh air output, heat valve.

JP6 Unloaders 1 & 2.

d. LEDS

D 2 Relay K1 output active (evaporator fans 1,2,3 &

4 energized)

D 6 Will be brightly lit if evaporator fans 1, 2, 3 & 4

are on high. Will be at half intensity of they are on low.

D14 Relay K3 output active (evaporator fans 5 & 6

energized).

D17 .Will be brightly lit if evaporator fans 5 &6 are

on high. Will be at half intensity of they are on low.

D26 Relay K7 output active (condenser fans 1, 2, 3

& 4 energized).

D30 Will be brightly lit if condenser fans 1, 2, 3 & 4

are on high. Will be at half intensity of they are on low.

D38 Relay K9 output active (condenser fans 5 & 6

energized).

D41 Will be brightly lit if condenser fans 5 &6 are on

high. Will be at half intensity of they are on low.

D51 A/C clutch output active. D54 Unloader 1 output active. D57 Unloader 2 output active. D60 Fresh air output active. D63 Heat valve output active. D66 Fault output active. D69 Boost pump output active. D72 Spare output active.

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1-10

1.10.2 Electronically Communtated DC Motors with 2--speed Evaporator Input Signal (Option 2)

JP6

D2 D6

CB 1

CB 2

CB 3

CB 4

EF1

EF3

EF2

EF4

K14

K16

K18

K20

K15

K17

K19

K13

JP1

CB 13

CB 11

CF1

CF3

K11

CF2

CF4

K24

K10

D41D38

K22

CB 12

D85

CF HIGH SIGNAL

CF6 CF5

K23K21

D30

CB 7

CB 8

CB 9

CB 10

CB 5

CB 6

D81

D17D14

EF HIGH SIGNAL

EF6 EF5

D26

JP5

JP4

JP3

3 4

4 5 6

2 3

JP2

D57

D54

D63 D60

D72 D66 D51

D69

Figure 1-9 Relay Board (Option 2)

a Relays

K1 Energizes evaporator fans 1 & 2 K2 Energizes evaporator fans 3 & 4. K3 Energizes evaporator fan 5. K4 Energizes evaporator fan 6. K5 Provides evaporator fan high output signal.

(Motors are in low speed when K5

is de--energized) K6 Not Used K 7 Energizes condenser fans 1 & 2. K 8 Energizes condenser fans 3 & 4. K 9 Energizes condenser fan 5 K10 Energizes condenser fan 6. K13 Energizes the A/C clutch. K14 Energizes unloader 1. K15 Energizes unloader 2. K16 Energizes the fresh air damper. K17 Energizes the heat . K18 Energizes the fault light output. K19 Energizes the Boost Pump. K20 Energizes the spare output. K21 or K22 Is energized by the logic board to

turn the evaporator fans on. The contacts

of these relays energize the coils of relays K1,

K2, K3 & K4.

K23 or K24 Is energized by the logic board to

turn the condenser fans on high. The contacts of these relays energize the coils of relays K7, K8, K9 & K10.

b Thermal Circuit Breakers

Refer to paragraph 1.10.1b.

c. Connectors

Refer to paragraph 1.10.1c. EF HIGH SIGNAL Output to the evaporator fans

to operate on high. CF HIGH SIGNAL Output to the condenser fans to operate on high.

d. LEDS

Refer to paragraph 1.10.1d. D81 Evaporator fans on high D85 Condenser fans on high

1-11

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1.11 LOGIC BOARD

J1 Logic board power in. J2 Display interface. J3 Manual control inputs. J4 Interlock Inputs

(WTS, low side pressure switch etc.) J5 Relay board interface. J6 Sensor inputs (Thermistors, etc.).

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J7 Diagnostics interface (RS232, DB9). D2 Blinks once per second in normal operation.

On steady to indicate alarms detected.

D3 Off In normal operation, blinks out alarm

codes (2 digits each) when alarms detected.

A-P Configuration Jumpers

Figure 1-10 Logic Board

1-12

1.12 CONTROL PANEL (Diagnostic Module)

123 4 5 6

1. Display

2. DOWN Button -- decrease selection

3. UP Button -- increase selection

4. VENT (Only) Button

5. AUTO Button (Automatic Control)

6. COOLING (Only) Button

Figure 1-11. Micromate Control Panel

91011

7. HEAT (Only) Button

8. FAN SPEED Button

9. FRESH AIR Button

10. TEMPERATURE ( Inside / Outside) Button

11. ON/OFF Button

1-13

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SECTION 2

OPERATION

2.1 STARTING, STOPPING AND OPERATING INSTRUCTIONS

2.1.1 Power to Logic Board

Before starting, electricalpower must beavailable from the bus power supply. The system components receive power from two sources:

a. 24 vdc power for the microprocessor electronics is

supplied through the bus multiplex module.

b. 24 vdc, 125 amp, power from a fuse in the battery

compartment supplies power for the, clutch, compressor unloader solenoids, evaporator and condenser assemblies; this power is controlled by the Logic Board.

2.1.2 Starting

a. If the engine is not running, start the engine. b. OEM SUPPLIED SWITCHES

Actual start sequence depends on the operating controlssupplied.If only an ON/OFF switch issupplied, placethe switch in the ON position to start thesystem in the automatic mode. If additional OEM switches are supplied, refer to the following Micromate control description for operating instructions.

c. MICROMATE CONTROL PANEL

It is suggested the system be started in the automatic mode.

1 The Micromate Control Panel Display (see

Figure 1-11) may be programmed to display the set pointtemperatureor returnairtemperature.Todetermine which display temperature is programmed, press the TEMPERATURE button so that the OUT SIDE AIR indicator is illuminated. If the controller cycles back to the INSIDE AIR indicator, than the controller is programmed to display return air temperature. If the controller does not automatically cycle back to the return air indicator, than the controller is programmed to display set point temperature.

2 Tostartthesystem,pressthe I/Obutton to illuminate

theindicatorlight and signal the Logic Board to perform start up. Ensure the AUTO button indicator is illuminated. If not, press the AUTO button to place the system in the automatic mode. Afterthe pre--trip inspection is completed, the switches may be set in accordance with the desired control modes.

3 If cooling only, heating only or ventilation only is

desired, press the corresponding button (refer to Figure 1-11) to illuminate the indicator light and place the system in that mode of operation.

4 Iflow or high speedevaporatorfan speed is desired,

press the FAN SPEED button to illuminate the indicator light and bring speed to the desired level.

5 To open or close the fresh air damper, press the

FRESH AIR button to illuminate the indicator light and bring the damper to the desired position.

6 To read interior or exterior temperature, press the

TEMPERATUREbutton to illuminate the indicator lightandbringthedisplayto the desiredtemperature reading.After a short delay,thedisplaywillreturnto the default set point or return air temperature reading.

7 Setpoint may be changed by pressing the UP or

DOWN arrow button. The UP button will increase the setpoint temperatureand the DOWN button will decrease the setpoint temperature.

8 For additional Micromate operating data refer to

paragraph 2.4.

2.1.3 Self-Test and Diagnostics (Check for Errors and/or Alarms)

Self-test of the main Logic Board electrical circuit is automaticallyinitiated when the system is powered up. If there is an error in the circuit, an alarm will be indicated by flashing LED’s on the Logic Board. If a Micromate is connected to the Logic Board, the error codecanalso be read on thedisplay. If there are no errors inthecircuit,system will operatenormally andflashthe status LED at a one second interval. During normal operation, the Logic Board monitors system operating parameters for out of tolerance conditions. If an out of tolerance condition occurs, ALARM will be indicated through the code LED or on the Micromate display. Refer to section 3 for definition of system errors and alarms and general troubleshooting procedures.

2.1.4 Stopping

Placing the ON/OFF switch in the OFF position or pressing the Micromate ON/OFF button will stop the system operation by removing power to the Logic Board.

2.2 PRE--TRIP INSPECTION

Afterstartingsystem, allowsystemto stabilizefor tento fifteen minutes and check for the following:

a. Listen for abnormalnoises in compressor or fan mo-

tors. b. Checkcompressoroil level. (Refer to section 4.20.3) c. Check refrigerant charge. (Refer to section 4.8.1 ) d. Ensure that self-test has been successfullyperformed

andthat there are noerrors oralarms indicated. (Refer

to section 2.1.3.)

2-1

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AUTO MODE REHEAT

AUTO MODE CYCLE

HEAT MODE

3°F

2°F

1°F

SETPOINT

-- 1 °F

-- 2 °F

-- 3 °F

COOL

HIGH SPEED

LOADED

COOL

HIGH SPEED

4 CYLINDERS

COOL

LOW SPEED

2 CYLINDERS

REHEAT 100%

DUTY CYCLE

LOW SPEED

4 CYLINDERS

3°F

2°F

1°F

SETPOINT

-- 1 °F

-- 2 °F

-- 3 °F

COOL

HIGH SPEED

LOADED

COOL

HIGH SPEED

4 CYLINDERS

COOL

LOW SPEED

2 CYLINDERS

VENT

HEAT

2°F

1°F

SETPOINT

VENT

-- 1 °F

-- 2 °F

HEAT

-- 3 °F

-- 4 °F

3°F

2°F

1°F

SETPOINT

-- 1 °F

HEAT

COOLING MODE COOLING MODE

REHEAT

COOL

HIGH SPEED

LOADED

COOL

HIGH SPEED

4 CYLINDERS

COOL

LOW SPEED

2 CYLINDERS

REHEAT 100%

DUTY CYCLE

LOW SPEED

4 CYLINDERS

3°F

2°F

1°F

SETPOINT

-- 1 °F

CYCLE

COOL

HIGH SPEED

LOADED

COOL

HIGH SPEED

4 CYLINDERS

COOL

LOW SPEED

2 CYLINDERS

VENT

-- 2 °F

Figure 2-1 Capacity Control Diagram

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-- 2 °F

2-2

2.3 MODES OF OPERATION

The system is operated by a Carrier Transicold Micromax microprocessor controllerwhich consists of a logic board (Figure 1-10), relay board (Figure 1-8 or Figure 1-9), and manual operator switches. The logic board regulates operational cycles of the system by energizing or de--energizing Relay Board relays in responsetodeviationsin interiortemperature.Modes of operation include Cooling, Heat and Vent. Refer toFigure 2-1 and the following paragraphs for a description of each mode.

Figure 2-1 shows the Logic Board actions at various temperature deviations from setpoint. On rising temperature, changes occur when the temperature rises above Logic Board setpoints, On falling temperature, changes occur when temperatures falls below Logic Boardsetpoint. The system will operatein thesemodes unless pressures override the Logic Board settings.

2.3.1 T emperature Control

Temperature is controlledby maintaining the return air temperature measured at the return air grille.

2.3.2 Cooling Mode

Coolingis accomplished by energizing the compressor and condenser fans, opening the liquid line solenoid valve and closing the heating valve. Once interior temperature reaches the desired set point, the system may operate in the clutch cycle or reheat mode. Selection of clutch cycle or reheat is factory programmed in accordance with the bus purchase specification.

A controller programmed for clutch cycle will de--energizethecompressorclutchandallowthesystem to operate in the vent mode until further cooling is required.

A controller programmed for reheat will maintain compressor operation and cycle the heat valve to allow reheating of the return air. In the reheat mode interior temperatureis maintained at the desired set point while additional dehumidification takes place.

2.3.3 Heating Mode

In the heat mode the liquid line solenoid is closed and the compressor and condenser fans are shut down. The heat valve is opened to allow a flow of engine coolant through the heat section of the evaporator coil. The evaporator fans speed is varied as required to circulate air over the evaporator coil based on the temperature difference from setpoint.

Heatingwill not startuntil thewatertemperatureswitch (WTS) closes. The WTS is located on the block of the vehicleandisprovidedby theOEM. Itsensestheengine coolant temperature and closes on temperature rise at 105F . Theswitch preventsthe circulationof cooler air throughout the vehicle as the engine comes up to temperature.

2.3.4 Boost Pump

When the unit is in heat the boost pump relay is energized, providing 24 VDC to activate the boost pump.

2.3.5 Vent Mode

In the vent mode the evaporator fans are operated to circulate air in the bus interior.

2.3.6 Fresh Air System

The fresh air damper is opened to allow entrance of ambientair into theairenteringtheevaporatorcoil. The damperisoperatedby thecontrollertoopenwhenreturn airt emperatureiswithin+/--5F (+/--2.8C)of setpoint.

2.3.7 Compressor Unloader Control

When operating in cooling, the unloaders are used to reduce system capacity as return air temperature approaches set point. Operation of the unloaders balances system capacity with the load and thereby prevents overshoot from set point.

