OUTDOOR UNIT - MyLinkDrive · MUZ-GC25NA MUZ-GC35NA 4 WIRING DIAGRAM. 10 MUZ-GC50NA-C1...

SERVICE MANUAL

CONTENTS1. PART NAMES AND FUNCTIONS· ···················· 32. SPECIFICATION ················································ 43. OUTLINES AND DIMENSIONS ························ 84. WIRING DIAGRAM ············································ 95. REFRIGERANT SYSTEM DIAGRAM ············· 146. PERFORMANCE CURVES ····························· 187. ACTUATOR CONTROL ··································· 238. SERVICE FUNCTIONS ··································· 249. TROUBLESHOOTING ····································· 24

10. DISASSEMBLY INSTRUCTIONS ···················· 54

Models

SPLIT-TYPE AIR CONDITIONERS

MUZ-GC25NA - C1

MUZ-GC35NA - C1

MUZ-GC35NA - C2

MUZ-GC50NA - C1

MUZ-GC50NA - C2

MUZ-GC60NA - C1

MUZ-GC60NA - C2

MUZ-GC71NA - C1

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

HFCutilized

R410A

No. OBH482REVISED EDITION-C

OUTDOOR UNIT

Indoor unit service manualMSZ-GC•NA Series (OBH481)

MUZ-GC25/35NA PARTS CATALOG (OBB482)

Please void OBH482 REVISED EDITION-B.

Revision C:• MUZ-GC35NA - C2 has been added.

2

Revision A: • MUZ-GC60NA - C2 has been added.

MUZ-GC60NA - C1 → MUZ-GC60NA - C2

1. Compressor has been changed. (SNB130FLDH1 → SNB130FGBH)2. Outdoor electronic control P.C. board has been changed.3. Refrigerant circuit has been changed.


1. Compressor has been changed. (SNB130FLDH1 → SNB130FGBH)2. Outdoor electrical parts have been changed.3. Refrigerant circuit has been changed.


1. Outdoor electrical parts have been changed.2. Compressor has been changed. (KNB073FGDH → KNB073FGDHC)

Revision B: • MUZ-GC50NA - C2 has been added.

Revision C: • MUZ-GC35NA - C2 has been added.

3

Air outlet

Drain outlet

Piping

Drain hose

Air inlet

MUZ-GC25NA MUZ-GC35NA

Piping

Air outlet

Air inlet(back and side)

Drain hose

Drain outlet

MUZ-GC50NA MUZ-GC60NA MUZ-GC71NA

1 PART NAMES AND FUNCTIONS

4

Outdoor model MUZ-GC25NA MUZ-GC35NAFunction Cooling Heating Cooling Heating

Power supply Single phase 220 - 230 V, 60 HzCapacity

Rated frequency (Min.-Max.) kW 2.5 (0.9-3.0) 3.2 (0.9-4.5) 3.2 (1.0-3.7) 3.6 (0.9-4.8)

Elec

trica

l dat

a Power outlet A 10Running current (Total) A 3.88 4.44 5.26 5.14Power input (Total) W 735 860 1,065 1,040Power factor (Total) % 86 88 92 92Starting current 1 (Total) A 4.44 5.26

Coeffi cient of performance (C.O.P) 1 (Total) 3.40 3.72 3.00 3.46

CompressorModel KNB065FDTHC C1 KNB073FGDH

C2 KNB073FGDHCOutput W 500 550Current 1 A 3.35 3.91 4.73 4.61

Fan motor Model RA6V21-BD Current A 0.29

Dimensions W×H×D mm 684 × 540 × 255 Weight kg 26

Spe

cial

rem

arks

Dehumidifi cation /h 1.4 — 2 — Air fl ow (High/Low) m3/h 1,860Sound level dB 47 48 48 49Fan speed rpm 830Fan speed regulator 1Refrigerant fi lling capacity (R410A) kg 0.75

Refrigeration oil (Model) NEO22 NOTE : Test conditions are based on CNS 14464, ISO 5151. Cooling : Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C Outdoor Dry-bulb temperature 35°C Heating : Indoor Dry-bulb temperature 20°C Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C 1 Measured under rated operating frequency.

