Mitsubishi Electronics MUZ-FH06NA, MUZ-FH09NA, MUZ-FH12NA, MUZ-FH15NA, MUZ-FH18NA User Manual

HFC

utilized

R410A

OUTDOOR UNIT

SERVICE MANUAL

Models

Revision D:

• Capacity corrections have been corrected [7-1. 2), 3)].

OBH684 REVISED EDITION-C is void.

No. OBH684

REVISED EDITION-D

MUZ-FH06NA
MUZ-FH09NA

MUZ-FH09NA

-

MUZ-FH12NA
MUZ-FH12NA

-

MUZ-FH15NA
MUZ-FH18NA
MUZ-FH18NA2

MUZ-FH06NAH
MUZ-FH09NAH

1

MUZ-FH09NAH

-

1

MUZ-FH12NAH

1

MUZ-FH12NAH

-

1

MUZ-FH15NAH
MUZ-FH18NAH
MUZ-FH18NAH2

Indoor unit service manual
MSZ-FH•NA Series (OBH683)

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. ACTUA TOR CONTROL ·····························27

9. SERVICE FUNCTIONS ······························28

10. TROUBLESHOOTING ······························· 29

11. DISASSEMBLY INSTRUCTIONS ·················51

MUZ-FH06NA
MUZ-FH09NA
MUZ-FH12NA

NOTE:

RoHS compliant products have <G> mark on the spec name plate.

MUZ-FH06NAH
MUZ-FH09NAH
MUZ-FH12NAH

PARTS CATALOG (OBB684)

Use the specifi ed refrigerant only

OBH684D

Never use any refrigerant other than that specified.

Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the spec labels provided with our products.
We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by
failure to follow the instructions.

Revision A:

• 3. SPECIFICATION has been modified.
(The values of COP have been modified.)

• 10. TROUBLESHOOTING has been modified.

Revision B:

• MUZ-FH18NA and MUZ-FH18NAH have been added.

Revision C:

• MUZ-FH06NA, MUZ-FH09/12NA- 1, MUZ-FH18NA2, MUZ-FH06NAH, MUZ-FH09/12NAH- 1 and MUZ-FH18NAH2 have
been added.

Revision D:

• Capacity corrections have been corrected [7-1. 2), 3)].

1

TECHNICAL CHANGES

MUZ-FH09NA MUZ-FH09NAH
MUZ-FH12NA MUZ-FH12NAH
MUZ-FH15NA MUZ-FH15NAH

1. New model

MUZ-FH18NA MUZ-FH18NAH

1. New model

MUZ-FH06NA MUZ-FH06NAH

1. New model

MUZ-FH09NA
MUZ-FH12NA

1. Model name has been changed.

2. New service part numbers have been set. (Refer to OBB684, 1-2.)

MUZ-FH18NA

1. Model name has been changed.

MUZ-FH09NA ­MUZ-FH12NA -

MUZ-FH18NA2

1

MUZ-FH09NAH

1

MUZ-FH12NAH

MUZ-FH18NAH

MUZ-FH09NAH ­MUZ-FH12NAH -

MUZ-FH18NAH2

1

1

2

2

OBH684D

PART NAMES AND FUNCTIONS

MUZ-FH06NA MUZ-FH06NAH
MUZ-FH09NA MUZ-FH09NAH
MUZ-FH12NA MUZ-FH12NAH

(back and side)

Air inlet

Piping

Air outlet

Drain hose

Drain outlet

MUZ-FH15NA MUZ-FH15NAH
MUZ-FH18NA MUZ-FH18NAH
MUZ-FH18NA2 MUZ-FH18NAH2

(back and side)

Drain hose

Air outlet

Drain outlet

Air inlet

Piping

3

3

OBH684D

SPECIFICATION

Outdoor unit model

Capacity

Cooling 1

Rated (Minimum~Maximum)

Capacity

Rated (Maximum)

Power consumption

Rated (Minimum~Maximum)

Power consumption

Rated (Maximum)

1

EER

HSPF IV

[SEER] 3 Cooling 19.1 [33.1] 16.1 [30.5] 13.8 [26.1] 12.5 [22.0] 12.0 [21.0] 12.5 [21.0]

4

Heating 47 1

Heating 17 2

Cooling 1

Heating 47 1

Heating 17 2

Heating

COP Heating

MUZ-FH06NA

MUZ-FH06NAH

Btu/h

Btu/h

Btu/h

W

W

W

6,000

(1,700 ~ 9,000)

8,700

(1,600 ~ 14,000)

5,900 (10,700) 6,700 (12,200) 8,000(13,600) 11,000 (18,000) 13,700 (20,300)

315

(100 ~ 560)

545

(110 ~ 1,270)

500

(1,000) 600 (1,440) 720 (1,900) 1,020 (2,480) 1,320 (2,800)

NA: 13.5 NA: 13.5 NA: 12.5 NA: 12.0 NA: 12.0 NA2: 12.0

NAH: 12.5 NAH: 12.5 NAH: 11.5 NAH: 11.0 NAH: 11.0 NAH2: 11.0

1 4.68 4.50 4.20 4.06 3.46

MUZ-FH09NA

MUZ-FH09NAH

MUZ-FH12NAH

9,000

(1,700 ~ 12,000)

(2,500 ~ 13,600)

10,900

(1,600 ~ 18,000)

(3,700 ~ 21,000)

560

(100 ~ 1,000)

710

(110 ~ 1,470)

MUZ-FH12NA

12,000

13,600

870

(170 ~ 1,150)

950

(280 ~ 2,300)

MUZ-FH15NA

MUZ-FH15NAH

MUZ-FH18NAH

15,000

(6,450 ~ 19,000)

18,000

(5,150 ~ 24,000)

1,200

(410 ~ 2,200)

1,300

(430 ~ 3,360)

MUZ-FH18NA

(6,450 ~ 21,000)

(5,150 ~ 30,000)

1,430

(410 ~ 2,220)

(430 ~ 3,390)

Power supply V , phase , Hz 208/230, 1 , 60
Max. fuse size (time delay) A 15 20
Min. circuit ampacity A 11 16
Fan motor F.L.A 0.50 0.93

Compressor

Model

R.L.A 8.2 12.0
L.R.A 10.3 15.0

Refrigeration oil L (Model)

SNB092FQAMT SNB140FQUMT

SNB172FQKMT

0.35 (FV50S) 0.35 (FV50S) 0.40 (FV50S)

Refrigerant control Linear expansion valve

Sound level

Cooling dB(A) 47 48 49 51 52

1

Heating dB(A) 48 49 51 55 55

Defrost method Reverse cycle

W in. 31-1/2 33-1/16

Dimensions

D in. 11-1/4 13
H in. 21-5/8 34-5/8

Weight Ib. 81 83 124
External fi nish Munsell 3Y 7.8/1.1
Remote controller Wireless type
Control voltage (by built-in transformer) VDC 12 - 24
Refrigerant piping Not supplied

Refrigerant pipe size
(Min. wall thickness)

Connection meth­od

Between the indoor
& outdoor units

Liquid in. 1/4 (0.0315)
Gas in. 3/8 (0.0315) 1/2 (0.0315)
Indoor Flared
Outdoor Flared
Height difference

ft. 40 50

Piping length ft. 65 100

Refrigerant charge (R410A) 2 lb. 9 oz. 3 lb. 7 oz.

NOTE: Test conditions are based on AHRI 210/240.

1: Rating conditions (Cooling) — Indoor: 80˚FDB, 67˚FWB, Outdoor: 95˚FDB, (75˚FWB)
(Heating) — Indoor: 70˚FDB, 60˚FWB, Outdoor: 47˚FDB, 43˚FWB
2: (Heating) — Indoor: 70˚FDB, 60˚FWB, Outdoor: 17˚FDB, 15˚FWB

MUZ-FH18NA2

MUZ-FH18NAH2

17,200

20,300

1,375

(410 ~ 2,220)

1,720

4

Test condition

OBH684D

3, 4

Mode Test

ARI

"A-2" Cooling Steady State
at rated compressor Speed

"B-2" Cooling Steady State
at rated compressor Speed

SEER

(Cooling)

HSPF

(Heating)

5

: At Intermediate compressor Speed

"B-1" Cooling Steady State
at minimum compressor Speed

"F-1" Cooling Steady State
at minimum compressor Speed

"E-V" Cooling Steady State
at Intermediate compressor Speed

"H1-2" Heating Steady State
at rated compressor Speed

"H3-2" Heating
at rated compressor Speed

"H0-1" Heating Steady State
at minimum compressor Speed

"H1-1" Heating Steady State
at minimum compressor Speed

"H2-V" Heating
at Intermediate compressor Speed

5

5

= ("Rated compressor speed" - "minimum compressor speed") / 3 + "minimum compressor speed".

Indoor air condition (°F) Outdoor air condition (°F)

Dry bulb Wet bulb Dry bulb Wet bulb

80 67 95 (75)

80 67 82 (65)

80 67 82 (65)

80 67 67 (53.5)

80 67 87 (69)

70 60 47 43

70 60 17 15

70 60 62 56.5

70 60 47 43

70 60 35 33

OPERATING RANGE

(1) POWER SUPPLY

Outdoor unit

(2) OPERATION

Mode Condition

Standard temperature 80 67 95 —

Cooling

Heating

Maximum temperature 90 73 115 —
Minimum temperature 67 57 14 —
Maximum humidity 78 % —
Standard temperature 70 60 47 43
Maximum temperature 80 67 75 65
Minimum temperature 70 60 -13 -14

Rated voltage Guaranteed voltage (V)

208/230 V

1 phase

60 Hz

Min. 187

Indoor Outdoor

DB WB DB WB

208 230 Max. 253

Intake air temperature (°F)

5

4

OBH684D

OUTLINES AND DIMENSIONS

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH

Unit: inch

REQUIRED SPACE

*1

4 in. (100 mm) or more when

front and sides of the unit are clear

clear *1

(MUZ-FH06/09/12NA)

(MUZ-FH06/09/12NAH)

2 x hole 3/8 x 13/16

4 in. (100 mm)

or more

8 in. (200 mm)

or more *2

*2

When any 2 sides of left, right

and rear of the unit are clear

14 in. (350 mm)

or more

4 in. (100 mm)

or more

Liquid refrigerant pipe joint
Refrigerant pipe (flared) Ø 1/4

Gas refrigerant pipe joint
Refrigerant pipe (flared)

Ø 3/8

6

MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

OBH684D

Unit: inch

REQUIRED SPACE

Air in

13

34-5/8

2

17-25/32

6-7/8

16-7/16

Air in

19-11/16

4-5/16

Air out

33-1/16

*1 20 in. (500 mm) or more when front
and sides of the unit are clear

Drain hole

1-9/16

1-5/8

14-3/16

2 x hole 13/32 x 13/16

3-3/16

4 in. (100 mm)

or more

Clear *1

20 in. (500 mm)

or more *2

*2 When any 2 sides of left, right
and rear of the unit are clear

Service panel

Liquid refrigerant pipe joint
Refrigerant pipe (flared)

35

44

4 in. (100 mm)

or more

14in. (350 mm)

or more

Ø 1/4

6-1/2

3-29/32

7-11/16

Gas refrigerant pipe joint
Refrigerant pipe (flared)

Ø 1/2

7

5

OBH684D

WIRING DIAGRAM

MUZ-FH06NA MUZ-FH09NA-1 MUZ-FH12NA-

1

MUZ-FH06NAH MUZ-FH09NAH-1 MUZ-FH12NAH-

1

8

MUZ-FH09NA MUZ-FH12NA

OBH684D

MUZ-FH09NAH MUZ-FH12NAH

9

MUZ-FH15NA MUZ-FH18NA

OBH684D

10

MUZ-FH18NA2

OBH684D

11

MUZ-FH15NAH MUZ-FH18NAH

OBH684D

12

MUZ-FH18NAH2

OBH684D

13

6

Outdoor
heat
exchanger

Flared connection

Defrost
thermistor
RT61

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve
(with strainar)

Stop valve

Refrigerant flow in cooling

Compressor

4-way valve

Refrigerant flow in heating

Refrigerant pipe ø3/8
(with heat insulator)

Refrigerant pipe ø1/4
(with heat insulator)

R.V. coil
heating ON
cooling OFF

Strainer
#100

LEV

Ambient
temperature
thermistor
RT65

Muffler

Capillary tube

O.D. 0.157 ×
I.D. 0.094 × 9-7/16
(

ø4.0 × ø2.4 × 240

)

Outdoor heat
exchanger
temperature
thermistor
RT68

Capillary tube
O.D. 0.118 ×
I.D. 0.079 × 8-9/32
(ø3.0 × ø2.0 × 210)

Service
port

Service
port

Muffler

OBH684D

REFRIGERANT SYSTEM DIAGRAM

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH

Unit: inch

MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

Muffler

#100

Discharge
temperature
thermistor
RT62

Capillary tube
O.D. 0.157 ×
I.D. 0.094× 3-15/16
(ø4.0×ø2.4×100)

Compressor

14

Service port

LEV

Strainer

#100

Outdoor
heat

Defrost
thermistor
RT61

Refrigerant flow in cooling
Refrigerant flow in heating

exchanger

Outdoor heat
exchanger
temperature
thermistor
RT68

R.V. coil
heating ON
cooling OFF

Ambient
temperature
thermistor
RT65

Refrigerant pipe
(with heat insulator)

Flared connection

ø

Flared connection

Refrigerant pipe ø1/4
(with heat insulator)

1/2

Stop valve

Stop valve

Strainer

#100

4-way valve

Service
port

Muffler

Max. Length
A

Max. Height

difference

B

Indoor
unit

Outdoor unit

MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE

OBH684D

Refrigerant piping: ft. Piping size O.D: in.

