Carrier 38MGRQ18B 3 Series User Manual

TABLE of CONTENTS
PAGE
SAFETY CONSIDERATIONS ....................................................... 1
INTRODUCTION............................................................................1
MODEL / SERIAL NUMBER NOMENCLATURES .................... 2
SPECIFICATIONS .......................................................................... 3
DIMENSIONS ................................................................................. 4
CLEARANCES................................................................................ 8
ELECTRICAL DATA ..................................................................... 9
WIRING........................................................................................... 9
CONNECTION DIAGRAMS .........................................................10
AUTOMATIC WIRING/PIPING CORRECTION ......................... 13
WIRING DIAGRAMS..................................................................... 14
REFRIGERATION CYCLE DIAGRAMS......................................22
REFRIGERANT LINES .................................................................. 24
SYSTEM EVACUATION AND CHARGING ............................... 25
ELECTRONIC FUNCTION............................................................26
TROUBLESHOOTING................................................................... 31
OUTDOOR UNIT DIGITAL DISPLAY.........................................32
OUTDOOR UNIT DISPLAY.......................................................... 32
APPENDICES..................................................................................64
DISASSEMBLY INSTRUCTIONS SIZE 18.................................. 72
DISASSEMBLY INSTRUCTIONS SIZE 24.................................. 80
DISASSEMBLY INSTRUCTIONS SIZE 30.................................. 89
DISASSEMBLY INSTRUCTIONS SIZES 36 AND 48................. 96
SAFETY CONSIDERATIONS
Installing, starting up, and servicing air-conditioning equipment can
be hazardous due to system pressures, electrical components, and
equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service mechanics should install,
start-up, and service this equipment.
Untrained personnel can perform basic maintenance functions such as
coil cleaning. All other operations should be performed by trained
service personnel.
When working on the equipment, observe precautions in the literature
and on tags, stickers, and labels attached to the equipment.
Follow all safety codes. Wear safety glasses and work gloves. Keep a
quenching cloth and fire extinguisher nearby when brazing. Use care
in handling, rigging, and setting bulky equipment.
Read this manual thoroughly and follow all warnings or cautions
included in the literature and attached to the unit. Consult local
building codes and National Electrical Code (NEC) for special
requirements. Recognize safety information.
This is the safety-alert symbol . When you see this symbol on the
unit and in instructions or manuals, be alert to the potential for
personal injury. Understand these signal words: DANGER,
WARNING, and CAUTION.
These words are used with the safety-alert symbol. DANGER
identifies the most serious hazards which will result in severe personal
injury or death. WARNING signifies hazards which could result in
personal injury or death. CAUTION is used to identify unsafe
practices which may result in minor personal injury or product and
property damage. NOTE is used to highlight suggestions which will
result in enhanced installation, reliability, or operation.
INTRODUCTION
This service manual provides the necessary information to service,
repair, and maintain the multi-zone family of heat pumps. This
manual has an appendix with data required to perform
troubleshooting. See “APPENDICES” on page 64. Use the “TABLE
of CONTENTS” on page 1 to locate a desired topic.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position.
There may be more than 1 disconnect switch.
Lock out and tag switch with a suitable warning label.
WARNING
EXPLOSION HAZARD
Failure to follow this warning could result
in death, serious personal injury, and/or
property damage. Never use air or gases
containing oxygen for leak testing or
operating refrigerant compressors.
Pressurized mixtures of air or gases
containing oxygen can lead to an explosion.
WARNING
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage
or improper operation.
Do not bury more than 36 in. (914 mm) of refrigerant pipe in
the ground. If any section of pipe is buried, there must be a 6
in. (152 mm) vertical rise to the valve connections on the
outdoor units. If more than the recommended length is buried,
refrigerant may migrate to the cooler buried section during
extended periods of system shutdown. This causes refrigerant
slugging and could possibly damage the compressor at start-up.
CAUTION
SERVICE MANUAL
38MGR
Multi-zone Outdoor Unit Ductless System
Sizes 18, 24, 30, 36 and 48

Carrier 38MGRQ18B 3 Series Specifications

General

Refrigerant	R-410A
Compressor Type	Rotary
Cooling Capacity	18000 BTU/h
Indoor Noise Level	42 dB
Power Supply	208/230V, 1Ph, 60Hz
Outdoor Unit Dimensions (H x W x D)	31.5" x 11.4"

Summary

SAFETY CONSIDERATIONS

General Safety Guidelines

Safety Alerts and Signal Words

Electrical Hazard Warning

Details the risk of electrical shock and proper lockout/tagout procedures.