2 SPECIFICATION

5

Outdoor model MUZ-GC50NA MUZ-GC60NA MUZ-GC71NAFunction Cooling Heating Cooling Heating Cooling Heating

Power supply Single phase 220 - 230 V, 60 HzCapacity Rated frequency

(Min.-Max.) kW 5.0 (1.2-5.8) 5.6 (1.2-7.8) 6.0 (1.2-6.7) 6.8 (1.2-8.1) 7.1 (1.4-8.3) 8.1 (1.4-9.6)

Ele

ctric

al d

ata

Power outlet A 20

Running current 1 (Total) AC1 8.26 8.22

C1 10.33 9.72 12.03 11.96C2 8.08 C2 10.05

Power input 1 (Total) WC1 1,800 1,790

C1 2,160 2,010 2,540 2,500C2 1,760 C2 2,100

Power factor 1 (Total) % 99 99 95 94 96 95

Starting current 1 (Total) AC1 8.26 C1 10.33 12.03C2 8.22 C2 10.05

Coeffi cient of performance (C.O.P) 1 (Total)

C1 2.78 3.13C1 2.78 3.38 2.80 3.24

C2 2.84 C2 2.86

CompressorModel

C1 SNB130FLDH1 C1 SNB130FLDH1 TNB220FMCHTC2 SNB130FGBH C2 SNB130FGBH

Output W 850 1,300Current 1 A 7.59 7.55 9.41 8.80 11.11 11.04

Fan motor Model RC0J60-AACurrent 1 A 0.32

Dimensions W×H×D mm 840 × 850 × 330Weight kg 53 58

Spe

cial

rem

arks

Dehumidifi cation /h 1.7 — 1.6 — 2.5 —Air fl ow 1 m3/h 2,940/1,650 2,940/2,210 2,940/1,650 2,940/2,210 2,940/1,650 2,940/2,210Sound level 1 (High/Low) dB (A) 52/51 55/53 53/51 55/53 53/51 55/53Fan speed (High/Low) rpm 800/480 800/620 800/480 800/620 800/480 800/620Fan speed regulator 2Refrigerant fi lling capacity (R410A) kg 1.5 1.8 2

Refrigeration oil (Model) NEO22NOTE : Test conditions are based on CNS 14464, ISO 5151. Cooling : Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C Outdoor Dry-bulb temperature 35°C Heating : Indoor Dry-bulb temperature 20°C Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C 1 Measured under rated operating frequency.

6

Specifi cations and rating conditions of main electric parts Model

Item MUZ-GC25NA MUZ-GC35NA

Current transformer (CT) 20 A Smoothing capacitor (C61, C62) 500 μF 420 V Diode module (DB61) 15 A 600 V

(DB65) 10 A 600 V Fuse (F61) 250 V 20 A

(F701, F801) 250 V 3.15 A Intelligent power module (IPM) 10 A 600 V Expansion valve coil (LEV) DC 12 V Reactor (L61) 18 mH 7 A

Current-detecting resistor (R61) 45 mΩ 5 W

(R825) 25 mΩ 5 W Current-limiting PTC thermistor (PTC64) 33 Ω Terminal block (TB1,TB2) 3 P Relay (X61) 5 A 250 V

(X63) 3 A 250 V (X64) 20 A 250 V

R.V. coil (21S4) AC 220 - 240 V Outdoor fan motor thermal fuse Open 126°C (RA6V21-BD) IGBT (TR821) 30 A 600 V

Model

Item MUZ-GC50NA - C1 MUZ-GC60NA MUZ-GC71NA

Current transformer (CT1,2) ETQ19Z68AY(CT61) ETQ19Z53AY

Smoothing capacitor (CB1,2,3) 560 μF 450 VFuse (F64) 250 V 2 A

(F801) 250 V 3.15 A (F911) 250 V 1 A

Expansion valve coil (LEV) DC 12 V Intelligent power module (IPM) PS21244-A

(HC930) PS21661-RZHigh pressure switch (HPS) – ACB-DB156 (for C2 ) ACB-DB156Reactor (L) 340 μH 20 APower factor controller (PFC) PS51259-AResistor (R64A,B) 10 Ω 10 W