Model

MUZ-FH06NA
MUZ-FH06NAH
MUZ-FH09NA
MUZ-FH09NAH
MUZ-FH12NA
MUZ-FH12NAH

MUZ-FH15NA
MUZ-FH15NAH
MUZ-FH18NA
MUZ-FH18NAH
MUZ-FH18NA2
MUZ-FH18NAH2

Max. Length

A

Max. Height difference

B

Gas Liquid

65 40 3/8 1/4

100 50 1/2 1/4

ADDITIONAL REFRIGERANT CHARGE (R410A: oz.)

NOTE: Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.

NOTE: Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.

NOTE: Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation.

Model

MUZ-FH06NA
MUZ-FH06NAH
MUZ-FH09NA
MUZ-FH09NAH

Model

MUZ-FH12NA
MUZ-FH12NAH

Model

MUZ-FH15NA
MUZ-FH15NAH
MUZ-FH18NA
MUZ-FH18NAH
MUZ-FH18NA2
MUZ-FH18NAH2

Outdoor unit

precharged

25 30 40 50 60 65

Refrigerant piping length (one way): ft.

2 lb. 9 oz. 0 1.08 3.24 5.40 7.56 8.64

Calculation: X oz. = 1.08/5 oz./ft. × (Refrigerant piping length (ft.) - 25)

Outdoor unit

precharged

25 30 40 50 60 65

Refrigerant piping length (one way): ft.

2 lb. 9 oz. 0 1.62 4.86 8.10 11.34 12.96

Calculation: X oz. = 1.62/5 oz./ft. × (Refrigerant piping length (ft.) - 25)

Outdoor unit

precharged

25 30 40 50 60 70 80 90 100

Refrigerant piping length (one way): ft.

3 lb. 7 oz. 0 1.08 3.24 5.40 7.56 9.72 11.88 14.04 16.20

Calculation: X oz. = 1.08/5 oz./ft. × (Refrigerant piping length (ft.) - 25)

15

DATA7

OBH684D

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH
MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

7-1. PERFORMANCE DATA

1) COOLING CAPACITY

Indoor air Outdoor intake air DB temperature (˚F)

Model

MUZ-FH06NA
MUZ-FH06NAH

MUZ-FH09NA
MUZ-FH09NAH

MUZ-FH12NA
MUZ-FH12NAH

MUZ-FH15NA
MUZ-FH15NAH

MUZ-FH18NA
MUZ-FH18NAH

MUZ-FH18NA2
MUZ-FH18NAH2

NOTE: 1. IWB : Intake air wet-bulb temperature TC : Total Capacity (x10

2. SHC is based on 80˚F of indoor Intake air DB temperature.

IWB (˚F)

71 7.4 6.1 0.28 6.9 5.7 0.31 6.5 5.3 0.33 6.0 5.0 0.35 5.5 4.6 0.36
67 7.0 6.7 0.26 6.5 6.2 0.29 6.0 5.8 0.32 5.6 5.4 0.33 5.1 4.9 0.35
63 6.5 7.2 0.25 6.1 6.6 0.28 5.6 6.2 0.30 5.1 5.6 0.32 4.7 5.1 0.33
71 11.0 8.7 0.50 10.3 8.1 0.55 9.7 7.6 0.59 9.0 7.1 0.62 8.3 6.5 0.64
67 10.4 9.6 0.47 9.7 8.9 0.52 9.0 8.3 0.56 8.4 7.7 0.59 7.7 7.1 0.62
63 9.8 10.3 0.45 9.1 9.6 0.50 8.5 8.9 0.53 7.7 8.1 0.57 7.0 7.4 0.59
71 14.7 10.2 0.77 13.7 9.6 0.85 12.9 9.0 0.91 12.0 8.4 0.96 11.0 7.7 1.00
67 13.9 11.6 0.73 13.0 10.8 0.80 12.0 10.0 0.87 11.2 9.3 0.92 10.3 8.5 0.97
63 13.1 12.6 0.70 12.1 11.7 0.77 11.3 10.9 0.83 10.3 9.9 0.89 9.4 9.0 0.92
71 18.4 10.4 1.07 17.2 9.7 1.17 16.1 9.1 1.26 15.0 8.5 1.33 13.8 7.8 1.38
67 17.4 12.2 1.01 16.2 11.3 1.11 15.0 10.5 1.20 14.0 9.8 1.27 12.8 9.0 1.33
63 16.4 13.6 0.96 15.2 12.6 1.06 14.1 11.8 1.15 12.8 10.7 1.22 11.7 9.8 1.27
71 21.1 11.3 1.27 19.7 10.6 1.39 18.5 9.9 1.50 17.2 9.2 1.58 15.8 8.5 1.64
67 20.0 13.4 1.20 18.6 12.4 1.32 17.2 11.5 1.43 16.0 10.7 1.52 14.7 9.9 1.59
63 18.7 15.1 1.14 17.4 14.0 1.27 16.2 13.0 1.37 14.7 11.8 1.46 13.4 10.8 1.52
71 21.1 11.3 1.22 19.7 10.6 1.34 18.5 9.9 1.44 17.2 9.2 1.52 15.8 8.5 1.58
67 20.0 13.4 1.16 18.6 12.4 1.27 17.2 11.5 1.38 16.0 10.7 1.46 14.7 9.9 1.53
63

SHC : Sensible Heat Capacity (x10

75 85 95 105 115

TC SHC TPC TC SHC TPC TC SHC TPC TC SHC TPC TC SHC TPC

18.7 15.1 1.10 17.4 14.0 1.22 16.2 13.0 1.31 14.7 11.8 1.40 13.4 10.8 1.46

3

Btu/h) TPC : Total Power Consumption (kW)

3

Btu/h)

2) COOLING CAPACITY CORRECTIONS

Refrigerant piping length (one way: ft.)

25 (std.) 40 65 100

MUZ-FH06NA
MUZ-FH06NAH
MUZ-FH09NA
MUZ-FH09NAH
MUZ-FH12NA
MUZ-FH12NAH

MUZ-FH15NA
MUZ-FH15NAH
MUZ-FH18NA
MUZ-FH18NAH
MUZ-FH18NA2
MUZ-FH18NAH2

3) HEATING CAPACITY CORRECTIONS

MUZ-FH06NA
MUZ-FH06NAH
MUZ-FH09NA
MUZ-FH09NAH
MUZ-FH12NA
MUZ-FH12NAH

MUZ-FH15NA
MUZ-FH15NAH
MUZ-FH18NA
MUZ-FH18NAH
MUZ-FH18NA2
MUZ-FH18NAH2

1.0 0.988 0.967 -

1.0 0.985 0.963 0.933

Refrigerant piping length (one way: ft.)

25 (std.) 40 65 100

1.0 0.977 0.993 -

1.0 0.977 0.993 0.987

16

4) HEATING CAPACITY

OBH684D

Indoor air Outdoor intake air WB temperature (˚F)

Model

MUZ-FH06NA

MUZ-FH06NAH

MUZ-FH09NA

MUZ-FH09NAH

MUZ-FH12NA

MUZ-FH12NAH

MUZ-FH15NA

MUZ-FH15NAH

MUZ-FH18NA

MUZ-FH18NAH

MUZ-FH18NA2

MUZ-FH18NAH2

NOTE: 1. IDB : Intake air dry-bulb temperature

2. Above data is for heating operation without any frost.

IDB (˚F)

75 3.8 0.32 5.0 0.41 6.3 0.48 7.5 0.53 8.5 0.56 8.7 0.57 9.9 0.59
70 4.1 0.31 5.4 0.39 6.5 0.47 7.7 0.52 8.7 0.55 9.0 0.56 10.1 0.58
65 4.4 0.29 5.5 0.38 6.8 0.45 8.0 0.50 9.0 0.53 9.2 0.54 10.4 0.57
75 3.8 0.45 5.0 0.53 6.3 0.60 7.5 0.53 8.5 0.55 8.7 0.56 9.9 0.58
70 4.1 0.44 5.4 0.52 6.5 0.59 7.7 0.51 8.7 0.54 9.0 0.55 10.1 0.57
65 4.4 0.42 5.5 0.50 6.8 0.58 8.0 0.50 9.0 0.53 9.2 0.53 10.4 0.56
75 4.8 0.42 6.3 0.53 7.9 0.62 9.4 0.69 10.6 0.73 11.0 0.74 12.4 0.77
70 5.2 0.40 6.7 0.51 8.2 0.61 9.6 0.67 10.9 0.71 11.2 0.72 12.7 0.75
65 5.5 0.38 6.9 0.49 8.6 0.59 10.0 0.66 11.2 0.69 11.6 0.70 13.0 0.74
75 4.8 0.55 6.3 0.66 7.9 0.75 9.4 0.69 10.6 0.73 11.0 0.74 12.4 0.77
70 5.2 0.53 6.7 0.64 8.2 0.74 9.6 0.67 10.9 0.71 11.2 0.72 12.7 0.75
65 5.5 0.51 6.9 0.62 8.6 0.72 10.0 0.66 11.2 0.69 11.6 0.70 13.0 0.74
75 6.0 0.56 7.9 0.71 9.9 0.83 11.8 0.93 13.3 0.97 13.7 0.99 15.5 1.03
70 6.5 0.54 8.4 0.68 10.2 0.81 12.0 0.90 13.6 0.95 14.0 0.97 15.8 1.01
65 6.8 0.51 8.6 0.66 10.7 0.78 12.4 0.88 14.0 0.93 14.4 0.94 16.2 0.99
75 6.0 0.69 7.9 0.84 9.9 0.96 11.8 0.93 13.3 0.97 13.7 0.99 15.5 1.03
70 6.5 0.67 8.4 0.81 10.2 0.94 12.0 0.90 13.6 0.95 14.0 0.97 15.8 1.01
65 6.8 0.64 8.6 0.79 10.7 0.91 12.4 0.88 14.0 0.93 14.4 0.94 16.2 0.99
75 7.9 0.77 10.4 0.97 13.1 1.14 15.6 1.27 17.6 1.33 18.1 1.35 20.5 1.40
70 8.6 0.73 11.1 0.94 13.5 1.11 15.9 1.24 18.0 1.30 18.5 1.33 21.0 1.38
65 9.0 0.70 11.3 0.90 14.1 1.07 16.5 1.20 18.5 1.27 19.1 1.29 21.4 1.35
75 7.9 0.90 10.4 1.10 13.1 1.27 15.6 1.27 17.6 1.33 18.1 1.35 20.5 1.40
70 8.6 0.86 11.1 1.07 13.5 1.24 15.9 1.24 18.0 1.30 18.5 1.33 21.0 1.38
65 9.0 0.83 11.3 1.03 14.1 1.20 16.5 1.20 18.5 1.27 19.1 1.29 21.4 1.35
75 8.9 1.01 11.8 1.28 14.7 1.51 17.6 1.68 19.8 1.76 20.4 1.79 23.1 1.86
70 9.6 0.97 12.5 1.24 15.2 1.47 18.0 1.63 20.3 1.72 20.9 1.75 23.6 1.82
65 10.2 0.93 12.8 1.19 15.9 1.42 18.6 1.59 20.9 1.68 21.5 1.70 24.2 1.79
75 8.9 1.14 11.8 1.41 14.7 1.64 17.6 1.68 19.8 1.76 20.4 1.79 23.1 1.86
70 9.6 1.10 12.5 1.37 15.2 1.60 18.0 1.63 20.3 1.72 20.9 1.75 23.6 1.82
65 10.2 1.06 12.8 1.32 15.9 1.55 18.6 1.59 20.9 1.68 21.5 1.70 24.2 1.79
75 8.9 1.01 11.8 1.28 14.7 1.51 17.6 1.68 19.8 1.76 20.4 1.79 23.1 1.86
70 9.6 0.97 12.5 1.24 15.2 1.47 18.0 1.63 20.3 1.72 20.9 1.75 23.6 1.82
65 10.2 0.93 12.8 1.19 15.9 1.42 18.6 1.59 20.9 1.68 21.5 1.70 24.2 1.79
75 8.9 1.14 11.8 1.41 14.7 1.64 17.6 1.68 19.8 1.76 20.4 1.79 23.1 1.86
70 9.6 1.10 12.5 1.37 15.2 1.60 18.0 1.63 20.3 1.72 20.9 1.75 23.6 1.82
65 10.2 1.06 12.8 1.32 15.9 1.55 18.6 1.59 20.9 1.68 21.5 1.70 24.2 1.79

TC : Total Capacity (x10

5 152535434555

TC TPC TC TPC TC TPC TC TPC TC TPC TC TPC TC TPC

3

Btu/h) TPC : Total Power Consumption (kW)

How to operate with fixed operational frequency of the compressor.

