Mitsubishi MUZ-GB50VA-E1, MUZ-GB50VA-E2 Service Manual

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

OUTDOOR UNIT

HFC

utilized

R410A

SERVICE MANUAL

Wireless type
Models

Revision D:

• RoHS PARTS LIST has been changed.

Please void OB455 REVISED EDITION-C.

No. OB455

REVISED EDITION-D

MUZ-GB50VA ­MUZ-GB50VA -

E1

E2

Indoor unit service manual
MSZ-GB·VA Series (OB454)
Refrigerant service manual

R410A REFRIGERANT (OBR01)

CONTENTS

1. TECHNICAL CHANGES ····································2

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

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

4. NOISE CRITERIA CURVES·······························4

5. OUTLINES AND DIMENSIONS·························5

6. WIRING DIAGRAM ············································6

7. REFRIGERANT SYSTEM DIAGRAM················7

8. PERFORMANCE CURVES································9

9. ACTUA TOR CONTROL····································14

10. TROUBLESHOOTING ······································15

11. DISASSEMBLY INSTRUCTIONS·····················34

12. RoHS PARTS LIST···········································38

NOTE:

• This service manual describes technical data of the outdoor units.

Revision A:

• Compressor has been changed.

Previous
New

Model
SNB130FLDH
SNB130FLDH1

RoHS PARTS LIST number
E12 851 900
E12 939 900

Revision B:

• REFRIGERANT SYSTEM DIAGRAM has been changed.

• Oil separator has been added.

• Capillary tube has been added. ([1.8✕[0.6✕1000)

• MUZ-GB50VA- has been added.

• Check of outdoor thermistors(10-6.B) has been corrected.

E2

Revision C:

• RoHS PARTS LIST has been changed.

Revision D:

• RoHS PARTS LIST has been changed.

1

MUZ-GA50VA - ➔ MUZ- GB50VA -

1. Refrigerant filling capacity has been changed.

2. Outdoor electronic control P.C. board has been changed.

MUZ-GB50VA - ➔ MUZ- GB50VA -

1. Compressor has been changed. (SNB130FLDH1 ➔ SNB130FLEH1)

2. Outdoor electronic control P.C. board has been changed.

TECHNICAL CHANGES

E1E1

E2E1

2

2

Air inlet

Piping

Air outlet

(back and side)

Drain hose

Drain outlet

Outdoor model

Function

Power supply

Capacity Rated frequency(Min.-Max.)
Dehumidification
Air flow ✽1

(High/Low)
Power outlet
Running current ✽1
Power input ✽1
Power factor ✽1
Starting current ✽1
Compressor motor current ✽1
Fan motor current ✽1

Model

Output
Winding
resistance(at 20:)
Model

Winding
resistance(at 20:)

Dimensions WOHOD
Weight
Sound level ✽1

(High/Low)
Fan speed (High/Low)
Fan speed regulator
Refrigerant filling
capacity(R410A)
Refrigeration oil (Model)

kW

r/h

K /h

A

A
W
%

A

A

A

✽1

W

"

"

mm

kg

dB(A)

rpm

kg

Compressor

Fan

motor

Special

remarks

Capacity

Electrical

data

Coefficient of performance(C.O.P)

Single phase

230V,50Hz

20

97

7.46

0.32

SNB130FLDH or SNB130FLDH1

SNB130FLEH1

850

U-V 0.45 W-U 0.45

V-W 0.45

RC0J60-AA
BLK-WHT 15.2
WHT-RED 15.2

RED-BLK 15.2

840o850o330

53

2

1.50

NEO22

Cooling

5.0(0.9-5.8)

2.5

2,940/1,650

7.23

1,610

6.91

3.03

52/51

800/480

Heating

5.8(0.9-7.8)

—

2,940/2,210

7.43

1,660

7.11

3.41

55/53

800/620

MUZ-GB50VA

E1
E2

PART NAMES AND FUNCTIONS

MUZ-GB50VA

ACCESSORIES

MUZ-GB50VA

3

NOTE : Test conditions are based on ISO 5151.

SPECIFICATION

Cooling : Indoor Dry-bulb temperature 27:Wet-bulb temperature 19:
Heating : Indoor Dry-bulb temperature 20:Wet-bulb temperature 15:
Refrigerant piping length (one way): 5m

✽1 Measured under rated operating frequency

Outdoor Dry-bulb temperature 35:Wet-bulb temperature 24:
Outdoor Dry-bulb temperature 7: Wet-bulb temperature 6:

Drain socket

1

Drain cap [33

2

3

1
2

OUTDOOR UNIT

MICROPHONE

1m

Test conditions
Cooling : Dry-bulb temperature 35:
Wet-bulb temperature (24:)
Heating : Dry-bulb temperature 7:
Wet-bulb temperature 6:

COOLING

FUNCTION

SPL(dB(A)) LINE

High

FAN SPEED

HEATING

52
55

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

BAND CENTER FREQUENCIES, Hz

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

OCTAVE BAND SOUND PRESSURE LEVEL, 0dB=20µPa

Specifications and rating conditions of main electric parts

Model

Item

Current transformer
Current transformer
Smoothing capacitor
Fuse
Fuse
Fuse
Expansion valve coil
Intelligent power module
Intelligent power module
Reactor
Power factor controller
Resistor
Resistor
Resistor
Solenoid coil relay
Terminal block
Terminal block
Relay
R.V. coil

MUZ-GB50VA

(CT1,2)

(CT61)

(CB1,2,3)

(F64)
(F801)
(F911)

(LEV)

(IPM)

(HC930)

(L)

(PFC)

(R64A,B)

(R937A,B)

(RS1~4)

(SSR61)

(TB1)
(TB2)

(X64)

(21S4)

ETQ19Z68AY
ETQ19Z53AY

560+ 450V

250V 2A

250V 3.15A

250V 1A

CAM-MD12ME

PS21244-A

PS21661-RZ

340µH 20A
PS51259-A

10" 10W

1.1" 2W 2%

0.04" 7W
TLP3506

3P
3P

G4A

LD30013

4

NOISE CRITERIA CURVES

MUZ-GB50VA

4

5

30-

35-

155

90

198

40

515

299

66

34

51

330

360

850

430

500

80

121

840

Open as a rule
500 mm or more if
the front and both
sides are open

100 mm or more
200 mm or more if
there are obstacles
to both sides

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

350 mm or more

100 mm or more

Service panel

Gas refrigerant
pipe joint
Refrigerant pipe
(flared) [12.7

Liquid refrigerant
pipe joint
Refrigerant pipe
(flared) [6.35

REQUIRED SPACE

OUTLINES AND DIMENSIONS

MUZ-GB50VA

Unit: mm

5

6

R64B

YLW

230V~

12-24V

CN912

CN663

WHT

BLU

NOISE

FILTER

P.C.BOARD

BRN

TO INDOOR

UNIT

CONNECTING

RED

S3

RT65

21

CN61

13

GRN/YLW

5

PFC

GRN

LD9

POWER

BOARD

RT64

21

CN3

RED

WHT

RS2

RS1

R64A

RS3

RS4

F801

CN901

NR64

ELECTRONIC

CONTROL

P.C.BOARD

CB1

CB2

CB3

HC930

IPM

NF

BLK

BLK

BLK

BLK

WHT

RED

YLW

BLU

ORN

PNK

GRY

BLU

WHT

GRN

GRN

BLU
BLU

BLK

BLK

BLK

BLK

BLK

BLK

BLK

BLK

BLK
BLK

BLK

RED

BLU

L

CT2

CT1

SSR61

U

6

CN7954123 78

CN661

W

CN4

TB2

S1

1

CN601

3

S2

1567

CN702

5321

CN781

13

CN701

12

12

CN931

LD1LD2

T801

R937A

R937B

CN801

23134512

MF

CN932

3X64

5123

LDE2

12

CT61

TAB1

F64

F911

LDE1

21S4

POWER SUPPLY

~/N 230V 50Hz

TAB2

N

PE

L

TB1

CIRCUIT

BREAKER

4

1

RED

YLW

3

2

RED

S

R

21

CN903

21

CN902

21

CN5

6543 1

CN2

27

TAB4

V

MC

W

U

V

WHT

RT61 RT62 RT68

LEV

:Terminal block :Connector

3.Symbols below indicate.

