Mitsubishi Electric MUZ-FH18NA2 User Manual

SERVICE MANUAL
Models
OUTDOOR UNIT
Indoor unit service manual
MSZ-FH•NA Series (OBH683)
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
HFC
utilized
R410A
No. OBH684
REVISED EDITION-C
PARTS CATALOG (OBB684)
MUZ-FH06NA
MUZ-FH09NA
MUZ-FH12NA
MUZ-FH06NAH
MUZ-FH09NAH
MUZ-FH12NAH
Please void OBH684 REVISED EDITION-B.
Revision C:
• MUZ-FH06NA, MUZ-FH09/12NA-
1
, MUZ-
FH18NA2, MUZ-FH06NAH, MUZ-
FH09/12NAH-
1
and MUZ-FH18NAH2
have been added.
MUZ-FH06NA
MUZ-FH09NA
MUZ-FH09NA
-
1
MUZ-FH12NA
MUZ-FH12NA
-
1
MUZ-FH15NA
MUZ-FH18NA
MUZ-FH18NA2
MUZ-FH06NAH
MUZ-FH09NAH
MUZ-FH09NAH
-
1
MUZ-FH12NAH
MUZ-FH12NAH
-
1
MUZ-FH15NAH
MUZ-FH18NAH
MUZ-FH18NAH2
CONTENTS
1. TECHNICAL CHANGES ······························2
2. PART NAMES AND FUNCTIONS ··················3
3. SPECIFICATION ········································4
4. OUTLINES AND DIMENSIONS ·····················6
5. WIRING DIAGRAM ·····································8
6. REFRIGERANT SYSTEM DIAGRAM ··········· 14
7. DATA······················································ 16
8. ACTUATOR CONTROL ····························· 27
9. SERVICE FUNCTIONS ······························ 28
10. TROUBLESHOOTING ······························· 29
11. DISASSEMBLY INSTRUCTIONS ················· 51

Mitsubishi Electric MUZ-FH18NA2 Specifications

General

Brand	Mitsubishi Electric
Model	MUZ-FH18NA2
Category	Air Conditioner
Language	English

Summary

1 TECHNICAL CHANGES

3 SPECIFICATION

5 WIRING DIAGRAM

6 REFRIGERANT SYSTEM DIAGRAM

9 SERVICE FUNCTIONS

10 TROUBLESHOOTING

10-2. FAILURE MODE RECALL FUNCTION

3. Outdoor unit failure mode table

Table listing outdoor unit failure modes, symptoms, and remedies.

10-3. TROUBLESHOOTING CHECK TABLE

A table cross-referencing symptoms with LED indications and actions.

10-4. TROUBLE CRITERION OF MAIN PARTS

Criteria for checking the resistance and condition of main components.

10-5. TROUBLESHOOTING FLOW

Detailed step-by-step troubleshooting procedures for various issues.

A How to check inverter/compressor

Procedure to check the inverter and compressor.

B Check of open phase

Steps to diagnose an open phase condition in the inverter.

C Check of compressor

Guidance on checking the compressor's basic functionality.

D Check of compressor winding

Procedure to measure compressor winding resistance.

E Check of compressor operation time

Method to measure compressor operation time until stop.

F Check of compressor start failure

Steps to diagnose and resolve compressor start failures.

G Check of outdoor thermistors

Procedure for checking the resistance of outdoor thermistors.

H Check of R.V. coil

Diagnostic steps for the Reversing Valve (R.V.) coil.

① Check of outdoor fan motor

Procedure to check the outdoor fan motor's resistance and voltage.

J Check of power supply

K Check of LEV (Expansion valve)

Check of inverter P.C. board

M How to check miswiring and serial signal error

N Check of defrost heater

Check of outdoor refrigerant circuit

10-6. TEST POINT DIAGRAM AND VOLTAGE

1. Inverter P.C. board

11 DISASSEMBLY INSTRUCTIONS