1. Press the EMERGENCY OPERATION switch on the front of the indoor unit, and select either EMERGENCY COOL
mode or EMERGENCY HEAT mode before starting to operate the air conditioner.

2. The compressor starts with operational frequency.

3. The fan speed of the indoor unit is High.

4. This operation continues for 30 minutes.

5. In order to release this operation, press the EMERGENCY OPERATION switch twice or once, or press any button on
the remote controller.

17

7-2. PERFORMANCE CURVE

71
67
63

65 75 85 95 105 115

0.1

0.2

0.3

0.4

0.5

Indoor intake air WB temperature (°F)

SHF at rating condition = 0.96

= 381 CFM

Airflow

Outdoor intake air DB temperature (°F)

Total power consumption

(kW)

OBH684D

Cooling

1.5

1.4

1.3

1.2

1.1

difference (°F)

1.0

Capacity correction factors

0.9

Indoor air Wet-bulb temperature

14 23 32 41 50 59 68 77 86 95 104 113

Cooling capacity (

Outdoor intake air DB temperature(°F)

MUZ-FH06NA MUZ-FH06NAH

at Rated frequency)

Indoor intake air Wet-bulb
temperature( F)

76

75

72
68
64

MUZ-FH09NA MUZ-FH09NAH

SHF at rating condition = 0.92

0.8

Airflow

= 381 CFM

0.7

0.6

(kW)

0.5

0.4

Total power consumption

Indoor intake air WB temperature (°F)

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

MUZ-FH12NA MUZ-FH12NAH MUZ-FH15NA MUZ-FH15NAH

SHF at rating condition = 0.83

1.1

1.0

0.9

(kW)

0.8

0.7

0.6

Total power consumption

Indoor intake air WB temperature (°F)

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

MUZ-FH18NA MUZ-FH18NAH

SHF at rating condition = 0.67

1.8

1.7

1.6

1.5

1.4

(kW)

1.3

1.2

1.1

Total power consumption

This value of frequency is not the same as the actual frequency in operating. Refer to 7-5 and 7-6 for the relationships
between frequency and capacity.

Indoor intake air WB temperature (°F)

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

= 398 CFM

Airflow

Airflow

= 437 CFM

1.4

71
67
63

1.3

1.2

(kW)

1.1

1.0

0.9

Total power consumption

MUZ-FH18NA2 MUZ-FH18NAH2

1.7

71
67
63

1.6

1.5

1.4

1.3

(kW)

1.2

1.1

1.0

Total power consumption

18

SHF at rating condition = 0.7

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

SHF at rating condition = 0.67

Indoor intake air WB temperature (°F)

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

= 411 CFM

Airflow

Indoor intake air WB temperature (°F)

= 437 CFM

Airflow

71
67
63

71
67
63

71
67
63

Heating

65

70

75

-5 5 1525354555

65

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Indoor intake air DB temperature (°F)

= 437 CFM

Airflow

Outdoor intake air WB temperature (°F)

Total power consumption

(kW)

OBH684D

Heating capacity (

1.3

1.2

1.1

1.0

0.9

0.8

0.7

difference (°F)

0.6

0.5

Capacity correction factor

Indoor air Dry-bulb temperature

0.4

-4 5 142332415059
Outdoor intake air WB temperature (°F)

Indoor intake air Dry-bulb temperature ( F)

at Rated frequency)

59
68
79

MUZ-FH06NA MUZ-FH06NAH

= 437 CFM

0.8

Airflow

MUZ-FH09NA

MUZ-FH12NA

MUZ-FH15NA

0.6

(kW)

0.4

Total power consumption

0.2

-5 5 1525354555

0.8

0.6

(kW)

0.4

Total power consumption

0.2

-5 5 1525354555

1.2

0.9

(kW)

0.6

Total power consumption

0.3

-5 5 1525354555

1.50

1.25

1.00

(kW)

0.75

Total power consumption

0.50

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Airflow

Airflow

Airflow

= 437 CFM

= 454 CFM

= 454 CFM

75
70
65

65

MUZ-FH09NAH

= 437 CFM

65
70
75

65

1.0

0.9

0.8

0.7

0.6

(kW)

0.5

0.4

Total power consumption

0.3

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Airflow

75
70
65

65

MUZ-FH12NAH

= 454 CFM

65
70
75

65

1.1

1.0

0.9

0.8

0.7

(kW)

0.6

0.5

Total power consumption

0.4

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Airflow

75
70
65

65

MUZ-FH15NAH

= 497 CFM

65
70
75

65

1.5

1.3

1.1

(kW)

0.9

0.7

Total power consumption

0.5

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

19

Airflow

75
70
65

65

MUZ-FH18NA

OBH684D

2.00

1.75

1.50

1.25

(kW)

1.00

0.75

Total power consumption

0.50

-5 5 1525354555

Airflow

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

= 514 CFM

65

MUZ-FH18NAH

65
70
75

Total power consumption

2.00

1.75

1.50

(kW)

1.25

1.00

0.75

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Airflow

= 514 CFM

MUZ-FH18NA2 MUZ-FH18NAH2

2.00

1.75

1.50

1.25

(kW)

1.00

0.75

Total power consumption

0.50

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

Airflow

65
70
75

65

2.00

1.75

1.50

(kW)

1.25

1.00

Total power consumption

0.75

-5 5 1525354555

Indoor intake air DB temperature (°F)

Outdoor intake air WB temperature (°F)

= 514 CFM

This value of frequency is not the same as the actual frequency in operating. Refer to 7-5 and 7-6 for the relationships
between frequency and capacity.

Airflow

= 514 CFM

75
70
65

65

75
70
65

65

7-3. CONDENSING PRESSURE
Cooling

Data are based on the condition of indoor humidity 50 %.
Air flow should be set to High speed.

MUZ-FH06NA MUZ-FH06NAH

(PSIG)

500

450

400

350

Indoor DB temperature (°F)

300

Condensing pressure

250

200

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

(PSIG)

190

86
80
75
70

170

150

130

Suction pressure

110

90

(°F) (°F)

Indoor DB temperature (°F)

60 65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

MUZ-FH09NA MUZ-FH09NAH

(PSIG)

500

450

400

350

Indoor DB temperature (°F)

300

Condensing pressure

250

200

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

(PSIG)

190

86
80
75
70

170

150

130

Suction pressure

110

90

(°F) (°F)

Indoor DB temperature (°F)

60 65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

20

86
80

75
70

86
80

75
70

MUZ-FH12NA MUZ-FH12NAH

OBH684D

(PSIG)

500

450

400

Indoor DB temperature (°F)

350

300

Condensing pressure

250

200

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

MUZ-FH15NA MUZ-FH15NAH

(PSIG)

500

450

400

Indoor DB temperature (°F)

350

300

Condensing pressure

250

200

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

MUZ-FH18NA MUZ-FH18NAH

(PSIG)

500

(PSIG)

86
80

180

75
70

160

140

120

Suction pressure

100

80

(°F) (°F)

(PSIG)

86
80

180

75
70

160

140

120

Suction pressure

100

80

(°F) (°F)

Indoor DB temperature (°F)

65 70 75 80 85 90 95 100 105

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

Indoor DB temperature (°F)

Outdoor ambient temperature

86
80

75
70

86
80

75
70

450

400

Indoor DB temperature (°F)

350

300

Condensing pressure

250

200

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

MUZ-FH18NA2 MUZ-FH18NAH2

(PSIG)

500

450

400

350

300

Condensing pressure

250

200

65 70 75 80 85 90 95 100 105

Indoor DB temperature (°F)

Outdoor ambient temperature

86

(PSIG)

80

180

75
70

160

140

120

Suction pressure

100

80

(°F) (°F)

(PSIG)

86
80

180

75
70

160

140

120

Suction pressure

100

80

(°F) (°F)

Indoor DB temperature (°F)

65 70 75 80 85 90 95 100 105

65 70 75 80 85 90 95 100 105

Outdoor ambient temperature

Indoor DB temperature (°F)

Outdoor ambient temperature

86
80

75
70

86
80

75
70

21

Heating

OBH684D

Data are based on the condition of outdoor humidity 75%.
Air flow should be set to High speed.
Data are for heating operation without any frost.

MUZ-FH06NA MUZ-FH06NAH

(PSIG)

450

410

370

330

Condensing pressure

290

250

5 15253545556575

Indoor DB temperature (°F)

Outdoor ambient temperature

(PSIG)

210

75

190

70

170

65

150

130

110

Suction pressure

90

70

50

5 15253545556575

(°F) (°F)

Indoor DB temperature (°F)

Outdoor ambient temperature

MUZ-FH09NA MUZ-FH09NAH

(PSIG)

450

410

370

330

Condensing pressure

290

250

5 15253545556575

Indoor DB temperature (°F)

Outdoor ambient temperature

(PSIG)

210

75

190

70

170

65

150

130

110

Suction pressure

90

70

50

5 15253545556575

(°F) (°F)

Indoor DB temperature (°F)

Outdoor ambient temperature

MUZ-FH12NA MUZ-FH12NAH

(PSIG)

450

410

(PSIG)

200

75
70

65

175

75
70
65

75
70
65

75
70
65

370

330

Condensing pressure

290

250

5 15253545556575

Indoor DB temperature (°F)

Outdoor ambient temperature

MUZ-FH15NA MUZ-FH15NAH

(PSIG)

550

500

450

400

350

Condensing pressure

300

250

5 15253545556575

Indoor DB temperature (°F)

Outdoor ambient temperature

150

125

Suction pressure

100

75

50

5 15253545556575

(°F) (°F)

(PSIG)

200

75
70

175

65

150

125

Suction pressure

100

75

50

5 15253545556575

(°F) (°F)

Indoor DB temperature (°F)

Outdoor ambient temperature

Indoor DB temperature (°F)

Outdoor ambient temperature

22

75
70
65

MUZ-FH18NA MUZ-FH18NAH

OBH684D

(PSIG)

600

550

500

450

400

Condensing pressure

350

Indoor DB temperature (°F)

(PSIG)

75
70
65

Suction pressure

200

175

150

125

100

75
70
65

Indoor DB temperature (°F)

75

300

5 15253545556575

Outdoor ambient temperature

MUZ-FH18NA2 MUZ-FH18NAH2

(PSIG)

600

550

500

450

400

Condensing pressure

350

300

5 15253545556575

Indoor DB temperature (°F)

Outdoor ambient temperature

50

5 15253545556575

(°F) (°F)

(PSIG)

200
75
70
65

175

150

125

Suction pressure

100

75

50

5 15253545556575

(°F) (°F)

Outdoor ambient temperature

Indoor DB temperature (°F)

Outdoor ambient temperature

75
70
65

23

7-4. STANDARD OPERATION DATA

OBH684D

Model

Item Unit

Capacity Btu/h 6,000 8,700 9,000 10,900 12,000 13,600 15,000 18,000 17,200 20,300 17,200 20,300

SHF — 0.96 — 0.92 — 0.83 — 0.70 — 0.67 — 0.69 —

Total

Input kW 0.315 0.545 0.560 0.710 0.870 0.950 1.200 1.300 1.430 1.720 1.375 1.72

Rated frequency Hz 28 50 47 58.5 46 49 50.5 50 59.5 61 57.0 61

Indoor unit

Power supply

Input kW 0.029 0.029 0.029 0.031 0.033 0.033

Fan motor current A 0.30/0.27 0.30/0.27 0.30/0.27 0.31/0.28 0.34/0.31 0.34/0.31

Outdoor unit

Electrical circuit

Power supply

Input kW 0.243 0.475 0.531 0.681 0.841 0.921 1.169 1.269 1.397 1.687 1.342 1.687

Comp. current A

Fan motor current A

Condensing
pressure

Suction
pressure

Discharge
temperature

Condensing
temperature

Suction
temperature

Refrigerant circuit

Comp. shell bottom
temperature

Ref. pipe length ft. 25

Refrigerant charge (R410A) 2 lb. 9 oz. 3 lb 7 oz.