2.Use copper conductors only (for field wiring).

diagram for servicing.

refer to the indoor unit electric wiring

1.About the indoor side electric wiringNOTES:

SYMBOL

NAME

SYMBOL

NAME

CURRENT TRANSFORMER

FUSE (T1AL 250V)

LEV

EXPANSION VALVE COIL

L

REACTOR

IPM

INTELLIGENT POWER MODULE

CT61

FUSE (T2AL 250V)

F64

CT1, 2

CURRENT TRANSFORMER

HC930

INTELLIGENT POWER MODULE

F911

F801

FUSE (T3.15AL 250V)

SMOOTHING CAPACITOR

CB1~3

OUTDOOR FAN MOTOR

POWER FACTOR CONTROLLER

NOISE FILTER

RT61

DISCHARGE TEMPERATURE THERMISTOR

RS1~4

RESISTOR

R937A, B

RESISTOR

MF

MC

COMPRESSOR

R64A,B

RESISTOR

PFC

NF

NR64

VARISTOR

AMBIENT TEMPERATURE THERMISTOR

SOLENOID COIL RELAY

21S4

R.V. COIL

X64

RELAY

TB1

TERMINAL BLOCK

TB2

TERMINAL BLOCK

RT65

FIN TEMPERATURE THERMISTOR

RT64

T801

TRANSFORMER

SSR61

RT68

OUTDOOR HEAT EXCHANGER

TEMPERATURE THERMISTOR

DEFROST THERMISTOR

RT62

NAME

SYMBOL

WIRING DIAGRAM

MUZ-GB50VA

6

7

Outdoor
heat
exchanger

Flared connection

Defrost
thermistor
RT61

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve

Stop valve
(with service port)

Capillary tube
[3.6✕[2.4✕50

Refrigerant flow in cooling

Compressor

4-way valve

Refrigerant flow in heating

Refrigerant pipe [12.7
(with heat insulator)

Refrigerant pipe [6.35
(with heat insulator)

LEV

R.V. coil
OFF
ON

Muffler

#100

Strainer

#100

Receiver

Outdoor heat
exchanger
temperature
thermistor
RT68

Ambient
temperature
thermistor
RT65

Strainer

#100

Outdoor
heat
exchanger

Flared connection

Defrost
thermistor
RT61

Discharge
temperature
thermistor
RT62

Flared connection

Stop valve

Stop valve
(with service port)

Capillary tube
[3.6✕[2.4✕50

Capillary tube
[1.8✕[0.6✕1000

Refrigerant flow in cooling

Compressor

4-way valve

Refrigerant flow in heating

Refrigerant pipe [12.7
(with heat insulator)

Refrigerant pipe [6.35
(with heat insulator)

LEV

R.V. coil
heating ON
cooling OFF

Oil separator

Strainer

#100

Receiver

Outdoor
heat
exchanger
temperature
thermistor
RT68

Strainer

#100

Strainer

#100

Ambient
temperature
thermistor
RT65

REFRIGERANT SYSTEM DIAGRAM

MUZ-GB50VA-

E1

Unit:mm

MUZ-GB50VA­MUZ-GB50VA-

E1
E2

7

Unit:mm

Max. length
A

Max. Height

difference

B

Indoor
unit

Outdoor unit

MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE

Max. length

A

30

Max. Height difference

B

15

Model

Gas

12.7

Liquid

6.35

Piping size O.D : mm

Refrigerant piping : m

MUZ-GB50VA

Model

MUZ-GB50VA

Refrigerant piping length (one way)

Outdoor unit

precharged

1,500

15m

160

20m

260

25m

360

30m

460

7m

0

10m

60

ADDITIONAL REFRIGERANT CHARGE (R410A:g)

Calculation : Xg=20g/m ✕ (Refrigerant piping length (m)–7)

NOTE : Refrigerant piping exceeding 7m requires additional refrigerant charge according to the calculation.

8

PERFORMANCE CURVES8

MUZ-GB50VA

The standard specifications apply only to the operation of the air conditioner under normal conditions. Since operating condi­tions vary according to the areas where these units are installed, the following information has been provided to clarify the
operating characteristics of the air conditioner under the conditions indicated by the performance curve.

(1) GUARANTEED VOLTAGE

198 ~ 264V, 50Hz

(2) AIR FLOW

Air flow should be set at MAX.

(3) MAIN READINGS

(1) Indoor intake air wet-bulb temperature : °C [WB]
(2) Indoor outlet air wet-bulb temperature : °C [WB]
(3) Outdoor intake air dry-bulb temperature : °C [DB]
(4) Total input: W
(5) Indoor intake air dry-bulb temperature : °C [DB]
(6) Outdoor intake air wet-bulb temperature : °C [WB]
(7) Total input : W
Indoor air wet/dry-bulb temperature difference on the left side of the following chart shows the difference between the
indoor intake air wet/dry-bulb temperature and the indoor outlet air wet/dry-bulb temperature for your reference at service.

How to measure the indoor air wet-bulb / dry-bulb temperature difference

1. Attach at least 2 sets of wet and dry-bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets
of wet and dry-bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air
speed is high.

2. Attach at least 2 sets of wet and dry-bulb thermometers to the outdoor air intake.
Cover the thermometers to prevent direct rays of the sun.

3. Check that the air filter is cleaned.

4. Open windows and doors of room.

5. Press the EMERGENCY OPERATION switch once (twice) to start the EMERGENCY COOL (HEAT) MODE.

6. When system stabilizes after more than 15 minutes, measure temperature and take an average temperature.

7. 10 minutes later, measure temperature again and check that the temperature does not change.

}

}

Cooling

Heating

INDOOR UNIT

Wet and dry-bulb
thermometers

8-1. Capacity and input curves

8.7

8.0

7.3

6.6

difference (:)

5.9

5.3

Indoor air Wet-bulb temperature

Indoor intake air Wet-bulb temperature (

Outdoor intake air Dry-bulb temperature (:)

OUTDOOR UNIT

Wet and dry-bulb
thermometers

)

:

:)

Indoor intake air W

Outdoor intake air Dry-bulb temperature (:)

et-bulb tem

perature (

MUZ-GB50VA

MSZ-GB50VA

at Rated frequency

9

Indoor air Dry-bulb temperature

difference (

:)

Indoor intake air Dry-bulb tem

perature (

:

)

Outdoor intake air Wet-bulb temperature (:)

Outdoor intake air Wet-bulb temperature (:)

Indoor intake air Dry-bulb temperature (

:)

24.1

22.3

20.4

18.5

16.7

14.8

13.0

11.1

at Rated frequency

MUZ-GB50VA

MSZ-GB50VA

NOTE:The above broken lines are for the heating operation without any

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-GB50VA

(Hz)

0 50 100 150

0.0

0.5

1.0

1.5

(Hz)

(Hz)

(Hz)

0 50 100 150

0.0

0.5

1.0

1.5

0 50 100 150

0.0

0.5

1.0

1.5

0 50 100 150

0.0

0.5

1.0

1.5

0 50 100 150

0.0

0.5

1.0

1.5

2.0

frost and defrost operation.

8-2. Capacity and input correction by operational frequency of compressor

8-3. 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 58Hz 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.

10

8-4. OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT

Ambient temperature(˚C)
Ambient humidity(%)

18 32

15 2050256030

70 (%)

35(˚C)

Ambient temperature(˚C)
Ambient humidity(%)

18 32

15 2050256030

70 (%)

35(˚C)

MUZ-GB50VA

(MPa [Gauge])

(kgf/F [Gauge])

Outdoor low pressure

Outdoor unit current(A)

4

5

6

7

8

0.5

0.6

0.7

0.8

0.9

1.0

5

6

7

8

9

10

Dry bulb temperature (°C)

Indoor

20.0

14.521

Outdoor
7
6

151220.0

14.5

Wet bulb temperature (°C)

0 5 10 15 20 25(˚C)

4

5

6

7

8

Outdoor unit current (A)

Ambient temperature(˚C)

MUZ-GB50VA

2

NOTE: The unit of pressure has been changed to MPa based on the international system of units (SI unit system).
The conversion factor is: 1(MPa [Gauge] = 10.2 (Kgf/

ff

[Gauge])

COOL operation

1 Both indoor and outdoor unit are under the

same temperature/humidity condition.

