Carrier 38MGRBQ18B-3 User Manual

Specifications subject to change without notice.
TABLE of CONTENTS
PAGE
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
MODEL / SERIAL NUMBER NOMENCLATURES . . . . . . . . . . . 2
CONNECTION DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
AUTOMATIC WIRING/PIPING CORRECTION . . . . . . . . . . . . . . 6
WIRING DIAGRAMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
REFRIGERATION CYCLE DIAGRAMS . . . . . . . . . . . . . . . . . . . 15
REFRIGERANT LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SYSTEM EVACUATION AND CHARGING. . . . . . . . . . . . . . . . 19
ELECTRONIC FUNCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
OUTDOOR UNIT DIGITAL DISPLAY. . . . . . . . . . . . . . . . . . . . . 28
OUTDOOR UNIT DISPLAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
DIAGNOSIS AND SOLUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
DISASSEMBLY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . 81
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 73 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.
WA RNIN G
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.
WA RNIN G
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
38MG(R/H)B
Multi-zone Outdoor Unit Ductless System
Sizes 18R, 24HH, 30HH, 36R, 36HH, 48R and 48HH

Carrier 38MGRBQ18B-3 Specifications

General

Brand	Carrier
Model	38MGRBQ18B-3
Category	Chiller
Language	English

Summary

SAFETY CONSIDERATIONS

General Safety Precautions

Guidelines for safe installation, servicing, and general precautions.

Hazard Signal Words

Explains DANGER, WARNING, CAUTION, and NOTE used in safety communications.

MODEL / SERIAL NUMBER NOMENCLATURES

Unit Sizes and Model Breakdown

Details the nomenclature for unit models and their corresponding sizes.

CONNECTION DIAGRAMS

Multi-Zone Unit Wiring

Provides wiring diagrams for various multi-zone unit configurations.

AUTOMATIC WIRING/PIPING CORRECTION

Procedure for Wiring/Piping Correction

Step-by-step guide for the automatic wiring/piping correction feature.

WIRING DIAGRAMS

Diagrams by Unit Size

Detailed wiring diagrams specific to different unit sizes and configurations.

REFRIGERATION CYCLE DIAGRAMS

Refrigeration Cycles by Unit Size

Illustrates the refrigerant flow for various unit sizes.

REFRIGERANT LINES

General Refrigerant Line Sizing

Guidelines for proper sizing and installation of refrigerant lines.

Long Line Applications:

Additional Refrigerant Charge Table

Table detailing additional refrigerant needed for longer line applications.

SYSTEM EVACUATION AND CHARGING

System Vacuum and Charge Using Vacuum Pump

Procedure for evacuating and charging the system using a vacuum pump.

Deep Vacuum Method

Explanation of the deep vacuum method for system evacuation.

Triple Evacuation Method

Detailed steps for performing the triple evacuation method.

Final Tubing Check

Final inspection procedures for refrigerant tubing connections.

ELECTRONIC FUNCTION

Compressor Protections

Covers discharge temperature and current limit protections for the compressor.

Fan and Voltage Protections

Details fan speed malfunction and low voltage protection mechanisms.

Indoor / Outdoor Units Communication Protection

High Condenser Coil Temperature Protection

Protection against high condenser coil temperatures.

Outdoor Unit Anti-Freezing Protection

Mechanism to prevent freezing of the outdoor unit.

Low Outdoor Ambient Temperature Protection

Protection triggered by low outdoor ambient temperatures.

Oil Return

Procedures and rules governing the oil return operation.

Heating Mode

Defrosting Control

Conditions, stop criteria, and actions for defrosting the unit.

CONTROL FUNCTIONS

Outdoor Fan Control

Manages outdoor fan speed based on operating conditions.

Electronic Expansion Valve (EXV) Control

Manages EXV operation for cooling and heating modes.

Four-Way Valve Control

Manages the operation of the four-way valve in different modes.

TROUBLESHOOTING

Recommended Steps

Step-by-step guide for diagnosing and resolving issues.

DIAGNOSTIC GUIDES

Outdoor Unit Error Display Codes

Lists and explains various error codes displayed by the outdoor unit.

OUTDOOR UNIT DIGITAL DISPLAY

Outdoor Unit Point Function

Description of the check switch and its function on the outdoor PCB.

DIAGNOSIS AND SOLUTION

Indoor Unit EEPROM Parameter Error

Diagnosis and solution for indoor unit EEPROM parameter errors.

DIAGNOSIS AND SOLUTION (CONT)

Communication Malfunction Between Indoor and Outdoor Units

Troubleshooting for communication issues between units.

DIAGNOSIS AND SOLUTION (CONT)

Zero-Crossing Signal Detection Error

Diagnosis for errors related to zero-crossing signal detection.