Intake air
temperature

Discharge air
temperature

Fan speed (High) rpm 1,150 1,280 1,150 1,280 1,190 1,320 1,220 1,420 1,280 1,460 1,330 1,460

Indoor unit

Airfl ow (High) CFM

Intake air
temperature

Fan speed rpm 810 900 810 900 810 900 840 810 840 810 840 810

Airfl ow CFM 1,074 1,202 1,074 1,202 1,074 1,202 1,692 1,634 1,692 1,634 1,692 1,634

Outdoor unit

phase,

phase,

PSIG 332 297 352 323 374 340 361 391 370 445 367 445

PSIG 174 112 153 110 135 106 131 108 125 107 128 107

DB ˚F807080708070807080708070

WB ˚F676067606760676067606760

DB ˚F 64 94 58 99 56 101 52 111 50 119 52 119

WB ˚F60— 55—54—51—49—51—

DB ˚F954795479547954795479547

WB ˚F — 43 — 43 — 43 — 43 — 43 — 43

MSZ-FH06NA MSZ-FH09NA MSZ-FH12NA MSZ-FH15NA MSZ-FH18NA MSZ-FH18NA2

Cooling Heating Cooling Heating Cooling Heating Cooling Heating Cooling Heating Cooling Heating

MSZ-FH06NA MSZ-FH09NA MSZ-FH12NA MSZ-FH15NA MSZ-FH18NA MSZ-FH18NA2

V,

Hz

MUZ-FH06NA

MUZ-FH06NAH

V,

Hz

1.22/1.10 2.23/2.02 2.32/2.10 3.01/2.72 3.60/3.26 4.06/3.67 4.46/4.03 4.87/4.40 5.64/5.10 7.04/6.37 5.53/5.00 7.04/6.37

0.36/0.33 0.34/0.31 0.36/0.33 0.34/0.31 0.41/0.37 0.40/0.36 1.21/1.09 1.24/1.12 1.21/1.09 1.24/1.12 1.21/1.09 1.24/1.12

˚F 136 140 148 145 156 148 152 170 153 189 164 189

˚F 104 96 107 101 112 105 109 115 111 123 109 123

˚F694464415636524543345934

˚F 120 120 129 125 137 128 135 147 141 167 154 167

328

(Wet)

MUZ-FH09NA

MUZ-FH09NAH

437

(Wet)

328

MUZ-FH12NAH

437

208/230, 1, 60

MUZ-FH12NA

208/230, 1, 60

342

(Wet)

454

MUZ-FH15NA

MUZ-FH15NAH

354

(Wet)

497

MUZ-FH18NA

MUZ-FH18NAH

376

(Wet)

514

MUZ-FH18NA2

MUZ-FH18NAH2

395

(Wet)

514

24

7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY

OBH684D

MUZ-FH06NA MUZ-FH06NAH

Correction of Cooling capacity

2.0

Correction of Cooling total input

2.0

Correction of Heating capacity

2.0

Correction of Heating total input

2.5

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

The operational frequency of compressor

MUZ-FH09NA MUZ-FH09NAH

Correction of Cooling capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

2.0

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

The operational frequency of compressor

MUZ-FH12NA MUZ-FH12NAH

Correction of Cooling capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

2.0

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

The operational frequency of compressor

0 25 50 75 100

Correction of Cooling total input

0 25 50 75 100

Correction of Cooling total input

0 25 50 75 100

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

(Hz) (Hz)

The operational frequency of compressor

Correction of Heating capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

(Hz) (Hz)

The operational frequency of compressor

Correction of Heating capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

(Hz) (Hz)

2.0

1.5

1.0

0.5

Input correction factors

0.0
0 255075100

The operational frequency of compressor

Correction of Heating total input

2.5

2.0

1.5

1.0

0.5

Input correction factors

0.0
0 255075100

The operational frequency of compressor

Correction of Heating total input

2.5

2.0

1.5

1.0

0.5

Input correction factors

0.0
0 255075100

The operational frequency of compressor

MUZ-FH15NA MUZ-FH15NAH

Capacity correction factors

Correction of Cooling capacity

2.0

1.5

1.0

0.5

0.0
0 255075100

The operational frequency of compressor

(Hz) (Hz)

Correction of Cooling total input

2.0

1.5

1.0

0.5

Input correction factors

0.0
0 25 50 75 100

The operational frequency of compressor

Correction of Heating capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

25

Correction of Heating total input

3.0

2.5

2.0

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

0 255075100

The operational frequency of compressor

MUZ-FH18NA MUZ-FH18NAH

OBH684D

Correction of Cooling capacity

2.0

2.0

Correction of Cooling total input

Correction of Heating capacity

2.0

Correction of Heating total input

2.5

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

0 255075100

The operational frequency of compressor

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

2.0

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

0 255075100

The operational frequency of compressor

MUZ-FH18NA2 MUZ-FH18NAH2

Correction of Cooling capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

Correction of Cooling total input

2.0

1.5

1.0

0.5

Input correction factors

0.0

(Hz) (Hz)

0 255075100

The operational frequency of compressor

Correction of Heating capacity

2.0

1.5

1.0

0.5

Capacity correction factors

0.0
0 255075100

The operational frequency of compressor

(Hz) (Hz)

Correction of Heating total input

2.5

2.0

1.5

1.0

0.5

Input correction factors

0.0
0 255075100

The operational frequency of compressor

7-6. HOW TO OPERATE FIXED-FREQUENCY OPERATION (Test run operation)

1. Press EMERGENCY OPERATION switch to start COOL or HEAT mode (COOL: Press once, HEAT: Press twice).

2. Test run operation starts and continues to operate for 30 minutes.

3. Compressor operates at rated frequency in COOL mode or 58 Hz in HEAT mode.

4. Indoor fan operates at High speed.

5. After 30 minutes, test run operation finishes and EMERGENCY OPERATION starts (operation frequency of compressor var­ies).

6. To cancel test run operation (EMERGENCY OPERATION), press EMERGENCY OPERATION switch or any button on
remote controller.

26

8

OBH684D

ACTUATOR CONTROL

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH
MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

8-1. OUTDOOR FAN MOTOR CONTROL

The fan motor turns ON/OFF, interlocking with the compressor.
[ON] The fan motor turns ON 5 seconds before the compressor starts up.
[OFF] The fan motor turns OFF 15 seconds after the compressor has stopped running.

5 seconds 15 seconds

ON

Compressor

OFF

ON

Outdoor fan
motor

OFF

8-2. R.V. COIL CONTROL

Heating
Cooling
Dry

NOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.

8-3. RELATION BETWEEN MAIN SENSOR AND ACTUATOR

Discharge temperature
thermistor

Indoor coil temperature
thermistor

Defrost thermistor Heating: Defrosting

Fin temperature thermistor Protection

Ambient temperature
thermistor

Outdoor heat exchanger tem­perature thermistor

*. MUZ-FH•NAH only.

. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . .

Compressor

R.V.coil

Outdoor fan
motor

Sensor Purpose

ON
OFF
OFF

<COOL>

ON
OFF

ON
OFF

ON
OFF

Protection

Cooling: Coil frost prevention

Heating: High pressure protec­tion

Cooling: Low ambient tempera­ture operation

Heating: Defrosting (Heater)

Cooling: Low ambient tempera­ture operation

Cooling: High pressure protec­tion

5 seconds

<HEAT>

5 seconds

Compressor

LEV

○○
○

○○
○○○○○

○○
○○○

○○○
○○○

Actuator

Outdoor fan

motor

R.V.coil

Indoor fan

motor

Defrost

heater *

○

27

9

OBH684D

SERVICE FUNCTIONS

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH
MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

9-1. CHANGE IN DEFROST SETTING

Changing defrost finish temperature

<JS> To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board (Refer to 10-6.1.).

Defrost fi nish temperature

Jumper

MUZ-FH06/09/12NA

MUZ-FH06/09/12NAH

MUZ-FH15/18NA MUZ-FH18NA2

MUZ-FH15/18NAH MUZ-18NAH2

Soldered

(Initial setting)

JS

None

(Cut)

41°F (5°C) 50°F (10°C)

50°F (10°C) 64°F (18°C)

9-2. PRE-HEAT CONTROL SETTING

MUZ-FH06/09/12

When moisture gets into the refrigerant cycle, it may interfere with the start-up of the compressor at low outside tempera­ture. The pre-heat control prevents this interference. The pre-heat control turns ON when the discharge temperature ther­mistor is 68°F (20°C) or below. When the pre-heat control turns ON, the compressor is energized. (About 50 W)

MUZ-FH15/18

Prolonged low load operation, in which the thermostat is OFF for a long time, at low outside temperature [32°F (0°C) or
less] may cause the following troubles. To prevent those troubles, activate the pre-heat control.

1) If moisture gets into the refrigerant cycle and freezes, it may interfer the start-up of the compressor.

2) If liquid refrigerant collects in the compressor, a failure in the compressor may occur.

The pre-heat control turns ON when the compressor temperature is 68°F (20°C) or below. When the pre-heat control
turns ON, the compressor is energized. (About 70 W)

Pre-heat control setting

<JK>
ON: To activate the pre-heat control, cut JK wire of the inverter P.C. board.
OFF: To deactivate the pre-heat control, solder JK wire of the inverter P.C. board.
(Refer to 10-6.1)

Pre-heat control setting

Jumper

MUZ-FH06/09/12NA

MUZ-FH06/09/12NAH

MUZ-FH15/18NA MUZ-FH18NA2

MUZ-FH15/18NAH MUZ-18NAH2

Soldered

JK

Cut Activated

NOTE: When the inverter P.C. board is replaced, check the jumper wires, and cut/solder them if necessary.

Deactivated

(Initial setting)

Deactivated

Activated

(Initial setting)

28

10

Lead wiring

<Incorrect>

Connector housing

<Correct>

OBH684D

TROUBLESHOOTING

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH
MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

10-1. CAUTIONS ON TROUBLESHOOTING

1. Before troubleshooting, check the following

1) Check the power supply voltage.

2) Check the indoor/outdoor connecting wire for miswiring.

2. Take care of the following during servicing

1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, then after con­firming the horizontal vane is closed, turn off the breaker and/or disconnect the power plug.

2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.

3) When removing the electrical parts, be careful of the residual voltage of smoothing capacitor.

4) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.

5) When connecting or disconnecting the connectors, hold the connector housing. DO NOT pull the lead wires.

3. Troubleshooting procedure

1)

Check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality. To make

sure, check how many times the OPERATION INDICATOR lamp is flashing on and off before starting service work.

2) Before servicing, check that the connector and terminal are connected properly.

3) When the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the

components for bursting and discoloration.

4) Refer to 10-2 and 10-3.

29

10-2. FAILURE MODE RECALL FUNCTION

OBH684D

Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though LED indication listed on the troubleshooting check table (10-3.) disappears, the memorized failure details can be recalled.

1. Flow chart of failure mode recall function for the indoor/outdoor unit

Operational procedure

Setting up the failure mode recall function

Judgment of indoor/outdoor abnormality

The cause of abnormality cannot be found because the abnormality does not recur.

Turn ON the power supply.
<Preparation of the remote controller>

While pressing OPERATION SELECT button and TEMP

controller at the same time, press RESET button.

First, release RESET button.

Hold down the other 2 buttons for another 3 seconds. Make sure that the indicators on

the LCD screen shown in the right fi gure are all displayed. Then release the buttons.

Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit.

Does the left lamp of the OPERATION INDICATOR lamp on
the indoor unit blink at the interval of 0.5 seconds?
Blinks: Either indoor or outdoor unit is abnormal. Beep is emit-

ted at the same timing as the blinking of the left lamp of
the OPERATION INDICATOR lamp.

Before blinking, does the left lamp of the OPERATION INDI­CATOR lamp stay ON for 3 seconds?
When it stays ON for 3 seconds (without beep): The outdoor unit

The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the
indoor unit failure mode table. (Refer to indoor unit service manual.)
Make sure to check at least 2 consecutive blinking cycles.

button on the remote

1

1. Regardless of normal or abnormal condition,
a short beep is emitted once the signal is
received.

No
(OFF)

Yes
(Blinks)

No

2

is abnormal.

2

Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnor­malities that cannot be recalled with this way.
Check if outdoor unit is abnormal according to the detailed outdoor unit
failure mode recall function. (Refer to 10-2.2)

Yes

The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring
to the outdoor unit failure mode table. (Refer to 10-2.3)
Make sure to check at least 2 consecutive blinking cycles.

3

Releasing the failure mode recall function

Deleting the memorized abnormal condition

Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.

Repair the failure parts.

After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall

function" mentioned above.

Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is displayed)

with the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release the failure mode recall function according to "Releasing the failure mode recall function" men-

tioned above.

NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.

2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.

2. Blinking pattern when the indoor unit is abnormal:

2.5-second OFF

Blinking at 0.5­second interval

2.5-second OFF

Blinking at 0.5­second interval

ON

OFF

Repeated cycle Repeated cycle

Beeps

3.Blinking pattern when the outdoor unit is abnormal:

2.5-second OFF 3-second ON

Blinking at 0.5­second interval

Beeps

Repeated cycle

2.5-second OFF 3-second ON

ON

OFF

No beep Beeps

Repeated cycle

No beep Beeps

Repeated cycle

30

Beeps

Blinking at 0.5­second interval

Repeated cycle

2. Flow chart of the detailed outdoor unit failure mode recall function

OBH684D

Operational procedure

The outdoor unit might be abnormal.
Check if outdoor unit is abnormal according to the following procedures.

Make sure that the remote controller is set to the failure mode recall function.

With the remote controller headed towards the indoor unit, press TEMP

button to adjust the set temperature to 77°F (25°C). 1

Does the left lamp of the OPERATION INDICATOR lamp
on the indoor unit blink at the interval of 0.5 seconds?
Blinks: The outdoor unit is abnormal. Beep is emitted

at the same timing as the blinking of the left
lamp of the OPERATION INDICATOR lamp.

2

The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to
the outdoor unit failure mode table (10-2.3.).
Make sure to check at least 2 consecutive blinking cycles.

Releasing the failure mode recall function

Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.

Repair the failure parts.

Deleting the memorized abnormal condition

After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall

function" (10-2.1.).

Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is displayed) with

the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release the failure mode recall function according to "Releasing the failure mode recall function" men-

tioned above.

Yes
(Blinks

1. Regardless of normal or abnormal condition, 2 short
beeps are emitted as the signal is received.

No
(OFF)

)

The outdoor unit is normal.

2

Release the failure mode recall function accord­ing to the left mentioned procedure.

NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.

2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.

2.Blinking pattern when outdoor unit is abnormal:

2.5-second OFF 3-second ON

ON

OFF

No beep

Repeated cycle

Blinking at 0.5­second interval

Beeps

2.5-second OFF 3-second ON

No beep Beeps

Repeated cycle

Blinking at 0.5-

second interval

31

Repeated cycle

3. Outdoor unit failure mode table

OBH684D

The left

lamp of the

OPERATION

INDICATOR

lamp

(Indoor unit)

OFF None (Normal) — — — — —
1-time fl ash

2.5 seconds
OFF

2-time fl ash

2.5 seconds
OFF

3-time fl ash

2.5 seconds
OFF

4-time fl ash

2.5 seconds
OFF

5-time fl ash

2.5 seconds
OFF

6-time fl ash

2.5 seconds
OFF

7-time fl ash

2.5 seconds
OFF

8-time fl ash

2.5 seconds
OFF

9-time fl ash

2.5 seconds
OFF

Abnormal point

(Failure mode/protection)

Indoor/outdoor
communication, receiving
error

Indoor/outdoor
communication, receiving
error

Outdoor power system

Discharge temperature
thermistor

Defrost thermistor

Fin temperature thermistor 3-time fl ash

P.C. board temperature
thermistor

Ambient temperature
thermistor

Outdoor heat exchanger
temperature thermistor

Overcurrent 11-time fl ash

Compressor synchronous
abnormality (Compressor
start-up failure protection)

Discharge temperature

High pressure

Fin temperature/ P.C. board
temperature

Outdoor fan motor

Nonvolatile memory data 5-time fl ash

Power module (IC700)
(FH09/12)
IGBT module (IC700)
(FH15/18)

LED indication

(Outdoor P.C. board)

—

—

—

1-time fl ash every

2.5 seconds

2.5 seconds OFF
4-time fl ash

2.5 seconds OFF
2-time fl ash

2.5 seconds OFF

—

2.5 seconds OFF

12-time fl ash

2.5 seconds OFF

—

—

7-time fl ash

2.5 seconds OFF

—

2.5 seconds OFF
6-time fl ash

2.5 seconds OFF

Condition Remedy

Any signals from the inverter P.C.
board cannot be received normally for
3 minutes.

Although the inverter P.C. board
sends signal "0", signal "1" has been
received 30 consecutive times.

Overcurrent protection cut-out
operates 3 consecutive times within
1 minute after the compressor gets
started.

Thermistor shorts or opens during
compressor running.

Large current fl ows into the power
module (IC700) (FH06/09/12)/ IGBT
module (IC700) (FH15/18).

Waveform of compressor current is
distorted.

Temperature of discharge temperature
thermistor exceeds 241°F (116°C),
compressor stops.
Compressor can restart if discharge
temperature thermistor reads
212°F (100°C) or less 3 minutes later.

Temperature indoor coil thermistor
exceeds 158°F (70°C) in HEAT
mode. Temperature defrost thermistor
exceeds 158°F (70°C) in COOL mode.

Temperature of the fi n temperature
thermistor on the inverter P.C. board
exceeds 167 - 187°F (75 - 86°C)
(FH06/09/12)/167 - 176°F (75 - 80°C)
(FH15/18), or temperature of P.C.
board temperature thermistor on the
inverter P.C. board exceeds 162 ­185°F (72 - 85°C) (FH06/09/12)/158 ­167°F (70 - 75°C) (FH15/18).

Outdoor fan has stopped 3 times in a
row within 30 seconds after outdoor
fan start-up.

Nonvolatile memory data cannot be
read properly.

The interface short circuit occurs in the
output of the power module (IC700)
(FH06/09/12)/IGBT module (IC700)
(FH15/18).
The compressor winding shorts circuit.

•Refer to 10-5.
to check miswiring and
serial signal error.

•Refer to 10-5.
to check miswiring and
serial signal error.

Reconnect

•
connectors.

Refer to 10-5.

•
to check inverter/
compressor".
Check stop valve.

•
Refer to 10-5.

•
"Check of outdoor
thermistors".
Defective outdoor
thermistors can be
identifi ed by checking
the blinking pattern of
LED.

Reconnect

•
compressor connector.

Refer to 10-5.

•
to check inverter/
compressor".
Check stop valve.

•
Reconnect

•
compressor connector.

Refer to 10-5.

•
to check inverter/
compressor".

Check refrigerant

•
circuit and refrigerant

amount.
Refer to 10-5.

•
of LEV".

Check refrigerant

•
circuit and refrigerant

amount.
Check stop valve.

•
Check around outdoor

•
unit.

Check outdoor unit air

•
passage.

Refer to 10-5.

•
of outdoor fan motor".

Refer to 10-5.

•
of outdoor fan motor".
Refer to 10-5.
of inverter P.C. board".

Replace the inverter

•
P.C. board.

Refer to 10-5.

•
to check inverter/
compressor".

How

How

"How

"How

"How

"Check

"Check

"Check

"Check

"How

Indoor/outdoor

unit failure

mode recall

function

Outdoor unit
failure mode

recall function

○○

○○

○○

—

—

—

—

—

—

○○

NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.).

○

○

○

○

○

○

32

The left

OBH684D

lamp of the

OPERATION

INDICATOR

lamp

(Indoor unit)

10-time fl ash

2.5 seconds
OFF

11-time fl ash

2.5 seconds
OFF

14-time fl ash
or more

2.5 seconds
OFF

Abnormal point

(Failure mode/protection)

Discharge temperature

DC voltage 8-time fl ash

Each phase current of
compressor

Stop valve (Closed valve) 14-time fl ash

4-way valve/
Pipe temperature

Outdoor refrigerant system
abnormality

LED indication

(Outdoor P.C. board)

—

2.5 seconds OFF
9-time fl ash

2.5 seconds OFF

2.5 seconds OFF

16-time fl ash

2.5 seconds OFF

17-time fl ash

2.5 seconds OFF

Condition Remedy

Temperature of discharge temperature
thermistor has been 122°F (50°C) or
less for 20 minutes.

DC voltage of inverter cannot be
detected normally.

Each phase current of compressor
cannot be detected normally.

Closed valve is detected by
compressor current.

The 4-way valve does not work
properly.
The indoor coil thermistor detects an
abnormal temperature.

A closed valve and air trapped in the
refrigerant circuit are detected based
on the temperature sensed by the
indoor and outdoor thermistors and the
current of the compressor.

Refer to 10-5.

•
of LEV".
Check refrigerant

•
circuit and refrigerant

amount.
Refer to 10-5.

•
to check inverter/
compressor".

Check stop valve.

•

Check the 4-way

•
valve.

Replace the inverter

•
P.C. board.

Check for a gas leak

•
in a connecting piping
etc.
Check the stop valve.

•
Refer to 10-5.

•
“Check of outdoor
refrigerant circuit”.

Indoor/outdoor

mode recall

"Check

"How

NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.).

unit failure

function

—

—

Outdoor unit
failure mode

recall function

○

○

○○

○○

33

10-3. TROUBLESHOOTING CHECK TABLE

OBH684D

No. Symptom LED indication

Outdoor unit
does not op­erate.

1

2

3

4

5

6

7

'Outdoor unit
stops and

8

restarts 3
minutes later'
is repeated.

9

10

11

12

13

14

15

NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 10-6.1.

2. LED is lighted during normal operation.

The fl ashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the fl ashing frequency is “2”.

ON

2.5-second OFF

OFF

1-time fl ash every

2.5 seconds

6-time fl ash

2.5 seconds OFF

11-time fl ash

2.5 seconds OFF

16-time fl ash

2.5 seconds OFF

17-time fl ash

2.5 seconds OFF

2-time fl ash

2.5 seconds OFF

3-time fl ash

2.5 seconds OFF

4-time fl ash

2.5 seconds OFF

5-time fl ash

2.5 seconds OFF

8-time fl ash

2.5 seconds OFF

10-time fl ash

2.5 seconds OFF

12-time fl ash

2.5 seconds OFF
13-time fl ash

2.5 seconds OFF

Abnormal point/

Condition

Outdoor power sys­tem

Outdoor thermistors Discharge temperature thermistor, fi n temperature thermistor,

Outdoor control sys­tem

Serial signal The communication fails between the indoor and outdoor unit

Stop valve/
Closed valve

4-way valve/

Pipe temperature

Outdoor refrigerant
system abnormality

Overcurrent protec­tion

Discharge tem­perature overheat
protection

Fin temperature
/P.C. board tem­perature thermistor
overheat protection

High pressure pro­tection

Compressor syn­chronous abnormal­ity

Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds

Each phase current
of compressor

DC voltage DC voltage of inverter cannot be detected normally.

0.5-second ON

2.5-second OFF

Overcurrent protection cut-out operates 3 consecutive times
within 1 minute after the compressor gets started.

defrost thermistor, P.C. board temperature thermistor, outdoor
heat exchanger temperature thermistor or ambient tempera­ture thermistor shorts or opens during compressor running.

Nonvolatile memory data cannot be read properly.

(The left lamp of the OPERATION INDICATOR lamp on the
indoor unit lights up or fl ashes 7-time.)

for 3 minutes.

Closed valve is detected by compressor current.

The 4-way valve does not work properly.
The indoor coil thermistor detects an abnormal temperature.

A closed valve and air trapped in the refrigerant circuit are
detected based on the temperature sensed by the indoor and
outdoor thermistors and the current of the compressor.

Large current fl ows into the power module (IC700)
(FH06/09/12)/ IGBT module (IC700) (FH15/18).

Temperature of discharge temperature thermistor exceeds
241°F (116°C), compressor stops. Compressor can restart if
discharge temperature thermistor reads 212°F (100°C) or less
3 minutes later.

Temperature of the fi n temperature thermistor on the heat sink
exceeds 167 - 187°F (75 - 86°C) (FH06/09/12)/167 - 176°F
(75 - 80°C) (FH15/18) or temperature of P.C. board tempera­ture thermistor on the inverter P.C.board exceeds 162 - 185°F
(72 - 85°C) (FH06/09/12)/158 - 167°F (70 - 75°C) (FH15/18).

Indoor coil thermistor exceeds 158°F (70°C) in HEAT mode.
Defrost thermistor exceeds 158°F (70°C) in COOL mode.

The waveform of compressor current is distorted.

after outdoor fan start-up.

Each phase current of compressor cannot be detected nor­mally.

Condition Remedy

0.5-second ON

Reconnect connector of compres-

•
sor.

Refer to 10-5.

•
inverter/compressor".
Check stop valve.

•
Refer to 10-5.

•
thermistors".

Replace inverter P.C. board.

•

Check connection between the in-

•
verter P.C. board and the relay P.C.

board. (FH15/18)
Refer to 10-5.

•
miswiring and serial signal error.

Check stop valve.

•

Refer to 10-5.

•
coil".
Replace the inverter P.C. board.

•

Check for a gas leak in a

•
connecting piping etc.
Check the stop valve.

•
Refer to 10-5.

•
refrigerant circuit”.

Reconnect connector of compressor.

•
Refer to 10-5.

•
inverter/compressor".
Check stop valve.

•

Check refrigerant circuit and refrig-

•
erant amount.

Refer to 10-5.

•

Check around outdoor unit.

•
Check outdoor unit air passage.

•
Refer to 10-5.

•
fan motor".

Check refrigerant circuit and refrig-

•
erant amount.

Check stop valve.

•
Reconnect connector of compressor.

•
Refer to 10-5.

•
inverter/compressor".

Refer to 10-5.

•
fan motor.
Refer to 10-5.

•
P.C. board.

Refer to 10-5.

•
inverter/compressor".

It occurs with following case.

•
Instantaneous power voltage

drop. (Short time power failure)
(FH15/18)
Refer to 10-5.

•
supply". (FH15/18)
Refer to 10-5.

•
verter/compressor".

Inverter P.C. board

MUZ-FH06/09/12NA(H)

Flashing →

MUZ-FH15/18NA(H)

Flashing

"How to check

"Check of outdoor

"How to check

"Check of R.V.

“Check of outdoor

"How to check

"Check of LEV".

"Check of outdoor

"How to check

"Check of outdoor

"Check of inverter

"How to check

"Check of power

"How to check in-

LED

→

LED

34

No. Symptom LED indication

OBH684D

Outdoor unit
operates.

16

17

18

19

Outdoor unit
operates.

20

21

22

NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 10-6.1.

2. LED is lighted during normal operation.

The fl ashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the fl ashing frequency is “2”.