2 Operation : TEST RUN OPERATION (refer to 8-3.)

HEAT operation

1 Condition :

Dry-bulb temperature(:)

20
25
30 70

Relative humidity(%)

50
60

2 Operation : TEST RUN OPERATION (refer to 8-3.)

11

21 18 5.88 3.00 0.51 1320 5.63 2.87 0.51 1386 5.40 2.75 0.51 1452 5.20 2.65 0.51 1518
21 20 6.13 2.39 0.39 1386 5.88 2.29 0.39 1469 5.70 2.22 0.39 1502 5.50 2.15 0.39 1568
22 18 5.88 3.23 0.55 1320 5.63 3.09 0.55 1386 5.40 2.97 0.55 1452 5.20 2.86 0.55 1518
22 20 6.13 2.63 0.43 1386 5.88 2.53 0.43 1469 5.70 2.45 0.43 1502 5.50 2.37 0.43 1568
22 22 6.38 1.98 0.31 1436 6.15 1.91 0.31 1526 6.00 1.86 0.31 1568 5.75 1.78 0.31 1634
23 18 5.88 3.47 0.59 1320 5.63 3.32 0.59 1386 5.40 3.19 0.59 1452 5.20 3.07 0.59 1518
23 20 6.13 2.88 0.47 1386 5.88 2.76 0.47 1469 5.70 2.68 0.47 1502 5.50 2.59 0.47 1568
23 22 6.38 2.23 0.35 1436 6.15 2.15 0.35 1526 6.00 2.10 0.35 1568 5.75 2.01 0.35 1634
24 18 5.88 3.70 0.63 1320 5.63 3.54 0.63 1386 5.40 3.40 0.63 1452 5.20 3.28 0.63 1518
24 20 6.13 3.12 0.51 1386 5.88 3.00 0.51 1469 5.70 2.91 0.51 1502 5.50 2.81 0.51 1568
24 22 6.38 2.49 0.39 1436 6.15 2.40 0.39 1526 6.00 2.34 0.39 1568 5.75 2.24 0.39 1634
24 24 6.70 1.81 0.27 1502 6.45 1.74 0.27 1584 6.30 1.70 0.27 1634 6.10 1.65 0.27 1716
25 18 5.88 3.94 0.67 1320 5.63 3.77 0.67 1386 5.40 3.62 0.67 1452 5.20 3.48 0.67 1518
25 20 6.13 3.37 0.55 1386 5.88 3.23 0.55 1469 5.70 3.14 0.55 1502 5.50 3.03 0.55 1568
25 22 6.38 2.74 0.43 1436 6.15 2.64 0.43 1526 6.00 2.58 0.43 1568 5.75 2.47 0.43 1634
25 24 6.70 2.08 0.31 1502 6.45 2.00 0.31 1584 6.30 1.95 0.31 1634 6.10 1.89 0.31 1716
26 18 5.88 4.17 0.71 1320 5.63 3.99 0.71 1386 5.40 3.83 0.71 1452 5.20 3.69 0.71 1518
26 20 6.13 3.61 0.59 1386 5.88 3.47 0.59 1469 5.70 3.36 0.59 1502 5.50 3.25 0.59 1568
26 22 6.38 3.00 0.47 1436 6.15 2.89 0.47 1526 6.00 2.82 0.47 1568 5.75 2.70 0.47 1634
26 24 6.70 2.35 0.35 1502 6.45 2.26 0.35 1584 6.30 2.21 0.35 1634 6.10 2.14 0.35 1716
26 26 6.90 1.59 0.23 1584 6.70 1.54 0.23 1667 6.60 1.52 0.23 1716 6.40 1.47 0.23 1766
27 18 5.88 4.41 0.75 1320 5.63 4.22 0.75 1386 5.40 4.05 0.75 1452 5.20 3.90 0.75 1518
27 20 6.13 3.86 0.63 1386 5.88 3.70 0.63 1469 5.70 3.59 0.63 1502 5.50 3.47 0.63 1568
27 22 6.38 3.25 0.51 1436 6.15 3.14 0.51 1526 6.00 3.06 0.51 1568 5.75 2.93 0.51 1634
27 24 6.70 2.61 0.39 1502 6.45 2.52 0.39 1584 6.30 2.46 0.39 1634 6.10 2.38 0.39 1716
27 26 6.90 1.86 0.27 1584 6.70 1.81 0.27 1667 6.60 1.78 0.27 1716 6.40 1.73 0.27 1766
28 18 5.88 4.64 0.79 1320 5.63 4.44 0.79 1386 5.40 4.27 0.79 1452 5.20 4.11 0.79 1518
28 20 6.13 4.10 0.67 1386 5.88 3.94 0.67 1469 5.70 3.82 0.67 1502 5.50 3.69 0.67 1568
28 22 6.38 3.51 0.55 1436 6.15 3.38 0.55 1526 6.00 3.30 0.55 1568 5.75 3.16 0.55 1634
28 24 6.70 2.88 0.43 1502 6.45 2.77 0.43 1584 6.30 2.71 0.43 1634 6.10 2.62 0.43 1716
28 26 6.90 2.14 0.31 1584 6.70 2.08 0.31 1667 6.60 2.05 0.31 1716 6.40 1.98 0.31 1766
29 18 5.88 4.88 0.83 1320 5.63 4.67 0.83 1386 5.40 4.48 0.83 1452 5.20 4.32 0.83 1518
29 20 6.13 4.35 0.71 1386 5.88 4.17 0.71 1469 5.70 4.05 0.71 1502 5.50 3.91 0.71 1568
29 22 6.38 3.76 0.59 1436 6.15 3.63 0.59 1526 6.00 3.54 0.59 1568 5.75 3.39 0.59 1634
29 24 6.70 3.15 0.47 1502 6.45 3.03 0.47 1584 6.30 2.96 0.47 1634 6.10 2.87 0.47 1716
29 26 6.90 2.42 0.35 1584 6.70 2.35 0.35 1667 6.60 2.31 0.35 1716 6.40 2.24 0.35 1766
30 18 5.88 5.11 0.87 1320 5.63 4.89 0.87 1386 5.40 4.70 0.87 1452 5.20 4.52 0.87 1518
30 20 6.13 4.59 0.75 1386 5.88 4.41 0.75 1469 5.70 4.28 0.75 1502 5.50 4.13 0.75 1568
30 22 6.38 4.02 0.63 1436 6.15 3.87 0.63 1526 6.00 3.78 0.63 1568 5.75 3.62 0.63 1634
30 24 6.70 3.42 0.51 1502 6.45 3.29 0.51 1584 6.30 3.21 0.51 1634 6.10 3.11 0.51 1716
30 26 6.90 2.69 0.39 1584 6.70 2.61 0.39 1667 6.60 2.57 0.39 1716 6.40 2.50 0.39 1766
31 18 5.88 5.35 0.91 1320 5.63 5.12 0.91 1386 5.40 4.91 0.91 1452 5.20 4.73 0.91 1518
31 20 6.13 4.84 0.79 1386 5.88 4.64 0.79 1469 5.70 4.50 0.79 1502 5.50 4.35 0.79 1568
31 22 6.38 4.27 0.67 1436 6.15 4.12 0.67 1526 6.00 4.02 0.67 1568 5.75 3.85 0.67 1634
31 24 6.70 3.69 0.55 1502 6.45 3.55 0.55 1584 6.30 3.47 0.55 1634 6.10 3.36 0.55 1716
31 26 6.90 2.97 0.43 1584 6.70 2.88 0.43 1667 6.60 2.84 0.43 1716 6.40 2.75 0.43 1766
32 18 5.88 5.58 0.95 1320 5.63 5.34 0.95 1386 5.40 5.13 0.95 1452 5.20 4.94 0.95 1518
32 20 6.13 5.08 0.83 1386 5.88 4.88 0.83 1469 5.70 4.73 0.83 1502 5.50 4.57 0.83 1568
32 22 6.38 4.53 0.71 1436 6.15 4.37 0.71 1526 6.00 4.26 0.71 1568 5.75 4.08 0.71 1634
32 24 6.70 3.95 0.59 1502 6.45 3.81 0.59 1584 6.30 3.72 0.59 1634 6.10 3.60 0.59 1716
32 26 6.90 3.24 0.47 1584 6.70 3.15 0.47 1667 6.60 3.10 0.47 1716 6.40 3.01 0.47 1766

INDOOR INDOOR

CAPACITY:5.0(kW)

INPUT:1650(W)SHF:0.69

21

OUTDOOR DB(:)

25 27 30

WB(:)

Q SHC SHF Q SHC SHF Q SHC SHF Q SHC SHFINPUT INPUT INPUT INPUT

DB(:)

PERFORMANCE DATA COOL operation at Rated frequency

MSZ-GB50VA : MUZ-GB50VA

NOTE Q : Total capacity (kW) SHF : Sensible heat factor DB : Dry-bulb temperature

SHC : Sensible heat capacity (kW) INPUT : Total power input (W) WB : Wet-bulb temperature

12

PERFORMANCE DATA COOL operation at Rated frequency

MSZ-GB50VA : MUZ-GB50VA

CAPACITY:5.0(kW)

INDOOR INDOOR

DB(:)

NOTE Q : Total capacity (kW) SHF : Sensible heat factor DB : Dry-bulb temperature

WB(:)

