Mitsubishi Electric Mr. Slim MUZ-D30NA, Mr. Slim MUZ-D36NA, Mr. Slim MUY-D30NA, Mr. Slim MUY-D36NA Service Manual

SERVICE MANUAL

CONTENTS

1. TECHNICAL CHANGES ··································· 3

2. PART NAMES AND FUNCTIONS ····················· 3

3. SPECIFICATION ················································ 4

4. OUTLINES AND DIMENSIONS ························ 6

5. WIRING DIAGRAM ············································ 7

6. REFRIGERANT SYSTEM DIAGRAM ··············11

7. DATA ································································ 13

8. ACTUATOR CONTROL ··································· 20

9. SERVICE FUNCTIONS ··································· 21

10. TROUBLESHOOTING ····································· 22

11. DISASSEMBLY INSTRUCTIONS ···················· 41

Models

MUZ-D30NA / -

1

/ - U1 / -

U2

MUZ-D36NA / -

1

/ - U1 / -

U2

MUY-D30NA / -

1

MUY-D36NA / -

1

SPLIT-TYPE AIR CONDITIONERS

OUTDOOR UNIT

Indoor unit service manual
MSZ-D•NA Series (OBH501)
MSY-D•NA Series (OBH501)

NOTE:

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

TM

HFC

utilized

R410A

No. OBH502

REVISED EDITION-B

PARTS CATALOG (OBB502)

Revision B:

• MUZ-D•NA-1/-U2 and MUY-D•NA-1 have
been corrected.

Please void OBH502 REVISED EDITION-A.

2

Revision A:

• 3. SPECIFICATION has been corrected.

Revision B:

• MUZ-D•NA-1/-U2 and MUY-D•NA-1 have been corrected.

3

MUZ-D30NA MUZ-D30NA-

U1

MUZ-D36NA MUZ-D36NA-

U1

MUY-D30NA
MUY-D36NA

1. New model

MUZ-D30NA → MUZ-D30NA-

1

MUZ-D30NA-U1 → MUZ-D30NA-

U2

MUZ-D36NA → MUZ-D36NA-

1

MUZ-D36NA-U1 → MUZ-D36NA-

U2

MUY-D30NA → MUY-D30NA-

1

MUY-D36NA → MUY-D36NA-

1

1. Wiring diagram has been changed.

2. Fan motor has been changed.

PART NAMES AND FUNCTIONS

2

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

Piping

Air outlet

Drain hose

Drain outlet

Air inlet

(back and side)

1

TECHNICAL CHANGES

4

Item Model MSZ-D30NA MSY-D30NA MSZ-D36NA MSY-D36NA

Capacity

Rated (Minimum ~
Maximum)

Cooling 1

Btu/h

30,700

(9,800 ~ 30,700)

30,700

(9,800 ~ 30,700)

32,000/33,200

(9,800 ~ 32,000) /

(9,800 ~ 33,200)

33,200/34,600

(9,800 ~ 33,200) /

(9,800 ~ 34,600)

Heating 47

1

32,600

(8,700 ~ 34,000)

—

35,200

(8,700 ~ 36,000)

—

Capacity Heating 17 2 Btu/h 20,800 — 22,800 —

Power consumption

Rated (Minimum ~
Maximum)
(TOTAL)

Cooling 1

W

3,850

(620 ~ 3,850)

3,380

(620 ~ 3,380)

4,140/4,360

(620 ~ 4,140) /

(620 ~ 4,360)

4,

210/4,240

(620 ~ 4,210) /

(620 ~ 4,240)

Heating 47 1

3,360

(520 ~ 3,600)

—

3,840

(520 ~ 4,100)

—

Power consumption Heating 17 2 W 2,620 — 3,000 —

EER

1

[SEER] 3 Cooling 8.0 [14.5] 9.1 [16.0]

7.7/7.6
[14.5]

7.9/8.2
[15.1]

HSPF IV(V)

4 Heating 8.2 (6.7) — 8.2 (6.7) —

COP Heating 1 2.84 — 2.69 —
Outdoor unit model MUZ-D30NA MUY-D30NA MUZ-D36NA MUY-D36NA
Power supply V , phase , Hz 208/230 , 1 , 60
Max. fuse size (time delay) A 25
Min. circuit ampacity A 21
Fan motor F.L.A 0.93

Compressor

Model TNB220FMCHT

R.L.A 16

L.R.A 20

Refrigeration oil cc 870 (NEO22)

Refrigerant control Linear expansion valve

Sound level 1

Cooling

dB(A)

55 55 56 56

Heating 57 — 57 —

Defrost method Reverse cycle — Reverse cycle —

Dimensions

W

in.

33-1/16
D13
H 33-7/16

Weight Ib. 141 126 141 126
External fi nish Munsell 3Y 7.8/1.1
Remote controller Wireless type
Control voltage (by built-in transformer) 12 - 24 VDC
Refrigerant piping Not supplied

Refrigerant pipe size
(Min. wall thickness)

Liquid

in.

3/8 (0.0315)

Gas 5/8 (0.0394)

Connection method

Indoor

Flared

Outdoor

Between the indoor
& outdoor units

Height
difference

ft.

50

Piping length 100

Refrigerant charge (R410A) 4 lb. 10 oz. 4 lb. 4 lb. 10 oz. 4 lb.

NOTE: Test conditions are based on ARI 210/240.
1: Rating conditions (Cooling) — Indoor: 80˚FDB, 67˚FWB, Outdoor: 95˚FDB, (75˚FWB) Rated frequency
(Heating) — Indoor: 70˚FDB, 60˚FWB, Outdoor: 47˚FDB, 43˚FWB Rated frequency
2: (Heating) — Indoor: 70˚FDB, 60˚FWB, Outdoor: 17˚FDB, 15˚FWB Maximum frequency

3

SPECIFICATION

5

Test condition

ARI

Mode Test

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

Dry bulb Wet bulb Dry bulb Wet bulb

SEER

(Cooling)

"A" Cooling Steady State
at rated compressor Speed

80 67 95 (75)

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

80 67 82 (65)

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

80 67 82 (65)

Low ambient Cooling Steady State
at minimum compressor Speed

80 67 67 (53.5)

Intermediate Cooling Steady State
at Intermediate compressor Speed 5

80 67 87 (69)

HSPF

(Heating)

Standard Rating-Heating
at rated compressor Speed

70 60 47 43

Low temperature Heating
at rated compressor Speed

70 60 17 15

Max temperature Heating
at minimum compressor Speed

70 60 62 56.5

High temperature Heating
at minimum compressor Speed

70 60 47 43

Frost Accumulation
at rated compressor Speed

70 60 35 33

Frost Accumulation
at Intermediate compressor Speed

5

70 60 35 33

5: At Intermediate compressor Speed

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

3, 4

OPERATING RANGE

(1) POWER SUPPLY

Rated voltage Guaranteed voltage (V)

Outdoor unit

208/230 V

1 phase

60 Hz

Min. 187

208 230 Max. 253

(2) OPERATION

Mode Condition

Intake air temperature (°F)

Indoor Outdoor

DB WB DB WB

Cooling

Standard temperature 80 67 95 —
Maximum temperature 90 73 115 —
Minimum temperature 67 57 14 —
Maximum humidity 78% —

Heating

Standard temperature 70 60 47 43
Maximum temperature 80 67 75 65
Minimum temperature 70 60 14 13