(R937A,B) 1.1 Ω 2 W 2%(RS1 - 4) 0.04 Ω 7 W

Solenoid coil relay (SSR61) TLP3506Terminal block (TB1) 3 P

(TB2) 3 PRelay (X64) G4AR.V. coil (21S4) AC 220 - 240 V

7

Model

Item MUZ-GC50NA- C2

Current transformer (CT) 20 A(CT761, CT781) 15 A

Smoothing capacitor (C61, C62, C63) 620 μF 420 V

Diode module (DB61) 25 A 600 V(DB65) 25 A 600 V

Fuse (F61) T20AL250V(F701, F801, F901) T3.15AL250V

Intelligent power module (IPM) 20 A 600 VExpansion valve coil (LEV) DC 12 VReactor (L61) 23.0 mH

Current-detecting resistor(R61, R62) 180 mΩ 5 W (2 elements)

(R825) 25 mΩ 5 W(R937A, R937B) 1.1 Ω 2 W

Current-limiting PTC thermistor (PTC64, PTC65) 33 ΩTerminal block (TB1, TB2) 3 P

Relay (X63) 3 A 250 V(X64) 20 A 250 V

R.V. coil (21S4) AC 220 - 240 VIGBT (TR821) 30 A 600 V

8


30°

35°

155

90

198

40

515299

66

345133

0

360

850

430

50016980

121840

Open as a rule500 mm or more ifthe front and bothsides are open

100 mm or more 200 mm or more if there are obstaclesto both sides

Open as a rule500 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 jointRefrigerant pipe(flared) ø12.7 (MUZ-GC50)

ø15.88 (MUZ-GC60/71)

Liquid refrigerant pipe jointRefrigerant pipe(flared) ø6.35 (MUZ-GC50/60)

ø9.52 (MUZ-GC71)

REQUIRED SPACE

Drain holes ø33

20.814

4.6

89.6

255

145.5

Service panel

Service port

Air out

Liquid refrigerant pipe jointRefrigerant pipe (flared) ø6.35

Gas refrigerant pipe jointRefrigerant pipe (flared) ø9.52

43°

40°

REQUIRED SPACE Basically open 100 mm or more without any obstruction in front and on both sides of the unit.

350 mm or more100 mm or more

100 mm or more

100 mm or more

Open two sides of left, right, or rear side.

Drain hole ø33

Air in

Air in

381.5

Bolt

pitc

h fo

r in

stal

latio

n26

4~28

0

300

540

270

10

47.5

22.5

17.5

243

Bolt pitch for installation500

684

61

105

Handle

2 holes 10×16

40

Unit : mmMUZ-GC25NA MUZ-GC35NA

3 OUTLINES AND DIMENSIONS

9


4 WIRING DIAGRAM

10

MUZ-GC50NA- C1 MUZ-GC60NA- C1

11

MUZ-GC50NA- C2

12

MUZ-GC60NA- C2

13

MUZ-GC71NA

14

OutdoorheatexchangerFlared connection

DefrostthermistorRT61

DischargetemperaturethermistorRT62

Flared connection

Stop valve(with strainer)

Stop valve(with service port)

Capillary tubeø3.0×ø2.0×260

Refrigerant flow in cooling

Compressor

4-way valve

Refrigerant flow in heating

Refrigerant pipe ø9.52(with heat insulator)


LEVR.V. coilheating ONcooling OFF

Strainer#100

Muffler

Muffler


MUZ-GC50NA- C1

Outdoorheatexchanger

Flared connection DefrostthermistorRT61


Flared connection

Stop valve


Capillary tubeø3.6ø×2.4×50



Compressor

4-way valve





Oil separator

Strainer#100Receiver

OutdoorheatexchangertemperaturethermistorRT68

Strainer#100

Strainer#100 Ambient

temperaturethermistorRT65

Unit : mm

Unit : mm

5 REFRIGERANT SYSTEM DIAGRAM

15

MUZ-GC60NA- C1


Flared connection



Flared connection

Stop valve




Compressor

4-way valve





Muffler#100


Outdoor heat exchangertemperaturethermistorRT68

AmbienttemperaturethermistorRT65

Strainer#100

MUZ-GC50NA - C2


Flared connection



Flared connection

Stop valve(with strainer)


Capillary tube ø3.6ø×2.4×50


Compressor

4-way valve


Refrigerant pipe ø12.7 (with heat insulator)