Relay Board mounted unloader outputs control the capacity of the compressor by energizing or de-energizing unloader solenoid valves. The model 05K (GR45)has two banks of twocylinders each while the model 05G compressor (GR60) has three banks of two cylinders each. Energizing a valve de-activates a bankofcylinders.The05K right cylinder bank(looking at the pump end) and theoutboardcylinderbanks of the 05G are equipped with unloader valves (UV1 and, for the 05G, UV2), each controlling two cylinders; this allowsthe05Ktobeoperatedwithtwoorfourcylinders and the 05G to be operated with two, four or six cylinders.

Whenever the compressor is started, the unloaders are energized for thirty seconds to reduce starting torque. After thirty seconds, unloaders may be de-energized. Any subsequent changes between energizing and de-energizing the unloaders for temperature control must be staged with a thirty second delay. Once an unloader is energized for pressure control, it remains energized for two seconds to prevent short cycling. Only one unloader may change state at a time when staging is required. Operating parameters for temperature control, suction pressure control and discharge pressure control are as follows.

a. Temperature Control

The unloaders are used to control system capacity by controlling compressor capacity.

1 Compressor Unloader UV1 Relay.

When return air temperature falls to less than 2F (1.1C) above set point unloader UV1 is energized. If temperature rises to greater than 3F (1.7C) above set point, UV--1 will be de--energized to place the compressor at 100% capacity.

2 Compressor Unloader UV2 Relay. When return air

temperature falls to less than 1F (0.6C) above set point unloader UV2 is energized. If temperature rises to greater than 2F (1.1C) above set point, UV--2 will be de--energized to place the compressor (GR60 only) at 66% capacity.

b. Suction Pressure

2-3

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The unloaders are used to control suction pressure and thereby prevent coil frosting:

1 CompressorUnloaderUV1Relay.

Whenthe suction pressuredecreasesbelow26 psig (1.77 bar),unloader UV1 is energizedunloading a cylinder bank (two cylinders); this output will remain energized until the pressure increases to above 34 psig (2.31 bar).

2 Compressor Unloader UV2 Relay.

When suction pressure decreases below 23 psig (1.56 bar) [on a GR60], unloader UV2 is energized unloading the second compressor cylinder bank; this output will remain energized until the pressure increases to above 31 psig (2.11 bar).

c. Discharge Pressure

Dischargepressure is also controlled by the unloaders: 1 Compressor Unloader UV1 Relay.

When the discharge pressure increases above 275 psig (18.71 bar), unloader UV1 is energized; this output will remain energized until the pressure decreases below 220 psig (14.97 bar). Staging is ignored during discharge pressure override.

2 Compressor Unloader UV2 Relay.

When the discharge pressure increases above 285 psig (19.39 bar),unloader UV2 is energized; this output will remain energized until the pressure decreases below 225 psig(15.31 bar).

2.3.8 Evaporator Fan Speed Selection

Temperature control is the primary method of determining the fan speed selection. The following table indicates relay operational status for the various fanmotorstates while Figure 2-1provides Logic Board speed selections at various deviations form set point..

Table 2-1. Evaporator Fan Speed Relay Operation

STATE

HIGH

SPEED

RELA YS

EVAP FAN

RELA Y

Off Off Off Low Off On High On On

2.3.9 Condenser Fan Control

The condenser fans are energized when the compressor clutch output is energized. The fans are started in low speed and will remain in low speed until the discharge pressureincreases to 225 psig(15.31 bar). The fanswill remainin high speed until dischargepressuredecreases below 190 psig (12.93 bar). The fans will also be

activated if a highpressure alarmhas been activated and operation has not been locked out (refer to Table 3-3).

2.3.10 Compressor Clutch Control

A belt driven electric clutch is employed to t ransmit engine power to the air conditioning compressor. De-energizing the clutch electric coil disengages the clutch and removes power from the compressor. The clutch will be engaged when in cooling and disengaged whenthesystemisoff,inheatingor duringhighandlow pressure conditions.

The clutch coil is prevented from engagement when the ambient temperature is below 45F (7.2C).

The clutch coil will be de-energized if the discharge pressure rises to the 300 psig (20.41 bar) cutout setting of the compressor mounted high pressure switch. The clutch coil will energize when the discharge pressure falls to 200 psig (13.61 bar).

The clutch coil will be de-energized if the suction pressure decreases below 10 psig (0.68 bar).

2.3.11 Alarm Description

Alarm descriptions and troubleshooting procedures are provided in section 3.

2.3.12 Hour Meters

Hourmeterreadings are available in the parametercode list of the Micromate. The hour meters record the compressor run time and the total time the evaporator fans are on. The maximum hours is 999,999. Refer to paragraph 2.4.3 for instructions on reading parameter codes.

2.4 MICROPROCESSOR DIAGNOSTICS

The Micromate allows the user to interface with the microprocessor based control. This allows system parameters, alarms and settings to be viewed and modified. On systems with OEM supplied operating switches, a Micromate may be connected as a service tool using a special harness. The following instructions supplement those provided in paragraph 2.1.2. Once a Micromate is connected as a service tool, the following instructions are applicable.

2.4.1 Connecting

Connect the Micromate harness to the service port locatedinthereturnairsectionoftheA/C system.When the Micromate is connected, the panel lights will be energized and the currently stored setpoint will be displayed. If any alarm is active, the reading will be A##, where A indicates that the alarm is active and ## indicates the alarm number.

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2-4

2.4.2 Control

NOTE

1 This procedure should be performed by an

HVAC technician who has been trained on Carrier Model GR system design. Control configuration is preset by the manufacturer and resetting of the parameters should not berequired.ItisrecommendedthatCarrier Service or Engineering is contacted before any control configuration is changed. Carriercannot beresponsibleforfailuresor damage resulting from unauthorized changes.

2 If a replacement LogicModule is installed,

it is necessary to match the configuration jumpers (see Figure 1-10) to the original board. Refer to paragraph 4.24.

a. Turnthe A/C main power switch (located in thedriv-

er’s area) to OFF.

b. Connect the Micromateto the serviceport located in

the return air section. c. Unplug the logic board connector J3. d. Turn theA/Cmain powerswitchback to the ONposi-

tion. e. Activate the system by pressing the 1/0 key on the

Micromate panel.

NOTE

Be sure to reconnect J3 when testing is completed or the system will fail to operate when the Micromate is disconnected.

NOTE

When modifying the setpoint temperature for diagnostic purposes, be sure to reset the setpoint when testing is complete.

2.4.3 Diagnostic Mode

Diagnostic mode can be entered by pressing the up and down arrow keys simultaneously for 5 seconds. Diagnostic mode allows alarms and system parameters to be viewed. If there are any alarms stored, the most recent alarm will be shown. To view additional alarm information, refer to section 3. Press the up and down arrow keys to view parameters.

2.4.4 System Parameters

Pressing the up/down arrow keys will allow the user to scroll up or down through the parameters. If no key is pressed for 30 seconds this mode is exited and the display will revert back to the default display.Pressing the on/off key any time will exit this mode and the display will again indicate the default. The parameters are shown in Table 2-3. When scrolling through the parameters, the current parameter will be displayed for two seconds. After two seconds, the display will show the data for the current parameter. When the last parameter is reached, the list will wrap back to P1.

2.4.5 T est Mode

Withthe system in normal operation,thecontrollermay be placed in the test mode, by doing the following:

a. Enter the diagnostic mode by pressing the up and

downarrow keyssimultaneouslyfor5 seconds. Enter the test mode by pressing the COOL key five times.

b. In the test mode, the display will read “T##” where

“##” indicated the test number t hat is currently running.

c. The initial indication will be “T00”. This indicates

thecontrolleris in thetestmodeand all relays arede-energized. Press the arrow keys to scroll through and perform each test When the highest test number is reached, thedisplaywill increment back tothelowest test number. A listing of tests is provided in Table 2-2.

d. To terminate testing, press the I/0 key.

Table 2-2. Controller Test List

TEST

OUTPUT STATE

T00 All Relays Off T01 Evaporator High On T02 Evaporator Low On T03 Condenser High On T04 Condenser Low On T05 Compressor On T06 Unloader Valve 1 On T07 Unloader Valve 2 On T08 Fresh Air Damper On T09 Heat On T10 Fault On T11 Boost On T12 Spare/Motor Input On

2-5

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Table 2-3. Parameter Codes

CODE

P1 Return Air

CODE NAME DESCRIPTION

This value is the temperature measured by the return air sensor. If the sensor is

Temperature

shorted it will display CL. If it is open circuited it will display OP.

P2 Coil Temperature This value is the coil temperature measured by the evaporator temperature sen-

sor. If the sensor is shorted it will display CL. If it is open circuited it will display OP.

P3 Ambient Temperature This value is the outside temperature measured by the ambient temperature

sensor. If the sensor is shorted it will display CL. If it is open circuited it will display OP.

P4 Suction Line Temper-

Not used.

ature

P5 Suction Pressure This value is the suction pressure measured by the suction pressure transducer.

If the sensor is shorted it will display CL If it is open circuited it will display OP.

P6 Discharge Pressure This value is the discharge pressure measured by the discharge pressure trans-

ducer. If the sensor is shorted it will display “CL” and if it is open circuited it

will display “OP”. P7 Superheat Not used. P8 Analog Set Point

Not used.

Temperature

P9 A/C Control Window#1This is the number of degrees F above setpoint at which the unloaders will be

both energized. This value can be modified between 0 and 10 degrees F. The

default value is 1 degree F.

P10 A/C Control Window#2This is the number of degrees F above AC control window one at which the

first unloader will be energized. This value can be modified between 0 and 10

degrees F. The default value is 1 degree F.

P11 A/C Control Window#3This is the number of degrees F above AC control window two at which the

evaporator fan speed will be set to low. This value can be modified between 0

and 10 degrees F . The default value is 1 degree F .

P12 Heat Control Window This is the number of degrees F below setpoint before the heat valve is energi-

zed. This value can be modified between 0 and 10 degrees F. The default value

is 2 degree F for heat and 4 degrees F for reheat.

P13 Compressor Safety

Off Delay

This number is the minimum time in minutes that the compressor must be off

after a high or low pressure alarm before it can be restarted. This value can be

modified between one and five minutes. The default value is 1.

P14 Fan Delay This is the minimum time (in seconds) that the fans must run at a particular

speed before changing to another speed. This value can be modified between

one and 60 seconds. The default value is two seconds.

P15 Unloader/Heat Valve

Delay

This is the minimum time (in seconds) that the unloaders and heat valve must

be in a particular state (open /closed) before changing to another state. This

value can be modified between 1 and 60 seconds. The default value is 2 sec-

onds.

P16 Compressor High

Pressure Switch

P17 Condenser Fan Speed

This is the current state of the compressor high pressure switch input. “CL”

will be displayed i f it is closed and “OP” will be displayed if it is open.

Not used.

Switch

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2-6

Table 2-3. Parameter Codes -- Continued

Code

Code Name Description

P18 Maximum Setpoint This is the maximum value that the operator will be allowed to set the setpoint

temperature. The value can be modified in degrees with the up and down keys to a value between 60F and 80F.

P19 Minimum Setpoint This is the minimum value that the operator will be allowed to set the setpoint

temperature. The value can be modified in degrees with the up and down keys to a value between 60F and 80F.

P20 Compressor Hours

High

P21 Compressor Hours

Low

P22 Evaporator Hours

High

P23 Evaporator Hours

Low

P24 Maintenance 1 Hour

High

This is the number of hours of operation that the compressor has run with the clutch energized in thousands

This is the number of hours of operation that the compressor has run with the clutch energized in hundreds, tens and ones.

This is the number (in thousands) of hours of operation with the evaporator fans energized.

This is the number (in hundreds, tens and ones) of hours of operation with the evaporator fans energized.

This is the value of compressor hours high (P20) at which maintenance alarm #1 will be activated. This value can be modified by the up and down arrow keys. If both high and low values are zero the alarm is disabled.

P25 Maintenance 1 Hour

Low

This is the value of compressor hours low (P21) at which maintenance alarm #1 will be activated. This value can be modified by the up and down arrow keys. If both high and low values are zero the alarm is disabled.

P26 Maintenance 2 Hours

High

This is the value of evaporator fan hours high (P22) at which maintenance alarm #2 will be activated. This value can be modified by the up and down arrow keys. If both high and low values are zero the alarm is disabled.