6

Open as a rule
20 inch or more if
the front and both
sides are open

4 inch or more /
8 inch or more if
there are obstacles
to both sides

Open as a rule
20 inch or more if the back,
both sides and top are open

14 in. or more

4 in. or more

REQUIRED SPACE

Unit: inch

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

4

OUTLINES AND DIMENSIONS

7

MUZ-D30NA MUZ-D30NA-

U1

MUZ-D36NA MUZ-D36NA-

U1

5

WIRING DIAGRAM

8

MUZ-D30NA-1 MUZ-D30NA-

U2

MUZ-D36NA-1 MUZ-D36NA-

U2

9

MUY-D30NA MUY-D36NA

10

MUY-D30NA-1 MUY-D36NA-

1

11

Unit: inch

MUZ-D30NA MUZ-D36NA

MUY-D30NA MUY-D36NA

Outdoor
heat
exchanger

Flared connection

Defrost
thermistor
RT61

Service
port

Service
port

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve

Stop valve
(with service port)

Capillary tube

Refrigerant flow in cooling

Compressor

4-way valve

Refrigerant flow in heating

LEV

R.V. coil
heating ON
cooling OFF

Strainer

#100

Receiver

Outdoor heat
exchanger
temperature
thermistor
RT68

Ambient
temperature
thermistor
RT65

Strainer

#100

Refrigerant pipe

5/8

(with heat insulator)

Refrigerant pipe 3/8
(with heat insulator)

O.D. 0.142 I.D. 0.094

1-31/32

(

3.6 2.4 50

)

Oil
separator

Strainer

#100

High-pressure
Switch

Capillary tube

O.D. 0.071 x I.D. 0.024
x 39-3/8
( 1.8 x 0.6 x 1,000)

O.D. 0.142 x I.D. 0.094
x 1-31/32
( 3.6 x 2.4 x 50)

Capillary tube

High-pressure
Switch

Flared connection

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve

Stop valve
(with service port)

Capillary tube

Refrigerant flow in cooling

Refrigerant pipe 5/8
(with heat insulator)

Refrigerant pipe 3/8
(with heat insulator)

Strainer

#100

Strainer

#100

Oil separator

Outdoor
heat
exchanger

Ambient
temperature
thermistor
RT65

Outdoor heat
exchanger
temperature
thermistor
RT68

Compressor

Service
port

LEV

Service
port

O.D. 0.071 x I.D. 0.024
x 39-3/8
( 1.8 x 0.6 x 1,000)

6

REFRIGERANT SYSTEM DIAGRAM

Unit: inch

12

Max. Length
A

Max. Height

difference

B

Indoor
unit

Outdoor unit

MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE

Model

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

Max. Length

A

Max. Height difference

B

Gas Liquid

MUZ-D30NA
MUZ-D36NA
MUY-D30NA
MUY-D36NA

100 50 5/8 3/8

ADDITIONAL REFRIGERANT CHARGE (R410A: oz.)

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

Model

Outdoor unit

precharged

Refrigerant piping length (one way): ft.

25 30 40 50 60 70 80 90 100

MUZ-D30NA
MUZ-D36NA

4 lb. 10 oz. 0 2.96 8.88 14.80 20.72 26.64 32.56 38.48 44.40

Calculation: X oz. = 2.96/5 oz. / ft. × (Refrigerant piping length (ft.) - 25)

Model

Outdoor unit

precharged

Refrigerant piping length (one way): ft.

25 30 40 50 60 70 80 90 100

MUY-D30NA
MUY-D36NA

4 lb. 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)

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

13

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

7-1. PERFORMANCE DATA

1) COOLING CAPACITY

Model

Indoor air Outdoor intake air DB temperature (˚F)

IWB (˚F)

75 85 95 105 115

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

MUZ-D30NA

71 37.6 19.1 3.43 35.2 17.8 3.75 33.0 16.7 4.04 30.7 15.6 4.25 28.2 14.3 4.43
67 35.6 22.8 3.23 33.2 21.2 3.56 30.7 19.6 3.85 28.6 18.3 4.08 26.2 16.8 4.27
63 33.5 25.9 3.08 31.0 24.0 3.41 28.9 22.3 3.68 26.2 20.3 3.93 23.9 18.5 4.08

MUZ-D36NA

71 40.7 19.8 3.88 38.0 18.5 4.25 35.7 17.4 4.58 33.2 16.2 4.82 30.5 14.9 5.01
67 38.5 23.9 3.66 35.9 22.2 4.03 33.2 20.6 4.36 30.9 19.1 4.62 28.4 17.6 4.84
63 36.2 27.3 3.49 33.5 25.3 3.86 31.2 23.5 4.16 28.4 21.4 4.45 25.9 19.5 4.62

MUY-D30NA

71 37.6 19.1 3.01 35.2 17.8 3.30 33.0 16.7 3.55 30.7 15.6 3.73 28.2 14.3 3.89
67 35.6 22.8 2.84 33.2 21.2 3.13 30.7 19.6 3.38 28.6 18.3 3.58 26.2 16.8 3.75
63 33.5 25.9 2.70 31.0 24.0 2.99 28.9 22.3 3.23 26.2 20.3 3.45 23.9 18.5 3.58

MUY-D36NA

(208 V)

71 40.7 19.8 3.75 38.0 18.5 4.10 35.7 17.4 4.42 33.2 16.2 4.65 30.5 14.9 4.84
67 38.5 23.9 3.54 35.9 22.2 3.89 33.2 20.6 4.21 30.9 19.1 4.46 28.4 17.6 4.67
63 36.2 27.3 3.37 33.5 25.3 3.73 31.2 23.5 4.02 28.4 21.4 4.29 25.9 19.5 4.46

MUY-D36NA

(230 V)

71 42.4 20.6 3.77 39.6 19.3 4.13 37.2 18.1 4.45 34.6 16.8 4.69 31.8 15.5 4.88
67 40.1 24.9 3.56 37.4 23.2 3.92 34.6 21.5 4.24 32.2 20.0 4.49 29.6 18.3 4.71
63 37.7 28.4 3.39 34.9 26.3 3.75 32.5 24.5 4.05 29.6 22.3 4.32 27.0 20.3 4.49

NOTE: 1. IWB : Intake air wet-bulb temperature

TC : Total Capacity (x10

3

Btu/h)

SHC : Sensible Heat Capacity (x10

3

Btu/h)

TPC : Total Power Consumption (kW)

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

2) COOLING CAPACITY CORRECTIONS

Refrigerant piping length (one way: ft.)

25 (std.) 40 65 100

MUZ-D30NA
MUZ-D36NA
MUY-D30NA
MUY-D36NA

1.0 0.95 0.878 0.713

3) HEATING CAPACITY

Model

Indoor air Outdoor intake air WB temperature (˚F)

IDB (˚F)

15 25 35 43 45 55

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

MUZ-D30NA

75 18.9 2.50 23.6 2.94 28.2 3.28 31.8 3.44 32.8 3.49 37.2 3.63
70 20.0 2.42 24.5 2.87 28.9 3.19 32.6 3.36 33.6 3.43 38.0 3.56
65 20.5 2.32 25.6 2.77 29.8 3.11 33.6 3.28 34.6 3.33 38.8 3.49

MUZ-D36NA

75 20.4 2.86 25.5 3.36 30.4 3.74 34.3 3.94 35.4 3.99 40.1 4.15
70 21.6 2.76 26.4 3.28 31.2 3.65 35.2 3.84 36.3 3.92 41.0 4.07
65 22.2 2.65 27.6 3.17 32.2 3.55 36.3 3.74 37.3 3.80 41.9 3.99

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

TC : Total Capacity (x103 Btu/h)
TPC : Total Power Consumption (kW)

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

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.

