Carrier 40MBAB Service Manual Download Page 1

Page: 1 / 44

Specifications subject to change without notice.

TABLE OF CONTENTS

PAGE

SAFETY CONSIDERATIONS

Installing, starting up, and servicing air-conditioning equipment can
be hazardous due to unit 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

only

When working on the equipment, observe the 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 the warnings or cautions
included in the literature and attached to the unit. Consult local
building codes and the 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 of 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 indoor units. This manual contains an
“APPENDICES” on page 36 with data required to troubleshoot issues.
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 the unit, 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.

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 the extended periods
of unit shutdown. This causes refrigerant slugging and could
possibly damage the compressor at start-up.

CAUTION

Service Manual

40MBAB
Air Handler Unit Ductless System

Sizes 18 to 60