Service Manual
38MHRB
Outdoor Unit Single Zone Ductless System
Sizes 09 to 24
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS 1.........................
INTRODUCTION 1...................................
MODEL/SERIAL NUMBER NOMENCLATURES 2.........
SPECIFICATIONS 3...................................
DIMENSIONS 5.....................................
CLEARANCES 8.....................................
ELECTRICAL DATA 9................................
WIRING 9...........................................
CONNECTION DIAGRAMS 10.........................
WIRING DIAGRAMS 11...............................
REFRIGERATION CYCLE DIAGRAMS 17................
REFRIGERANT LINES 18.............................
SYSTEM EVACUATION AND CHARGING 19.............
ELECTRONIC FUNCTIONS 18.........................
TROUBLESHOOTING 23..............................
OUTDOOR UNIT DIAGNOSTIC GUIDES 24..............
PCB DIAGRAMS 25..................................
DIAGNOSIS AND SOLUTION 27.......................
DISASSEMBLY INSTRUCTIONS 48.....................
APPENDIX 71.......................................
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 cleaning coils. 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
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 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.
!
WARNING
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.
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
CAUTION
!
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. Section 2 of this manual has
an appendix with data required to perform troubleshooting. Use the
Table of Contents to locate a desired topic.
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