P27 Maintenance 2 Hours

Low

This is the value of evaporator fan hours low (P23) at which maintenance alarm #2 will be activated. This value can be modified by the up and down arrow keys. If both high and low values are zero the alarm is disabled.

P28 Freeze Alarm Setting This is the value at which the freeze alarm will be activated. The default value

is 32F. This value can be modified between 20F and 40F in one degree in-

crements by using the arrow keys P29 Relay Module Voltage This is the voltage being supplied to the relay module. P30 Main Board Software

This is the software version of the logic board.

Version

P31 Display Software

This is the software version of the display module.

Version P32 Ki Not used. P33 Kp Not used. P34 Default Display This is the value displayed on the Micromate control panel. It is set to OFF to

display set point temperature or set to ON to display return air temperature. This feature is available in software revision 1.9 and later.

P33

Not Defined Not used. These codes will show in software revision 1.9 and later.

P34

2-7

T--295

SECTION 3

TROUBLESHOOTING

CAUTION Donot under anycircumstancesattempt toservicethemicroprocessor. should aproblem developwith the microprocessor, replace it.

3.1 SELF DIAGNOSTICS

errorcodes can be read by counting thenumber of times

that the Logic Board STATUS and CODE LED’s (see A self test is performed by the Micromax Logic Board each time the boardis poweredup.Errors,ifany,willbe indicated and the unit will not be allowed to start. The

Table 3-1 Error Codes

CODE

NAME DESCRIPTION

Figure 1-10) flash simultaneously. The Micromate

display will indicate errors with the code ER-#, where

“ER” is the error prefix and # is the error number.

ER 1 Data Memory Logic board data memory failure. ER 2 Program Memory Logic board program memory failure. ER 3 A/D A/D and multiplexer failure. ER 4 Communication Failure Failure in communication between the logic board and MDST. ER 5 Program Memory Display program memory failure.

3.2 SYSTEM ALARMS

3.2.2 Activation

When alarms are detected, they are placed in an alarm

3.2.1 Alarm Codes

queue in the order at which they initiated unless the

alarm is already present. Each alarm recorded will also

captureanevaporatorhourmeterreadingcorresponding The Micromax Logic Board continuously monitors

system parameters and will generate an ALARM if a parameter exceeds preset limits. Alarms are indicated and the controller will respond in accordance with the informationprovided in Table 3-2.Thealarmcodescan be read by counting the number of times that the Logic Board CODE LED (see Figure 1-10) flashes. Each alarm code is a two digit number,the first set of flashes is the first digit and (after a slight pause) the second set of flashes is the second digit. The Micromate display will indicate alarms with the code A-## or i--##, where “A” is an active alarm prefix, “i” is an inactive alarm prefixand ## is the errornumber. If multiple alarmsare present the user can scroll through each alarm by pressing the ARROW keys. When the end of the alarm list is reached the display will show “------”. If the auto key is held down for five seconds while “------” is displayed all inactive alarms are cleared. A listing of alarm codes is provided in Table 3-2.

to the activation time. If the AUTO key is pressedwhile

analarmisdisplayed,the activationtimecapturewillbe

shown.

3.2.3 Alarm Queue

The alarm queue consist of 10 alarm locations. When

the alarm queue is full the Logic Board will take the

requiredactionbut the alarmwill not be recorded.When

this situation occurs, an “AlarmQueue Full”alarm will

be generated. When the alarms are viewed this will be

the first alarm to be shown.

3.2.4 Alarm Clear

Theuser may clearinactivealarmsusingtheMicromate

keypad. Refer to paragraph 3.2.1.

3.3 TROUBLESHOOTING

General procedures for system troubleshooting are

provided in Table 3-3

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3-1

Table 3-2 Alarm Codes

ALARM

NO.

TITLE CAUSE REMEDY CONTROLLER

A11 Coil Freeze Coil temperature is

less than 32F and the compressor is operating.

A12 High Voltage The battery voltage is

greater than 32 volts.

A13 Low Voltage The battery voltage is

less than 17 volts.

A14 Return Air Probe Failure Return air temperature

sensor failure or wiring defective.

A15 Suction Pressure

Transducer Failure

Suction pressure transducer failure or wiring defective.

A16 Discharge Pressure

Transducer Failure

Discharge pressure transducer failure or wiring defective.

A17 Low Pressure Shutdown Low suction pressure

switch open or wiring defective.

A21 High Discharge Pressure High discharge pres-

sure switch open or wiring defective.

Check causes of coil freezing. (Refer to section 3.3.6)

Check, repair or replace alternator.

Check, repair or replace wiring or alternator.

Ensure all connectors are plugged in. Check sensor resistance or wiring. Refer to paragraph 4.21. Replace sensor or repair wiring.

Ensure all connectors are plugged in. Check sensor voltage or wiring. Replace sensor or repair wiring.

Check cause of low suction pressure. (Refertosection3.5.3)

Check discharge pressure transducer reading, wiring or cause of high discharge pressure. (Refer to section

3.3.3)

RESPONSE

An alarm will be generated and the system will shutdown. The evaporator fans will remain running while the compressor is off.

The system is shut down until the voltage returns to normal levels.

All outputs except the evaporator fans will be de-energized.

Both unloaders are energized.

One unloader is energized.

The clutch is de-energized for the minimum off time. The evaporator fans will remain running during this period. After the compressor cycles off three times in 30 minutes all outputs will be de-energized and the system is locked out until the power is cycled or the alarm is reset.

The clutch is de-energized for the minimum off time. The condenser and evaporator fans will remain running during this period. After the compressor cycles off three times in 30 minutes all outputs will be de-energized and the system is locked out until the power is cycled or the alarm is reset.

3-2

T--295

Table 3-2 Alarm Codes -- Continued

ALARM

TITLE CAUSE REMEDY CONTROLLER

A22 Breaker Trip Alarm A breaker on the relay

board has tripped or a fan relay has failed.

A23 Evaporator Fan Overload Evaporator fan over-

load jumper is open.

A24 Condenser Fan Overload Condenser fan over-

load jumper is open.

A25 Motor Failure A brushless motor has

not reached full operating speed or a motor

failure. A26 Not used A31 Maintenance Alarm 1 The compressor hour

meter is greater than

the value in Mainte-

nance Hour Meter 1. A32 Maintenance Alarm 2 The evaporator hour

meter is greater than

the value in Mainte-

nance Hour Meter 2.

Check breakers for tripped device. Repair short and reset breaker .

Ensure connector is plugged in or repair wiring.

Replace motor, or correct pressure shutdown.

Reset the maintenance hour meter.

RESPONSE

Alarm will be generated.

Alarm displayed and the motor fail output is energized.

Alarm will be generated.

A99 Alarm Queue Full All locations of the

alarm queue are cur-

rently full and no

more alarms can be

saved.

Record and clear alarm queue.

Alarm will be generated.

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3-3

Table 3-3 General System Troubleshooting Procedures

INDICATION/

TROUBLE

3.3.1 System Will Not Cool

POSSIBLE CAUSES

Compressor will not run Active system alarm

V-Belt loose or defective Clutch coil defective Clutch malfunction Compressor malfunction

Electrical malfunction Coach power source defective

Circuit Breaker/safety device open

3.3.2 System Runs But Has Insufficient Cooling

Compressor V-Belt loose or defective

Compressor valves defective

Refrigeration system Abnormal pressures

No or restricted evaporator air flow Expansion valve malfunction Restricted refrigerant flow Low refrigerant charge Service valves partially closed Safety device open Liquid solenoid valve stuck closed

REFERENCE

SECTION

3.2

Check Check/Replace Check/Replace

See Table 1-2.

Check/Repair

Check/Reset

Check

See Table 1-2.

3.3.3

3.3.6

3.3.7

4.11

4.8

Open

1.6

Check

Restricted air flow No evaporator air flow or restriction 3.3.6 Heating system Heat valve stuck open 3.3.8

3.3.3 Abnormal Pressures

High discharge pressure Discharge transducer failure

Refrigerant overcharge Noncondensable in system Condenser motor failure Condenser coil dirty

Low discharge pressure Discharge transducer failure

Compressor valve(s) worn or broken Low refrigerant charge

Replace

4.8.1 Check Check

Clean

See Note.

See Table 1-2.

4.8 High suction pressure Compressor valve(s) worn or broken See Table 1-2. Low suction pressure Suction service valve partially closed

Filter-drier inlet valve partially closed Filter-drier partially plugged Low refrigerant charge Expansion valve malfunction Restricted air flow Suction transducer failure

Suction and discharge pressures

Compressor valve defective See Table 1-2.

Open

Check/Open

4.11

4.8

3.3.7

3.3.6

Replace

tend to equalize when system is operating

3.3.4 Abnormal Noise Or Vibrations

Compressor Loose mounting hardware

Worn bearings Worn or broken valves Liquid slugging Insufficient oil Clutch loose, rubbing or is defective V-belt cracked, worn or loose Dirt or debris on fan blades

Check/Tighten See Table 1-2.

SeeTable 1-2.

3.3.7

4.20.3 Check

Check/Adjust

Clean

3-4

T--295

Table 3-3 General System Troubleshooting Procedures -- Continued

INDICATION/

TROUBLE

3.3.4 Abnormal Noise Or Vibrations -- Continued

POSSIBLE CAUSES

Condenser or evaporator fans Loose mounting hardware

Defective bearings Blade interference Blade missing or broken

3.3.5 Control System Malfunction

Will not control Sensor or transducer defective

Relay(s) defective Microprocessor controller malfunction

REFERENCE

SECTION

Check/Tighten

Replace

Check

Check/Replace

4.21 or 4.22 Check Check

Logic Board J3 connector unplugged

3.3.6 No Evaporator Air Flow Or Restricted Air Flow

Air flow through coil blocked Coil frosted over

Dirty coil Dirty filter

No or partial evaporator air flow Motor(s) defective

Motor brushes defective Evaporator fan loose or defective Fan damaged Return air filter dirty Icing of coil Fan relay(s) defective Safety device open Fan rotation incorrect

3.3.7 Expansion Valve Malfunction

Low suction pressure with high superheat

Low refrigerant charge Wax, oil or dirt plugging valve orifice Ice formation at valve seat Power assembly failure Loss of bulb charge Broken capillary tube

Low superheat and liquid slugging in the compressor

Bulb is loose or not installed. Superheat setting too low

Defrost coil

Clean

Clean/Replace

Repair/Replace

Replace Repair/Replace Repair/Replace

Clean/Replace

Clean/Defrost

Check/Replace

1.6

Check

4.8

Check

4.6 Replace Replace

4.19

Ice or other foreign material holding valve open

Side to side temperature difference (Warm Coil)

3.3.8 Heating Malfunction

Insufficient heating Dirty or plugged heater core

No Heating Coolant solenoid valve(s) malfunctioning or plugged

Wax, oil or dirt plugging valve orifice Ice formation at valve seat Power assembly failure Loss of bulb charge Broken capillary

Coolant solenoid valve(s) malfunctioning or plugged Low coolant level Strainer(s) plugged Hand valve(s) closed Water pumps defective Auxiliary Heater malfunctioning.

Controller malfunction Pump(s) malfunctioning Safety device open

Check

4.7 Replace Replace

4.19

Clean

Check/Replace

Check

Clean

Open Repair/Replace Repair/Replace

Check/Replace

Replace

Repair/Replace

1.6

Continuous Heating Coolant solenoid valve stuck open Replace

T-295

3-5

SECTION 4

SYSTEMREFERENCE

SERVICE

WARNING

BE SURE TO OBSERVEWARNINGS LISTED IN THE SAFETY SUMMARY INTHE FRONT OF THIS MANUAL BEFORE PERFORMING MAINTENANCE ON THE HVAC SYSTEM

NOTE

Followingcompletionofallmaintenanceorserviceactivities,the alarmqueueshouldbe clearedof anyoriginal alarms and any alarms generated during service. Refer to paragraph 3.2.1

4.1 MAINTENANCE SCHEDULE SYSTEM

ON OFF

a. Daily Maintenance

Pre-trip Inspection -- after starting

Check tension and condition of V-belt

b. W eekly Inspection

Perform daily inspection

Check condenser, evaporator coils and air filters for cleanliness

Check refrigerant hoses and compressor shaft seal for leaks

Feel filter-drier for excessive temperature drop across drier

c. Monthly Inspection and Maintenance

Perform weekly inspection and maintenance

Clean evaporator drain pans and hoses

Check wire harnesses for chafing and loose terminals

Check fan motor bearings

Check compressor mounting bolts for tightness

Check fan motor brushes

4.2 OPENING TOP COVER

To open the top cover, push in on the latches and pull forward as the cover is lifted . (See Figure 4-1.)

