Mitsubishi Electric MSZ-WR18NA-U1 User Manual

Outdoor unit service manual
MUZ-WR•NA Series (OBH819)
PARTS CATALOG (OBB818)
MSZ-WR24NA
INDOOR UNIT
SERVICE MANUAL
INDOOR UNIT
Models
MSZ-WR09NA
-
U1
,
U2
MSZ-WR12NA
-
U1
,
U2
MSZ-WR18NA
-
U1
MSZ-WR24NA
-
U1
CONTENTS
1. TECHNICAL CHANGES
· ·······························
2
2. PART NAMES AND FUNCTIONS ··················3
3. SPECIFICATION ········································5
4. OUTLINES AND DIMENSIONS ·····················7
5. WIRING DIAGRAM ·····································8
6. REFRIGERANT SYSTEM DIAGRAM ···········10
7. SERVICE FUNCTIONS ······························11
8. MICROPROCESSOR CONTROL ················13
9. TROUBLESHOOTING ······························· 17
10. DISASSEMBLY INSTRUCTIONS ·················32
No. OBH818
REVISED EDITION-C
OBH818 REVISED EDITION-B is void.
Revision C:
• MSZ-WR09/12NA -
U2
have been added.

Mitsubishi Electric MSZ-WR18NA-U1 Specifications

General

Brand	Mitsubishi Electric
Model	MSZ-WR18NA-U1
Category	Air Conditioner
Language	English

Summary

1 TECHNICAL CHANGES

5 WIRING DIAGRAM

7 SERVICE FUNCTIONS

8 MICROPROCESSOR CONTROL

WIRELESS REMOTE CONTROLLER

8-1. COOL () OPERATION

8-2. DRY (0) OPERATION

8-3. HEAT (0) OPERATION

8-6. EMERGENCY/TEST OPERATION

Details how to use emergency and test operation modes.

9 TROUBLESHOOTING

9-1. CAUTIONS ON TROUBLESHOOTING

Outlines important precautions to take before and during troubleshooting.

9-2. FAILURE MODE RECALL FUNCTION

Explains how to recall and interpret stored failure modes.

9-3. INSTRUCTION OF TROUBLESHOOTING

Provides a flowchart for diagnosing unit malfunctions based on symptoms.

9-4. TROUBLESHOOTING CHECK TABLE

A table detailing abnormalities, symptoms, conditions, and remedies for troubleshooting.

9-5. TROUBLESHOOTING CRITERION OF MAIN PARTS

Guides on checking resistance and voltage for key components.

A Check of indoor fan motor

A detailed troubleshooting flow for indoor fan motor issues.

B Check of remote controller and indoor electronic control P.C. board

A flowchart for diagnosing remote controller and indoor control board issues.

C Check of indoor P.C. board and indoor fan motor

Guides for checking indoor P.C. boards and the indoor fan motor.

D How to check miswiring and serial signal error

Details procedures for checking miswiring and serial signal errors.

9-7. Test point diagram and voltage

10 DISASSEMBLY INSTRUCTIONS

10-1. MSZ-WR09NA MSZ-WR12NA

2. Removing the indoor electronic control P.C. board and the electrical box

6. Removing the indoor fan motor, the indoor coil thermistor, and the line flow fan

10-2. MSZ-WR18NA MSZ-WR24NA

2. Removing the indoor power P.C. board and the electrical box

3. Removing the indoor electronic control P.C. board

5. Removing the indoor fan motor, the indoor coil thermistor and the line flow fan