7 DATA

14

7-2. PERFORMANCE CURVE

65
70
75

75
70
65

45

40

35

30

25

20

15

Indoor intake air DB temperature (°F)

= 848 CFM

Airflow

15 25 35 45 55

Outdoor intake air WB temperature (°F)

4.0

3.6

3.2

2.8

2.4

Ind

oor intake air DB temperature (°F)

Total power consumption

(kW)

Total capacity

(10

3

Btu/h)

65
70
75

75
70
65

48

43

38

33

28

23

18

Indoor intake air DB temperature (°F)

= 848 CFM

Airflow

15 25 35 45 55

Outdoor intake air WB temperature (°F)

4.5

4.1

3.7

3.3

2.9

Ind

oor

intake air

DB

tem

perature (°F)

Total power consumption

(kW)

Total capacity

(10

3

Btu/h)

Cooling

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.

71
67
63

71
67
63

24

26

28

30

32

34

36

38

40

Indoor intake air WB temperat

ure (°F)

Indoor intake air

WB te

mperature (°F)

4.5

4.3

4.1

3.9

3.7

3.5

3.3

3.1

SHF at rating condition = 0.64

= 763 CFM

Airflow

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

Total power consumption

(kW)

Total capacity

(10

3

Btu/h)

71
67
63

71
67
63

27

29

31

33

35

37

39

41

43

Indoor intake air

WB te

mperature (°F)

5.2

4.8

4.4

4.0

3.6

Indoor intake air WB temperat

ure (°F)

SHF at rating condition = 0.62

= 763 CFM

Airflow

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

Total power consumption

(kW)

Total capacity

(10

3

Btu/h)

MUZ-D30NA

MUZ-D36NA

Heating

MUZ-D30NA

MUZ-D36NA

MUY-D36NA

MUY-D30NA

71
67
63

71
67
63

24

26

28

30

32

34

36

38

40

Ind

oor intak

e air WB temperature (°F)

Indoor intake air WB temperature (°F

)

4.0

3.8

3.6

3.4

3.2

3.0

2.8

2.6

SHF at rating condition = 0.64

= 763 CFM

Airflow

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

Total power consumption

(kW)

Total capacity

(10

3

Btu/h)

71

67

63

71

67

63

46

42

38

34

30

26

Indoor intake air WB temperature (°F

)

5.0

4.6

4.2

3.8

3.4

Indoor intake air WB te

mpe

rat

ure

(°F

)

SHF at rating condition = 0.62

= 763 CFM

Airflow

65 75 85 95 105 115

Outdoor intake air DB temperature (°F)

Total power consumption

(kW)

Total capacity

(10

3

Btu/h)

15

7-3. CONDENSING PRESSURE
Cooling

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

MUZ-D36NA

(PSIG)

Condensing pressure

86
80
75
70

68 70 75 80 85 90 95 100 105(°F)

90

100

110

120

130

140

150

Suction pressure

Outdoor ambient temperature

(PSIG)

86

80

75

70

68 70 75 80 85 90 95 100 105(°F)

260

300

340

380

420

460

500

540

580

Indoor DB temperature

(°F)

Outdoor ambient temperature

Indoor DB temperature (°F)

MUZ-D30NA

(PSIG)

Condensing pressure

86
80
75
70

68 70 75 80 85 90 95 100 105(°F)

90

100

110

120

130

140

150

Suction pressure

Outdoor ambient temperature

(PSIG)

86

80

75

70

68 70 75 80 85 90 95 100 105(°F)

260

300

340

380

420

460

500

540

580

Indoor DB temperature (°F)

Outdoor ambient temperature

Indoor DB temperature (°F)

MUY-D30NA

(PSIG)

Condensing pressure

86
80
75
70

68 70 75 80 85 90 95 100 105(°F)

90

100

110

120

130

140

150

Suction pressure

Outdoor ambient temperature

(PSIG)

86

80

75

70

68 70 75 80 85 90 95 100 105(°F)

260

300

340

380

420

460

500

540

580

Indoor DB temperature (°F)

Outdoor ambient temperature

Indoor DB temperature (°F)

16

75

70

65

75
70
65

(PSIG)

(PSIG)

Condensing pressure

Outdoor ambient temperature

14 20 25 30 35 40 45 50 55 60 65 70(°F)

200

500

480

460

440

420

400

380

360

340

320

300

280

260

240

220

Ind

oor DB tem

perat

ure(

°F)

Suction pressure

Outdoor ambient temperature

14 20 25 30 35 40 45 50 55

58Hz

58Hz

60 65 70(°F)

140

130

120

150

110

100

90

80

70

60

50

Indoor DB temperature (°F)

Heating

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

MUZ-D36NA

MUZ-D30NA

75

70

65

75
70
65

(PSIG)

(PSIG)

Condensing pressure

Outdoor ambient temperature

14 20 25 30 35 40 45 50 55 60 65 70(°F)

200

500

480

460

440

420

400

380

360

340

320

300

280

260

240

220

Indoor DB temperature(

°F)

Suction pressure

Outdoor ambient temperature

14 20 25 30 35 40 45 50 55

58Hz

58Hz

60 65 70(°F)

140

150

130

120

110

100

90

80

70

60

50

Indoor DB temperature (°F)

MUY-D36NA

(PSIG)

Condensing pressure

86
80
75

70

68 70 75 80 85 90 95 100 105(°F)

90

100

110

120

130

140

150

Suction pressure

Outdoor ambient temperature

(PSIG)

86

80

75

70

68 70 75 80 85 90 95 100 105(°F)

260

300

340

380

420

460

500

540

580

Indoor DB temperature (°F)

Outdoor ambient temperature

Indoor DB temperature (°F)

17

7-4. STANDARD OPERATION DATA

Model MSZ-D30NA MSZ-D36NA MSY-D30NA MSY-D36NA

Item Unit Cooling Heating Cooling Heating Cooling Cooling

Total

Capacity Btu/h 30,700 32,600 32,000/33,200 35,200 30,700 33,200/34,000

SHF — 0.64 — 0.62 — 0.64 0.62

Input kW 3.85 3.36 4.14/4.36 3.84 3.38 4.21/4.24

Rated frequency Hz 84 84 91 91 79 92

Electrical circuit

Indoor unit MSZ-D30NA MSZ-D36NA MSY-D30NA MSY-D36NA

Power supply

V,

phase,

Hz

208/230 , 1 , 60

Input kW 0.058

Fan motor current A 0.45/0.42

Outdoor unit MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

Power supply

V,

phase,

Hz

208/230 , 1 , 60

Input kW 3.792 3.302 4.082/4.302 3.782 3.322 4.152/4.182

Comp. current A 17.25/15.56 14.95/13.46 18.65/17.86 17.25/15.56 15.05/13.56 18.95/17.26

Fan motor current A 0.80/0.72

Refrigerant circuit

Condensing pressure PSIG 468 404 480 420 453 475

Suction pressure PSIG 126 96 122 94 125 119

Discharge temperature ˚F 186.8 169.7 198.7 168.8 191.3 197.1

Condensing temperature ˚F 126.5 114.3 128.5 117.0 123.8 127.4

Suction temperature ˚F 45.5 29.8 48.0 29.1 54.7 48.6

Comp. shell bottom temperature ˚F 175.6 156.4 187.0 155.7 177.4 182.7

Ref. pipe length ft. 25

Refrigerant charge (R410A) — 4 lb. 10 oz. 4 lb.