REFERENCE

SECTION

2.2 None

See above None

4.6

4.11

See above None Replace/Tighten None None None

4.3 SUCTION AND DISCHARGE SERVICE VALVES

The suction and discharge service valves (Figure 4-2) areprovidedwith a double seat and a gauge port, which allowsservicingofthe compressorand refrigerantlines.

PUSH IN ON LATCHES

Figure 4-1. Opening Top Cover

PULL & LIFT

Turning the valve stem counterclockwise (all the way out) will backseat the valve to open the line to the compressor and close off the gauge port. In normal operation, the valve is backseated to allow full flow through the valve. The valve should always be backseated before removing the gauge port cap.

Turning the valve stem clockwise(all the wayforward) will frontseat the valve to isolate the compressor line and open the gauge port.

To measure suction or discharge pressure, midseat the valve by opening the valve clockwise 1/4 to 1/2 turn. With the valve stem midway between frontseated and backseated positions, the suction or discharge gauge port is open to both the compressor and the line.

4-1

T-295

TO DISCHARGE OR FROM SUCTION LINE

PORT TO COMPRESSOR

Service Valve Frontseated (clockwise)

Figure 4-2.Suction or Discharge Service Valve

4.4 INSTALLING MANIFOLD GAUGE SET

SERVICE PORT

Service Valve Backseated (counterclockwise)

VALVE CAP

VALVE STEM

e. Frontseat (clockwise) both manifold gauge hand

valves.

f. Turn the service valve connected to the discharge

gauge port toward frontseat (clockwise) approximately 1/4 to 1/2 turn.

g. Slowly turn the manifold discharge hand valve to-

ward backseat (counterclockwise) approximately

one turn. h. Tighten charging hose onto dummy fitting. i. Slowly turn the manifold suction hand valve toward

backseat (counter--clockwise) to remove air from

line. j. Tighten suction hose at the service valve port. k. Frontseat (close) both manifold hand valves. l. Turntheservicevalve connectedto the suction gauge

port toward frontseat (clockwise) approximately 1/4

to 1/2 turn.

A manifold gauge set (Figure 4-3) can be used to determine system operating pressures, add charge, equalize or evacuate the system.

Suction Pressure Gauge

Hand Valve (Backseated)

A. Connection to Low Side of System B. Connection to High Side of System C. Connection to Vacuum Pump, Refrigerant

Cylinder, Oil Container or Evacuation Line

Figure 4-3. Manifold Gauge Set

ABC

Discharge Pressure Gauge

Hand Valve (Frontseated)

When the suction pressure hand valve is frontseated (turnedall the wayin), thesuction(low)pressure can be read. When the discharge pressure hand valve is frontseated, discharge (high) pressure can be read. When both valves are open (turned counterclockwise), high pressure vapor will flow into the low side. When only the low pressure valve is open, the system can be charged or evacuated. To install a manifold gauge set, do the following (refer to Figure 4-4, Figure 4-5 or Figure 4-6 as applicable).

a. Remove the service valve stem caps and backseat

(counterclockwise) both valves. Remove the service port caps.

b. Connectthe discharge side hose tightly to the service

valve port.

c. Connect the suction side hoselooselyto theotherser-

vice valve port.

d. Loosen charging (center) hose at dummy fitting of

manifold set.

4.5 PUMPING THE SYSTEM DOWN OR REMOV-

ING THE REFRIGERANT CHARGE

NOTE

To avoid damage to the earth’sozone layer, use arefrigerant recovery system wheneverremoving refrigerant.

4.5.1 System Pump Down For Low Side Repair

To service or replace the filter--drier, thermostatic expansionvalve, suction lineor evaporator coils, pump the refrigerant to the condenser and receiver as follows:

a. Install m anifold gauge set. Refer to Figure 4-4 b. Frontseat the filter--drier inlet service valve by turn-

ingclockwise.Disconnectsuction pressuretransduc-

er and install a jumper on the compressor mounted

low pressure switch. c. St art the system and run in cooling. Stop the unit

when suction reaches 10 ”/hg (25.4 cm/hg) vacuum. d. Frontseatcompressor suction servicevalvetotrapre-

frigerant in the high side of the system between the

compressor suction service valve and the filter--drier

inlet valve. Wait 5 minutes to verify that system re-

mains in a vacuum. If system pressure rises above

vacuum, open compressor suction service valve and

repeat steps c and d until system remains in vacuum. e. Service or replace necessary components. f. Leak check connections and replace filter--drier. Re-

fer to paragraph 4.6. g. Usingrefrigeranthoses designed for vacuum service,

evacuateand dehydratethe low side of the system by

connecting a vacuum pump to center connection of

manifoldgauge set. Evacuate system to 500microns.

Closeoffpump valve,isolatevacuum gauge andstop

pump. Wait 5 minutes to verify that vacuum holds. h. Recharge low side to 20 to 30 psig (1.36 to 2.04 bar)

by admitting vapor from the refrigerant cylinder.

T-295

4-2

f. Check refrigerant level. Refer to paragraph 4.8.1. It

may be necessary to clear any alarms that have been generated.

9 8

1. Filter-Drier Inlet Service Valve

2. Thermostatic Expansion Valve

3. Manifold Gauge Set

4. Thermistor Vacuum Gauge

Figure 4-4. Low Side Pump Down Connections

5. Vacuum Pump

6. Refrigerant Cylinder

7. Reclaimer

8. Filter-Drier

9. Liquid Solenoid Valve

10. Filter-Drier Outlet Service Valve

i. Re--connect suction pressure transducer and remove

low pressure switch jumper. If required, clear any alarms that have been generated during this procedure.

j. Open service valves and check refrigerant level. Re-

fer to paragraph 4.8.1.

4.5.2 Refrigerant Removal From An Inoperative Compressor.

Toremove the refrigerant from a compressor that isnot operational, do the following:

a. Attach a manifold gauge set as shown in Figure 4-5

andisolatethecompressorbyfrontseatingthesuction and discharge valves.

b. Recoverrefrigerantwitharefrigerantreclaimer. Ifthe

discharge service valve port is not accessible, it will be necessary to recover refrigerant through the suction service valve port only.

c. Service or replace components as required and leak

check the compressor.

d. Usingrefrigeranthoses designed for vacuum service,

connect a vacuum pumpto centerconnection ofmanifold gauge set. Evacuate system to 500 microns. Closeoffpump valve,isolatevacuum gauge andstop pump. Wait 5 minutes to verify that vacuum holds.

e. Once vacuum is maintained, recharge low side to 20

to 30 psig (1.36 to 2.04 bar) by admitting vapor from the refrigerant cylinder. Disconnect manifold gauge set and backseat compressor service valves.

1. Discharge Service Valve and Port

2. Suction Service Valve and Port

3. Manifold Gauge Set

Figure 4-5. Compressor Service Connections

4.5.3 Pump Down An Operable Compressor For Repair

4. Vacuum Pump

5. Reclaimer

6. Refrigerant Cylinder

7. Thermistor Vacuum Gauge

To servicean operablecompressor,pumptherefrigerant into the condenser coil and receiver as follows:

a. Install m anifold gauge set. Refer to Figure 4-5. b. Frontseat the compressor suction service valve by

turning clockwise.

c. Place a jumper on the low pressure switch. Start the

unit and run in cooling until 10 ”/hg (25.4 cm/hg) of vacuum is reached. Shut the system down.

d. Frontseatthe compressor dischargeservice valve and

wait5 minutes to verify vacuum is maintained.If the pressure rises above vacuum, open the compressor dischargeservicevalveand repeatsteps candd until a vacuum is maintained.

e. Service or replace components as required and leak

check the compressor.

f. Usingrefrigeranthoses designed for vacuumservice,

connect a vacuum pumpto centerconnection ofmanifold gauge set. Evacuate system to 500 microns. Closeoffpump valve,isolatevacuum gauge andstop pump. Wait 5 minutes to verify that vacuum holds.

g. Oncevacuum is maintained,re--connectlowpressure

switch,disconnect manifoldgaugesetand open compressor service valves.

h. Check refrigerant level. Refer to paragraph 4.8.1. It

may be necessary to clear any alarms that have been generated.

4-3

T-295

1. Suction Service Valve and Port

2. Discharge Line Service Port

3 Check Valve

4. Manifold Gauge

Figure 4-6. System Charge Removal Connections

4.5.4. Removing Entire System Charge

Set

5. Vacuum Pump

6. Reclaimer

7. Refrigerant Cylinder

8. Thermistor Vacuum Gauge

To remove the entire refrigerant charge, do the following:

a. Connect a manifold gauge setto the system asshown

in Figure 4-6.

b. Connect a reclaimer to the center manifold gauge set

connection.

c. Recover refrigerant in accordance with reclaimer

manufacturers instructions.

4.6 REFRIGERANT LEAK CHECK

A refrigerant leak check should always be performed after the system has been opened to replace or repair a component.

To check for leaks in the refrigeration system, perform the following procedure:

NOTE

It must be emphasized that only the correct refrigerant should be used to pressurize the system. Use of any other refrigerant will contaminate the system, and require additional evacuation.

a. Ensure theliquid line serviceandsolenoid valves are

open.

b. If system is without refrigerant, charge system with

refrigerant vapor to build up pressure between 20 to 30psig(1.36to2.04bar).

c. Add sufficient nitrogen to raise system pressure to

150 to 200 psig (10.21 to 13.61 bar).

d. Check for leaks. The recommended procedure for

finding leaksina system is withan electronic leak detector. Testing joints with soapsuds is satisfactory

only for locating large leaks. e. Remove test gas and replace filter--drier. f. Evacuate and dehydrate the system. (Refer to para-

graph 4.7.) g. Charge the unit. (Refer to paragraph 4.8.) h. Ensure that a Logic Board self-test has been per-

formed and that there are no errors or alarms indi-

cated. (Refer to paragraph 2.1.3.)

4.7 EVACUATION AND DEHYDRATION

4.7.1 General

The presence of moisture in a refrigeration system can have many undesirable effects. The most common are copper plating, acid sludge formation, “freezing-up”of metering devices by free water, and formation of acids, resulting in metal corrosion.

4.7.2 Preparation

NOTE

Using a compound gauge for determination of vacuum level is not recommended because of its inherent inaccuracy.

a. Evacuate and dehydrateonly after pressure leak test.

(Refer to paragraph 4.6) b. Essential tools to properly evacuate and dehydrate

anysystem includeagood vacuumpumpwithamini-

mum of 5 cfm (8.5 m

/hr) volume displacement,

(CTD P/N 07-00176-01), and a good vacuum indica-

tor (available through Robinair Manufacturing,

Montpelier, Ohio, Part Number 14010). c. Keep the ambient temperature above 60F (15.6C)

tospeed evaporationofmoisture.Ifambienttempera-

tureis lowerthan 60F (15.6C),i ce may form before

moisture removal is complete.

4.7.3 Procedure for Evacuation and Dehydrating

System

a. Remove refrigerant using a refrigerant recovery sys-

tem. Refer to paragraph 4.5.4 b. The recommended method is connecting lines (3/8”

OD copper tubing or refrigerant hoses designed for

vacuum service) as shown in Figure 4-6. c. Make sure vacuum pump valve is open. d. Startvacuumpump. Slowly openvalves halfway and

then open vacuum gauge valve. e. Evacuate unit until vacuum gaugeindicates1500mi-

crons Hg vacuum. Close gauge valve, vacuum pump

valve, and stop vacuum pump. f. Break the vacuum with clean dry refrigerant. Use re-

frigerantthat the unit callsfor. Raise system pressure

to approximately 2 psig (0.14 bar).

T-295

4-4

g. Remove refrigerant using a refrigerant recovery sys-

tem.

h. Start vacuum pump and open all valves. Dehydrate

unit to 500 microns Hg vacuum.

i. Closeoffpump valve, and stop pump. Waitfive min-

utes to see if vacuum holds.

j. Charge system. Refer to paragraph 4.8.2

4.8 ADDING REFRIGERANT TO SYSTEM

4.8.1 Checking Refrigerant Charge

The following conditions must be met to accurately check the refrigerant charge.

a. Coach engine operating at high idle. b. Unit operating in cool mode for 15 minutes. c. Headpressure at least 150psig (10.21 bar). (It maybe

necessary to block condenser air flow to raise head pressure.)

d. Under the above conditions, the system is properly

charged when the refrigerant liquid level is at 1/2 to 3/4 of the lower receiver sight glass. If it is not at the proper level, add or remove refrigerant to bring it to the proper level. Refrigerant level should not appear

in the upper sight glass, as this would indicate an overcharge.