ON

2.5-second OFF

OFF

1-time fl ash

2.5 seconds OFF

3-time fl ash

2.5 seconds OFF

4-time fl ash

2.5 seconds OFF

MUZ-FH06/09/12

5-time fl ash

2.5 seconds OFF

7-time fl ash

2.5 seconds OFF

8-time fl ash

2.5 seconds OFF

9-time fl ash

2.5 seconds OFF

Abnormal point/

Condition

Frequency drop by
current protection

Frequency drop by
high pressure pro­tection

Frequency drop by
defrosting in COOL
mode

Frequency drop by
discharge tempera­ture protection

Outside temperature
thermistor protec­tion

Low discharge tem­perature protection

MUZ-FH06/09/12

PAM protection
PAM: Pulse Ampli­tude Modulation

MUZ-FH15/18

Zero cross detecting
circuit

Inverter check mode The connector of compressor is disconnected, inverter check

0.5-second ON

2.5-second OFF

FH06/09/12

FH15/18 Current from power outlet is nearing breaker ca-

Temperature of indoor coil thermistor exceeds 131 °F (55°C)
in HEAT mode, compressor frequency lowers.

Indoor coil thermistor reads 46°F (8°C) or less in COOL mode,
compressor frequency lowers.

Temperature of discharge temperature thermistor exceeds
232°F (111°C), compressor frequency lowers.

When the outside temperature thermistor shorts or opens,
protective operation without that thermistor is performed.

Temperature of discharge temperature thermistor has been
122°F (50°C) or less for 20 minutes.

The overcurrent fl ows into PFC (Power factor correction
:IC820) or the DC voltage reaches 394 V or more, PAM stops
and restarts.

Zero cross signal cannot be detected.

mode starts.

When the input current exceeds approximately
10A (FH06/09)/10.5A (FH12), compressor fre­quency lowers.

pacity.

Condition Remedy

0.5-second ON

The unit is normal, but check the
following.
Check if indoor fi lters are clogged.

•
Check if refrigerant is short.

•
Check if indoor/outdoor unit air

•
circulation is short cycled.

Check refrigerant circuit and refrig-

•
erant amount.

Refer to 10-5.

•
Refer to 10-5.

•
thermistors".

Refer to 10-5.

•
thermistors.

Refer to 10-5.

•
Check refrigerant circuit and refrig-

•
erant amount.

This is not malfunction. PAM pro­tection will be activated in the fol­lowing cases:

1 Instantaneous power voltage

drop. (Short time power failure)

2 When the power supply voltage

is high.

It occurs with following cases.

•

1 Instantaneous power voltage

drop. (Short time power failure)

2 Distortion of primary voltage

Refer to 10-5.

•
supply".

Check if the connector of the com-

•
pressor is correctly connected.

Refer to 10-5.
inverter/compressor".

Inverter P.C. board

MUZ-FH06/09/12

Flashing →

MUZ-FH15/18

Flashing

→

LED

"Check of LEV".
"Check of outdoor

Check of outdoor

"Check of LEV".

"Check of power

"How to check

LED

35

10-4. TROUBLE CRITERION OF MAIN PARTS

OBH684D

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH
MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH MUZ-FH18NA2 MUZ-FH18NAH2

Part name Check method and criterion Figure

Defrost thermistor (RT61)

Fin temperature
thermistor (RT64)

Ambient temperature
thermistor (RT65)

Outdoor heat exchanger
temperature thermistor
(RT68)

Discharge temperature
thermistor (RT62)

Compressor

Measure the resistance with a tester.

Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, for the chart of thermistor.

Measure the resistance with a tester. Before measurement, hold the
thermistor with your hands to warm it up.

Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, for the chart of thermistor.

Measure the resistance between terminals using a tester.
[Temperature: 14 - 104°F (-10 - 40°C)]

Normal (Ω)

MUZ-FH06/09 MUZ-FH12 MUZ-FH15/18

U-V

U-W

1.60 - 2.17 1.66 - 2.26 0.87 - 1.18

V-W

WHT

V

RED BLK

W

U

Outdoor fan motor

R. V. coil (21S4)

Expansion valve coil
(LEV)

Measure the resistance between lead wires using a tester.
[Temperature: 14 - 104°F (-10 - 40°C)]

Color of lead wire

MUZ-FH06/09/12 MUZ-FH15/18

Normal (Ω)

RED – BLK

BLK – WHT

29 - 40 12 - 16

WHT – RED

Measure the resistance using a tester.
[Temperature: 14 - 104°F (-10 - 40°C)]

Normal (kΩ)

0.97 - 1.38

Measure the resistance using a tester.
[Temperature: 14 - 104°F (-10 - 40°C)]

Color of lead wire Normal (Ω)

RED – ORN
RED – WHT

RED – BLU

37 - 54

RED – YLW

Measure the resistance using a tester.
[Temperature: 14 - 104°F (-10 - 40°C)]

WHT

V

WHT
ORN

RED

(+12V)

RED BLK

W

U

LEV

YLW

BLU

Defrost heater

Normal (Ω)

MUZ-FH06/09/12NAH

349 - 428 376 - 461

36

MUZ-FH15/18NAH

MUZ-FH18NAH2

10-5. TROUBLESHOOTING FLOW

OBH684D

A How to check inverter/compressor

Disconnect the connector between the compressor

and the power module (IC700) (MUZ-FH06/09/12)/
IGBT module (IC700) (MUZ-FH15/18).

Check the voltage between terminals.

Are the voltages balanced?

Yes

Check the compressor.

No

See 10-5. “Check of open phase”.

Replace the inverter P.C. board.

See 10-5. “Check of compressor”.

B Check of open phase

● With the connector between the compressor and the power module (IC700) (MUZ-FH06/09/12)/IGBT module (IC700) (MUZ-
FH15/18) disconnected, activate the inverter and check if the inverter is normal by measuring the voltage balance between

the terminals.

Output voltage is 50 - 130 V. (The voltage may differ according to the tester.)

<< Operation method>>
Start cooling or heating operation by pressing EMERGENCY OPERATION switch on the indoor unit. (TEST RUN OPERA-

TION: Refer to 7-6.)
<<Measurement point>>
At 3 points
BLK (U)-WHT (V)
BLK (U)-RED (W)
WHT(V)-RED (W)

Measure AC voltage between the lead wires at 3 points.

NOTE: 1. Output voltage varies according to power supply voltage.

2. Measure the voltage by analog type tester.

3. During this check, LED of the inverter P.C. board fl ashes 9 times. (Refer to 10-6.1.)

C Check of compressor

Refer to 10-5. “Check of compressor
winding”.
Is the compressor normal?

Yes

Refer to 10-5. “Check of compressor
operation time”.
Does the compressor operate continuously?

Yes

OK

No

No

Replace the compressor.

Refer to 10-5. “Check of compressor start failure”.

37

D Check of compressor winding

OBH684D

●Disconnect the connector between the compressor and the power module (IC700) (MUZ-FH06/09/12)/IGBT module (IC700)
(MUZ-FH15/18), and measure the resistance between the compressor terminals.

<<Measurement point>>
At 3 points
BLK-WHT
BLK-RED
WHT-RED
<<Judgement>>
Refer to 10-4.
0 [Ω] ················Abnormal [short]
Infinite [Ω] ·······Abnormal [open]

NOTE: Be sure to zero the ohmmeter before measurement.

Measure the resistance between the lead wires at 3 points.

E Check of compressor operation time

<<Judgement>>

● Connect the compressor and activate the inverter. Then measure

the time until the inverter stops due to overcurrent.
<<Operation method>>
Start heating or cooling operation by pressing EMERGENCY
OPERATION switch on the indoor unit. (TEST RUN OPERATION:
Refer to 7-6.)
<<Measurement>>
Measure the time from the start of compressor to the stop of
compressor due to overcurrent.

0 second

1 second

2 seconds

10 seconds

Compressor starts

Abnormal
(IC700 failure)
(Compressor winding short)

Abnormal
(Compressor lock out)
(Starting defect)

Abnormal
(Poor contact)
(Inverter P.C. board defect)
(Disconnected connector)

F Check of compressor start failure

Confi rm that ~ is normal.

•Electrical circuit check
. Contact of the compressor connector
. Output voltage of inverter P.C. board and balance of them (See 10-5. )

. Direct current voltage between DB61(+) and (-) (MUZ-FH06/09/12)/

JP715(+) and JP30(-) (MUZ-FH15/18) on the inverter P.C. board

. Voltage between outdoor terminal block S1-S2

Does the compressor run for 10 seconds or
more after it starts?

No

After the compressor is heated with a drier,
does the compressor start?

Yes

Compressor start failure. Activate pre-heat control.
(Refer to 9-2. "PRE-HEAT CONTROL SETTING")

1

Yes

No

Check the refrigerant circuit.
Check the stop valve.

Replace the compressor.

Abnormal
(Refrigerant circuit defect)
(Closed valve)

10 minutes

Normal

1
Heat the compressor with
a drier for about 20 minutes.
Do not recover refrigerant
gas while heating.

Heating part

38

G Check of outdoor thermistors

OBH684D

Disconnect the connector of thermistor in the inverter P.C. board (see
below table), and measure the resistance of thermistor.

Is the resistance of thermistor normal?
(Refer to 10-6.1.)

Yes

Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.

Does the unit operate for 10 minutes or more
without showing thermistor abnormality?

Yes

OK
(Cause is poor contact.)

No

No

Replace the thermistor except RT64.
When RT64 is abnormal, replace the inverter P.C.
board.

Replace the inverter P.C. board.

MUZ-FH06/09/12

Thermistor Symbol Connector, Pin No. Board
Defrost RT61 Between CN641 pin1 and pin2
Discharge temperature RT62 Between CN641 pin3 and pin4
Fin temperature RT64 Between CN642 pin1 and pin2
Ambient temperature RT65 Between CN643 pin1 and pin2
Outdoor heat exchanger temperature RT68 Between CN644 pin1 and pin3

MUZ-FH15/18

Thermistor Symbol Connector, Pin No. Board
Defrost RT61 Between CN671 pin1 and pin2
Discharge temperature RT62 Between CN671 pin3 and pin4
Fin temperature RT64 Between CN673 pin1 and pin2
Ambient temperature RT65 Between CN672 pin1 and pin2
Outdoor heat exchanger temperature RT68 Between CN671 pin5 and pin6

Inverter P.C. board

Inverter P.C. board

39

H Check of R.V. coil

OBH684D

MUZ-FH06/09/12

First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4.
In case CN721 is disconnected or R.V. coil is open, voltage is generated between the terminal pins of the connector

although no signal is being transmitted to R.V. coil.

Check if CN721 is connected.

Unit operates COOL mode even if it is set to HEAT mode.

Disconnect connector between the
compressor and the power module
(IC700).
Turn ON the power supply and press
EMERGENCY OPERATION switch
twice (HEAT mode).

Is there 208/230 VAC between CN721
and

on the inverter P.C. board
3 minutes after the power supply is turned
ON?

Yes

Replace the 4-way valve.

Replace the inverter

No

P.C. board.

Unit operates HEAT mode even if it is set to COOL mode.

Disconnect connector between the
compressor and the power module
(IC700).
Turn ON the power supply and
press EMERGENCY OPERATION
switch once (COOL mode).

Is there 208/230 VAC between CN721
and

on the inverter P.C. board
3 minutes after the power supply is turned
ON?

No

Replace the inverter

Yes

P.C. board.

Replace the 4-way valve.

MUZ-FH15/18

First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4.
In case CN602 is disconnected or R.V. coil is open, voltage is generated between the terminal pins of the connector

although no signal is being transmitted to R.V. coil.

Check if CN602 is connected.

Unit operates COOL mode even if it is set to HEAT mode.

Disconnect connector between the
compressor and the IGBT module
(IC700).
Turn ON the power supply and press
EMERGENCY OPERATION switch
twice (HEAT mode).

Is there 208/230 VAC between CN602
and

on the inverter P.C. board
3 minutes after the power supply is turned
ON?

Yes

Replace the 4-way valve.

Replace the inverter

No

P.C. board.

Unit operates HEAT mode even if it is set to COOL mode.

Disconnect connector between the
compressor and the IGBT module
(IC700).
Turn ON the power supply and
press EMERGENCY OPERATION
switch once (COOL mode).

Is there 208/230 VAC between CN602
and

on the inverter P.C. board
3 minutes after the power supply is turned
ON?

No

Replace the inverter

Yes

P.C. board.

Replace the 4-way valve.

40

I Check of outdoor fan motor

OBH684D

Disconnect the connectors CN931
and CN932 from the inverter P.C.
board.
Check the connection between the
connector CN931 and CN932.

Is the resistance between each ter­minal of outdoor fan motor normal?
(Refer to 10-4.)

No

Yes

Disconnect CN932 from the inverter P.C. board, and turn on the
power supply.

Rotate the outdoor fan motor manually and measure the voltage
of CN931.
Between 1(+) and 5(-)
Between 2(+) and 5(-)
Between 3(+) and 5(-)

(Fixed to either 5 or 0 VDC)

Replace the outdoor fan motor.

Does the voltage between each terminal become 5 and 0

No

VDC repeatedly?

Yes

Does the outdoor fan motor rotate smoothly?

No

Replace the inverter P.C. board.

Yes

41

J Check of power supply

OBH684D

Disconnect the connector between the
compressor and the power module

(IC700) (MUZ-FH06/09/12)/IGBT module
(IC700) (MUZ-FH15/18).