Indoor unit

Intake air temperature

DB ˚F 80 70 80 70 80 80

WB ˚F 67 60 67 60 67 67

Discharge air temperature

DB ˚F 53.9 112.2 53 114.9 53.7 51.7

WB ˚F 53 73.9 52.1 74.6 52.8 50.8

Fan speed (High) rpm 1,100

Airfl ow (High) CFM 741 (Wet) 795 738 (Wet) 794 718 (Wet) 710 (Wet)

Outdoor unit

Intake air temperature

DB ˚F 95 47 95 47 95 95

WB ˚F — 43 — 43 — —

Fan speed rpm 800

Airfl ow CFM 1,941

18

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

MUZ-D36NA

Capacity correction factors

Input correction factors

Input correction factors

Capacity correction factors

Correction of Cooling capacity

The operational frequency of compressor

Correction of Cooling total input

The operational frequency of compressor

Correction of Heating total input

The operational frequency of compressor

Correction of Heating capacity

The operational frequency of compressor

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

MUY-D36NA

Capacity correction factors

Input correction factors

Correction of Cooling capacity

The operational frequency of compressor

Correction of Cooling total input

The operational frequency of compressor

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

(Hz)

Capacity correction factors

Input correction factors

Input correction factors

Capacity correction factors

Correction of Cooling capacity

The operational frequency of compressor

Correction of Cooling total input

The operational frequency of compressor

Correction of Heating total input

The operational frequency of compressor

Correction of Heating capacity

The operational frequency of compressor

MUZ-D30NA

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

(Hz)

Capacity correction factors

Input correction factors

Correction of Cooling capacity

The operational frequency of compressor

Correction of Cooling total input

The operational frequency of compressor

MUY-D30NA

0 50 100 150

0.5

1.0

1.5

(Hz)

0 50 100 150

0.5

1.0

1.5

19

7-6. TEST RUN OPERATION (How to operate fixed-frequency operation)

1. Press EMERGENCY OPERATION switch to 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.

20

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

8-3. Relation between main sensor and actuator

Sensor Purpose

Actuator

Compressor

LEV

Outdoor

fan motor

R.V. coil

Indoor

fan motor

Discharge temperature thermistor Protection

○○

Indoor coil temperature thermistor

Cooling: Coil frost prevention

○

Heating: High pressure protection

○○○

Defrost thermistor Defrosting

○○○○○

Fin temperature thermistor Protection

○○

Outdoor heat exchanger temperature

Protection

○○○

Ambient temperature thermistor

Cooling: Low ambient temperature operation

○○○

8-2. R.V. COIL CONTROL
<MUZ>

Heating

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

ON

Cooling

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

OFF

Dry

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

OFF

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

ON

OFF

ON

OFF

Outdoor fan
motor

Compressor

5 seconds 15 seconds

Outdoor fan

motor

ON

OFF

<COOL>

5 seconds

<HEAT>

5 seconds

R.V.coil

ON

OFF

ON or OFF

ON or OFF

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.

8

ACTUATOR CONTROL

21

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

9-1. PRE-HEAT CONTROL

If moisture gets into the refrigerant cycle, or when refrigerant is liquefi ed and col-
lected in the compressor, it may interfere the start-up of the compressor.
To improve start-up condition, the compressor is energized even while it is not
operating.
This is to generate heat at the winding.
The compressor uses about 50 W when pre-heat control is turned ON.
Pre-heat control is OFF at initial setting.

[How to activate pre-heat control]

1. Turn OFF the power supply for the air conditioner before making the setting.

2. Set the 2nd Dip Switch of SW1 on the outdoor electronic control P.C. board to
ON to activate pre-heat control function.

1234

ON

9-2. CHANGE IN DEFROST SETTING

Changing defrost finish temperature

1. Turn OFF the power supply for the air conditioner before making the setting.

2. Set the 4th Dip Switch of SW1 on the outdoor electronic control P.C. board to
ON to change the defrost finish temperature. (Refer to 10-6-1.)

4th Dip Switch of SW1 Defrost fi nish temperature

OFF

(Initial setting)

49.5°F (9.7°C)

ON 64.9°F (18.3°C)

1234

ON

9

SERVICE FUNCTIONS

22

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 housing of the connector. DO NOT pull the lead wires.

3. Troubleshooting procedure

1) First, 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 abnormality indication 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.

Lead wiring Housing point

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

10

TROUBLESHOOTING

23

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.

10-2. FAILURE MODE RECALL FUNCTION

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

This figures show about MSZ type.

2. Blinking pattern when the indoor unit is abnormal:

3.Blinking pattern when the outdoor unit is abnormal:

ON

OFF

Beeps

Repeated cycle Repeated cycle

ON

OFF

No beep Beeps

Repeated cycle

2.5-second OFF

Blinking at 0.5­second interval

2.5-second OFF 3-second ON

Blinking at 0.5­second interval

Beeps

Repeated cycle

2.5-second OFF

Blinking at 0.5-

second interval

No beep Beeps

Repeated cycle

2.5-second OFF 3-second ON

Blinking at 0.5­second interval

Repeated cycle

Beeps

Does the left lamp of 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 OPERATION INDICATOR lamp.

2

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

No

Yes

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

Setting up the failure mode recall function

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

While pressing both OPERATION SELECT button and TOO COOL button on the

remote controller at the same time, press RESET button.

First, release RESET button.

And release the other two buttons after all LCD in operation display section of the

remote controller is displayed after 3 seconds.

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

1

Judgment of indoor/outdoor abnormality

Before blinking, does the left lamp of OPERATION INDICA­TOR lamp stay ON for 3 seconds?
Stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.

The indoor unit is abnormal.
Check the blinking pattern, and confi rm the abnormal point with the indoor unit
failure mode table. (Refer to indoor unit service manual.)
Make sure to check at least two consecutive blinking cycles.

2

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.

The outdoor unit is abnormal.
Check the blinking pattern, and confi rm the abnormal point with the
outdoor unit failure mode table. (Refer to 10-2.3)
Make sure to check at least two consecutive blinking cycles.

3

Repair the defective parts.

Deleting the memorized abnormal condition

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

function" mentioned above.

Press OPERATE/STOP (ON/OFF) 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"

mentioned above.

Operational procedure

Yes
(Blinks)

No
(OFF)

NOTE: 1. Make sure to release the failure mode recall function once 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.

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

24

Does left lamp of 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 OPERATION INDICATOR lamp.

2

Yes
(Blinks

)

No
(OFF)

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

Operational procedure

Confi rm that the remote controller is in the failure mode recall function.

With the remote controller headed towards the indoor unit, press TOO
COOL or TOO WARM button to adjust the set temperature to 77˚F (25˚C).

1

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

The outdoor unit is abnormal.
Check the blinking pattern, and confi rm the abnormal point with the out-
door unit failure mode table. (10-2.3.)
Make sure to check at least two consecutive blinking cycles. 2

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 defective parts.

The outdoor unit is normal.

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

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 OPERATE/STOP (ON/OFF) 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"

mentioned above.

NOTE: 1. Make sure to release the failure mode recall function once 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. Flow chart of the detailed outdoor unit failure mode recall function

2.Blinking pattern when outdoor unit is abnormal:

ON

OFF

No beep

Beeps

Repeated cycle

2.5-second OFF 3-second ON

Blinking at 0.5­second interval

No beep Beeps

Repeated cycle

2.5-second OFF 3-second ON

Blinking at 0.5-

second interval

Repeated cycle

25

3. Outdoor unit failure mode table

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

The left lamp of OPERA-

TION INDICATOR lamp

(Indoor unit)

Abnormal point

(Failure mode / protection)

LED indication

(Outdoor P.C.

board)

Condition Correspondence

Indoor/outdoor

unit failure mode

recall function

LED 1 LED 2

OFF Non (Normal) Lighting Lighting — — —

2-time fl ash Outdoor power system Lighting Lighting

IPM protection stop or lock protection stop is continuously
performed 3 times within 1 minute after the compres­sor gets started, or converter protection stop or bus-bar
voltage protection stop is continuously performed 3 times
within 3 minutes after start-up.