21 18 4.90 2.50 0.51 1617 4.50 2.30 0.51 1716 4.30 2.19 0.51 1749
21 20 5.15 2.01 0.39 1683 4.80 1.87 0.39 1766 4.60 1.79 0.39 1815
22 18 4.90 2.70 0.55 1617 4.50 2.48 0.55 1716 4.30 2.37 0.55 1749
22 20 5.15 2.21 0.43 1683 4.80 2.06 0.43 1766 4.60 1.98 0.43 1815
22 22 5.45 1.69 0.31 1749 5.10 1.58 0.31 1848 4.90 1.52 0.31 1881
23 18 4.90 2.89 0.59 1617 4.50 2.66 0.59 1716 4.30 2.54 0.59 1749
23 20 5.15 2.42 0.47 1683 4.80 2.26 0.47 1766 4.60 2.16 0.47 1815
23 22 5.45 1.91 0.35 1749 5.10 1.79 0.35 1848 4.90 1.72 0.35 1881
24 18 4.90 3.09 0.63 1617 4.50 2.84 0.63 1716 4.30 2.71 0.63 1749
24 20 5.15 2.63 0.51 1683 4.80 2.45 0.51 1766 4.60 2.35 0.51 1815
24 22 5.45 2.13 0.39 1749 5.10 1.99 0.39 1848 4.90 1.91 0.39 1881
24 24 5.75 1.55 0.27 1815 5.40 1.46 0.27 1898 5.25 1.42 0.27 1947
25 18 4.90 3.28 0.67 1617 4.50 3.02 0.67 1716 4.30 2.88 0.67 1749
25 20 5.15 2.83 0.55 1683 4.80 2.64 0.55 1766 4.60 2.53 0.55 1815
25 22 5.45 2.34 0.43 1749 5.10 2.19 0.43 1848 4.90 2.11 0.43 1881
25 24 5.75 1.78 0.31 1815 5.40 1.67 0.31 1898 5.25 1.31 0.25 1947
26 18 4.90 3.48 0.71 1617 4.50 3.20 0.71 1716 4.30 3.05 0.71 1749
26 20 5.15 3.04 0.59 1683 4.80 2.83 0.59 1766 4.60 2.71 0.59 1815
26 22 5.45 2.56 0.47 1749 5.10 2.40 0.47 1848 4.90 2.30 0.47 1881
26 24 5.75 2.01 0.35 1815 5.40 1.89 0.35 1898 5.25 1.21 0.23 1947
26 26 6.05 1.39 0.23 1881 5.70 1.31 0.23 1964 5.50 1.27 0.23 2013
27 18 4.90 3.68 0.75 1617 4.50 3.38 0.75 1716 4.30 3.23 0.75 1749
27 20 5.15 3.24 0.63 1683 4.80 3.02 0.63 1766 4.60 2.90 0.63 1815
27 22 5.45 2.78 0.51 1749 5.10 2.60 0.51 1848 4.90 2.50 0.51 1881
27 24 5.75 2.24 0.39 1815 5.40 2.11 0.39 1898 5.25 1.10 0.21 1947
27 26 6.05 1.63 0.27 1881 5.70 1.54 0.27 1964 5.50 1.49 0.27 2013
28 18 4.90 3.87 0.79 1617 4.50 3.56 0.79 1716 4.30 3.40 0.79 1749
28 20 5.15 3.45 0.67 1683 4.80 3.22 0.67 1766 4.60 3.08 0.67 1815
28 22 5.45 3.00 0.55 1749 5.10 2.81 0.55 1848 4.90 2.70 0.55 1881
28 24 5.75 2.47 0.43 1815 5.40 2.32 0.43 1898 5.25 1.00 0.19 1947
28 26 6.05 1.88 0.31 1881 5.70 1.77 0.31 1964 5.50 1.71 0.31 2013
29 18 4.90 4.07 0.83 1617 4.50 3.74 0.83 1716 4.30 3.57 0.83 1749
29 20 5.15 3.66 0.71 1683 4.80 3.41 0.71 1766 4.60 3.27 0.71 1815
29 22 5.45 3.22 0.59 1749 5.10 3.01 0.59 1848 4.90 2.89 0.59 1881
29 24 5.75 2.70 0.47 1815 5.40 2.54 0.47 1898 5.25 0.89 0.17 1947
29 26 6.05 2.12 0.35 1881 5.70 2.00 0.35 1964 5.50 1.93 0.35 2013
30 18 4.90 4.26 0.87 1617 4.50 3.92 0.87 1716 4.30 3.74 0.87 1749
30 20 5.15 3.86 0.75 1683 4.80 3.60 0.75 1766 4.60 3.45 0.75 1815
30 22 5.45 3.43 0.63 1749 5.10 3.21 0.63 1848 4.90 3.09 0.63 1881
30 24 5.75 2.93 0.51 1815 5.40 2.75 0.51 1898 5.25 0.79 0.15 1947
30 26 6.05 2.36 0.39 1881 5.70 2.22 0.39 1964 5.50 2.15 0.39 2013
31 18 4.90 4.46 0.91 1617 4.50 4.10 0.91 1716 4.30 3.91 0.91 1749
31 20 5.15 4.07 0.79 1683 4.80 3.79 0.79 1766 4.60 3.63 0.79 1815
31 22 5.45 3.65 0.67 1749 5.10 3.42 0.67 1848 4.90 3.28 0.67 1881
31 24 5.75 3.16 0.55 1815 5.40 2.97 0.55 1898 5.25 0.68 0.13 1947
31 26 6.05 2.60 0.43 1881 5.70 2.45 0.43 1964 5.50 2.37 0.43 2013
32 18 4.90 4.66 0.95 1617 4.50 4.28 0.95 1716 4.30 4.09 0.95 1749
32 20 5.15 4.27 0.83 1683 4.80 3.98 0.83 1766 4.60 3.82 0.83 1815
32 22 5.45 3.87 0.71 1749 5.10 3.62 0.71 1848 4.90 3.48 0.71 1881
32 24 5.75 3.39 0.59 1815 5.40 3.19 0.59 1898 5.25 0.58 0.11 1947
32 26 6.05 2.84 0.47 1881 5.70 2.68 0.47 1964 5.50 2.59 0.47 2013

SHC : Sensible heat capacity (kW) INPUT : Total power input (W) WB : Wet-bulb temperature

Q SHC SHF Q SHC SHF Q SHC SHFINPUT INPUT INPUT

35

INPUT:1650(W)SHF:0.69

OUTDOOR DB(:)

40 43

13

PERFORMANCE DATA HEAT operation at Rated frequency

CAPACITY:5.8(kW)

INPUT:1700(W)

OUTDOOR WB(:)

INDOOR

-10 -5 0 5 10 15 20

DB(:)

Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT
15
21
26

3.65 1105 4.41 1326 5.16 1496 5.92 1615 6.67 1717 7.37 1768 8.12 1802

3.48 1190 4.18 1411 4.93 1564 5.63 1683 6.38 1768 7.08 1819 7.80 1887

3.13 1275 3.89 1496 4.58 1649 5.34 1768 6.09 1853 6.79 1904 7.54 1955

ON

OFF

ON

OFF

Outdoor fan
motor

Compressor

5 seconds 15 seconds

ON
OFF

Compressor

Outdoor fan
motor

ON
OFF

<COOL>

5 seconds

<HEAT>

5 seconds

R.V.coil

ON
OFF

ON or OFF

ON or OFF

MSZ-GB50VA : MUZ-GB50VA

NOTE Q : Total capacity (kW) INPUT : Total power input (W) DB : Dry-bulb temperature WB : Wet-bulb temperature

9

ACTUATOR CONTROL

MUZ-GB50VA

9-1. 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.

9-2. R.V. coil control

Heating

Cooling

Dry

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

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

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

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

ON
OFF
OFF

14

Housing point

9-3. Relation between main sensor and actuator

Discharge temperature thermistor
Indoor pipe temperature thermistor
Defrost thermistor
Fin temperature thermistor
Outdoor heat exchanger temperature
Ambient temperature thermistor

Purpose

Protection

Defrosting Protection

Defrosting
Protection
Protection

Protection

Compressor

LEV

Outdoor

fan motor

R.V. coil

Sensor

Actuator

10

TROUBLESHOOTING

MUZ-GB50VA

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 to 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.

Lead wiring

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) When troubleshooting, refer to 10-2., 10-3. and 10-4.

15

10-2. Failure mode recall function

Operational procedure

Yes

(Blinks)

No

(OFF)

Yes

No

Releasing the failure mode recall function

Note1.Make sure to release the failure mode recall function once it's 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.

W2. Blinking pattern when the indoor unit is abnormal:

W3.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 0.5­second 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 emitted at the same timing
as the blinking of the left lamp of
OPERATION INDICATOR lamp. W2

The cause of abnormality cannot be found because the abnormality doesn't recur.