Explosion Hazard Warning

Warns against using oxygen for leak testing or operating compressors due to explosion risk.

Equipment Damage Caution

Advises on preventing equipment damage, such as proper refrigerant pipe burial limits.

ELECTRICAL DATA

Unit Size Electrical Parameters

Lists electrical data like voltage, MCA, MOCP, RLA, FLA, HP, and W for each unit size.

WIRING DIAGRAMS

Size 18K 2 Zone Connection

Illustrates the wiring connections for the 18K unit with 2 zones.

Size 18K Wiring Details

Details wiring codes and connections for the 18K unit, including main and IPM boards.

Size 24K 3 Zone Connection

Shows the wiring diagram for the 24K unit supporting up to 3 zones.

WIRING DIAGRAMS (CONTINUED)

Size 30K 4 Zone Connection

Depicts the wiring configuration for the 30K unit with 4 zones.

Size 48K 5 Zone Connection

Illustrates the wiring layout for the 48K unit with 5 zones.

Size 24K Wiring Details

Provides wiring codes and connections for the 24K unit, covering main and IPM boards.

Size 30K Wiring Details

Details wiring codes and connections for the 30K unit, including main and PFC/IPM boards.

Size 30K PFC & IPM Board Details

Lists component codes and names for the PFC & IPM board and DC motor driver board.

Size 36K Wiring Diagram

Illustrates the wiring diagram for the 36K unit, showing connections to various boards.

Size 36K Board and Component Details

Lists codes and part names for outdoor unit main board, PFC/IPM board, and DC motor driver board.

Size 48K Wiring Diagram

Presents the wiring diagram for the 48K unit, illustrating connections to various components.

Size 48K Board and Component Details

Lists codes and part names for outdoor unit main board, PFC/IPM board, and DC motor driver board.

Size 36K 4 Zone Connection

Provides the wiring diagram for the 36K unit supporting up to 4 zones.

AUTOMATIC WIRING AND PIPING CORRECTION

REFRIGERATION CYCLE DIAGRAMS

Size 18K Refrigeration Cycle

Size 24K Refrigeration Cycle

REFRIGERATION CYCLE DIAGRAMS (CONTINUED)

Size 30K and 36K Refrigeration Cycle

Size 48K Refrigeration Cycle

SYSTEM EVACUATION AND CHARGING

Deep Vacuum Method

Explains the deep vacuum method for system evacuation, detailing required equipment and procedure.

Triple Evacuation Method

Details the triple evacuation method for system evacuation, including steps and hold tests.

HIGH CONDENSER COIL TEMPERATURE PROTECTION

OUTDOOR UNIT ANTI-FREEZING PROTECTION

LOW OUTDOOR AMBIENT TEMPERATURE PROTECTION

DEFROSTING CONTROL

Defrosting Conditions

Defrost Stop Conditions

TROUBLESHOOTING

Diagnostic Tools and Steps

Outdoor Unit Digital Display Codes

Outdoor Unit Error Display Table

A table listing error codes, their status, and corresponding indoor unit display indicators.

OUTDOOR UNIT DIGITAL DISPLAY AND FUNCTION

OUTDOOR UNIT DISPLAY CODES

DIAGNOSIS AND SOLUTION: Indoor Fan Speed Error

Indoor Fan Speed Control Error (E0/E4)

Troubleshooting flowchart for indoor fan speed issues, including causes and resolution steps.

DIAGNOSIS AND SOLUTION: Mode Conflict Error

Indoor Units Mode Conflict Error (P5)

Troubleshooting for mode conflicts between indoor units, detailing conditions and solutions.

DIAGNOSIS AND SOLUTION: EEPROM Parameter Error

EEPROM Parameter Error (E0/E4)

Troubleshooting steps for EEPROM parameter errors, involving checking connections and replacing the PCB.

DIAGNOSIS AND SOLUTION: Communication Malfunction

Communication Malfunction Error (E2/E1)

Troubleshooting for communication issues between indoor and outdoor units, including wiring and PCB checks.

DIAGNOSIS AND SOLUTION: DC Voltage Testing

DC Voltage Testing on IPM Board

DIAGNOSIS AND SOLUTION: Board Status Indicators

IPM and Main Board Status Indicators

DIAGNOSIS AND SOLUTION: Zero Crossing Detection Error

Zero Crossing Detection Error (E2)

Troubleshooting steps for zero crossing detection errors, focusing on connections and PCB integrity.