Check the connection of the
compressor connecting wire.
Refer to 10-5. "How to check
inverter/compressor".
Refer to 10-5. "Check of
compressor start failure".
Check the stop valve.

•

•

•

•

○

3-time fl ash

Discharge temperature thermistor Lighting Once

Thermistor shorts or opens during compressor running.

Refer to 10-5.

"Check of

outdoor thermistors".

•

○

Defrost thermistor (MUZ) Lighting Once

Ambient temperature thermistor Lighting Twice

Fin temperature thermistor Lighting 3 times

P.C. board temperature thermistor Lighting 4 times

Replace the outdoor electronic
control P.C. board.

•

Outdoor heat exchanger tempera­ture thermistor

Lighting 9 times

Refer to 10-5. "Check of
outdoor thermistors".

•

4-time fl ash Overcurrent Once

Goes

out

28 A current fl ow into intelligent power module.

Reconnect compressor con­nector.
Refer to 10-5.

"How to check
inverter/compressor."
Refer to 10-5. "Check of
compressor start failure".
Check the stop valve.

•

•

•

•

—

5-time fl ash Discharge temperature Lighting Lighting

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.

Check refrigerant circuit and
refrigerant amount.
Refer to 10-5. "Check of
LEV".

•

•

—

6-time fl ash High pressure Lighting Lighting

The outdoor heat exchanger temperature exceeds 158°F
(70°C) during cooling or the indoor gas pipe temperature
exceeds 158°F (70°C) during heating (MUZ).

Check refrigerant circuit and
refrigerant amount.
Check the stop valve.

•

•

—

7-time fl ash

Fin temperature 3 times

Goes

out

The fi n temperature exceeds 189°F (87°C) during opera-
tion.

Check around outdoor unit.
Check outdoor unit air pas­sage.
Refer to 10-5.

"Check of
outdoor fan motor".

•

•

•

—

P.C. board temperature 4 times

Goes

out

The P.C. board temperature exceeds 158°F (70°C) during
operation.

8-time fl ash Outdoor fan motor Lighting Lighting

Failure occurs continuously 3 times within 30 seconds
after the fan gets started.

Refer to 10-5. "Check of
outdoor fan motor".

•
—

9-time fl ash Nonvolatile memory data Lighting 5 times Nonvolatile memory data cannot be read properly.

Replace the outdoor electronic
control P.C. board.

•

○

10-time fl ash Discharge temperature Lighting Lighting

The frequency of the compressor is kept 80 Hz or more
and the discharge temperature is kept under 102°F (39°C)
for more than 20 minutes.

Check refrigerant circuit and
refrigerant amount.
Refer to 10-5. "Check of
LEV".

•

•

—

11-time fl ash

Communication error between
P.C. boards

Lighting 6 times

Communication error occurs between the electronic control
P.C. board and power board for more than 10 seconds.

Check the connecting wire
between outdoor electronic
control P.C. board and power
board.

•
—

The communication between boards protection stop is
continuously performed twice.

○

Current sensor Lighting 7 times

A short or open circuit is detected in the current sensor
during compressor operating.

Replace the power board. •

—

Current sensor protection stop is continuously performed
twice.

○

Zero cross detecting circuit 5 times Goes out

Zero cross signal cannot be detected while the compres­sor is operating.

Check the connecting wire
among electronic control P.C.
board, noise fi lter P.C. board
and power board.

•
—

The protection stop of the zero cross detecting circuit is
continuously performed 10 times.

○

NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).

26

The left lamp of OPERA-

TION INDICATOR lamp

(Indoor unit)

Abnormal point

(Failure mode / protection)

LED indication (Out-

door P.C. board)

Condition Correspondence

Indoor/outdoor

unit failure mode

recall function

LED 1 LED 2

11-time fl ash

Converter 5 times Goes out

A failure is detected in the operation of the converter dur­ing operation.

• Check the voltage of
power supply.

•

Replace the power board.

—

Bus-bar voltage (1) 5 times Goes out

The bus-bar voltage exceeds 400 V or falls to 200 V or
below during compressor operating.

Bus-bar voltage (2)

Even if this protection stop

is performed continuously 3
times, it does not mean the
abnormality in outdoor power
system.

6 times Goes out

The bus-bar voltage exceeds 400 V or falls to 50 V or
below during compressor operating.

• Check the voltage of
power supply.

• Replace the outdoor

electronic control P.C.
board.

27

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

ON

OFF

2.5-second OFF

2.5-second OFF

0.5-second ON

0.5-second ON

10-3. TROUBLESHOOTING CHECK TABLE

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

No. Symptom

Indication

Abnormal point / Condition Condition Correspondence

LED1
(Red)

LED2

(Yellow)

1

Outdoor
unit does
not oper­ate.

Lightning Twice Outdoor power system

IPM protection stop or lock protection stop is continuously
performed three times within 1 minute after the compressor
gets started, or converter protection stop or bus-bar voltage
protection stop is continuously performed 3 times within 3
minutes after start-up.

Check the connection of the compressor connect­ing wire.
Refer to 10-5.

"How to check inverter/compres­sor".
Refer to 10-5. "Check of compressor start failure".
Check the stop valve.

•

•

•

•

2 Lightning 3 times

Discharge temperature therm­istor

A short circuit is detected in the thermistor during opera­tion, or an open circuit is detected in the thermistor after 10
minutes of compressor start-up.

Refer to 10-5. "Check of outdoor thermistor". •

3 Lightning 4 times

Fin temperature thermistor

A short or open circuit is detected in the thermistor during
operation.

Refer to 10-5.

"Check of outdoor thermistor". •

P.C. board temperature therm­istor

Replace the outdoor electronic control P.C. board. •

4 Lightning 5 times

Ambient temperature thermis­tor

A short or open circuit is detected in the thermistor during
operation.

Refer to 10-5. "Check of outdoor thermistor".•

Outdoor heat exchanger
temperature thermistor

A short circuit is detected in the thermistor during operation,
or an open circuit is detected in the thermistor after 5 minutes
(in cooling) and 10 minutes (in heating (MUZ)) of compressor
start-up.

Defrost thermistor (MUZ)

A short circuit is detected in the thermistor during operation,
or an open circuit is detected in the thermistor after 5 minutes
of compressor start-up.

5 Lightning 6 times Serial signal

The communication fails between the indoor and outdoor unit
for 3 minutes.

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

•

6 Lightning 7 times Nonvolatile memory data The nonvolatile memory data cannot be read properly. Replace the outdoor electronic control P.C. board. •

7 Lightning 8 times Current sensor

Current sensor protection stop is continuously performed
twice.

Replace the power board. •

8 Lightning 11 times

Communication error between
P.C. boards

The communication protection stop between boards is con­tinuously performed twice.

Check the connecting wire between outdoor elec­tronic control P.C. board and power board.

•

9 Lightning 12 times Zero cross detecting circuit

The protection stop of the zero cross detecting circuit is
continuously performed 10 times.

Check the connecting wire among outdoor elec­tronic control P.C. board, noise fi lter P.C. board and
power board.

•

10

'Outdoor
unit stops
and restarts
3 minutes
later' is
repeated.

Twice Goes out

IPM protection

Overcurrent is detected after 30 minutes of compressor start­up.

Reconnect compressor connector.
Refer to 10-5.

"How to check inverter/compres­sor".
Refer to 10-5. "Check of compressor start failure".
Check the stop valve.
Check the power module (PAM module).