Setting up the failure mode recall function

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 confirm 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. W2

Turn ON the power supply.
<

Preparation of the remote controller

>

1 While pressing both OPERATION SELECT

button and TOO COOL button on the remote controller at the same time, press
RESET button.

2 First, release RESET button.

And release the other two buttons after all LCD except the set temperature in
operation display section of the remote controller is displayed after 3 seconds.

Deleting the memorized abnormal condition

1After repairing the unit, recall the failure mode again according to

"Setting up the failure mode recall function" mentioned above.

2Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature is displayed)

with the remote controller headed towards the indoor unit.

3Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
4Release the failure mode recall function according to "Releasing the failure mode recall function"

mentioned above.

Repair the defective parts.

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.

Judgment of indoor/outdoor abnormality

Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit. w1

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

The outdoor unit is abnormal.
Check the blinking pattern, and confirm 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. W3

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

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 (10-4.) disappears, the memorized failure details
can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.

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

16

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

Operational procedure

Note1. Make sure to release the failure mode recall function once it's 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.
W2.Blinking pattern when outdoor unit is abnormal:

Yes

(Blinks)

No

(OFF)

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 0.5­second interval

Repeated cycle

W1. Regardless of normal or abnormal condition, 2 short
beeps are emitted as the signal is received.

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. W2

Deleting the memorized abnormal condition

1After repairing the unit, recall the failure mode again according to

"Setting up the failure mode recall function" mentioned above.

2Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature is displayed)

with the remote controller headed towards the indoor unit.

3Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
4Release the failure mode recall function according to "Releasing the failure mode recall function"

mentioned above.

Repair the defective parts.

With the remote controller headed towards the indoor unit, press TOO COOL or TOO
WARM button to adjust the set temperature to 25:. W1

The outdoor unit is normal.

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 confirm 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. W2

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

Confirm that the remote controller is in the failure mode recall
function.

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

17

OFF None (Normal)
2-time flash

3-time flash

4-time flash

5-time flash

6-time flash

7-time flash

8-time flash

Lighting Lighting

Lighting Once

Lighting Once
Lighting Twice

Lighting 3 times
Lighting 4 times

Lighting 9 times

Once Goes

out

Lighting

Lighting

Lighting

Lighting

3 times

Goes

out

4 times Goes

out

Lighting

Lighting

Lighting

Lighting

Lighting

5 times

9-time flash

10-time flash

• Check the connection
of the compressor
connecting wire.

• Refer to 10-6.A

"How to check
inverter / compressor".

• Check the stop valve.

• Replace the outdoor

electronic control
P.C. board.

•Check refrigerant circuit

and refrigerant amount.

• Refer to 10-6.G "Check

of LEV".

• Refer to 10-6.D "Check

of outdoor fan motor".

• Replace the outdoor

electronic control
P.C. board.

•Check refrigerant circuit

and refrigerant amount.

• Refer to 10-6.G "Check

of LEV".

• Reconnect compressor

connector.

• Refer to 10-6.A "How to

check inverter/
compressor."

• Check the stop valve.

•Check refrigerant circuit

and refrigerant amount.

• Check the stop valve.

• Check around outdoor

unit.

• Check outdoor unit air

passage.

• Refer to 10-6.D "Check

of outdoor fan motor".

• Refer to 10-6.B "Check

of outdoor thermistors".

• Refer to 10-6.B "Check

of outdoor thermistors".

Overcurrent 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.

Thermistor shorts or opens during
compressor running.

28A current flows into intelligent
power module.

Tthe outdoor heat exchanger
temperature exceeds 70: during
cooling or the indoor gas pipe
temperature exceeds 70: during
heating.

The fin temperature exceeds 87:
during operation.

The P.C. board temperature exceeds
70: during operation.

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

Nonvolatile memory data cannot be
read properly.

The frequency of the compressor is
kept 80Hz or more and the discharge
temperature is kept under 39:
for more than 20 minutes.

Outdoor power system

Discharge temperature
thermistor

Defrost thermistor
Ambient temperature thermistor
Fin temperature thermistor
P.C. board temperature

thermistor

Outdoor heat exchanger
temperature thermistor

Overcurrent

Discharge temperature

High pressure

Fin temperature

P.C. board temperature

Outdoor fan motor

Nonvolatile memory data

Discharge temperature

--

Abnormal point

(Failure mode / protection)

Condition

Correspondence

Indoor/outdoor

unit failure mode

recall function

LED indication

(Outdoor P.C. board)

LED 1 LED 2

Discharge temperature exceeds
116°C during operation.
Compressor can restart if discharge
temperature thermistor reads 100: or
less 3 minutes later.

The left lamp of

OPERATION INDICATOR

lamp (Indoor unit)

3. Outdoor unit failure mode table

MUZ-GB50VA

NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-4.).

18

The left lamp of

OPERATION INDICATOR

lamp (Indoor unit)

11-time flash

(Failure mode / protection)

Communication error
between P.C. boards

Current sensor

Zero cross detecting circuit

Converter

Bus-bar voltage
(1)

Bus-bar voltage
(2)
wEven if this protection stop is
performed continuously 3 times,
it does not mean the abnormality
in outdoor power system.

Abnormal point

LED indication

(Outdoor P.C. board)

LED 1 LED 2

Lighting 6 times

Lighting 7 times

5 times Goes

5 times

5 times

6 times

out

Goes

out

Goes

out

Goes

out

Condition

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

The communication between boards
protection stop is continuously
performed twice.

A short or open circuit is detected
in the current sensor during
compressor operating.
Current sensor protection stop is
continuously performed twice.

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

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

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

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

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

Correspondence

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

• Replace the power
board.

• Check the connecting
wire among electronic
control P.C. board,
noise filter P.C. board
and power board.

• Replace the power
board.

Indoor/outdoor

unit failure mode

recall function

NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-4.).

19

Start

Indoor unit
operates.
Outdoor unit
doesn't
operate.

Indoor unit
doesn't receive
the signal from
remote controller.

OPERATION
INDICATOR
lamp on the indoor
unit is flashing on
and off.

Outdoor unit
operates only
in Test Run
operation.
(Refer to 8-3.)

w

Outdoor unit
doesn't
operate
even in
Test Run
operation.
(Refer to 8-3.)

w

Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.

Indoor unit
doesn't operate,
when
EMERGENCY
OPERATION
switch is pressed.

Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage".

Refer to 10-6.A
"How to check
inverter/
compressor".

Refer to
"Check of
remote controller
and receiver
P.C. board".

1. Check indoor / outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)

2. Refer to
"Check of indoor
electronic control
P.C. board and indoor
fan motor".

Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.

Refer to 10-6.C
"Check of
R.V. coil".

Left lamp
Flash on and
off at

0.5-second
intervals
Cause:
Indoor/
Outdoor unit

• Miswiring or
trouble of
serial signal.

Left

lamp
2-time flash
Cause:
Indoor unit

• Trouble of
room temp­ erature/
indoor coil
thermistor

Left

lamp
3-time flash
Cause:
Indoor unit

• Trouble of
indoor fan
motor

Left

lamp
5-time flash
Cause:
Outdoor unit

• Outdoor
power
system
abnormality

Left

lamp
6-time flash
Cause:
Outdoor unit

• Trouble of
thermistor
in outdoor
unit

Left

lamp
7-time flash
Cause:
Outdoor unit

• Trouble of
outdoor
control
system

Refer to 10-6.H
"How to check
miswiring
and serial
signal error".

Check room
temperature
thermistor
and indoor
coil thermis­tor.
Refer to "Test
point diagram
and voltage".

Refer to
"Check of
indoor fan
motor".

Refer to 10-6.A
"How to check
inverter/
compressor".

Refer to 10-6.B
"Check of
outdoor
thermistors".

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

Left

lamp
14-time flash
Cause:
Outdoor unit

• Other
abnormality

Check 10-2.2.
"Flow chart of
the detailed
outdoor unit
failure mode
recall function."

Left lamp
4-time flash
Cause:
Indoor unit

• Trouble of
indoor unit
control
system

Replace the
indoor
electronic
control
P.C. board.

Refer to indoor unit
service manual.

Indoor unit operates.
Outdoor unit doesn't
operate normally.

If blinking of OPERATION
INDICATOR lamp cannot
be checked, it can be checked
with failure mode recall function.

w "Test Run operation" means
the operation within 30 minutes
after EMERGENCY OPERATION
switch is pressed.

All lamps
Flash on and off
at 0.5-second
intervals
Cause:
Indoor unit

• The horizontal
vane is not
installed
correctly.

Refer to
"Check of
installation of
the horizontal
vane".

10-3. Instruction of troubleshooting

20

10-4. Troubleshooting check table

MUZ-GB50VA

Symptom

No.