LEV R.V. coil OFF ON

Muffler#100

Receiver



Strainer#100

Unit : mm

Unit : mm

16

MUZ-GC71NA


Flared connection DefrostthermistorRT61


Flared connection

Stop valve





Compressor

4-way valve





Oil separator High-pressureswitch


OutdoorheatexchangertemperaturethermistorRT68

Strainer#100

Strainer#100 Ambient

temperaturethermistorRT65

MUZ-GC60NA- C2 Unit : mm


Flared connection



Flared connection

Stop valve




Compressor

4-way valve





Muffler#100




Strainer#100

High-pressureswitch

Unit : mm

17

Max. Length A

Max. Heightdifference

B

Indoorunit

Outdoor unit

MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE

Model

Refrigerant piping : m Piping size O.D : mm

Max. Length A

Max. Height difference B Gas Liquid

MUZ-GC25NA MUZ-GC35NA 20 12 9.52

6.35MUZ-GC50NA 30 15

12.7MUZ-GC60NA 15.88MUZ-GC71NA 9.52

ADDITIONAL REFRIGERANT CHARGE (R410A : g)

Model Outdoor unit precharged

Refrigerant piping length (one way) 5 m 6 m 7 m 8 m 9 m 10 m 11 m 12 m 13 m 14 m 15 m 20 m

MUZ-GC25NA MUZ-GC35NA 750 0 0 0 90 120 150 180 210 240 270 300 450

Calculation : X g = 30 g/m × (Refrigerant piping length (m) – 5)


Refrigerant piping length (one way) 7 m 10 m 15 m 20 m 25 m 30 m

MUZ-GC50NA 1,5000 60 160 260 360 460

MUZ-GC60NA 1,800Calculation : X g = 20 g/m × (Refrigerant piping length (m) – 7)


Refrigerant piping length (one way) 7 m 10 m 15 m 20 m 25 m 30 m

MUZ-GC71NA 2,000 0 165 440 715 990 1,265

Calculation : X g = 55 g/m × (Refrigerant piping length (m) – 7)

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

18

MUZ-GC25NA MUZ-GC35NA MUZ-GC50NA MUZ-GC60NA MUZ-GC71NAThe standard specifications apply only to the operation of the air conditioner under normal conditions. Since operating condi-tions 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 ~ 253V, 60Hz(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.

}}

Cooling

Heating

How to measure the indoor air wet-bulb/dry-bulb temperature difference1. 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.

INDOOR UNIT OUTDOOR UNIT

Wet and dry-bulbthermometers

Wet and dry-bulbthermometers

8.7

8.0

7.3

6.6

5.9

5.3

MU

Z-G

C60

NA

Indo

or a

ir W

et-b

ulb

tem

pera

ture

diffe

renc

e (°

C)

MU

Z-G

C50

NA

8.7

8.0

7.3

6.6

5.9

5.3

MU

Z-G

C35

NA

9.0

8.3

7.5

6.8

6.1

5.4

MU

Z-G

C25

NA

7.5

6.8

6.3

5.7

5.1

4.5

MU

Z-G

C71

NA Outdoor intake air Dry-bulb temperature (°C) Outdoor intake air Dry-bulb temperature (°C)

10.7

9.8

8.9

8.0

7.2

6.4

Indoor intake air Wet-bulb temperature (°C) Indoor intake air Wet-bulb temperature (°C)

Cooling capacity (at Rated frequency) Total inpup (Cooling : at Rated frequency)6-1. CAPACITY AND INPUT CURVES

6 PERFORMANCE CURVES

19

20.919.317.716.114.512.911.39.7

22.420.719.017.215.513.812.110.3

Indo

or a

ir D

ry-b

ulb

tem

pera

ture

diffe

renc

e (°

C)

Indoor intake air D

ry-bulb temperature (°C)

Outdoor intake air Wet-bulb temperature (°C) Outdoor intake air Wet-bulb temperature (°C)

Indoor intake air Dry-bulb temperature (°C)M

UZ-

GC

35N

A

MU

Z-G

C25

NA

24.122.320.418.516.714.813.011.1

23.421.619.818.016.214.412.610.8

MU

Z-G

C60

NA

MU

Z-G

C50

NA

27.925.723.621.419.317.215.012.9

MU

Z-G

C71

NA

Heating capacity (at Rated frequency) Total inpup (Heating : at Rated frequency)

NOTE : The above broken lines are for the heating operation without any front and defrost operation.