•

•

•

•

•

Lock protection

Overcurrent is detected within 30 minutes of compressor
start-up

11 3 times Goes out

Discharge temperature protec­tion

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.

Check the amount of gas and refrigerant circuit.
Refer to 10-5.

"Check of LEV".

•

•

12 4 times Goes out

Fin temperature protection The fi n temperature exceeds 189°F (87°C) during operation.

• Check around outdoor unit.

• Check outdoor unit air passage.

• Refer to 10-5. "Check of outdoor fan motor".

P.C. board temperature pro­tection

The P.C. board temperature exceeds 158°F (70°C) during
operation.

13 5 times Goes out High-pressure protection

The outdoor heat exchanger temperature exceeds 158°F (70
°C) during cooling or indoor gas pipe temperature exceeds
158°F (70°C) during heating (MUZ).

Check around of gas and the refrigerant circuit.
Check of stop valve.

•

•

14 8 times Goes out Converter protection

A failure is detected in the operation of the converter during
operation.

Replace the power board. •

15 9 times Goes out

Bus-bar voltage protection (1)

The bus-bar voltage exceeds 400 V or falls to 200 V or below
during compressor operating.

• Check the voltage of power supply.

• Replace the power board or the outdoor electronic
control P.C. board.

• Refer to 10-5.

"Check of bus-bar voltage".

Bus-bar voltage protection (2)

The bus-bar voltage exceeds 400 V or falls to 50 V or below
during compressor operating.

16 13 times Goes out Outdoor fan motor

Failure occurs continuously three times within 30 seconds
after the fan gets started.

Refer to 10-5. "Check of outdoor fan motor". •

17 Lighting 8 times Current sensor protection

A short or open circuit is detected in the current sensor during
compressor operating.

Replace the power board. •

18 Lighting 11 times

Communication between P.C.
boards protection

Communication error occurs between the outdoor electronic
control P.C. board and power board for more than 10 sec­onds.

Check the connecting wire between outdoor elec­tronic control P.C. board and power board.

•

19 Lighting 12 times

Zero cross detecting circuit
protection

Zero cross signal cannot be detected while the compressor is
operating.

Check the connecting wire among outdoor elec­tronic control P.C. board, noise fi lter P.C. board and
power board.

•

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

2. LED is lighted during normal operation.

Outdoor electronic control P.C. board (Parts side)

LED2 LED1

Lighting

→

28

No. Symptom

Indication

Abnormal point / Condition Condition Correspondence

LED1
(Red)

LED2

(Yellow)

20

Outdoor
unit oper­ates.

Once Lighting

Primary current protection The input current exceeds 15 A.

These symptoms do not mean any abnormality of
the product, but check the following points.
Check if indoor fi lters are clogged.
Check if refrigerant is short.
Check if indoor/outdoor unit air circulation is short
cycled.

•

•

•

•

Secondary current protection The current of the compressor exceeds 15 A.

21 Twice Lighting

High-pressure protection
(MUZ)

The indoor gas pipe temperature exceeds 113°F (45°C) dur­ing heating.

Defrosting in cooling

The indoor gas pipe temperature falls 37°F (3°C) or below
during cooling.

22 3 times Lighting

Discharge temperature protec­tion

The discharge temperature exceeds 212°F (100°C) during
operation.

Check refrigerant circuit and refrigerant amount.
Refer to 10-5.

"Check of LEV".

Refer to 10-5. "Check of outdoor thermistors".

•

•

•

23 4 times Lighting

Low discharge temperature
protection

The frequency of the compressor is kept 80 Hz or more and
the discharge temperature is kept under 102°F (39°C) for
more than 20 minutes.

Refer to 10-5. "Check of LEV".
Check refrigerant circuit and refrigerant amount.

•

•

24 5 times Lighting

Cooling high-pressure protec­tion

The outdoor heat exchanger temperature exceeds 136°F (58
°C) during operation.

This symptom does not mean any abnormality of
the product, but check the following points.
Check if indoor fi lters are clogged.
Check if refrigerant is short.
Check if indoor/outdoor unit air circulation is short
cycled.

•

•

•

•

25

Outdoor
unit oper­ates

9 times Lighting Inverter check mode The unit is operated with emergency operation switch. –

26 Lighting Lighting Normal – –

29

10-4. TROUBLE CRITERION OF MAIN PARTS

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

Part name Check method and criterion Figure

Defrost thermistor
(RT61) (MUZ)

Ambient temperature
thermistor (RT65)

Outdoor heat ex­changer temperature
thermistor (RT68)

Fin temperature
thermistor (RT64)

Measure the resistance with a tester.

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

Discharge tem­perature thermistor
(RT62)

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. “Outdoor electron­ic control P.C. board”, for the chart of thermistor.

Compressor

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

Normal

1.24 ~ 1.53 Ω

Outdoor fan motor

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

Color of lead wire Normal

RED – BLK

13 ~ 16 ΩBLK – WHT

WHT – RED

R. V. coil (MUZ)

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

Normal

1.20 ~ 1.55 kΩ

Linear expansion
valve

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

Color of lead wire Normal

WHT – RED

38 ~ 50 Ω

RED – ORN
YLW – BRN

BRN – BLU

W

U

V

WHT

RED

BLK

LEV

WHT

RED

YLW

BRN

ORN

BLU

U

RED

WHT

BLK

V

W

(W)

(V)

(U)

30

10-5. TROUBLESHOOTING FLOW

Measure the voltage between each lead wire leading
to the compressor.
U (BLK) - V (WHT)
V (WHT) - W (RED)
W (RED) - U (BLK)
Is there output voltage?

Yes

No

Disconnect the terminal of the compressor. 3 minutes after turn­ing on the power supply, start EMERGENCY OPERATION.

Is output balanced?

Yes

No

Is the input voltage to the outdoor electronic control
P.C. board 370 V or more?

Yes

No

Replace the power board.

Turn off power supply of indoor and outdoor unit, and
measure the compressor winding resistance between
the compressor terminals.
Is the resistance between each terminal normal?

Yes

No

Replace the compressor.

Reconnect the lead wire of compressor, and turn on power
supply to indoor and outdoor unit.
3 minutes later, starts EMERGENCY OPERATION.

Clarify the causes by counting time until the inverter stops.
0 to 10 seconds: compressor rare short
10 to 60 seconds: compressor lock
60 seconds to 5 minutes: refrigerant circuit defective
5 minutes or more: normal

A How to check inverter/compressor

•After the outdoor fan starts running, wait for 1 minute or more before measur­ing the voltage.

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

31

Thermistor Symbol Connector, Pin No. Board

Defrost (MUZ) RT61 Between CN661 pin1 and pin2

Outdoor electronic control P.C. board

Discharge temperature RT62 Between CN661 pin3 and pin4
Outdoor heat exchanger temperature RT68 Between CN661 pin7 and pin8
Ambient temperature RT65 Between CN663 pin1 and pin2
Fin temperature RT64 Between CN3 pin1 and pin2 Outdoor power board

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

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

No

Replace the thermistor except RT64.
When RT64 is abnormal, replace the
outdoor power board.

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

OK.
(Cause is poor contact.)

Replace the outdoor power board.

Yes

Yes

No

B Check of outdoor thermistors

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

32

Heating operation does not work.•

Is there voltage of 208/230 VAC between pin1
and pin 2 at connector CN912?

Yes

No

Disconnect the lead wire leading to the compressor.
3 minutes after turning on the power supply, start EMERGENCY
OPERATION in HEAT mode.

1.

2.

Turn off power supply of indoor and outdoor unit, and discon­nect the connector CN781 in the outdoor electronic control P.C.
board.
3 minutes after turning ON the power supply, start EMER­GENCY OPERATION in HEAT mode.