Outdoor unit
does not
operate.

1

Indication

LED1(Red) LED2(Yellow)

Lightning Twice Outdoor power system

Abnormal point / Condition Correspondence

Condition

Overcurrent protection stop is continuously performed 3 times within
1 minute after the compressor gets started, or when 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 10-6.A "How to check inverter/compressor".

• Check the stop valve.

2

3

4

5

6

7

8

9

'Outdoor unit
stops and
restarts 3
minutes

10

later' is
repeated.

Lightning 3 times

Lightning 4 times

5 timesLightning

Lightning 6 times Serial signal

Lightning 7 times Nonvolatile memory data • Replace the outdoor electronic control P.C. board.

Lightning 8 times Current sensor • Replace the power board.

Lightning 11 times

Lightning 12 times

Twice Goes out

Discharge temperature
thermistor

Fin temperature thermistor
P.C board temperature

thermistor
Ambient temperature

thermistor

Outdoor heat exchanger
temperature thermistor

Defrost thermistor

Communication error
between P.C. boards

Zero cross detecting circuit

IPM protection

Lock protection

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.

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

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

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) of compressor start-up.

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.

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

The nonvolatile memory data cannot be read properly.

Current sensor protection stop is continuously performed twice.
The communication protection stop between boards is continuously

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

performed 10 times.

Overcurrent is detected after 30 minutes of compressor start-up.

Overcurrent is detected within 30 minutes of compressor start-up.

• Refer to 10-6.B "Check of outdoor thirmistors".

• Refer to 10-6.B "Check of outdoor thirmistors".

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

• Refer to 10-6.B "Check of outdoor thirmistors".

• Refer to 10-6.H "How to check miswiring and serial signal

error".

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

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

• Reconnect compressor connector.

• Refer to 10-6.A "How to check inverter/compressor".

• Check the stop valve.

• Check the power module (PAM module).

11

12

13

14

15

16

17

18

19

3 times Goes out

4 times Goes out

5 times Goes out

8 times Goes out

9 times Goes out

13 times Goes out Outdoor fan motor • Refer to 10-6.D "Check of outdoor fan motor".

Lighting 8 times

Lighting 11 times

Lighting 12 times

Discharge temperature
protection

Fin temperature protection
P.C. board temperature

protection
High-pressure protection

Converter protection

Bus-bar voltage protection (1)

Bus-bar voltage protection (2)

Current sensor protection
Communication between P.C.

boards protection
Zero cross detecting circuit

protection

Discharge temperature exceeds 116:during operation and compressor
stops. Compressor can restart if discharge temperature thermistor reads
100: or less 3 minutes later.

The fin temperature exceeds 87: during operation.

The P.C. board temperature exceeds 70: during operation.
The outdoor heat exchanger temperature exceeds 70: during cooling or

indoor gas pipe temperature exceeds 70:during heating.

A failure is detected in the operation of the converter during operation.
The bus-bar voltage exceeds 400V or falls to 200V or below during

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

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

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

operating.
Communication error occurs between the outdoor electronic control P.C.

board and power board for more than 10 seconds.
Zero cross signal cannot be detected while the compressor is operating.

NOTE 1. The location of LED is illustrated at the right figure. Refer to 10-7.1.

2. LED is lighted during normal operation.

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

0.5-second ON

• Check the amount of gas and refrigerant circuit.

• Refer to 10-6.G "Check of LEV".

•Check refrigerant circuit and refrigerant amount.

•Refer to 10-6.D "Check of outdoor fan motor".

• Check the amount of gas and the refrigerant circuit.

• Check stop valve.

• Replace the power board.

• Replace the power board.

• Replace the power board.

• Check the connecting wire between outdoor electronic control

P.C. board and power board.

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

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

LED1

LED2

Lighting

0.5-second ON

ON
OFF

2.5-second OFF

2.5-second OFF

21

Primary current protection
Secondary current protection

High-pressure protection
Defrosting in cooling

3 times

Lighting

Discharge temperature
protection

• Check refrigerant circuit and refrigerant amount.

• Refer to 10-6.G "Check of LEV".

• Refer to 10-6.B "Check of outdoor thermistors".

4 times

Lighting

Low discharge
temperature protection

• Refer to 10-6.G "Check of LEV".

• Check refrigerant circuit and refrigerant amount.

5 times

Lighting

Cooling high-pressure
protection

This symptom does not mean any abnormality of the
product, but check the following points.

• Check if indoor filters are clogged.

• Check if refrigerant is short.

• Check if indoor/outdoor unit air circulation is short cycled.

-

-

These symptoms do not mean any abnormality of the
product, but check the following points.

• Check if indoor filters are clogged.

• Check if refrigerant is short.

• Check if indoor/outdoor unit air circulation is short cycled.

Twice Lighting

Once Lighting

The discharge temperature exceeds 100: during operation.

The frequency of the compressor is kept 80Hz or more and the discharge
temperature is kept under 39: for more than 20 minutes.

The outdoor heat exchanger temperature exceeds 58:
during operation.

9 times

Lighting

Inverter check mode

Lighting

Lighting

Normal

The unit is operated with emergency operation switch.

-

The input current exceeds 15A.

The current of the compressor exceeds 15A.
The indoor gas pipe temperature exceeds 45: during heating.

The indoor gas pipe temperature falls 3: or below during cooling.

LED1(Red) LED2(Yellow)

Abnormal point / Condition Correspondence

Indication

Condition

Outdoor unit
operates.

Outdoor unit
operates

No.

Symptom

20

21

22

23

24

25

26

22

W

U

V

WHT

RED

BLK

LEV

WHT
RED

YLW

BRN

ORN

BLU

U

RED

WHT

BLK

V

W

(W)

(V)

(U)

10-5. Trouble criterion of main parts

MUZ-GB50VA

Part name FigureCheck method and criterion

Defrost thermistor
(RT61)

Ambient temperature
thermistor (RT65)

Outdoor heat exchanger
temperature thermistor
(RT68)

Discharge temperature
thermistor (RT62)

Fin temperature
thermistor (RT64)

Compressor

Outdoor fan motor

Measure the resistance with a tester.
Refer to 10-7. “Test point diagram and voltage”,1. “Outdoor electronic

control P.C. board”, the chart of thermistor.

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

Refer to 10-7. “Test point diagram and voltage”,1. “Outdoor electronic
control P.C. board”, the chart of thermistor.

Measure the resistance between terminals using a tester.
(Winding temperature : -10 °C ~ 40 °C)

Normal

0.40 " ~ 0.49 "

Measure the resistance between lead wires using a tester.
(Part temperature : -10 °C ~ 40 °C)

Color of lead wire

Normal

RED - BLK

BLK - WHT

13.4 " ~ 16.4 "

WHT - RED

Measure the resistance using a tester. (Part temperature : -10 °C ~ 40 °C)

R. V. coil

Normal

2.6 k" ~ 3.3 k"

Measure the resistance using a tester.(Part temperature : -10 °C ~ 40 °C)

Normal

37.4 " ~ 53.9 "

Linear expansion valve

Color of lead wire

WHT - RED
RED - ORN
YLW - BRN

BRN - BLU

23

10-6. Troubleshooting flow

MUZ-GB50VA

AA

How to check inverter/ compressor

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

EMERGENCY OPERATION.

W • After the outdoor fan starts running, wait for 1 minute or more before
Measure the voltage between each
lead wire leading to the compressor.
U (BLK) - V (WHT)
V (WHT) - W (RED)
W (RED) - U (BLK)
Is voltage output on right table?

Yes

Is output balanced?

Yes

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

Yes

No

measuring the voltage.

•The output voltage values have the tolerance of i20%.

No

No

Replace the power board.

COOL HEAT

122V~154V

(56Hz~71Hz)

74V~126V

(30Hz~58Hz)

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

Reconnect the lead wire of compressor, and turn on
power supply to indoor and outdoor unit.
3 minutes later, start 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 5minutes: refrigerant circuit defective
5 minutes or more: normal

No

Replace the
compressor.

24

• When OPERATION INDICATOR lamp flashes 6-time.

Yes

Yes

No

No

Reconnect the connector CN661, CN663 and CN3.
3 minutes after turning on the power supply, start EMERGENCY OPERATION.

Defrost
Discharge temperature
Outdoor heat exchanger temperature
Ambient temperature
Fin temperature

Symbol

RT61
RT62
RT68
RT65
RT64

Connector, Pin No.Thermistor Board
Between CN661 pin1 and pin2
Between CN661 pin3 and pin4
Between CN661 pin7 and pin8
Between CN663 pin1 and pin2
Between CN3 pin1 and pin2

Outdoor electronic control P.C. board

Outdoor power board

W When RT64 is abnormal,
replace the

outdoor power

board.