4.8.2 Adding Full Charge

a. Install manifold gauge set at the compressor suction

service valve and service port above the discharge line check valve. See figure Figure 4-6.

b. Evacuate and dehydrate system. (Refer to paragraph

4.7)

c. Pl ace appropriate refrigerant cylinderon scales. Pre-

pare to charge liquid refrigerant by connect charging hose from container to center connection on gage

manifold . Purge air from hoses. d. Note weight of refrigerant and cylinder. e. Open cylinder valve, backseat discharge valve on

gauge manifold and allow liquid refrigerant to flow

into the high side of the system f. When correct charge has been added, refer to para-

graph 1.3, close cylinder valve and frontseat man-

ifold discharge valve. At this point, the high side of

thesystemhasbeencharged but the lowsideis still in

avacuum becausetheliquidline solenoid is normally

closed. g. Preparethe cylinder as requiredto allowvaporcharg-

ing. Backseat the manifold suction valve and charge

vapor to build 20 to 30 psig (1.36 to 2.04 bar) pres-

sure on the manifold suction gauge. Close cylinder

valve and frontseat suction manifold set. h. Check charge level inaccordancewith theprocedures

of paragraph 4.8.1.

4.8.3 Adding Partial Charge

a. Install manifold gauge set at the compressor suction

service valve and service port above the discharge line check valve. See figure Figure 4-6.

b. Place appropriate refrigerant cylinder on scales. Pre-

pareto chargevapor refrigerantby connecting charging hose from container to center connection on gauge manifold . Purge air from hoses.

c. Run unit in cool mode for 15 minutes. With suction

servicevalve midseated open cylinder valve and add vapor charge until refrigerant level appears in the lower receiver sight glass. Under the above conditions, the system is properly chargedwhen the refrigerant liquid levelis at 1/2 to 3/4 of the lower receiver sight glass. If it is not at the proper level, add or remove refrigerant to bring it to the proper level. Re-

frigerant level should not appear in the upper sight glass, as this would indicate an overcharge.

d. Backseat suction servicevalve. Closevapor valve on

refrigerant drum and note weight. Remove manifold gauge set and replace all valve caps.

4.9 CHECKING FOR NONCONDENSIBLES

T o check for noncondensibles, proceed as follows: a. Stabilize system to equalize pressure between the

suction and discharge side of the system. b. Check temperature at the condenser and receiver. c. Check pressure at the compressor discharge service

valve. d. Check saturation pressure as it corresponds to the

condenser/receiver temperature using the Tempera-

ture-Pressure Chart, Table 4-4. e. If gauge reading is 3 psig (0.20 bar) or more than the

saturation pressure in step d, noncondensibles are

present. f. Remove refrigerant using a refrigerant recovery sys-

tem. g. Evacuate and dehydrate the system. (Refer to para-

graph 4.7.) h. Charge the unit. (Refer to paragraph 4.8.2.)

4.10 CHECKING AND REPLACING HIGH PRES-

SURE SWITCH

WARNING DO NOT USE A NITROGEN CYLINDER WITHOUT A PRESSURE REGULATOR

WARNING DO NOT USE OXYGEN IN OR NEAR A REFRIGERATION SYSTEM AS AN EXPLOSION MAY OCCUR.

a. Disconnect wiring and remove switch from unit. All

units are equipped with a schrader valve at the high pressure switch connection.

b. Connect switch to a cylinder of dry nitrogen. (See

Figure 4-7.)

4-5

T-295

1. Cylinder Valve and Gauge

2. Pressure Regulator

3. Nitrogen Cylinder

4. Pressure Gauge (0 to 400 psig = 0 to 27.22 bar)

5. Bleed-Off Valve

6. 1/4 inch Connection

Figure 4-7. Checking High Pressure Switch

c. Connect an ohmmeter across switch terminals. d. Set nitrogen pressure regulator higher than switch

cutout setting. (refer to paragraph 1.3.)

e. Closecylinder valveand open bleed--offvalve. Open

cylinder valve andslowly closebleed--off valve. The switch should open, (no continuity) with in required cut out tolerance.

f. Closecylindervalveand releasepressure through the

bleed-off valve. As pressure drops, switch should close, (continuity) within required cut in tolerance.

g. Replace or re--install switch (as required) and recon-

nect wiring.

4.11.2 To Replace Filter--Drier

a. Perform a low side pump down. Refer to paragraph

4.5.1. b. Turn the driver’s A/C switch to “OFF” position. c. Frontseat the filter--drier outlet service valve and

place a new filter-drier near the unit for immediate installation.

WARNING THE FILTER-DRIER MAY CONTAIN LIQUID REFRIGERANT. SLOWLY LOOSEN THEFLARE NUTSANDAVOID

CONTACT WITH EXPOSED SKIN OR EYES.

d. Using two open end wrenches, slowly crack open the

flare nuts on each side of the filter-drier. Remove the filter- drie r.

e. Remove seal caps from the new filter-drier. Apply a

light coat of compressor oil to the flares.

f. Assemble the new filter-drier to lines ensuring that

the arrow on the body of the filter-drier points in the direction of the refrigerant flow (refrigerant flows from the receiver to the evaporator). Finger tighten flare nuts.

g. Tighten filter-drier flare nuts using two open end

wrenches.

h. Evacuate the filter--drier and lines by connecting a

vacuum pump as shown in Figure 4-4. Evacuate to 500 microns.

i. Backseat (fullyclose) bothservicevalve portsandre-

place valve caps.

4.11 FILTER-DRIER

1234 5 623

1. Filter-Drier Inlet Service Valve

2. Valve Service Port

3. Flare Nut

4. Filter-Drier

Figure 4-8. Filter--Drier Removal

4.11.1 To Check Filter--Drier

5 Liquid Line

Solenoid Valve

6. Filter-Drier Outlet Service Valve

The filter--drier (see Figure 4-8) must be changed if the receiver mounted moisture indicator shows high moisture content or the drier is partially restricted. Check for a restriction by feeling the inlet and outlet linesof thefilter--drier.If theoutletsidefeelscoolerthan the inlet side, then the filter--drier should be changed

j. Test filter-drier for leaks. k. Check refrigerant level.

4.12 CONDENSER COIL REPLACEMENT

a. Place the driver’sA/C switch in theOFF position and

tag to prevent unintentional starting.

b. Remove the refrigerant charge. Refer to paragraph

4.5.4.

c. Remove the connection access covers to gain access

to the mounting screws. Remove the mounting screwsin the connectioncompartmentandat the rear of the unit next to the receiver supports.

d. Removethefilter--driermounting screwsandremove

the filter--drier. Disconnect the discharge hose.

e. Begin to lift the coil assembly at the left rear. Lift to

clear the service valve then push to the right to clear theprecharge valve. Continue to lift towards thefront to clear the sight glasses and remove from the unit.

f. To install the coil assembly ,reverse the removal pro-

cedure.

T-295

4-6

4.13 EVAPORATOR COIL REPLACEMENT

a. If refrigerant remains in the system, perform a low

sidepumpdown to remove refrigerantfromtheevaporator coils.

CAUTION

If unit was recently operated, be careful of remaininghotcoolant in the hoses whendisassembling.

b. Remove fresh air intake. c. Drain heater coil by removing the required coolant

from the engine cooling system.

d. Remove 12 mounting screws, 4 each at the receiver

support, at the front of the unit and at the return air

opening. e. Remove the electronic board and harness. f. Remove the filter--drier. g. Disconnect suction line hose and lift coil out of unit. h. Toinstall the coilassembly, reverse the removal pro-

cedure.

4.14 SERVICING THE HEAT VALVE

The heat valve (Figure 4-9) requires no maintenance unless a malfunction to the internalparts or coil occurs. This may be caused by foreign material such as: dirt, scale, or sludge in the coolant system, or improper voltage to the coil.

There are only three possible valve malfunctions: coil burnout, failure to open, or failure to close.

Coil burnout may be caused by the following:

1 Improper voltage. 2 Continuous over-voltage, more than 10% or Under-

voltage of more than 15%.

3. Incomplete magnetic circuit due to the omission of

the coil housing or plunger.

4. Mechanical interference with movement of plunger

which may be caused by a deformed enclosing tube.

Failure to open may be caused by the following:

1 Coilburned out or anopencircuitto coil connections. 2 Improper voltage. 3 Torn diaphragm. 4 Defectiveplunger or deformedvalve body assembly.

Failure to close may be caused by the following:

1 Defective plunger or deformed valve body assem-

bly. 2 Foreign material in the valve. 3 Torn diaphragm.

4.14.1 Coil Replacement

a. It is not necessary to drain the coolant from the sys-

tem.

b. Placemainbatterydisconnectswitch in OFF position

and lock. c. Disconnect wire leads to coil. d. Remove coil retaining screw and nameplate. e. Li ft bur ned -out coil from enclo sing tube and replace. f. Connect wire leads and test operation.

4.14.2 Internal Part Replacement

a. PlacemainbatterydisconnectswitchinOFFposition

and lock. b. Openthe vent fitting at the top of the outlet headerof

the heater coil. c. Drain coilbyopeningthe drain-cockon theinlettube. d. Disassemble valve and replace defective parts. e. Assemble valve, refill and bleed coolant lines.

4.14.3 Replace Entire Valve

a. PlacemainbatterydisconnectswitchinOFFposition

and lock. b. Drain coolant from lines as previously describedand

disconnect hoses to valve . c. Disconnect wire leads to coil. d. Remove valve assembly from bracket. e. Install new valve and re-connect hoses. It is not ne-

cessary to disassemblethevalvewheninstalling. f. Refill and bleed coolant lines. g. Connect wire leads and test operation.

2 3

5 6

1. Coil Retaining Screw

2. Nameplate

3. Coil Housing Assembly

4. Enclosing Tube & Bonnet Assembly

Figure 4-9. Heat Valve

5. Kick-Off Spring

6. Plunger

7. Closing Spring

8. D iaphragm

9. O-Ring

10. Valve Body

4-7

T-295

4.15 SERVICING THE LIQUID LINE SOLENOID VALVE

The Liquid line solenoid valve (Figure 4-10) is very similar to the heat valve. It requires no maintenance unless a malfunction to the internalparts or coil occurs. This may be caused by foreign material such as: dirt, scale,or sludge in the refrigerationsystem, or improper voltage to the coil.

There are only three possible valve malfunctions: coil burnout, failure to open, or failure to close.

Coil burnout may be caused by the following:

1 Improper voltage. 2 Continuous over-voltage, more than 10% or under-

voltage of more than 15%.

3 Incompletemagnet circuit due to the omission of the

coil hosing or plunger.

4 Mechanical interface with movement of plunger

which may be caused by a deformed enclosing tube.

Failure to open may be caused by the following:

1 Coilburned out or anopencircuitto coil connections. 2 Improper voltage. 3 Defectiveplunger or deformedvalve body assembly.

Failure to close may be caused by the following:

1 Defectiveplunger or deformedvalve body assembly. 2 Foreign material in the valve.

4.15.1 Coil Replacement

a. It is not necessary to remove the refrigerant charge

from the system.

b. .Place main battery disconnect switch in OFF posi-

tion and lock. c. Disconnect wire leads to coil. d. Remove coil retaining clip and nameplate. e. Lift burned-out coil from enclosing tube and replace. f. Connect wire leads and test operation

1. Snap Cap

2. Coil Assembly

3. Enclosing Tube Assembly

4. Plunger Assembly

Figure 4-10. Liquid Line Solenoid Valve

4.15.3.Replace Entire Valve

5. Gasket

6. Piston Assembly

7. Body

8. Bracket Adapter

a. Perform a low side pump down, remove coil and

plunger assembly and un--braze valve from lines. b. Remove valve assembly from bracket. c. Disconnect wire leads to coil. d. Disassemblenew valve, to protect internal parts, and

solder to lines. e. Assemble and leak check valve. f. Evacuate low side and re--open system. g. Connect wire leads and test operation.

4.16 CONDENSER FAN/MOTOR ASSEMBLY

4.16.1 Removal

a. PlacemainbatterydisconnectswitchinOFFposition

and lock. b. Unlatch motor draw latches. See Figure 4-11. c. Disconnect motor wire harness and lift motor out of

unit.