6-2. CAPACITY AND INPUT CORRECTION BY OPERATIONAL FREQUENCY OF COMPRESSOR

The operational frequency of compressorThe operational frequency of compressor

Correction of Heating total input

The operational frequency of compressorThe operational frequency of compressor

MUZ-GC25NA

MUZ-GC35NA

Cap

acity

cor

rect

ion

fact

ors

Inpu

t cor

rect

ion

fact

ors

Inpu

t cor

rect

ion

fact

ors

Cap

acity

cor

rect

ion

fact

ors

Correction of Cooling capacity

The operational frequency of compressor

Correction of Cooling total input




Correction of Heating capacity


MUZ-GC50NA

0 50 100 150(Hz)0.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

0 50 1000.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

2.0


Cap

acity

cor

rect

ion

fact

ors



Inpu

t cor

rect

ion

fact

ors



Inpu

t cor

rect

ion

fact

ors



Cap

acity

cor

rect

ion

fact

ors

The operational frequency of compressor0 50 100 150(Hz)

0.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

2.0

0 50 100 150(Hz)0.0

0.5

1.0

1.5

2.0


Inpu

t cor

rect

ion

fact

ors


Cap

acity

cor

rect

ion

fact

ors

Correction of Heating total inputCorrection of Heating capacityC

apac

ity c

orre

ctio

n fa

ctor

s

Inpu

t cor

rect

ion

fact

ors

0 50 100 150(Hz)0.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

0 50 100 150(Hz)0.0

0.5

1.0

1.5

2.0

0 50 100 150(Hz)0.0

0.5

1.0

1.5

2.0

20

MUZ-GC71NA

Cap

acity

cor

rect

ion

fact

ors

Inpu

t cor

rect

ion

fact

ors

Inpu

t cor

rect

ion

fact

ors

Cap

acity

cor

rect

ion

fact

ors








The operational frequency of compressor0 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)

Cap

acity

cor

rect

ion

fact

ors

Inpu

t cor

rect

ion

fact

ors

Inpu

t cor

rect

ion

fact

ors

Cap

acity

cor

rect

ion

fact

ors









MUZ-GC60NA

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)

6-3. 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 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.

21

COOL operation Both indoor and outdoor unit are under the same tempera-ture/humidity condition.

Operation : TEST RUN OPERATION (refer to 6-3.)

6-4. OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT(M

Pa [G

auge

])

(MPa

[Gau

ge])

(MPa

[Gau

ge])

18 3215 2050

2560

3070 (%)

35(°C)0.2

0.4

0.6

0.8

1.0

1.2

1.4

Ambient temperature(°C) Ambient humidity(%)

18 3215 2050

2560

3070 (%)

35(°C)


18 3215 2050

2560

3070 (%)

35(°C)


18 3215 2050

2560

3070 (%)

35(°C)


18 3215 2050

2560

3070 (%)

35(°C)


18 3215 2050

2560

3070 (%)

35(°C)


MUZ-GC25NA

18 3215 2050

2560

3070 (%)

35(°C)


2

2.5

3

3.5

4(A)

(MPa

[Gau

ge])

(MPa

[Gau

ge])

0.2

18 3215 2050

2560

3070 (%)

35(°C)


2

3

4

5

6

MUZ-GC35NA


MUZ-GC71NA

MUZ-GC60NA(A)

MUZ-GC50NA

0.6

0.7

0.8

0.9

1.0

1.1

1.2MUZ-GC71NA

0.6

0.7

0.8

0.9

1.0

1.1

1.2

6

7

8

9

10

11

12

7

8

9

10

11

12

13

MUZ-GC60NA

(A)

(A)


18 3215 2050

2560

3070 (%)

35(°C)


18 3215 2050

2560

3070 (%)

35(°C)

4

5

6

7

8

0.5

0.6

0.7

0.8

0.9

1.0

(A)

2

4

6

8

10

kgf/

[G

auge

] 12

14

2

4

6

8

10

kgf/

[G

auge

] 12

14

5

6

7

8

kgf/

[G

auge

] 9

10

6

7

8

9

10

kgf/

[G

auge

] 11

12

6

7

8

9

10

kgf/

[G

auge

] 11

12

0.4

0.6

0.8

1.0

1.2

1.4

Outdoor low pressure

Outdoor unit current

NOTE : The unit of pressure has been changed to MPa on the international system of units (SI unit system). The conversion factor is : 1 (MPa [Gauge]) = 10.2 (kgf/cm2

[Gauge])

Dry-bulb temperature (°C) Relative humidity(%)20 5025 6030 70

22

Condition :

Indoor OutdoorDry bulb temperature (°C) 20.0 2 7 15 20.0Wet bulb temperature (°C) 14.5 1 6 12 14.5

Operation : TEST RUN OPERATION (refer to 6-3.)