1.

2.

Turn OFF power supply of indoor and outdoor unit.

Is there voltage 12 VDC be­tween the connector CN781
pin 5 (+) and pin 3 (-)?

No

Disconnect the connec­tor CN912 in noise fi lter
P.C. board. Is there normal
resistance to R.V. coil?

No

Replace the R.V. coil.

Replace the 4-way valve.

Replace the noise fi lter P.C. board.

Yes

Replace the electronic
control P.C. board.

Cooling operation does not work.

•

Is there voltage of 208/230 VAC between pin1
and pin 2 at connector CN912?

Disconnect the lead wire leading to the compressor.
3 minutes after turning on the power supply, start EMERGENCY
OPERATION in COOL mode.

1.

2.

Turn OFF power supply of indoor and outdoor unit, and
disconnect the connector CN781 in the outdoor electronic
control P.C. board.
3 minutes after turning ON the power supply, start EMER­GENCY OPERATION in COOL mode.

1.

2.

Yes

Is there voltage 12 VDC between the connector
CN781 pin 5 (+) and pin 3 (-)?

No

Replace the noise fi lter P.C. board.

Replace the outdoor electronic control P.C. board.

No

Replace the 4-way valve.

If the connector CN912 is not

connected or R.V. coil is open,
voltage occurs between terminals
even when the control is OFF.

Yes

MUZ-D30/36

C Check of R.V. coil

33

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

Check the connection between the
connector CN931 and CN932.

Disconnect CN932 from outdoor electronic control 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(-)

Does the voltage between each terminal become 5 VDC
and 0 VDC repeatedly?

Does the outdoor fan motor rotate smoothly?

Replace the outdoor DC fan motor. Replace the outdoor electronic control P.C. board.

Yes

Yes

No

(Fixed to either 5 or 0 VDC)

No

No

Yes

Is there voltage of 208/230 VAC in the power
supply terminal block?

Check the connecting of parts of main power
supply circuit.

Check the power supply cable.

Turn ON power supply.

Is the output voltage from the noise fi lter P.C.
board 208/230 VAC?

Replace the noise fi lter P.C. board.

No

Yes

No

Yes

Is the input voltage to the power board
208/230 VAC?

Replace the reactor.

No

Yes

Is the input voltage to the outdoor electronic
control P.C. board 294/325 VDC?

Replace the power board.

No

Replace the outdoor electronic control P.C. board.

Yes

D Check of outdoor fan motor

E Check of power supply

34

G Check of LEV

Turn ON power supply to the outdoor unit after checking
LEV coil is mounted to the LEV body securely.

Is "click - click" sound heard?
Or, do you feel vibration of the LEV coil with a hand?

Disconnect the connector CN795.
Is there normal resistance to LEV coil?

Normal

Replace the outdoor electronic
control P.C. board.

Replace the LEV coil.

Yes

No

No

Yes

F Check of compressor start failure

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

1

Replace the compressor.

Compressor start failure. Activate pre-heat control.
(Refer to 9-1. "PRE-HEAT CONTROL")

No

Yes

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

Check the refrigerant circuit.
Check the stop valve.

Yes

No

Confi rm that 1~4 is normal.

•Electrical circuit check
Contact of lead wire leading to compressor
Output voltage of the outdoor electronic control P.C. board and balance of them
(See 10-5. )
Direct current voltage to the outdoor electronic control P.C. board
Voltage between outdoor terminal block S1-S2

1.

2

.

3.

4.

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

Heating part

35

Turn OFF the power supply.

Is there rated voltage in the
power supply?

Yes

No

Turn ON the power supply.

Check the power supply.

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

No

Check the wiring.

Press EMERGENCY OPERATION switch once.

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

Yes

No

Is serial signal error indicated 6 minutes later?

Yes

No

Is there any miswiring, poor
contact, or wire disconnec­tion of the indoor/outdoor
connecting wire?
Is fuse (F65 or F66) broken?

Yes

Correct them.

No

A

Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
Short-circuit outdoor terminal block S2
and S3.

1

B

1. Miswiring may damage indoor electronic control P.C.
board during the operation.

Be sure to confi rm the wiring is correct before the opera-

tion starts.

3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board or the outdoor electronic control P.C.
board is normal, LED blinks 6 times after 3 minutes.

Turn ON the power supply.

Does the LED on the inverter P.C. board or
the outdoor electronic control P.C. board
repeat "3.6-second-OFF and 0.8-second­ON quick blinking"? 3

Yes

No
(Lighted
or not
lighted)

Replace the inverter P.C. board or
the outdoor electronic control P.C. board.

2

2. Be careful of the residual voltage
of smoothing capacitor.

Turn OFF the power supply.
Remove the short-circuit between
outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there amplitude of 10 to 20 VDC
between outdoor terminal block S2 and
S3? <Confi rmation of serial signal>

Yes

No

Is there any error of the in­door/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?

Yes

Replace the indoor/
outdoor connecting
wire.

Turn OFF inverter-controlled lighting
equipment.
Turn OFF the power supply and then
turn ON again.
Press EMERGENCY OPERATION
switch.

•

•

•

A

Is serial signal
error indicated 6
minutes later?

B

Yes

Reinstall
either the unit
or the light
away from
each other.
Attach a fi lter
on remote
control
receiving
section of the
indoor unit.

•

•

No

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

No

No

Is there any error of the in­door/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?

Yes

Replace the indoor/
outdoor connecting
wire.

No

Replace the indoor electronic control P.C. board.

Yes

Be sure to release the failure-mode recall function
after checking.

Yes

H How to check miswiring and serial signal error

Outdoor electronic control P.C. board

BlinkingLighted

(Parts side)

LED2

LED1

36

1. Disconnect the connector CN681 in the electronic control P.C. board.

2. Check the resistance of HPS 1 minute after the outdoor unit power supply was turned OFF.

Check the resistance between each terminal.

Is HPS protection displayed immediately after
compressor starts?

Replace HPS.

Replace the outdoor electronic
control P.C. board.

Normal

Infi nity

No

0 Ω

Yes

Reconnect CN681.
Turn ON power supply to the indoor and outdoor unit.
3 minutes later, start EMERGENCY OPERATION.

I Check of HPS

J Check of bus-bar voltage

•Check the voltage of power supply.

•Confi rm outdoor unit failure mode
recall function. (Refer to 10-2.2)

Blink 5 times

Confi rm LED1 indication lamp on
the outdoor electronic control P.C.

board.

Replace the power board.

Blink 9 times

Replace the outdoor elec­tronic control P.C. board.

Turn OFF power supply before removing P.C. board.

Confi rm LED1 indication lamp
on the outdoor electronic con-

trol P.C. board.

Turn ON power supply. Start
operation.

Blink 6 times

Replace the outdoor elec­tronic control P.C. board.

Lighting

Replace the outdoor elec­tronic control P.C. board.

Blink 9 times

Replace the power board.

Confi rm LED1 indication lamp
on the outdoor electronic con-

trol P.C. board.

Turn ON power supply. Start
operation.

Normal.

Lighting Lighting

37

K Electromagnetic noise enters into TV sets or radios

Yes

Is the unit grounded?

No

Ground the unit.

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

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

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.?

Yes

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

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

Yes

No

No

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

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

Yes

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

No

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 followings 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, grounding 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 OPERATE/STOP (ON/OFF) 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 OPERATE/STOP (ON/OFF) 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.