4.15.2 Internal Part Replacement

a. PlacemainbatterydisconnectswitchinOFFposition

and lock.

b. Perform a low side pump down. Refer to paragraph

4.5.1.

c. Slowly loosen enclosing tube assembly to bleed any

remaining pressure from the valve. Disassemble

valve and replace defective parts. d. Assemble valve and leak check. e. Evacuate low side and re--open system.

T-295

3 2

1. Motor Support

2. Draw Latch

3. Fan/Motor Assembly

Figure 4-11. Condenser Fan/Motor Assembly

4-8

4. Motor

5. Brush

4.16.2 Inspection And Cleaning

a. At regular maintenance periods, remove brush cov-

ers, examine and clean motor interior.

b. Placemainbatterydisconnectswitch in OFF position

and lock.

c. Remove all foreign material. such as dirt and carbon

dust with dry moderately compressed air. Clean by suction if possible to avoid blowing foreign matter into the motor.

d. Confirm free movement of brushes to prevent bind-

ing.

e. Examine brush wear and general condition. If bro-

ken, cracked chipped or worn to 1/3 the original length, replace. Refer to paragraph 4.16.3.

f. Examinethecondition of the brush springs. Adiscol-

oredspring isa sign of overheatingwhich may weaken the spring. If discolored, replace.

g. Observe condition of communtator and armature

coils

4.16.3 Brush Replacement

a. PlacemainbatterydisconnectswitchinOFFposition

and lock. b. Remove condenser motor, refer to paragraph 4.16.1. c. Remove brush covers, remove and inspect brush as-

semblies. Replace if required. d. Replace brush covers and reinstall condenser motor. e. To reassemble, reverse the above procedure. Ensure

motor is properly seated in support. f. Verify the proper operation of motor.

d. To reassemble, reverse procedure.

4.18 REPLACING RETURN AIR FILTERS

The return air filters are located behind the return air grill, inside the vehicle.

The filters should be checked for cleanliness periodicallydepending on operating conditions. A dirty filterwill restrictair flow overtheevaporatorcoilwhich may cause insufficient cooling or heating and possible frost buildup on the coil. To remove the filters, do the following.

a. PlacemainbatterydisconnectswitchinOFFposition

and lock. b. Remove the return air grille. c. Loosen filter retaining clips and remove the filter

from the grille. d. Reverse procedure to install new filters.

4.19 THERMOSTATIC EXPANSION VALVE

The thermostat expansion valve (Figure 4-13) is an automaticdevicewhich maintainsconstantsuperheatof the refrigerant gas leaving the evaporator regardless of suction pressure. The valve functionsare:(a)automatic control of refrigerantflow to match t he evaporator load and (b) prevention of liquid refrigerant entering the compressor. Unless the valve is defective, it seldom requires any maintenance.

3 4

MOUNTING CLIP

Figure 4-12. Evaporator Fan Removal

4.17 REPLACING EVAPORATOR FAN

a. PlacemainbatterydisconnectswitchinOFFposition

and lock.

b. Disconnect wire leads to the motor. Mark leads for

proper reassembly.

c. Remove motor by lifting the mounting clip (see

Figure 4-12) up and out. Slide motor from unit.

5 4

1. Power Head Assembly

2. Equalizer Connection

3. Bulb

Figure 4-13. Thermostatic Expansion Valve

4.19.1 Valve Replacement

4. Gasket

5. Cage Assembly

6. Body Flange

7. Cap screw

a. Pump down low side of the unit. (Referto paragraph

4.5.1)

b. Remove insulation from expansion valve bulb. (See

Figure 4-13 and Figure 4-14.)

c. Loosen retaining straps holding bulb to suction line

and detach bulb from the suction line.

d. Loosen flare nuts on equalizer line and disconnect

equalizer line from the expansion valve.

4-9

T-295

e. Remove capscrews and lift off power head and cage

assemblies and gaskets.

c. Loosen one TXV bulb clamp and make sure areaun-

der clamp is clean.

f. Check, clean and remove any foreign material from

the valve body, valve seat and mating surfaces. If required, replace valve body.

NOTE

Do not adjust the new replacement expansion valve. Valves are preset at the factory.

g. Using new gaskets, install new cage and power head

assemblies.

h. Leakcheckthenew valveandevacuateand dehydrate

low side. (Refer to paragraph 4.7.)

i. The thermal bulb is installed below the center of the

suctionline(fouror eighto’clockposition). This area must be clean to ensure positive bulb contact. Strap thermal bulb t o suction line. Ensure that retaining

straps are tight and renew insulation. j. Fasten equalizer line to the expansion valve. k. Open filter-drier inlet service valve and compressor

service valves.

l. R un the coach for approximately 30 minutes on fast

idle. m.Check refrigerant level. (Refer to paragraph 4.8.1) n. Check superheat. (Refer to paragraph 4.19.2.)

4.19.2 Superheat Measurement

NOTE

All readingsmust be taken from the TXV bulb location and out of the direct air stream.

d. Place temperature thermocouple in contact with the

suction tube and parallel to the TXV bulb, and then secure loosened clamp making sure both bulb and thermocouple are firmly secured to suction line. (SeeFigure 4-14.) Reinstall insulation around the bulb.

e. Connect an accurate low pressure gauge to the low

pressure port (9, Figure 1-6)

f. Close top cover being careful to route thermocouple

sensing wire and gauge hose outside the unit.

g. Start bus and run on fastidle until unit has stabilized,

about 20 to 30 minutes.

NOTE

Whenconductingthis test, the suction pressure must be at least 6 psig (0.41 bar) below theexpansion valve maximum operating pressure (MOP). Refer to paragraph 1.3 for MOP.

h. From the temperature/pressure chart (Table 4-4), de-

termine the saturation temperature corresponding to the evaporator outlet pressure.

i. Note the temperatureof the suction gas at the expan-

sion valve bulb. Subtract the saturation temperature fromthistemperature.The differenceisthesuperheat of the suction gas.

j. The superheat may cycle from a low to high reading.

Monitor the superheat taking readings every 3--5 minutes for a total of 5--6 readings. Calculate the superheats, add the readings and divide by the number of readings taken to determine average superheat. The superheat should be 10Fto12F.

k. Ifsuperheat is not withintolerance,replace the valve.

1. Suction Line (section view)

2. TXV Bulb Clamp

3. Nut & Bolt (clamp)

Figure 4-14.Thermostatic Expansion Valve Bulb

and Thermocouple

4. Thermocouple

5. TXV Bulb (Shown in the 4’clock position)

a. Open top cover. Refer to paragraph 4.2. b. Remove Presstite insulation from expansion valve

bulb and suction line.

T-295

4.20 COMPRESSOR MAINTENANCE

4.20.1 Removing the Compressor

If compressor is inoperative and the unit still has

refrigerant pressure,isolate the compressor and remove the refrigerant. R efer to paragraph 4.5.2. If compressor

is operative, perform a pump down. Refer to paragraph

4.5.3. a. PlacemainbatterydisconnectswitchinOFFposition

and lock.

b. Loosen bolts at suction and discharge service valve

flanges and break seal to be sure pressure isreleased. remove bolts.

c. Tag and disconnect wiring to the high pressure and

low pressure switch, unloaders and clutch. d. Remove four bolts holding compressor to base e. Attach sling or other deviceto the compressor and re-

movecompressorfrom thecoachthroughthe rearac-

cess door.

4-10

NOTES

1 Service replacement compressors are sold

without service valves. Valve pads are installed in their place. The optional unloaders are not supplied, as the cylinder heads are shipped with plugs. Customer should retain the original unloader valves for use on the replacement compressor.

2 The piston plug that is removed from the

replacement compressor head must be installed in the failed compressor if returning for warranty or core credit.

3 Do not interchange allen-head capscrews

that mount the piston plug and unloader, they are not interchangeable.

4 Check oil level in service replacement

compressor. (Refer to paragraphs 1.3 and

4.20.3.)

f. Remove the three socket head capscrews from the

cylinder head(s) t hat have unloader valves installed. See Figure 4-15. Remove the unloader valve and bypass piston assembly, keeping the same capscrews with the assembly. The original unloader valve must be transferred to the replacement compressor. The plug arrangement removed from the replacement is installedin theoriginalcompressorasaseal.Ifpiston is stuck, it may be extracted by threading a socket headcapscrewinto top of piston. A small Teflon seat ring at the bottom of the bypass piston plug must be removed.

GASKET

COMPRESSOR HEAD

BYPASS PISTON PLUG

Figure 4-15.Removing Bypass Piston Plug

SPRING

FLANGE COVER

CAPSCREWS

(NOT INTERCHANGEABLE WITH CONTROL VALVE SCREWS)

g. Remove the pressure switches and install on replace-

mentcompressoraftercheckingswitch operation(refer to paragraph 4.10).

h. Remove clutch assemble and retain original clutch

key. Install on replacement compressor. Refer to paragraph 4.20.2.

i. Install compressorin unit by performing the removal

stepsinreverse.It i s recommendedthat new locknuts be used when replacing compressor. Install new gaskets on service valves and tighten bolts uniformly.

j. Leak check connections and replace filter--drier. Re-

fer to paragraph 4.6.

k. Usingrefrigeranthoses designedforvacuum service,

connect a vacuum pump (see Figure 4-5) and evacu-

ate compressor to 500 microns. Front seat both manifold valves to isolate the pump.

l. Start unit and check refrigerant level (refer to para-

graph 4.8.1).

m.Check compressor oil level (refer to paragraph

4.20.3). Add or remove oil if necessary. n. Check compressor unloader operation. o. Remove manifold gauge set.

4.20.2 Transferring Compressor Clutch

To removea clutch (seeFigure 4-16)fromacompressor and install on a replacement compressor, do the following:

1. Compressor (typical)

2. Seal Cover

3. Coil

4. Rotor

Figure 4-16. Compressor Clutch

5. Rotor Nut

6. Armature 7SpacerNuts

8. Snap Ring

a. Using a wrench on the armature flats to keep it from

turning, remove the special bolt holding it to the shaft.

b. Using special tool (CTD Part Number 07--00242

--01), remove the rotor nut and rotor. Retain original

key.

c. Noting thepositionofthe wire,removethethreebolts

holding the coil to the compressor.

d. Remove every other bolt from the seal cover of the

new compressor in the same manner as the original compressor.Mount the coilassemblywiththewirein thesameorientationasitwasmountedon theoriginal compressor. Tighten the mounting bolts to 45 lbs/ft (6.2 mkg).

e. Mount rotor on shaft with rotor nut. Be sure pulley

turns freely without binding.

f. Install armatureon shaft using originalkey andtight-

en mounting bolt to 20 ft/lbs (2.8 mkg).

g. Perform acheck of theair gap betweentheinsideface

of the armature and the mating face of the rotor. The air gap should be measured with a minimum of 50 psig (3.4 bar) in the crankcase. A preliminary check may be performedbeforethecrankcase ispressurized but a finalcheckmust be performedbefore the clutch is operated. The gap should be between 0.016 and

4-11

T-295

0.030inch (0.41 to 0.76 mm).Ifrequired,removethe eight armaturespacer nutsand spacer. Add orremove shims to adjust gap. Reinstall spacer nuts and tighten to 7--8 ft/lbs(1.0 to 1,1 mkg).

h.Reconnect wiring and test clutch operation.

4.20.3 Compressor Oil Level

To check, and if required correct, the compressor oil level do the following:

a. Operate the coach for at least one--half hour at fast

idle speed, with the temperature controls at the coolestsetting,andthe compressorfully loaded.It may be necessary to pre--heat the coach and/or operate the system inthereheat mode to keepthe compressorfully loaded throughout this procedure

b. Ensure thesystem is fullycharged (refer to paragraph

4.8.1) and the compressor crankcase is warm to the touch after fifteen minutes of operation.

c. Shut off the system and immediately record the oil

level in the compressor sight glass. See Figure 4-17. Ifthe compressor is not level, an average between the sight glass levels will have to be made to determine level.

3. Evacuate compressor to 500 microns. Backseat compressor suction and discharge valves, start system and recheck oil level.

4. Remove manifold gauge set.

11 10

1 2

05G - GR60

d. Theproperoil levelisbetween the marks on the com-

pressor crankcase (05G compressors) or between 1/4 and1/2 of the sight glass (05Kcompressors).Refer to Figure 4-17. If the oil level is correct, release the coach into service. If the level is above the required amount, proceed to step e.. If the level is below the required amount proceed to step f.

e. To remove oil and bring the level to the proper

amount, do the following:

1. Pumpdown the compressor until only a slight positive pressureremains inthe crankcase.Refertoparagraph 4.5.3.

2. Shutoffthe coach engine and ensure thecompressor discharge and suction servicevalves are frontseated. Reclaimtheremaining refrigerantin thecompressor crankcase.