DIAGNOSIS AND SOLUTION (CONT)

Indoor Fan Speed Malfunction

Troubleshooting guide for indoor fan speed malfunctions.

DIAGNOSIS AND SOLUTION (CONT)

Temperature Sensor Malfunction

Diagnosis and troubleshooting for temperature sensor faults.

DIAGNOSIS AND SOLUTION (CONT)

Inverter Module (IPM) Malfunction

Diagnosis and solution for IPM module malfunctions.

DIAGNOSIS AND SOLUTION (CONT)

Over-Voltage or Under-Voltage Protection

Troubleshooting for over/under voltage protection errors.

DIAGNOSIS AND SOLUTION (CONT)

Water-Level Alarm Malfunction

Diagnosis and solution for water-level alarm malfunctions.

DIAGNOSIS AND SOLUTION (CONT)

Indoor Units Mode Conflict

Troubleshooting guide for conflicts in indoor unit operating modes.

DIAGNOSIS AND SOLUTION (CONT)

Outdoor Unit EEPROM Parameter Error

Diagnosis for outdoor unit EEPROM parameter errors.

DIAGNOSIS AND SOLUTION (CONT)

Communication Malfunction Between IPM Board and Outdoor Main Control Board

Troubleshooting for communication issues between IPM and main control boards.

DIAGNOSIS AND SOLUTION (CONT)

Sensor Malfunction Diagnosis

Diagnosing faults in various temperature and other sensors.

DIAGNOSIS AND SOLUTION (CONT)

PFC Module Protection Error

Diagnosis and solution for PFC module protection errors.

DIAGNOSIS AND SOLUTION (CONT)

Outdoor Fan Speed Malfunction

Troubleshooting guide for outdoor fan speed malfunctions.

DIAGNOSIS AND SOLUTION (CONT)

High Pressure Protection Diagnosis

Diagnosis and troubleshooting for high pressure protection.

DIAGNOSIS AND SOLUTION (CONT)

Low Pressure Protection Diagnosis

Diagnosis and troubleshooting for low pressure protection.

DIAGNOSIS AND SOLUTION (CONT)

Current Overload and Compressor Speed Malfunctions

Troubleshooting for current overload and compressor speed issues.

DIAGNOSIS AND SOLUTION (CONT)

Compressor Discharge Temperature Protection Diagnosis

Diagnosis for compressor discharge temperature protection issues.

DIAGNOSIS AND SOLUTION (CONT)

High Temperature Protection of Condenser

Diagnosis for high temperature protection of the condenser.

DIAGNOSIS AND SOLUTION (CONT)

High Temperature Protection of Compressor Top

Diagnosis for high temperature protection of the compressor top.

SPECIFIC ERROR DIAGNOSES

Outdoor DC Fan Motor Lack Phase Failure (EC72)

Diagnosis for DC fan motor lack phase failure.

Outdoor Compressor Lack Phase Protection (PC43)

Troubleshooting for compressor lack phase protection.

Outdoor Unit IR Chip Drive Failure (PC45)

Diagnosis for IR chip drive failure.

DIAGNOSIS AND SOLUTION (CONT)

Adapter Board Communication Malfunction

Troubleshooting for adapter board communication issues.

Temperature Sensor Checking Procedure

Procedure for checking temperature sensor resistance.

APPENDICES

Appendix 1: Temperature Sensor Resistance Values

Table of resistance values for temperature sensors.

Appendix 2: Discharge Temperature Sensor Values

Table of discharge temperature sensor values.

Appendix 3: General Reference Values

Table containing general reference values.

Compressor and IPM Checks

Compressor Check

Procedure for checking the compressor's resistance.

IPM Continuity Check

Procedure for checking IPM continuity.

4-Way Valve Checks

Voltage and Resistance Measurement

Measuring voltage and resistance of the 4-way valve.

EXV Check

Resistance to EXV Coil

Procedure for checking EXV coil resistance.

DISASSEMBLY INSTRUCTIONS

Fan Assembly Removal

Steps to remove the fan assembly from the unit.

DISASSEMBLY INSTRUCTIONS (CONT)

Panel Plate Removal

Steps to remove the panel plate from the unit.

DISASSEMBLY INSTRUCTIONS (CONT)

Electrical Parts Removal

Steps to remove electrical components and boards.

DISASSEMBLY INSTRUCTIONS (CONT)

Compressor Removal

Steps to remove the compressor from the unit.

DISASSEMBLY INSTRUCTIONS (CONT)

Reactor Removal

Steps to remove the reactor.

4-Way Valve Removal

Steps to remove the 4-way valve.

Expansion Valve Removal

Steps to remove the expansion valve.