Disconnect the connector in the outdoor electronic control P.C. board or the outdoor power board
(see below table), and measure the resistance of thermistor. Is the thermistor normal?

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

Replace the thermistor.

W

Normal

Replace the outdoor electronic
control P.C. board.

• When thermistor is abnormal.

BB

Check of outdoor thermistors

25

The cooling operation or heating operation does not operate. (LED display: Both LED1 and LED2 lighting)

CC

Check of R.V. coil

• When heating operation does not work.

1. Disconnect the lead wire leading to the compressor.

2. 3 minutes after turning on the power supply, start EMERGENCY
OPERATION in HEAT mode.

Is there voltage of 230V AC between pin1 and
pin 2 at connector CN912? W

Yes

Turn off power supply of indoor and outdoor unit.

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

Yes

Replace the 4-way valve.

• When cooling operation does not work.

1. Disconnect the lead wire leading to the compressor.

2. 3 minutes after turning on the power supply, start EMERGENCY
OPERATION in COOL mode.

Is there voltage of 230V AC between pin1 and
pin 2 at connector CN912? W

Yes

No

Replace the R.V. coil.

No

No

1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector CN781 in the outdoor electronic
control P.C. board.

2. 3 minutes after turning on the power supply, start
EMERGENCY OPERATION in HEAT mode.

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

Replace the noise filter P.C. board.

Replace the 4-way valve.

Yes

No

Replace the electronic
control P.C. board.

W If the connector CN912 is

not connected or R.V. coil
is open, voltage occurs
between terminals even
when the control is OFF.

1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector CN781 in the outdoor electronic
control P.C. board.

2. 3 minutes after turning on the power supply, start
EMERGENCY OPERATION in COOL mode.

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

Yes

Replace the outdoor electronic control P.C. board.

No

Replace the noise filter P.C. board.

26

• Fan motor does not operate or stops operating shortly after starting the operation.

Yes

No

No

Yes

Yes

No

(Fixed to either 5V or 0V DC)

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(-)

Is the resistance between each terminal
of outdoor fan motor normal?

Does the outdoor fan motor rotate smoothly?

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

Replace the outdoor DC fan motor.

Replace the outdoor electronic control P.C. board.

Turn on power supply.

No

Yes

Yes

No

No

Yes

No

Yes

Yes

No

Replace the power board.

Check the connecting of parts of main power supply circuit.

Is there voltage of 230V AC in the
power supply terminal block?

Is the output voltage from the noise
filter P.C. board 230V AC?

Is the input voltage to the outdoor
electronic control P.C. board 325V DC?

Check the power supply cable.

Replace the outdoor electronic control
P.C. board.

Replace the noise
filter P.C. board.

Is fuse (F64) blown?

Is the input voltage to the power board
230V AC?

Replace the fuse.

Replace the reactor.

DD

Check of outdoor fan motor

Outdoor unit does not operate. (LED display: display OFF)

EE

Check of power supply

27

Outdoor unit does not operate at all, or stops immediately due to overcurrent.

FF

Check of current-limiting resistor

When the current-limiting resistor is open, the rush current limiting relay (X64) may not work properly.

Is the resistance of current-limiting
resistor (R64A or R64B) on the
noise filter P.C. board normal?
(Normal resistance : 10' i5%)

Open

Replace the power P.C. board.

● Check other electric parts in the main circuit together in the case that the current-limiting resistor is defective.

Not
open

Turn ON the power
supply and press
EMERGENCY
OPERATION switch.

Does LED on the outdoor
electronic control P.C. board
light up?

Yes

Does the rush current
limiting relay (X64) work
properly?

No

Replace the noise filter P.C. board.

• When cooling, heat exchanger of non-operating indoor unit frosts.

• When heating, non-operating indoor unit gets warm.

GG

Check of LEV

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

Replace the noise filter P.C.

No

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

Replace the outdoor

Yes

electronic control P.C.
board or power P.C. board
or the compressor.

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

No

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

No

Replace the LEV coil.

Yes

Yes

Normal

Replace the outdoor electronic
control P.C. board.

28

• When unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch.

Is there rated voltage in
the power supply?

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

W1. Miswiring may damage indoor electronic control
P.C. board during the operation.
Be sure to confirm the wiring is correct before the
operation starts.
W3.Be sure to check this within 3 minutes after turning
ON. After 3 minutes, LED blinks 6 times. Even when
the outdoor electronic control P.C. board is normal,
LED blinks 6 times after 3 minutes.

(Lighted
or not
lighted)

No

Yes

No

Yes

Yes

No

Yes

No

Yes

W2 Be careful to the residual
voltage of smoothing capacitor.

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

No

No

Yes

No

Yes

Yes

Yes

No

Yes

Refer to indoor unit service manual.

Lighted Blinking

Turn OFF the power supply.

Turn ON the power supply.

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

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

Press EMERGENCY OPERATION switch once.

Check the power
supply.

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.
W1

B

Turn ON the power supply.

Check the wiring.

Correct them.

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 20V DC
between outdoor terminal block S2
and S3? <Confirmation of serial
signal>

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

Replace the indoor electronic control P.C. board.

Replace the outdoor electronic
control P.C. board. W2

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?

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?

No

Replace the
indoor/outdoor
connecting wire.

Replace the
indoor/outdoor
connecting wire.

Is serial signal
error indicated
6 minutes later?

Yes

No

· Turn OFF inverter-controlled lighting
equipment.

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

· Press EMERGENCY OPERATION
switch.

B

· Reinstall
either the
unit or the
light each
other away.

· Attach a filter
on remote
control
receiving
section of
the indoor
unit.

A

Is serial signal error indicated 6 minutes later?

No

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

W3

Outdoor electronic control P.C. board

(Parts side)

LED2

LED1

Indoor unit does not operate.

• When OPERATION INDICATOR lamp flashes ON and OFF every 0.5-second.
Outdoor unit doesn’t operate.

HH

How to check miswiring and serial signal error (when outdoor unit does not work)

29

II

Electromagnetic noise enters into TV sets or radios

Is the unit earthed?

Yes

Is the distance between the
antennas and the indoor
unit within 3m, or is the
distance between the
antennas and the outdoor
unit within 3m?

No

Is the distance between the
TV sets or radios and the
indoor unit within 1m, or is
the distance between the TV
sets or radios and the
outdoor unit within 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

Yes

Yes

Yes

Yes

Earth 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.

No

Even if all of the above conditions are fulfilled, the electromagnetic noise may enter, depending on
the electric field strength or the installation condition (combination of specific 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 field intensity of the broadcast station affected by the electromagnetic noise

6.Presence or absence of amplifier 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.

30

-20-100 10203040

100

90
80
70
60
50
40
30
20
10

0

0 1020304050607080

200
180
160
140
120
100

80
60
40
20

0

Resistance (k")

Resistance (k")

Temperature (°C)

Temperature (°C)

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

Fin temperature thermistor (RT64)

0 102030405060708090100110120

700
600
500
400
300
200
100

0

Resistance (k')

Temperature (;)

Discharge temperature thermistor (RT62)

10-7. Test point diagram and voltage

1. Outdoor electronic control P.C. board

MUZ-GB50VA

(

To fan

motor

(

CN931

5V DC

CN932

20-90V AC

(

pulse wave

(

5V

Discharge temperature

Defrost thermistor (RT61)

(

(

GND

CN661

CN663

(

CN701

Signal transmission

(–)

Ambient temperature

thermistor (RT65)

(

thermistor (RT62)

Outdoor heat exchanger

temperature thermistor (RT68)

(

CN702

Signal reception

(From power board)

(

(To power board)

5V DC pulse wave

(+)

(+)

(–)

GND

DC

12V

(

CN781

5V DC pulse wave

(+)

Rush current relay

15V

15V

GND (power board)

(–)R.V. coil

(–)

LEV

(+)

(

(

CN795

12V DC

(–)

(

pulse wave

LED 1
LED 2

CN801

325V DC

~

370V DC

Input

F801

FUSE

250V 3.15A

31

CN601

(

230V AC
Input

(

Serial signal
Room A

5~10V DC

2. Noise filter P.C. board

MUZ-GB50VA

CN901
To electronic
control
P.C. board

{

CN912
R.V. coil
230V AC

230V AC
Output

{

CN902
To power
board

CN903
To power
board

{

230V AC
Input

{

230V AC
Output

NR64 VARISTOR

F64 FUSE
250V 2A

F911 FUSE
250V 1A

32

3. Outdoor power board

MUZ-GB50VA

Connect to the compressor
Voltage among phases: 5V to
180V

325-370V DC
Output

(+)

(–)

(Red)

1

3

(White)

Connect to the earth

CN2
Connect to the controller board
(+)1-5(–): Signal transmission
(To electronic control P.C. board)

(+)2-5(–): Zero cross signal
(+)6-5(–): 15V

(+)7-5(–): 15V
CN3

Fin temperature thermistor RT64
Signal reception (From

)

electronic control P.C. board)
5V DC pulse wave

CN5
Primary current detection
(Connect to the noise filter)

Connect to the compressor
Voltage among phases: 5V to 180V

5V DC pulse wave

3-4 : Not used

325-370V DC
Output

(+)

(–)

(Red)

1

3
(White)

33

Connect to the earth

CN2
Connect to the controller board
(+)1-5(–): Signal transmission
(To electronic control P.C. board)

(+)2-5(–): Zero cross signal

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

CN3
Fin temperature thermistor RT64

Signal reception (From

)

electronic control P.C. board)
5V DC pulse wave

CN5
Primary current detection
(Connect to the noise filter)

5V DC pulse wave

11

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

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

1Slide the sleeve.
2Pull the terminal while

pushing the locking
lever.