3. Drain or pump out compressor oil until the level is brought to the minimum for this compressor.

4. Evacuate the compressor to 500 microns. Backseat thecompressorservicevalvesand repeattheoil level check procedure.

f. To addoiltothe compressorcrankcase,do thefollow-

ing:

1. With the system off,connectamanifoldgauge set to the compressor suction and dischargeservice valves (SeeFigure 4-5)and reclaim therefrigerantto below atmospheric pressure. Shut off the reclaimer and verify the pressuredoes notrise.Ifthe pressurerises, continue reclaiming until the pressure remains below atmospheric.

2. Addoil to compressor crankcaseslowly,throughthe oil fill plug opening (see Figure 4-17) to bring level to mid range of allowed levels.

05K - GR45

1. Electric Unloader Valve

2. Suction Service Valve Charging Port

3. Suction Service Valve

4. Clutch

5. OilFillPlug

Figure 4-17. Compressors

4.20.4 Checking Unloader Operation

6. Bottom Plate

7. Oil Drain Plug

8. Oil Level Sight Glass

9. Oil Pump

10. O-ring 11 .Discharge Service

Valve

12 .Service Port

To check unloader operation do the following: a. Install a manifold gauge set as shown in Figure 4-6.

Ensure both manifold valvesare frontseated and cen-

ter connection is tight on blank fitting. b. Midseat compressor suction service valve. c. At thebus roof, disconnect thesuctionpressuretrans-

ducer (

energize the unloader(s).

8, Figure 1-6). This will force the controller to

d. Start the bus and run in cooling lower set point if re-

quiredto ensuresystem remainsinfullspeedcooling. e. Locate the unloader connectorat the compressor. Ob-

serve manifold suction gauge while unplugging the

T-295

4-12

connector. Pressureshould decrease3 to 5 psi (0.2 to

0.4 bar) when theunloader is unplugged andincrease the same amount as the plug is reconnected. repeat test for second unloader if fitted.

f. If pressures do not react as described, checkunloader

coil or repair unloader mechanism as required.

g. When testing is complete, reconnect transducer and

unloaderconnectorsand remove manifold gauge set.

h. Disconnectionof the suction pressure transducerwill

cause an “A15” alarm. Once the transducer is reconnected, the alarm will go to inactive and can then be cleared.

Table 4-1. T emperature Sensor Resistance

Temperature

F C

Resistance In Ohms

-- 2 0 --28.9 165,300

-- 1 0 --23.3 117,800 0 --17.8 85,500

10 --12.2 62,400 20 -- 6.7 46,300 30 -- 1.1 34,500 32 0 32,700 40 4.4 26,200 50 10.0 19,900 60 15.6 15,300 70 21.1 11,900 77 25 10,000 80 26.7 9,300

90 32.2 7,300 100 37.8 5,800 110 43.3 4,700 120 48.9 3,800

4.21 TEMPERATURE SENSOR CHECKOUT

a. An accurate ohmmeter must be used to check resist-

ance values shown in Table 4-1.

b. Due to variations and inaccuracies in ohmmeters,

thermometers or other test equipment, a reading within two percent of the chart value would be considered accaptable. If a sensor is bad, the resistance valuewould usuallybe muchhigher orlowerthanthe value given in Table 4-1 .

c. At least one sensor lead must be disconnected from

the controller before any reading can be taken. Not doing so will result in a false reading. T wopreferred methodsof determiningthe actual test temperatureat the sensor are an ice bath at 32F (0C) and/or a calibrated digital temperature meter.

4.22 PRESSURE TRANSDUCER CHECKOUT

NOTE

System must beoperatingto checktransducers.

a. With the system running use the driver display or

manifold gauges to check suction and/or discharge pressure(s).

b. Use a digital volt-ohmmeter measure voltage across

the transducer at terminals A & C . See Figure 4-18. Comparetovaluesin Table 4-2. A readingwithintwo percentof the values in the tablewould be considered good.

Figure 4-18 Transducer Terminal Location

4.23 REPLACING SENSORS AND TRANSDUCERS

a. PlacemainbatterydisconnectswitchinOFFposition

and lock.

b. Tag and disconnect wiring from defective sensor or

transducer. c. Remove and replace defective sensor or transducer. d. Connect wiring to replacement sensor or transducer. e. Checkout replacement sensor ortransducer.(Refer to

section 4.21 or 4.22, as applicable.) f. Repair or replace any defective component(s), as re-

quired.

4.24 LOGIC BOARD CONFIGURATION

If a replacement Logic Board is installed, it is necessary to match the configuration jumpers (see Figure 1-10) to the original board.

Table 4-3 provides a list of jumper

functions

4-13

T-295

Table 4-2. PressureTransducer Voltage

Table 4-3. Logic Board Configuration

“/hg Voltage Psig Voltage Psig Voltage

20” 0.369 100 1.446 215 2.573 10” 0.417 105 1.495 220 2.622

Psig Voltage 110 1.544 225 2.671

0 0.466 115 1.593 230 2.720

5 0.515 120 1.642 235 2.769 10 0.564 125 1.691 240 2.818 15 0.614 130 1.740 245 2.867 20 0.663 135 1.789 250 2.916 25 0.712 140 1.838 255 2.965 30 0.761 145 1.887 260 3.014 35 0.810 150 1.936 265 3.063 40 0.858 155 1.985 270 3.112 45 0.907 160 2.034 275 3.161 50 0.956 165 2.083 280 3.210 55 1.007 170 2.132 285 3.259 60 1.054 175 2.181 290 3.308 65 1.103 180 2.230 295 3.357 70 1.152 185 2.279 300 2.406 75 1.204 190 2.328 305 3.455 80 1.250 195 2.377 310 3.504 85 1.299 200 2.426 315 3.553 90 1.348 205 2.475 320 3.602 95 1.397 210 2.524 325 3.651

Jumper

Description

A. High Reheat -- Selects fan speed B. High Vent -- Selects fan speed C. Dry Heat -- Selects re--heat configuration D. Reheat/Cycle -- Selects clutch cycle E. Transducers -- Selects transducer configu-

ration

F. Refrigerant -- Selects refrigerant G. Unit Type -- Selects software configuration H. Unit Type -- Selects software configuration

I. Factory -- Reserved for the manufacturer.

J. Invert H2O -- Selects temperature switch

configuration K. Voltage -- Selects unit voltage L. Factory -- Reserved for the manufacturer.

M. Psig/Bars -- Selects display configuration

N. C/F -- Selects display configuration O. Loaded Start -- Selects start --up configura-

tion

P. PI Reheat -- Selects reheat algorithm

T-295

4-14

Table 4-4. R-134a Temperature - Pressure Chart

Temperature Vacuum

F C

“/hg cm/hg kg/cm@@@@ bar

-- 4 0 -- 4 0 14.6 49.4 37.08 0.49 .35 .37 12.3 41.6 31.25 0.42

-- 3 0 -- 3 4 9.7 32.8 24.64 0.33

-- 2 5 -- 3 2 6.7 22.7 17.00 0.23

-- 2 0 -- 2 9 3.5 11.9 8.89 0.12

-- 1 8 -- 2 8 2.1 7.1 5.33 0.07

-- 1 6 -- 2 7 0.6 2.0 1.52 0.02

Temperature Pressure

F C

psig kPa kg/cm@@@@ bar

-- 1 4 -- 2 6 0.4 1.1 0.03 0.03

-- 1 2 -- 2 4 1.2 8.3 0.08 0.08

-- 1 0 -- 2 3 2.0 13.8 0.14 0.14

-- 8 -- 2 2 2.9 20.0 0.20 0.20

-- 6 -- 2 1 3.7 25.5 0.26 0.26

-- 4 -- 2 0 4.6 31.7 0.32 0.32

-- 2 -- 1 9 5.6 36.6 0.39 0.39 0 -- 1 8 6.5 44.8 0.46 0.45 2 -- 1 7 7.6 52.4 0.53 0.52 4 -- 1 6 8.6 59.3 0.60 0.59 6 -- 1 4 9.7 66.9 0.68 0.67 8 -- 1 3 10.8 74.5 0.76 0.74

10 -- 1 2 12.0 82.7 0.84 0.83 12 -- 1 1 13.2 91.0 0.93 0.91 14 -- 1 0 14.5 100.0 1.02 1.00 16 -- 9 15.8 108.9 1.11 1.09 18 -- 8 17.1 117.9 1.20 1.18 20 -- 7 18.5 127.6 1.30 1.28 22 -- 6 19.9 137.2 1.40 1.37 24 -- 4 21.4 147.6 1.50 1.48 26 -- 3 22.9 157.9 1.61 1.58

Temperature Pressure

F C

psig kPa kg/cm@@@@ bar

28 -- 2 24.5 168.9 1.72 1.69 30 -- 1 26.1 180.0 1.84 1.80 32 0 27.8 191.7 1.95 1.92 34 1 29.6 204.1 2.08 2.04 36 2 31.3 215.8 2.20 2.16 38 3 33.2 228.9 2.33 2.29 40 4 35.1 242.0 2.47 2.42 45 7 40.1 276.5 2.82 2.76 50 10 45.5 313.7 3.20 3.14 55 13 51.2 353.0 3.60 3.53 60 16 57.4 395.8 4.04 3.96 65 18 64.1 441.0 4.51 4.42 70 21 71.1 490.2 5.00 4.90 75 24 78.7 542.6 5.53 5.43 80 27 86.7 597.8 6.10 5.98 85 29 95.3 657.1 6.70 6.57 90 32 104.3 719.1 7.33 7.19

95 35 114.0 786.0 8.01 7.86 100 38 124.2 856.4 8.73 8.56 105 41 135.0 930.8 9.49 9.31 110 43 146.4 1009 10.29 10.09 115 46 158.4 1092 11.14 10.92 120 49 171.2 1180 12.04 11.80 125 52 184.6 1273 12.98 12.73 130 54 198.7 1370 13.97 13.70 135 57 213.6 1473 15.02 14.73 140 60 229.2 1580 16.11 15.80 145 63 245.6 1693 17.27 16.93 150 66 262.9 1813 18.48 18.13 155 68 281.1 1938 19.76 19.37

4-15

T-295

SECTION 5

ELECTRICAL

5--1 INTRODUCTION

This section includes electrical wiring schematics. The schematic shown in this section provides information for all unit models andoptional configurations. For model GR45 units, which arefittedwith four evaporator and condenser fans, the components used to control the fifth and sixth fans are not energized.For applications with OEM supplied operating switches, the switches arewired to Logic Board connector J3 as shown. For units with aMicromate as the operatorscontrol, there is no wiring to theLogicBoardJ3connector. The Micromateis hardwiredtothe LogicBoard connector J2 in the same manner as shown for service port use.

