Carrier 38MHRCQ12AA1 - User Manual

Specifications subject to change without notice.
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS ....................................................... 1
INTRODUCTION............................................................................ 1
MODEL / SERIAL NUMBER NOMENCLATURES .................... 2
SPECIFICATIONS (HEAT PUMP)................................................ 3
PERFORMANCE ............................................................................ 4
DIMENSIONS AND WEIGHTS .................................................... 5
CLEARANCES................................................................................ 9
ELECTRICAL DATA ..................................................................... 10
WIRING........................................................................................... 10
CONNECTION DIAGRAMS ......................................................... 11
WIRING DIAGRAMS (HEAT PUMP) .......................................... 12
REFRIGERATION CYCLE DIAGRAMS...................................... 15
SYSTEM EVACUATION AND CHARGING ............................... 20
TROUBLESHOOTING................................................................... 27
DIAGNOSIS AND SOLUTION...................................................... 31
DISASSEMBLY INSTRUCTIONS SIZES 9K (115V) - 18K (208/
230V)................................................................................................ 51
DISASSEMBLY INSTRUCTIONS SIZE 24K............................... 54
APPENDIX ...................................................................................... 57
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 outdoor units. This manual has an appendix
with data required to perform troubleshooting. Use the “Table of
Contents” 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.
WAR N I N 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.
WAR N I N 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
38MHRC
Outdoor Unit Single Zone Ductless System
Sizes 09 to 24

Summary

SAFETY CONSIDERATIONS

ELECTRICAL SHOCK HAZARD

Warning about electrical shock risk to personal injury or death.

EXPLOSION HAZARD

Warning about explosion from pressurized mixtures of air or gases containing oxygen.

EQUIPMENT DAMAGE HAZARD

Caution against burying pipes too deep, causing refrigerant migration and compressor damage.

INTRODUCTION

MODEL; SERIAL NUMBER NOMENCLATURES

SPECIFICATIONS (HEAT PUMP)

PERFORMANCE

DIMENSIONS AND WEIGHTS

CLEARANCES

ELECTRICAL DATA

WIRING

Covers power and communication wiring recommendations and precautions for installation.

CONNECTION DIAGRAMS

WIRING DIAGRAMS (HEAT PUMP)

REFRIGERATION CYCLE DIAGRAMS

SYSTEM EVACUATION AND CHARGING

Deep Vacuum Method

Details the deep vacuum method for achieving a 500-micron vacuum.

Triple Evacuation Method

Describes the triple evacuation method using dry nitrogen to remove moisture.

ELECTRONIC FUNCTIONS

Main Protection

Lists and explains key protection features like compressor restart delay and temperature cutouts.

Operation Modes and Functions

Describes different operating modes, fan speed control, and cooling/heating logic.

Compressor Temperature Protection

HEATING Mode Operation Rules

Indoor Fan Running Rules

AUTO FAN Mode Logic

DEFROST MODE

Forced DEFROSTING Mode

Describes how to manually activate and exit the defrosting mode using the remote control.

DRYING mode Operation

Forced Operation Function

Explains how to engage forced auto and cooling modes for testing or specific operations.

Auto-Restart Function

Describes the unit's ability to resume previous operation settings after a power failure.

POINT CHECK FUNCTION

TROUBLESHOOTING

Electrolytic Capacitors Safety

Highlights safety precautions for handling electrolytic capacitors and the need for discharging.

Outdoor Unit Diagnostic Guide

PCB DIAGRAMS

PCB DIAGRAMS (CONT)

DIAGNOSIS AND SOLUTION

EEPROM & Communication Errors

Troubleshoot EEPROM parameter errors (E0/F4) and unit communication errors (E1).

Sensor, Fan & Refrigerant Issues

Troubleshoot fan speed, temperature sensors, and refrigerant leakage detection (EC).

Electrical & Compressor Protection Faults

Address overload, IPM/IGBT protection, voltage issues, and compressor high temp faults.

Component Testing & Diagnosis

Guides for testing DC voltage, reactors, compressors, IPM, and fan motors.

Pressure on the Service Port - Cooling Charts

Pressure on the Service Port - Heating Charts

DISASSEMBLY INSTRUCTIONS SIZES 9 K-18 K

DISASSEMBLY INSTRUCTIONS SIZE 24 K

APPENDIX - Temperature Sensor Data

Appendix 2 - T5 Sensor Resistance Values

Appendix 3 - Temperature Conversion Tables

Carrier 38MHRCQ12AA1 Specifications

General

Brand	Carrier
Model	38MHRCQ12AA1
Category	Air Conditioner
Language	English