HEAT operation

Ambient temperature(°C) Ambient temperature(°C)

MUZ-GC25NA MUZ-GC35NA (A) (A)

(A) (A)

3.0

2.5

2.0

1.5

1.0

0.5

0.02 5 10 15 20 25(°C)

4.0

3.5

3.0

2.5

2.0

1.5

1.02 5 10 15 20 25(°C)

Ambient temperature(°C)

MUZ-GC50NA6.5

6.0

5.5

5.0

4.5

4.0

3.5


MUZ-GC60NA

2 5 7 10 15 20 25(°C)


MUZ-GC71NA14.0

13.0

12.0

11.0

10.0

9.0

8.02 5 7 10 15 20 25(°C)

(A)

5 10 15 20 25(°C)4.0

5.0

6.0

7.0

8.0

2

Outdoor unit current

23

MUZ-GC25NA MUZ-GC35NA MUZ-GC50NA MUZ-GC60NA MUZ-GC71NA

7-2. R.V. COIL CONTROLHeating . . . . . . . . . . . . . . . . . ONCooling . . . . . . . . . . . . . . . . . OFFDry . . . . . . . . . . . . . . . . . . . . OFFNOTE: The 4-way valve reverses for 5 seconds right before start-up of the compressor.

ON

OFF

ON

OFF

Outdoor fanmotor

Compressor

5 seconds 15 seconds

ONOFF

Compressor

Outdoor fanmotor

R.V.coil

<MUZ-GC25/35>ONOFF

ONOFF

<COOL>5 seconds

<HEAT>5 seconds

R.V.coil

<MUZ-GC50/60/71>ONOFF

ON or OFF ON or OFF

7-1. OUTDOOR FAN MOTOR CONTROLThe 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.

7-3. RELATION BETWEEN MAIN SENSOR AND ACTUATOR<MUZ-GC25/35>

Sensor PurposeActuator

Compressor LEV Outdoor fan motor R.V. coil Indoor fan

motorDischarge temperature thermistor Protection ○ ○Indoor coil temperature thermistor

Cooling : Coil frost prevention ○Heating : High pressure protection ○

Defrost thermistorCooling : High pressure protec-tion ○ ○ ○Heating : Defrosting ○ ○ ○ ○ ○

Fin temperature thermistor Protection ○ ○<MUZ-GC50/60/71>

Sensor PurposeActuator

Compressor LEV Outdoor fan motor R.V.coil Indoor fan

motorDischarge temperature thermistor Protection ○ ○Indoor coil temperature thermistor

Cooling : Coil frost prevention ○Heating : High pressure protection ○ ○

Defrost thermistor Heating : Defrosting ○ ○ ○ ○ ○Fin temperature thermistor Protection ○ ○Ambient temperature thermistor Cooling : Low ambient temperature operation ○ ○ ○Outdoor heat exchanger temperature thermistor

Cooling : Low ambient temperature operation ○ ○ ○Cooling : High pressure protection ○ ○ ○

ACTUATOR CONTROL7

24

8-1. CHANGE IN DEFROST SETTING [MUZ-GC25/35 MUZ-GC50NA- C2 ]Changing defrosting finish temperature<JS> When the JS wire of the outdoor Inverter P.C. board is cut/soldered, the defrost finish temperature is changed. (Refer to 9-6.1.)

Jumper wire Defrost fi nish temperature (°C)MUZ-GC25/35 MUZ-GC50NA- C2

JS

Soldered(Initial setting) 5 9

None(Cut) 8 18

8-2. PRE-HEAT CONTROL SETTING [MUZ-GC25/35 MUZ-GC50NA- C2 ]PRE-HEAT CONTROLWhen moisture gets into the refrigerant cycle, it may interfere the start-up of the compressor at low outside tempera-ture. The pre-heat control prevents this interference. The pre-heat control turns ON when outside temperature is 20°C or below. When pre-heat control is turned ON, compressor is energized. (About 50 W)

<JK> When the JK wire of the inverter P.C. board is cut, pre-heat control is activated. (Refer to 9-6.1)

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

9 TROUBLESHOOTING

3. Troubleshooting procedure1) 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) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and

the components for bursting and discoloration.4) Refer to 9-2. and 9-3.