DIAGNOSIS AND SOLUTION: IPM/Main Board Communication Error

Communication Malfunction IPM/Main Board (E3)

Troubleshooting for communication errors between IPM and main board, including LED checks and component replacement.

DIAGNOSIS AND SOLUTION: Signal Wire Voltage Testing

Signal Wire Voltage Testing

DIAGNOSIS AND SOLUTION: Sensor Circuit Errors

Sensor Circuit Error Diagnosis (E4/F1-F6)

Troubleshooting for sensor circuit errors, involving checking connections, resistance, and PCB faults.

DIAGNOSIS AND SOLUTION: Voltage Protection Error

Voltage Protection Error (E5)

Troubleshooting for voltage protection errors, checking power supply, IPM board voltage, and component rectifiers.

DIAGNOSIS AND SOLUTION: IPM and Rectifier Testing

IPM Board and Bridge Rectifier Testing

DIAGNOSIS AND SOLUTION: IPM Module Testing

Bridge Rectifier and IPM Module Testing

DIAGNOSIS AND SOLUTION: IPM Module Testing (5-Zone)

Bridge Rectifier and IPM Module Testing (5-Zone)

DIAGNOSIS AND SOLUTION: PFC Module Protection Error

PFC Module Protection Error (E6)

Troubleshooting for PFC module protection errors, checking connections, voltage, inductance, and module faults.

DIAGNOSIS AND SOLUTION: Inductance Component Check

Inductance Component Check

DIAGNOSIS AND SOLUTION: Outdoor Fan Speed Error

Outdoor Fan Speed Control Error (E8)

Troubleshooting for outdoor fan speed control errors, including wiring, motor, and PCB checks.

DIAGNOSIS AND SOLUTION: DC Fan Motor Voltage Check

DC Fan Motor Voltage Check

DIAGNOSIS AND SOLUTION: Compressor Top Temperature Error

Compressor Top Temperature Error (PO)

Troubleshooting for compressor top temperature errors, checking airflow, overload protector, and refrigerant charge.

DIAGNOSIS AND SOLUTION: Compressor Temperature Voltage Test

Compressor Temperature Voltage Test

DIAGNOSIS AND SOLUTION: High Pressure Protection Error

High Pressure Protection Error (P1)

Troubleshooting for high pressure protection, checking wiring, protector, ambient temp, ventilation, and heat exchanger.

DIAGNOSIS AND SOLUTION: High Pressure Protection Voltage Test

High Pressure Protection Voltage Test

DIAGNOSIS AND SOLUTION: Low Pressure Protection Error

Low Pressure Protection Error (P2)

Troubleshooting for low pressure protection, checking wiring, protector, ambient temp, high pressure valve, and refrigerant level.

DIAGNOSIS AND SOLUTION: Low Pressure Protection Voltage Test

Low Pressure Protection Voltage Test

DIAGNOSIS AND SOLUTION: Compressor Current Protection Error

Compressor Current Protection Error (P3)

Troubleshooting for compressor current protection, checking supply current, refrigerant system, ambient temp, ventilation, and heat exchanger.

DIAGNOSIS AND SOLUTION: Compressor Current Measurement

Compressor Current Measurement

DIAGNOSIS AND SOLUTION: Compressor Discharge Temperature Error

Compressor Discharge Temperature Error (P4)

Troubleshooting for compressor discharge temperature errors, checking refrigerant leak, wiring, sensor, and PCB.

DIAGNOSIS AND SOLUTION: High Condenser Temperature Error

High Condenser Temperature Error (P5)

Troubleshooting for high condenser temperature errors, checking sensor, ventilation, and refrigerant system.

DIAGNOSIS AND SOLUTION: IPM Module Protection Error

IPM Module Protection Error (P6)

Troubleshooting for IPM module protection errors, checking voltage, connections, fan assembly, compressor, and PFC module.

DIAGNOSIS AND SOLUTION: Operational Issues

Cooling/Heating Operation Issues

Temperature Sensor Resistance Check

COMPRESSOR CHECK

Compressor Resistance Measurement

4-WAY VALVE CHECK

4-Way Valve Voltage and Resistance Test

EXV CHECK

EXV Coil Resistance Measurement

EXV CHECK (CONTINUED)

EXV Coil Resistance Testing

EXV Coil Resistance Testing (Continued)