38

-4 14 32 50 68 86 104

100

90

80

70

60

50

40

30

20

10

0

32 50 68 86 104 122 140 158 176

200

180

160

140

120

100

80

60

40

20

0

Resistance (kΩ)

Resistance (kΩ)

Temperature (°F)

Temperature (°F)

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

Fin temperature thermistor (RT64)

1. Outdoor electronic control P.C. board

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

LED 1

LED 2

CN801

294 ~ 370

VDC
Input

CN932

20-90 VAC

GND

5 V

5 VDC

pulse wave

To fan

motor

Defrost thermistor (RT61)

(MUZ) CN661

Discharge temperature thermistor (RT62)

CN661

Outdoor heat exchanger temperature

thermistor (RT68) CN661

(

(

(+)

(–)

(+)

Rush current relay

(–)

R.V. coil (–)

12 V

DC

15 V

15 V

CN931

(+)

(–)

CN701

Signal transmission

(To power board)

5 VDC pulse wave

(+)

(–)

GND

CN702

Signal reception

(From power board)

5 VDC pulse wave

GND (power board)

CN781

CN795

12 VDC

pulse wave

LEV

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

700

600

500

400

300

200

100

0

Resistance (kΩ)

Temperature (°F)

Discharge temperature thermistor (RT62)

F801

FUSE

3.15 A/250 V

Ambient temperature

thermistor (RT65)

CN663

for indoor

5~10 VDC

CN601

208/230 VAC
60 Hz
Input

10-6. TEST POINT DIAGRAM AND VOLTAGE

CN681
High pressure switch

39

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

2. Noise filter P.C. board

MUZ

CN912
R.V. coil
208/230 VAC
60 Hz
Output

208/230 VAC
60 Hz
Input

208/230 VAC
60 Hz
Output

F64 FUSE
2 A / 250 V

CN902
To power
board

CN903
To power
board

CN61

NR64 VARISTOR

CN901
To electronic
control P.C.
board

40

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

3. Outdoor power board

294-370 VDC
Output

Connect to the compressor
Voltage among phases: 180 V

Connect to the ground

CN5
Primary current detection
(Connect to the noise filter)

CN2
Connect to the controller board
(+)1-5(–): Signal transmission
(To electronic control P.C. board)
5 VDC pulse wave
(+)2-5(–): Zero cross signal

3-4 : Not used
(+)6-5(–): 15 V
(+)7-5(–): 15 V

Signal reception (From electronic
control P.C. board)
5 VDC pulse wave

CN3
Fin temperature thermistor RT64

(Red)

(White)

(+)

(–)

1

3

41

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

NOTE: Turn OFF power supply before disassembling.

OPERATING PROCEDURE PHOTOS

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 top panel.
(6) Remove the valve cover.
(7) Remove the screws of the cabinet.
(8) Remove the cabinet.
(9) Remove the screws of the back panel.
(10)

Remove the back panel.

(1) Slide the sleeve and check if there is a locking lever or not.

(2) The terminal with this connector has the
locking mechanism.

Connector

Sleeve

Locking lever

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

Hold the sleeve, and
pull out the terminal
slowly.

Photo 2

Photo 1

Photo 3

Screws
of the
cabinet

Screws of the cabinet

Screw of
the top
panel

Screws of the
top panel

Screws
of the
cabinet

Screw of the service panel

Screw of the
valve cover

Set screws of
the back panel

Screw of the motor support

Screws of
the back
panel

Conduit plate

Set screws of the back panel

<"Terminal with locking mechanism" Detaching points>

The terminal which has the locking mechanism can be detached as shown below.
There are two 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.

11

DISASSEMBLY INSTRUCTIONS

42

OPERATING PROCEDURE

PHOTOS

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

(1) Remove the top panel, cabinet, service panel and the back

panel. (Refer to 1.)

(2) Disconnect the following connectors:

<Electronic control P.C. board>

CN931 and CN932 (Fan motor)
CN795 (LEV)
CN661 (Discharge temperature thermistor, defrost therm-

istor (MUZ) and outdoor heat exchanger tem-

perature thermistor)
CN663 (Ambient temperature thermistor)
CN681 (High pressure switch) (MUZ)

<Noise filter P.C. board>

CN912 (4-way valve) (MUZ)

<Compressor>

<Reactor>
(4) Remove the screws fixing the relay panel.
(5) Remove the inverter assembly.
(6) Disconnect all connectors and lead wires on the electronic

control P.C. board.
(7) Remove the electronic control P.C. board from the inverter

assembly.
(8) Remove the screws fixing the power board assembly.
(9) Disconnect all connectors and lead wires on the power

board.
(10)

Remove the power board from the inverter assembly.

(11)

Disconnect all connectors and lead wires on the noise filter

P.C. board.
(12)

Remove the noise filter P.C. board from the inverter assem-

bly.

3. Removing R.V. coil (MUZ)

(1) Remove the top panel, cabinet, service panel and the back

panel. (Refer to 1.)
(2) Disconnect the following connectors:

<Noise filter P.C. board>

CN912 (4-way valve)

(3) Remove the R.V. coil. (Photo 9)

Photo 4

Screws of the relay panel

Screws of the power board assembly

Photo 5 (Inverter assembly)

Screws of the reactor

HPS

Discharge temperature
thermistor

Photo 6

Screws of the
relay panel

Propeller

43

OPERATING PROCEDURE

PHOTOS

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

(1) Remove the top panel, cabinet, service panel and the back

panel. (Refer to 1.)

(2) Disconnect the following connectors:

<Electronic control P.C. board>

CN661 (Discharge temperature thermistor, defrost therm-

istor (MUZ) and outdoor heat exchanger tem­perature thermistor)

CN663 (Ambient temperature thermistor)

(3) Pull out the defrost thermistor from its holder. (Photo 7)

(MUZ)

(4) Pull out the discharge temperature thermistor from its hold-

er. (Photo 4)

(5) Pull out the outdoor heat exchanger temperature thermistor

from its holder. (Photo 7)

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

(Photo 7)

5. Removing outdoor fan motor

(1) Remove the top panel, cabinet, service panel and the back

panel. (Refer to 1.)

(2) Disconnect the following connectors:

<Electronic control P.C. board>

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

Photo 7

Defrost
thermistor
(for MUZ)

Outdoor heat
exchanger
temperature
thermistor

Ambient
temperature
thermistor

Photo 8

Propeller

Screws of the outdoor fan motor

OPERATING PROCEDURE

PHOTOS

6. Removing the compressor and 4-way valve

(1) Remove the top panel, cabinet, service panel and the back

panel. (Refer to 1.)
(2) Remove the inverter assembly. (Refer to 2.)
(3) Remove the R.V. coil. (Refer to 3.)
(4) Recover gas from the refrigerant circuit.

NOTE: Recover gas from the pipes until the pressure gauge

shows 0 PSIG.

(5) Detach the welded part of the suction and the discharge

pipe connected with compressor. (Photo 9)
(6) Remove the compressor nuts.
(7) Remove the compressor.
(8) Detach the welded part of 4-way valve and pipe. (Photo 8)

7. Removing the reactor

(1) Remove the top panel, cabinet, service panel and the back

panel. (Refer to 1.)
(2) Disconnect the reactor lead wire.
(3) Remove the screws of the reactor, and remove the reactor.

Photo 9

Welded parts of 4-way valve

R.V. coil

Photo 10

Welded part of the
discharge pipe

Welded part of the
suction pipe

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

© Copyright 2008 MITSUBISHI ELECTRIC CO.,LTD
Distributed in Jan. 2009. No. OBH502 REVISED EDITION-B 5
Distributed in Mar. 2008. No. OBH502 REVISED EDITION-A 7
Distributed in Feb. 2008. No. OBH502 7
Made in Japan

New publication, effective Jan. 2009
Specifications subject to change without notice.