Turn ON power supply and press
EMERGENCY OPERATION switch.

Does the left lamp of the
OPERATION INDICATOR lamp on
the indoor unit light up?

Yes

Is there DC voltage 260 - 370 VDC
between DB61 (+) and DB61 (–)

(MUZ-FH06/09/12)/294 - 370 VDC

between JP715 (+) and JP30 (–)

(MUZ-FH15/18) on the inverter P.C.

board? (Refer to 10-6.1.)

No

Check the electric parts in main circuit.

No

Yes

Rectify indoor/outdoor
connecting wire.

Yes

Is there voltage 208/230 VAC
between the indoor terminal
block S1 and S2?

Does LED on the inverter P.C.
board light up or fl ash?
(Refer to 10-6.1.)

Yes

If lights up, OK.
If fl ashes, refer to 10-3.

Replace the indoor
electronic control P.C.

No

board.

Replace the inverter

No

P.C. board.

DB61

Inverter P.C. board
(Solder side)

260 - 370 VDC

294 -370 VDC

MUZ-FH06/09/12

JP30

JP715

MUZ-FH15/18

42

K Check of LEV (Expansion valve)

OBH684D

Turn ON the power supply.
<Preparation of the remote controller>

While pressing both OPERATION SELECT button
and TEMP button on the remote controller at the
same time, press RESET button.
First, release RESET button.

Hold down the other 2 buttons for another 3 seconds.

Make sure that the indicators on the LCD screen
shown in the right fi gure are all displayed. Then re-
lease the buttons.

Press STOP/OPERATE (OFF/ON) button of the remote
controller (the set temperature is displayed) with the
remote controller headed towards the indoor unit.

Expansion valve operates in full-opening direction.

Do you hear the expansion valve "click,
click·······"?
Do you feel the expansion valve vibrate
when touching it ?

No

Yes

1

OK

1. Regardless of normal or abnormal condition, a short beep
is emitted once the signal is received.

Is LEV coil properly fi xed to
the expansion valve?

Yes

Does the resistance of LEV
coil have the characteristics?
(Refer to 10-4.)

No

Replace the LEV coil.

NOTE: After check of LEV, do the undermentioned operations.

1. Turn OFF the power supply and turn it ON again.

2. Press RESET button on the remote controller.

No

Yes

Properly fi x the LEV coil to the expansion valve.

Measure each voltage between connector
pins of CN724 on the inverter P.C. board.

1. Pin (-) — Pin (+)

2. Pin (-) — Pin (+)

3. Pin (-) — Pin (+)

4. Pin (-) — Pin (+)
Is there about 3 - 5 VAC between each?

NOTE: Measure the voltage by an analog

tester.

Replace the expansion valve.

Yes

Replace the inverter P.C.

No

board.

43

L Check of inverter P.C. board

OBH684D

Check the outdoor fan motor.
(Refer to 10-5.

.)

Is the fuse (F901) blown on the in­verter P.C. board?

No

Check the connection of the connectors
(CN931, CN932) of the outdoor fan motor.
If the connection is poor, make it correct.

Operate the outdoor unit by starting
EMERGENCY OPERATION.

Check the LED indication on the in­verter P.C. board.
Does the LED fl ash 10 times?

Yes
(10-time fl ash)

Replace the inverter P.C. board.

Yes

No

Check the corresponding parts
following LED indication.
(Refer to 10-3.)

44

M How to check miswiring and serial signal error

OBH684D

Turn OFF the power supply.

NOTE: Refer to the indoor unit service manual.

Is there rated voltage in the power supply?

Turn ON the power supply.

Is there rated voltage between the outdoor terminal block S1 and S2?

Press EMERGENCY OPERATION switch once.

Does the left lamp of OPERATION INDICATOR
lamp light up? <Confi rmation of the power to
the indoor unit>

Is serial signal error indicated 6 minutes later?

Turn OFF the power supply.
Check once more if the indoor/outdoor

B

connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and

1

S3.

Turn ON the power supply.

Is the bus-bar voltage of the inverter P.C. board normal?
(Refer to "TEST POINT DIAGRAM AND VOLTAGE" in the outdoor service manual.)

Yes

Yes

Yes

Yes

A

Yes

No

No

No

1. Miswiring may damage indoor electronic control P.C.

3. Be sure to check this within 3 minutes after turning ON.

Check the power supply.

No

Check the wiring.

Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connect­ing wire?

board during the operation.
Be sure to confi rm the wiring is correct before the opera-
tion starts.

After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board is normal, LED blinks 6 times after 3
minutes.

No

No

Check of power supply.
(Refer to the outdoor
service manual.)

Yes

Correct them.

Does the LED on the inverter P.C. board repeat
"3.6-second-OFF and 0.8-second-ON quick blinking"?

Turn OFF the power supply.
Remove the bridge between the outdoor terminal block S2 and S3.
Turn ON the power supply.

Is there rated voltage between the indoor terminal block S1 and S2?
<Confi rmation of power voltage>

Is there amplitude of 10 to 20 VDC between the indoor terminal block
S2 and S3? <Confi rmation of serial signal>

Yes

A

• Reinstall

• Attach a fi lter

No

either the unit
or the light
away from
each other.

on remote
control receiv­ing section
of the indoor
unit.

• Turn OFF inverter-controlled lighting
equipment.

• Turn OFF the power supply and then
turn ON again.

• Press EMERGENCY OPERATION
switch.

Is serial signal
error indicated 6
minutes later?

B

3

Yes

Yes

Yes

Is there 2 VDC or less between CN202 (+)
and JPG (GND)(-) on the indoor electronic
control P.C. board?

Yes

Is there 2 VDC or less between
CN202A (+) and JPG (GND)(-)
on the indoor electronic control P.C.
board?

Replace the indoor power
P.C. board.

No

No Yes No

No
(Lighted
or not
lighted)

No

No

Replace the indoor elec­tronic control P.C. board.

45

Replace the inverter P.C. board . 2

2. Be careful of the residual voltage of

smoothing capacitor.

Check the wiring
If there are any error of the indoor/outdoor connecting wire:
such as the damage of the wire, intermediate connection,
and/or poor contact to the terminal block, replace the indoor/
outdoor connecting wire.

Is there 2 VDC or less between
CN202 (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?

Yes

N Check of defrost heater

OBH684D

MUZ-FH06NAH MUZ-FH09NAH MUZ-FH12NAH MUZ-FH15NAH MUZ-FH18NAH MUZ-FH18NAH2

Check the following points before checking electric continuity.

1. Does the resistance of ambient temperature thermistor have the characteristics? Refer to 10-6.1.

2. Is the resistance of defrost heater normal? Refer to 10-4.

3. Does the heater protector remain conducted (not open)?

4. Are both ambient temperature thermistor and circuit of defrost heater securely connected to connectors?

In HEAT mode, for more than 5 minutes, let the ambient temperature thermistor continue to read
32°F (0°C) or below, and let the defrost thermistor continue to read 30°F (-1°C) or below.

NOTE: In case both thermistors are more than the above temperature, cool them with cold

water etc...

Is there 208/230 VAC between CN722 and

(MUZ-FH06/09/12)/CN601 and (MUZ-

FH15/18) on the inverter P.C. board? Refer to

10-6.1.

No

Replace the inverter P.C. board.

Yes

Not the problem of the inverter P.C. board.

O Check of outdoor refrigerant circuit

Has the operation stopped
during pump down?

Yes

The operation has stopped to pre­vent the diesel explosion caused by
air trapped in the refrigerant circuit.
Close the stop valve, and disconnect
the power plug or turn the breaker
OFF.

CAUTION : Do not start the opera-

tion again to prevent
hazards.

Was the operation started with

No

the stop valve closed, and was
it opened during operation?

No

The refrigerant gas amount may be
60% or less than the normal amount.
Identify where the gas is leaking from,
and fi x the leak.

The unit occasionally stops when the
stop valve is opened or closed during
operation. Open the stop valve and

Yes

start the cooling operation again.

46

P Electromagnetic noise enters into TV sets or radios

OBH684D

Is the unit grounded?

Yes

Is the distance between the antennas
and the indoor unit within 9.91 ft.
or is the distance between the antennas
and the outdoor unit within 9.91 ft.

No

Is the distance between the TV sets or ra­dios and the indoor unit within 3.28 ft.
or is the distance between the TV sets or
radios and the outdoor unit within

9.91 ft.

(3m)

?

No

Are the antennas damaged?
Is the coaxial cable damaged?
Is there any poor contact in the anten­na wiring?

No

Is the indoor/outdoor connecting wire
of the air conditioner and the wiring of
the antennas close?

No

(3m)

(3m)

(1m)

No

,

Yes

?

,

Yes

Yes

Yes

Ground the unit.

Extend the distance between the antennas and
the indoor unit, and/or the antennas and the
outdoor unit.

Extend the distance between the TV sets and/or
radios and the indoor unit, or the TV sets or
radios and the outdoor unit.

Replace or repair the antenna.
Replace or repair the coaxial cable.

Extend the distance between the indoor/outdoor
connecting wire of the air conditioner and the wir­ing of the antennas.

Even if all of the above conditions are fulfi lled, the electromagnetic noise may enter, depending on the electric fi eld strength
or the installation condition (combination of specifi c conditions such as antennas or wiring).
Check the following before asking for service.

1. Devices affected by the electromagnetic noise
TV sets, radios (FM/AM broadcast, shortwave)

2. Channel, frequency, broadcast station affected by the electromagnetic noise

3. Channel, frequency, broadcast station unaffected by the electromagnetic noise

4. Layout of:
indoor/outdoor unit of the air conditioner, indoor/outdoor wiring, ground wire, antennas, wiring from antennas, receiver

5. Electric fi eld intensity of the broadcast station affected by the electromagnetic noise

6. Presence or absence of amplifi er such as booster

7. Operation condition of air conditioner when the electromagnetic noise enters in

1) Turn OFF the power supply once, and then turn ON the power supply. In this situation, check for the electromagnetic
noise.

2) Within 3 minutes after turning ON the power supply, press STOP/OPERATE (OFF/ON) button on the remote controller
for power ON, and check for the electromagnetic noise.

3) After a short time (3 minutes later after turning ON), the outdoor unit starts running. During operation, check for the
electromagnetic noise.

4) Press STOP/OPERATE (OFF/ON) button on the remote controller for power OFF, when the outdoor unit stops but the
indoor/outdoor communication still runs on. In this situation, check for the electromagnetic noise.

47

10-6. TEST POINT DIAGRAM AND VOLTAGE

OBH684D

1. Inverter P.C. board

MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA

(+)

1

-

Smoothing
capacitor (C62)

Fuse (F801)
T3.15AL250V

MUZ-FH12NA

Back side of unit

208/230 VAC

Fuse (F901)
T3.15AL250V

Output to
drive outdoor
fan motor
(CN932)

Output to
drive
compressor
(LDU,
LDV,
LDW)

-1 MUZ-FH12NAH

DB61
260 - 370 VDC

(-)

-1 MUZ-FH09NAH

R.V.coil
Smoothing
capacitor (C61)

(CN721)

208/230 VAC

-1

Heater connector
(CN722)

(MUZ-FH06NAH

MUZ-FH09/12NAH-

Fuse (F701)
T3.15AL250V

208/230
VAC

1

)

LED

Front side of unit

Fin temperature

thermistor/RT64

(CN642)

Signal of outdoor

fan motor (CN931)

Defrost thermistor(RT61)
Ambient temperature thermistor(RT65)
Outdoor heat exchanger temperature thermistor(RT68)

100

90
80
70
60
50
40
30

5HVLVWDQFHN

20
10

0

-4 14 32 50 68 86 104
Temperature(°F)

Defrost thermistor

/RT61(CN641)

Ambient temperature

thermistor/RT65

(CN643)

Discharge temperature thermistor (RT62)

800
700
600
500
400
300

5HVLVWDQFHN

200
100

0

32 50 68 86 104 122 140 158 176 194 212 230 248

Discharge temperature

thermistor/RT62

(CN641)

Outdoor heat exchanger

temperature thermistor

Temperature (°F)

48

/RT68 (CN644)

LEV connector

(CN724)

Jumper wire for
changing defrost
setting (JS)

Jumper wire
for pre-heat
control setting
(JK)

Fin temperature thermistor(RT64)

200
180
160
140
120
100

80
60

5HVLVWDQFHN

40
20

0

32 50 68 86 104 122 140 158 176

Temperature(°F)

MUZ-FH09NA MUZ-FH09NAH MUZ-FH12NA MUZ-FH12NAH

OBH684D

Back side of unit

208/230 VAC

Fuse (F901)
T3.15AL250V

Output to
drive outdoor
fan motor
(CN932)

Output to
drive
compressor
(LDU,
LDV,
LDW)

DB61
260 - 370 VDC

(-)

(+)

Smoothing
capacitor
(C62)

Fuse (F801)
T3.15AL250V

Smoothing
capacitor
(C61)

R.V.coil
(CN721)
208/230 VAC

Heater connector

(CN722) (MUZ-
FH09/12NAH)

Fuse (F701)
T3.15AL250V

208/230
VAC

LED

Front side of unit

Fin temperature

thermistor/RT64

(CN642)

