Carrier 38MHRC Service Manual

TABLE OF CONTENTS

SAFETY CONSIDERATIONS

SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
MODEL / SERIAL NUMBER NOMENCLATURES . . . . . . . . . . . 2
WIRING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CONNECTION DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
WIRING DIAGRAMS (HEAT PUMP) . . . . . . . . . . . . . . . . . . . . . . 5
REFRIGERATION HEAT PUMP CYCLE DIAGRAMS . . . . . . . 11
REFRIGERATION COOLING ONLY CYCLE DIAGRAMS . . . 15
SYSTEM EVACUATION AND CHARGING . . . . . . . . . . . . . . . . 19
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
PCB DIAGRAMS (HEAT PUMP) . . . . . . . . . . . . . . . . . . . . . . . . . 28
PCB DIAGRAMS (COOLING ONLY) . . . . . . . . . . . . . . . . . . . . . 30
DIAGNOSIS AND SOLUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
DISASSEMBLY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . 56
APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
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.
Service Manual
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ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Before installing, modifying, or servicing the system, the
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.
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.
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.

INTRODUCTION

This service manual provides the necessary information to service,
repair, and maintain the outdoor units. This manual has an appendix
(see "APPENDIX"on page 82) with data required to perform
troubleshooting. Use the "Table of Contents" to locate a desired topic.
Specifications subject to change without notice.
WARNING
WARNING
CAUTION