1Hold the sleeve, and
pull out the terminal
slowly.

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.

<"Terminal with locking mechanism" Detaching points>

Connector

Sleeve

Locking lever

DISASSEMBLY INSTRUCTIONS

MUZ-GB50VA

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) Disconnect the power supply and indoor/ outdoor

connecting wire.
(8) Remove the screws of the cabinet.
(9) Remove the cabinet.
(10)

Remove the screws of the back panel.

(11)

Remove the back panel.

Photo 1

Screws
of the
cabinet

Photo 3

Screw of the motor support

Screws
of the
back
panel

Photo 2

Screws
of the
cabinet

Screw of the top panel

Screws of the cabinet

Screw of the service panel

Screws
of the
top
panel

Set screws of the back panel

34

Screw
of the
valve
cover

OPERATING PROCEDURE

PHOTOS

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

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

(Refer to 1.)
(2) Remove the back panel.(Refer to 1.)
(3) Disconnect the following connectors;

<Electronic control P.C. board>

CN931 and CN932 (Fan motor)

CN795 (LEV)

CN661 (Discharge temperature thermistor, defrost

thermistor and outdoor heat exchanger

temperature thermistor)
CN663 (Ambient temperature thermistor)
<Noise filter P.C. board>
CN912 (R.V. coil)

(4) Remove the compressor connector.
(5) Remove the screws fixing the relay panel.
(6) Remove the inverter assembly.
(7) Disconnect all connectors and lead wires on the electronic

control P.C. board.

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

assembly.

(9) Remove the screws fixing the power board assembly.
(10)

Disconnect all connectors and lead wires on the power
board.

(11)

Remove the power board from the inverter assembly.

(12)

Disconnect all connectors and lead wires on the noise filter

P.C. board.

(13)

Remove the noise filter P.C. board from the inverter
assembly.

Photo 4

Screws of the power board assembly

Screws of the relay panel

3. Removing R.V. coil

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

(Refer to 1.)

(2) Remove the back panel. (Refer to 1.)
(3) Disconnect the following connectors;

<Noise filter P.C. board>
CN912 (R.V. coil)

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

35

OPERATING PROCEDURE

PHOTOS

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

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

(Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Disconnect the following connectors;

<Electronic control P.C. board>
CN661 (Discharge temperature thermistor, defrost

thermistor and outdoor heat exchanger

temperature thermistor)

CN663 (Ambient temperature thermistor)
(4) Pull out the defrost thermistor from its holder. (Photo 6)
(5) Pull out the discharge temperature thermistor from its

holder. (Photo 5)

(6) Pull out the outdoor heat exchanger temperature thermistor

from its holder. (Photo 6)

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

(Photo 6)

Photo 5

Discharge temperature thermistor

Photo 6

Outdoor heat exchanger
temperature thermistor

Ambient
temperature
thermistor

5. Removing outdoor fan motor

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

(Refer to 1.)
(2) Remove the back panel. (Refer to 1.)
(3) Disconnect the following connectors;

<Electronic control P.C. board>

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

36

Photo 7

Propeller

Defrost
thermistor

Screws of the outdoor fan motor

OPERATING PROCEDURE

PHOTOS

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) Recover gas from the refrigerant circuit.

NOTE: Recover gas from the pipes until the pressure

gauge shows 0 kg/cm

(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)

2

(0 MPa).

Photo 8

Welded parts of 4-way valve

Photo 9

R.V. coil

7. Removing the reactor

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

Welded part
of the dis­charge pipe

Welded part
of the suction
pipe

Photo 10

37

Screws of the reactor

12

RoHS PARTS LIST (RoHS compliant)

MUZ-GB50VA
12-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND

FUNCTIONAL PARTS

25
24

2829

27

1

2
3
4

5

6
7

8

26

23

22

21
20
19

18

16

15

38

10

13

14

17

129 11

MUZ-GB50VA
12-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND

FUNCTIONAL PARTS

Part numbers that are circled are not shown in the illustration.

No.

1
2
3
4
5
6
7
8
9

10
11

12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35

Part No.

RoHS

E12 819 297

G

E12 851 630

G

E12 938 301

G

E12 851 501

G

E12 851 290

G

E12 819 232

G

E12 819 009

G

E12 819 521

G

E12 C34 506

G

E12 939 900

G

E12 C06 900

G

E12 851 661

G

E12 821 662

G

E12 851 640

G

E12 851 493

G

E12 935 490

G

E12 891 961

G

E12 819 650

G

E12 819 245

G

E12 C95 450

G

E12 935 374

G

E12 823 375

G

E12 A87 337

G

E12 935 444

G

E12 935 309

G

E12 851 308

G

E12 935 440

G

E12 819 233

G

E12 817 009

G

E12 851 515

G

E12 127 382

G

E12 737 382

G

E12 935 385

G

E12 851 936

G

E12 853 299

G

E12 861 936

G

Part Name

TOP PANEL
OUTDOOR HEAT EXCHANGER
OUTDOOR FAN MOTOR
PROPELLER
BASE
CABINET
HANDLE
FAN GUARD
COMPRESSOR RUBBER SET
COMPRESSOR
COMPRESSOR
STOP VALVE(GAS)
STOP VALVE(LIQUID)
EXPANSION VALVE
EXPANSION VALVE COIL
R.V. COIL
4-WAY VALVE
VALVE COVER
SERVICE PANEL
OUTDOOR ELECTRONIC CONTROL P.C. BOARD
TERMINAL BLOCK
TERMINAL BLOCK
REACTOR
NOISE FILTER P.C. BOARD
AMBIENT TEMPERATURE THERMISTOR
THERMISTOR SET
POWER BOARD
BACK PANEL(OUT)
HANDLE
MOTOR SUPPORT
FUSE
FUSE
FUSE & VARISTOR

CAPILLARY TUBE(TAPER PIPE)
OIL SEPARATOR
CAPILLARY TUBE

Symbol

in Wiring

Diagram

MF

MC
MC

LEV

21S4

TB1
TB2

L

RT65

RT61,RT62,RT68

F801
F911

F64,NR64

Q'ty/unit

MUZ-GB50VA -

E1 E2

1
1
1
1
1
1
1
1
3
1

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1

Remarks

1
1
1

RC0J60-

1
1
1
1
1
3

3RUBBERS/SET
SNB130FLDH1

1
1
1

SNB130FLEH1

{12.7
{6.35

1
1
1
1
1
1
1
1
1

3P
3P

1
1
1

DEFROST, DISCHARGE
OUTDOOR HEAT EXCHANGER

1
1

Including heat sink and RT64

1
1
1
1
1
1
1

T3.15AL250V
T1AL250V
T2AL250V

{3.6x{2.4x50
1
1

{1.8x{0.6x1000

39

MUZ-GB50VA

Symbol

in Wiring

Diagram

Q'ty/unit

Remarks

Part No.

No.

Part Name

MUZ-GB50VA -

E1 E2

E12 817 704
E12 444 705

1
2

DRAIN SOCKET
DRAIN CAP

[33

1
2

1
2

G
G

RoHS

12-2. ACCESSORY

1

2

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

CC

Copyright 2006 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Sep. 2007. No. OB455 REVISED EDITION-D 6
Distributed in Jun. 2007. No. OB455 REVISED EDITION-C 6
Distributed in Apr. 2007. No. OB455 REVISED EDITION-B 6
Distributed in Aug. 2006. No. OB455 REVISED EDITION-A 6
Distributed in Mar. 2006. No. OB455 6
Made in Japan

New publication, effective Sep. 2007
Specifications subject to change without notice.