Signal of outdoor

fan motor (CN931)

Defrost thermistor(RT61)
Ambient temperature thermistor(RT65)
Outdoor heat exchanger temperature thermistor(RT68)

100

90
80
70
60
50
40
30

5HVLVWDQFHN

20
10

0

-4 14 32 50 68 86 104
Temperature(°F)

Defrost thermistor

/RT61(CN641)

Ambient temperature

thermistor/RT65

(CN643)

Discharge temperature thermistor (RT62)

800
700
600
500
400
300

5HVLVWDQFHN

200
100

0

32 50 68 86 104 122 140 158 176 194 212 230 248

Discharge temperature

thermistor/RT62

(CN641)

Outdoor heat exchanger

temperature thermistor

Temperature (°F)

49

/RT68 (CN644)

LEV connector

(CN724)

Jumper wire for
changing defrost
setting (JS)

Jumper wire
for pre-heat
control setting
(JK)

Fin temperature thermistor(RT64)

200
180
160
140
120
100

80
60

5HVLVWDQFHN

40
20

0

32 50 68 86 104 122 140 158 176

Temperature(°F)

MUZ-FH15NA

-4 14 32 50 68 86 104

0

10

20

30

40

50

60

70

80

90

100

Temperature(°F)

Defrost thermistor(RT61)
Ambient temperature thermistor(RT65)
Outdoor heat exchanger temperature thermistor(RT68)

32 50 68 86 104 122 140 158 176

0

20

40

60

80

100

120

140

160

180

200

Temperature(°F)

Fin temperature thermistor(RT64)

Resistance(k )

Resistance(k )

Temperature (°F)

Discharge temperature thermistor (RT62)

5HVLVWDQFHN

0

100

200

300

400

500

600

700

800

32 50 68 86 104 122 140 158 176 194 212 230 248

OBH684D

MUZ-FH15NAH
MUZ-FH18NA
MUZ-FH18NA2
MUZ-FH18NAH
MUZ-FH18NAH2

Heater connector
(CN601)

208/230 VAC

(MUZ-FH15NAH
MUZ-FH18NAH(2))

Signal of out­door fan motor
(CN931)

Output to
drive outdoor
fan motor
(CN932)

Fuse (F901)

T3.15AL250V

Fuse (F880)

T3.15AL250V

JP715 (+)

294 - 370 VDC

JP30 (-)

Fuse (F601)

T3.15AL250V

R.V. coil (CN602)

208/230 VAC

LEV connector (CN724)

LED

Defrost thermistor
/RT61 (CN671)

Discharge temperature
thermistor/RT62
(CN671)

Outdoor heat exchanger
temperature thermistor
/RT68 (CN671)

Ambient temperature
thermistor/RT65
(CN672)

Fin temperature
thermistor/RT64
(CN673)

Jumper wire for
changing defrost
setting (JS)

Jumper wire for
pre-heat control
setting (JK)

50

11

OBH684D

DISASSEMBLY INSTRUCTIONS

<"Terminal with locking mechanism" Detaching points>

The terminal which has the locking mechanism can be detached as shown below.
There are 2 types (refer to (1) and (2)) of the terminal with locking mechanism.
The terminal without locking mechanism can be detached by pulling it out.
Check the shape of the terminal before detaching.

(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector has the

Sleeve

locking mechanism.

Locking lever

Slide the sleeve.
Pull the terminal while
pushing the locking
lever.

Hold the sleeve, and
pull out the terminal
slowly.

Connector

11-1. MUZ-FH06NA MUZ-FH06NAH MUZ-FH09NA MUZ-FH09NAH
MUZ-FH12NA MUZ-FH12NAH

NOTE: Turn OFF the power supply before disassembly.

OPERATING PROCEDURE PHOTOS

1. Removing the cabinet

(1) Remove the screw fixing the service panel.
(2) Pull down the service panel and remove it.
(3) Remove the screws fixing the conduit cover.
(4) Remove the conduit cover. (Photo 4)
(5) Remove the screw fixing the conduit plate. (Photo 5)
(6) Remove the conduit plate.
(7) Disconnect the power supply wire and indoor/outdoor

connecting wire.
(8) Remove the screws fixing the top panel.
(9) Remove the top panel.
(

10

) Remove the screws fixing the cabinet.

(

11

) Remove the cabinet.

(

12

) Remove the screws fixing the back panel.

(

13

) Remove the back panel.

Photo 1

Screws of
the top panel

Back
panel

Screws
of the
back
panel

Photo 2

Screws of the
top panel

Screws of the
cabinet

Photo 3

51

Screws of
the cabinet

Screws of
the cabinet

Screw of the
cabinet

Service
panel

Screws of
the terminal block
support and the
back panel

Direction
to remove

Hooks

OPERATING PROCEDURE PHOTOS

OBH684D

Photo 4 Photo 5

Screws of the

conduit cover

Screw of the
conduit plate

2. Removing the inverter assembly, inverter P.C. board

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following

connectors:

<Inverter P.C. board>

CN721 (R.V. coil)

CN722 (Defrost heater and heater protector) (MUZ-

FH06/09/12NAH)

CN931, CN932 (Fan motor)
CN641 (Defrost thermistor and discharge temperature ther-

mistor)
CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)
CN724 (LEV)

(3) Remove the compressor connector (CN61).
(4) Remove the screws fixing the heat sink support and the

separator.

(5) Remove the fixing screws of the terminal block support and

the back panel.
(6) Remove the inverter assembly.
(7) Remove the screw of the ground wire and screw of the ter-

minal block support.
(8) Remove the heat sink support from the P.C. board support.
(9) Remove the screw of the inverter P.C. board and remove the

inverter P.C. board from the P.C. board support.

3. Removing R.V. coil

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>

CN721 (R.V. coil)

(3) Remove the R.V. coil.

Photo 6

Screws of the heat sink
support and the separator

Photo 7

Heat sink

Heat sink support

P.C. board
support

Screws of the terminal block
support and the back panel

Screw of the
Terminal block
support

52

Screw of the

inverter P.C. board

Terminal
block
support

Screw of the
ground wire

OPERATING PROCEDURE PHOTOS

OBH684D

4. Removing the discharge temperature thermistor,
defrost thermistor, outdoor heat exchanger tempera­ture thermistor and ambient temperature thermistor

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following con-

nectors:
<Inverter P.C. board>

CN641 (Defrost thermistor and discharge temperature ther-

mistor)
CN643 (Ambient temperature thermistor)
CN644 (Outdoor heat exchanger temperature thermistor)

(3) Pull out the discharge temperature thermistor from its holder.
(4) Pull out the defrost thermistor from its holder. (Photo 6)
(5) Pull out the outdoor heat exchanger temperature thermistor

from its holder. (Photo 6)

(6) Pull out the ambient temperature thermistor from its holder.

Photo 8

Discharge temperature thermistor

Screw of the
R.V. coil

Photo 9

Photo 10

Outdoor heat
exchanger tempera­ture thermistor

Defrost thermistor

Ambient temperature
thermistor

53

OPERATING PROCEDURE

OBH684D

5. Removing outdoor fan motor

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connectors:
<Inverter P.C. board>

CN931, CN932 (Fan motor)
(3) Remove the propeller fan nut.
(4) Remove the propeller fan.
(5) Remove the screws fixing the fan motor.
(6) Remove the fan motor.

PHOTOS

Photo 11

Screws of the outdoor fan motor

6. Removing the compressor and 4-way valve

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Remove the inverter assembly. (Refer to 2.)
(3) Remove the screws fixing the reactor.
(4) Remove the reactor.
(5) Remove the soundproof felt.
(6) Recover gas from the refrigerant circuit.

NOTE: Recover gas from the pipes until the pressure gauge

shows 0 PSIG.

(7) Detach the brazed part of the suction and the discharge pipe

connected with compressor.
(8) Remove the nuts fixing the compressor.
(9) Remove the compressor.
(

10

) Detach the brazed part of pipes connected with 4-way valve.

Photo 13

Propeller fan

Photo 12

Propeller fan nut

Screws of
the reactor

Discharge pipe
brazed part

Brazed parts of
4-way valve

54

Soundproof
felt

Suction pipe

brazed part

11-2. MUZ-FH15NA MUZ-FH15NAH MUZ-FH18NA MUZ-FH18NAH

OBH684D

MUZ-FH18NA2 MUZ-FH18NAH2

NOTE: Turn OFF the power supply before disassembly.

OPERATING PROCEDURE

1. Removing the cabinet

(1) Remove the screws of the service panel.
(2) Remove the screws of the top panel.
(3) Remove the screw of the valve cover.
(4) Remove the service panel.
(5) Remove the screws fixing the conduit cover.
(6) Remove the conduit cover.
(7) Remove the screw of fixing the conduit plate.
(8) Remove the conduit plate.
(9) Remove the top panel.
(10)

Remove the valve cover.

(11)

Disconnect the power supply and indoor/outdoor connect-

ing wire.

(12)

Remove the screws of the cabinet.

(13)

Remove the cabinet.

(14)

Remove the screws of the back panel.

(15)

Remove the back panel.

Photo 2

Screws of the top panel

Screw of the back panel

Screws of the
cabinet

Photo 1

Screws of the top panel

Screws of the
cabinet

Photo 3

Screws of the conduit cover

PHOTOS

Screws of the
cabinet

Screws of
the cabinet

Screw of the
valve cover

Screws of the
service panel

Photo 4

Screw of the conduit plate

Screws of the
back panel

55

OPERATING PROCEDURE

OBH684D

PHOTOS

2. Removing the inverter assembly, inverter P.C. board
and relay P.C. board

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following con-

nectors:
<Inverter P.C. board>
CN602 (R.V. coil)
CN931, CN932 (Fan motor)
CN671 (Defrost thermistor, discharge temperature thermistor

and outdoor heat exchanger temperature thermistor)
CN672 (Ambient temperature thermistor)
CN724 (LEV)
CN601 (Defrost heater and heater protector)

(MUZ-FH15/18NAH/18NAH2)

(3) Remove the compressor connector.
(4) Remove the screws fixing the relay panel.
(5) Remove the relay panel.
(6) Remove the ground wires and the lead wires of the inverter

P.C. board.

(7) Remove the screws of the P.B. support.
(8) Remove the inverter P.C. board from the P.B. support.

Photo 5

Inverter P.C.
board

Screws of
the P.B.
support

Screw of the
relay panel

Screw of the
relay panel

Ground wires

Screw of the
relay panel

Screws of the
P.B. support

3. Removing R.V. coil

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the following connector:
<Inverter P.C. board>

CN602 (R.V. coil)

(3) Remove the R.V. coil.

Photo 6

Screw of the
R.V. coil

Brazed parts of
4-way valve

56

OPERATING PROCEDURE PHOTOS

OBH684D

4. Removing the discharge temperature thermistor,
defrost thermistor, outdoor heat exchanger tempera­ture thermistor and ambient temperature thermistor

(1) Remove the cabinet and panels. (Refer to 1.)
(2) Disconnect the lead wire to the reactor and the following

connectors:
<Inverter P.C. board>

CN671 (Defrost thermistor, discharge temperature thermis-

tor and outdoor heart exchanger temperature ther­mistor)

CN672 (Ambient temperature thermistor)

(3)

Pull out the discharge temperature thermistor from its holder.
(4) Pull out the defrost thermistor from its holder.
(5) Pull out the outdoor heat exchanger temperature thermistor

from its holder.

(6) Pull out the ambient temperature thermistor from its holder.

5. Removing outdoor fan motor

(1)

Remove the top panel, cabinet and service panel. (Refer to 1.)

(2) Disconnect the following connectors:

<Inverter P.C. board>

CN931 and CN932 (Fan motor)
(3) Remove the propeller fan.
(4) Remove the screws fixing the fan motor.
(5) Remove the fan motor.

Photo 7

Outdoor heat exchanger
temperature thermistor

Photo 8

Ambient temperature
thermistor

Defrost thermistor

6. Removing the compressor and 4-way valve

(1)

Remove the top panel, cabinet and service panel. (Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Remove the inverter assembly. (Refer to 2.)
(4) Remove the soundproof felt.
(5) Recover gas from the refrigerant circuit.

NOTE: Recover gas from the pipes until the pressure gauge

shows 0 PSIG.

(6) Detach the brazed part of the suction and the discharge

pipe connected with compressor.
(7) Remove the nuts fixing the compressor.
(8) Remove the compressor.
(9) Detach the brazed parts of 4-way valve and pipe. (Photo 4)

57

Photo 9

Brazed part of the
suction pipe

Screws of the
outdoor fan motor

Discharge temperature
thermistor

Soundproof felt

Brazed part of the
discharge pipe

HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN

© Copyright 2014 MITSUBISHI ELECTRIC CORPORATION

Issued: Jul. 2017. No. OBH684 REVISED EDITION-D
Issued: Oct. 2015. No. OBH684 REVISED EDITION-C
Issued: Dec. 2014. No. OBH684 REVISED EDITION-B
Issued: Apr. 2014. No. OBH684 REVISED EDITION-A
Published: Feb. 2014. No. OBH684
Made in Japan

Specifications are subject to change without notice.