5-1

T--295

SYMBOLS

LEGEND

SYMBOL

CONNECTOR TERMINAL

GROUND

FACTORYWIRING

OEM WIRING

GROUND STUD

POWER STUD

CONNECTOR

NORMALLY OPEN CONTACT

CONNECTOR, POSITON”A”

LAMP

DIODE

FUSE

COIL

MOTOR (EF or CF)

PRESSURE SENSOR

LED ASSEMBLY

PRESSURE SWITCH

TEMPERATURESENSOR

MANUAL RESET BREAKER

RELAY COIL

MANUAL SWITCH

POLYSWITCH

TEMPERATURESWITCH

MULTI--PLEX MODULE

RIBBON CABLE

ATS

BPS CB1 CB2 CB3 CB4 CB5 CB6 CB7 CB8 CB9 CB10 CB11 CB12 CB13

CF1

CF2

CF3

CF4

CF5

CF6

CTH

D14

D17

D26

D30

D38

D41

D51

D54

D57

D60

D63

D66

D72 DPT

EM1

EM2

EM3

EM4

EM5

EM6

FAV

FTS HV K1 K2 K3 K4 K7 K8 K9 K10 K13 K14 K15 UV2 RELAY K16 K17 K18 K19 K20 K21 K22 K23 K24 LPS LLS RAS SPT UV1 UV2

WTS WATER TEMPERATURE SWITCH

DESCRIPTION

AMBIENT TEMPERATURE SENSOR

BOOST PUMP SIGNAL CIRCUIT BREAKER, EF1 CIRCUIT BREAKER, EF2 CIRCUIT BREAKER, EF3 CIRCUIT BREAKER, EF4 CIRCUIT BREAKER, EF5 CIRCUIT BREAKER, EF6 CIRCUIT BREAKER, CF1 CIRCUIT BREAKER, CF2 CIRCUIT BREAKER, CF3 CIRCUIT BREAKER, CF4 CIRCUIT BREAKER, CF5 CIRCUIT BREAKER, CF6 CIRCUIT BREAKER, MISC

COND MOTOR 1

COND MOTOR 2

COND MOTOR 3

COND MOTOR 4

COND MOTOR 5

COND MOTOR 6

COMPRESSORCLUTCH

EF1/2 LEDASSEMBLY

EF3/4 LEDASSEMBLY

EF5 LED ASSEMBLY

EF6 LED ASSEMBLY

CF1/2 LEDASSEMBLY

CF3/4 LEDASSEMBLY

CF5 LED ASSEMBLY

CF6 LED ASSEMBLY

CLUTCH LED ASSEMBLY

UV1 LED ASSEMBLY

UV2 LED ASSEMBLY

FRESH AIR VALVE LED ASSEMBLY

RSV LED ASSEMBLY

ALARM LED ASSEMBLY

SPARELED ASSEMBLY DISCHARGE PRESSURE TRANSDUCER

EVAPMOTOR 1

EVAPMOTOR 2

EVAPMOTOR 3

EVAPMOTOR 4

EVAPMOTOR 5

EVAPMOTOR 6 FUSE FRESH AIR VALVE

FREEZE TEMPERATURE SENSOR HEAT VALV E EF1/2 RELAY EF3/4 REALY EF5 RELAY EF6 RELAY CF1/2 RELAY CF3/4 RELAY CF5 RELAY CF6 RELAY CLUTCH RELAY UV1 RALAY

FRESH AIR RELAY HEAT RELAY FAULT RELAY BOOST RELAY SPARERELAY EVAP. FAN HIGH RELAY EVAP. FAN LOW RELAY COND. FAN HIGH RELAY COND. FAN LOW RELAY LOW PRESSURE SWITCH LIQUIDLINE SOLENOID RETURN AIR SENSOR SUCTION PRESSURE TRANSDUCER UNLOADER SOLENOID VALVE #1 UNLOADER SOLENOID VALVE #2

CONNECTOR LEGEND

DESCRIPTIONSYMBOL

J1 J3 J4 J5 J6 J7 JP1 JP2 JP3 JP4 JP5 JP6 W_ATS W_COMP W_FAV W_HPS W_LPS W_LLS W_WTS

LOGIC POWER ON/TEST INPUT RELAY BOARD INTERFACE SENSOR DIAGNOSTIC LINK MOTOR OVERLOAD LOGIC BOARD INTERFACE BOOST PUMP CLUTCH HEAT/FAIL UNLOADER AMBIENT TEMPERATURE SENSOR COMPRESSOR FRESH AIR VALVE HIGH PRESSURE SWITCH LOW PRESSURE SWITCH LIQUIDLINE WATER TEMPERATURESWITCH

Figure 5--1. Electrical Wiring Schematic Diagram - Legend

T--295

5-2

K21SPB

K22

LOW

HIGH

D88

D24

D87

D22

D21

D79

D23

D80

K23

K24

LOW

HIGH

D90

D48

D89

D46

D45

D81

K11

D47

D82

K10

K12

86 85

RELAY BOARD

JP1

JUMPER

JP1

24V

JP2

1 24V

J1 1

12V

PORT

SERVICE

SPB

GND

DATA

SPA

SPC

SPD

SPA

SPD

SPC

JP1

JUMPER

JP1

JP4

W_HPS

HPS

W_HPS

JP4

K15

K14

K13

CLUTCH RELAY

UV1 RELAY

JP2

LOGIC BOARD

453

FRESH AIR

UV2 RELAY

JP2

JP1

JUMPER

JP1

K18

K17

K16

JP2

24VDC

FAULT REL AY

HEAT RELAY

JP2

BOOST RELAY

JP2

JP1

JUMPER

JP1

K21

K20

K19

SPARE

EVAP FAN HIGH RELAY

JP2

EVAP FAN LOW RELAY

JP2

564

W_ATS

K22

COND FAN HIGH RELAY

JP2

K24

K23

COND FAN LOW RELAY

JP2

MICROMATE

24VDC

SIGNAL

ALTERNATOR

SIGNAL

DIM

24VDC

Figure 5--2. Wiring Schematic, Permanent Magnet Motors - Interconnection

VENT

A B

W_LPS LPS W_LPS

WTS

24VDC

SPEEDLOW

HIGH SPEED

24VDC

HEAT

COOL

24VDC

AUTO/ON

24VDC

RAS

105F

GROUND (--)

5-3

ATS

FTS

(--)

(+)

SPT

(--)

(+)

DPT

T--295

POWER

CABLE

F(150A) +24VDC

1--120

(NOVA)

CB1

CB2

EF1

EF2

EF1

EF2

EM1

EM2

MOTOR CONNECTION

MARKING

TYPICAL ALL MOTORS

A B

CIRCUIT BREAKER

CONNECTION MARKING TYPICALALLBREAKERS

ALL BREAKERS 15 AMP

RELAY CONNECTION

MARKING

30 87

87A

RELAYSK5, K6

K11&K12

ALL OTHERS

K10

D14

D17

D26

D30

D38

D41

CB13

CB3

CB4

CB5

CB6

CB7

CB8

CB9

CB10

CB11

CB12

K16

K20

K14

K15

K13

K17

K18

K19

EF3

EF4

EF5

EF6

CF1

CF2

CF3

CF4

CF5

CF6

D60

D72

D54

D57

D51

D63

D66

D69

A EM3

EM4A

EM5

A EM6

CF1

CF2

A CF3

CF4

A CF5

A CF6

JP4

JP5

JP6

W_LLS

W_CTRL2 JP4

W_CTRL2

JP3

EF3

EF4

EF5

EF6

CF1

CF2

CF3

CF4

CF5

CF6

W_FAV

SPARE

W_COMP

LLS

K11

K12

FAV

UV1

UV2

W_COMP

W_LLS

A/C FAIL

F(15A)

W_CTRL2

1-- 121 (NOVA)

POWER CABLE (--)

W_FAV

B 4

W_COMP

A CTH

W_COMP

FLOOR HEATERS

JP5

JP6

JP4

+24VDC

BPM +

Figure 5--3. Wiring Schematic, Permanent Magnet Motors - Relays to External Components

T--295

5-4

K24

K22

K21

EVAP FAN HIGH

EVAP FAN LOW

D79

D21

8685

EF3/4 RELAY

EF1/2 RELAY

EF HIGH RELAY

D23

D22

8685

EF5 RELAY

EF6 RELAY

K23

COND FAN HIGH

COND FAN LOW

D47

D46

D24

D45

8685

CF1/2 RELAY

CF3/4 RELAY

D48

8685

CF5 RELAY

K10

CF6 RELAY

RELAY BOARD

105F

JP1

JUMPER

JP1

K21

K20

K19

K18

BOOST RELAY

JP2

(SEE FOLLOWING DIAGRAM)

RAS

SPARE

EVAP FAN HIGH RELAY

JP2

FTS

EVAP FAN LOW RELAY

JP2

564

W_ATS

ATS

K22

COND FAN HIGH RELAY

JP2

(--)

(+)

SPT

K24

K23

COND FAN LOW RELAY

JP2

(--)

(+)

DPT

JP1

JUMPER

JP1

24V

JP4

W_HPS

HPS

W_HPS

JP4

K13

CLUTCH RELAY

UV1 RELAY

JP2

1 24V

J1 1

12V

SPB

PORT

SERVICE

SPB

5 J2

GND

DATA

SPA

SPC

SPD

SPA

SPD

SPC

JP2

LOGIC BOARD

453

JP1

JUMPER

JP1

K15

K14

UV2 RELAY

JP2

FRESH AIR

JP2

JP1

JUMPER

JP1

K17

K16

24VDC

FAULT REL AY

HEAT RELAY

W_LPS LPS W_LPS

JP2

MOTOR FAIL SIGNAL

A B

WTS

MICROMATE

24VDC

SIGNAL

ALTERNATOR

SIGNAL

DIM

24VDC

Figure 5--4. Wiring Schematic, Electronically Communtated Motors - Interconnection

VENT

24VDC

HIGH SPEED

SPEEDLOW

24VDC

5-5

GROUND (--)

T--295

HEAT

COOL

24VDC

AUTO/ON

24VDC

POWER

CABLE

F (125A)

+24VDC

D26

D30

D38

CB7

CB8

CB9

CB10

CB11

CF1

CF2

CF3

CF4

CF5

CF1

CF2

CF3

CF4

CF5

CF1

CF2

CF3

CF4

CF5

TO J4--5

SEE PRECEEDING DIAGRAM

MOTOR CONNECTION

MARKING

TYPICAL ALL MOTORS

A B

CIRCUIT BREAKER

CONNECTION MARKING

TYPICALALLBREAKERS

ALL BREAKERS 15 AMP

RELAY CONNECTION

MARKING

30 87

TYPICAL ALL RELAYS

K10

D41

D14

D17

CB13

CB12

K16

K20

K14

K15

K13

K17

K18

K19

CB1

CB2

CB3

CB4

CB5

CB6

D81

D60

D72

D54

D57

D51

D63

D66

D69

CF6

EF1

EF2

EF3

EF4

EF5

EF6

CF6

W_COMP

EF1

EF2

EF3

EF4

CF5

EF6

W_FAV

SPARE

LLS

FAV

UV1

UV2

W_LLS

F(15A)

W_CTRL2

W_FAV

W_COMP

A/C FAIL

JP5

W_COMP

CTH

FLOOR HEATERS

JP6

JP4

+24VDC

BPM +

CF6

EF1

EF2

EF3

EF4

CF5

EF6

EF HIGH

JP5

JP6

JP4

W_LLS

JP5

JP4

JP3

Figure 5--5. Wiring Schematic, Electronically Communtated Motors - Relays To External Components

T--295

5-6

INDEX

Air Filters, 4-9 Alarm, 2-4, 3-1 Alarm Clear, 3-1 Alarm Codes, 3-1 Alarm Queue, 3-1 Ambient Lockout, 1-6 Apex Unit, 1-2

Boost Pump, 2-3

Circuit Breaker, 1-6, 1-10, 1-11 Clutch,2-4,4-11 Compressor, 1-4, 1-5, 4-10 Condenser Coil, 4-6

Filter-- Drier, 4-6 Fresh Air System, 1-4, 2-3 Fuse, 1-6

Heat V alve, 4-7 Heating Cycle, 1-8 Heating Mode, 2-3 High Pressure Switch, 1-5, 4-5 Hour Meter, 2-4

Liquid Line Solenoid, 4-8 Logic Board, 1-12, 2-1, 4-13 Low Pressure Switch, 1-5, 1-6

Condenser Fan, 1-5, 2-4, 4-8 Condensing Section, 1-2 Control Panel, 1-13 Cooling Mode, 2-3

DESCRIPTION, 1-1 Diagnostics, 2-1, 2-4, 2-5 Discharge Pressure, 2-4

ELECTRICAL, 5-1 Evacuation, 4-4 Evaporator, 1-3 Evaporator Coil, 4-7 Evaporator Fan, 1-5, 2-4, 4-9

Maintenance Schedule, 4-1 Manifold Gauge Set, 4-2 Modes Of Operation, 2-3

Noncondensibles, 4-5

Oil Charge, 4-12 Operating Controls, 1-4 Operating Instructions, 2-1 OPERATION, 2-1

Index-1

T--295

INDEX -- Continued

Pre--Trip Inspection, 2-1 Pressure Transducer, 1-5, 4-13 Pump Down, 4-2, 4-3

Refrigerant Charge, 1-5, 4-2, 4-4, 4-5 Refrigerant Removal, 4-3, 4-4 Refrigeration Cycle, 1-6 Relay Board, 1-9

SAFETY, i Self Diagnostics, 3-1 SERVICE, 4-1 Service Valves, 4-1 Starting, 2-1 Stopping, 2-1

Temperature Control, 2-3 Te mperature Pressure Chart, 4-15 Temperature Sensor, 1-5, 4-13 Thermostatic Expansion Valve, 1-5, 4-9 Top Cover, 4-1 TROUBLESHOOTING, 3-1

Unloaders, 2-3

Vent Mode, 2-3

Wiring Schematics, 5-1

Suction Pressure, 2-3 Superheat, 4-10 System Parameters, 2-5

T--295

Index-2

Carrier GR-45, GR-60 Operation And Service

Specifications and Main Features

Frequently Asked Questions

User Manual