9-1. 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 servicing1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and 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.

MUZ-GC25NA MUZ-GC35NA MUZ-GC50NA MUZ-GC60NA MUZ-GC71NA

Lead wiring Housing point

8 SERVICE FUNCTIONS

25

Outline of the functionThis air conditioner can memorize the abnormal condition which has occurred once.Even though LED indication listed on the troubleshooting check table (9-3.) 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.

9-2. FAILURE MODE RECALL FUNCTION

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

Does the upper or 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 upper or left lamp of OPERATION INDICATOR lamp. 2

Indoor unit is normal.But the outdoor unit might be abnormal because there are some abnor-malities that can't be recalled with this way.Confi rm if outdoor unit is abnormal according to the detailed outdoor unit failure mode recall function. (Refer to 9-2.2)

No

Yes

The cause of abnormality cannot be found because the abnormality doesn't 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 abnormalityBefore blinking, does the upper or 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 functionRelease 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 9-2.3)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'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.

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

2. Blinking pattern when the indoor unit is abnormal:

3.Blinking pattern when the outdoor unit is abnormal:

ONOFF

BeepsRepeated cycle Repeated cycle

ONOFF

No beep BeepsRepeated cycle

2.5-second OFFBlinking at 0.5-second interval

2.5-second OFF 3-second ONBlinking at 0.5-second interval

BeepsRepeated cycle

2.5-second OFFBlinking at 0.5-second interval



Repeated cycle

Beeps

<MUZ-GC25/35/50> <MUZ-GC60/71>

26

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

2.Blinking pattern when outdoor unit is abnormal:

ONOFF





Repeated cycle

Does the upper or left lamp of OPERATION INDICA-TOR 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 upper or 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 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 (9-2.3.).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 accord-ing 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" (9-2.1.). 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" men-tioned above.

NOTE: 1. 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.

27

3. Outdoor unit failure mode table MUZ-GC25/35NA

The upper lamp of OPERATION

INDICATOR lamp (Indoor unit)

Abnormal point (Failure mode / protection)

LED indication (Outdoor P.C.

board)Condition Correspondence

Indoor/outdoor unit failure mode recall

function

Outdoor unit failure mode

recall function

OFF None (Normal) — — — — —2-time fl ash 2.5 seconds OFF

Outdoor power system

—

Overcurrent protection stop is continuously performed 3 times within 1 minute after the compressor gets started.

•Reconnect connectors.•Refer to 9-5. "How to check inverter/compressor"

•Check stop valve. ○ ○

3-time fl ash 2.5 seconds OFF

Discharge temperature thermistor

1-time fl ash every 2.5 seconds

Thermistor shorts or opens during compressor running.

•Refer to 9-5. "Check of outdoor thermistors". Defective outdoor thermistors can be identifi ed by checking the blinking pattern of LED.

○ ○Defrost thermistor Fin temperature thermistor 3-time fl ash

2.5 seconds OFF P.C. board temperature thermistor



Overcurrent 11-time fl ash 2.5 seconds OFF

Large current fl ows into intelligent power module.

•Reconnect compressor connector

•Refer to 9-5. "How to check inverter/compressor"

•Check stop valve.

— ○Compressor synchronous abnormality (Compressor start-up failure protection)


Waveform of compressor current is distorted.

•Reconnect compressor connector.

•Refer to 9-5. "How to check inverter/compressor".

— ○5-time fl ash 2.5 seconds OFF

Discharge temperature

—

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

•Check refrigerant circuit and refrigerant amount.

•Refer to 9-5. "Check of LEV".


High pressure —

Temperature indoor coil thermistor exceeds 70°C in HEAT mode. Temperature defrost thermistor exceeds 70°C in COOL mode.


•Check stop valve. — ○7-time fl ash 2.5 seconds OFF

Fin temperature / P.C. board temperature


Temperature of fi n temperature thermistor on the inverter P.C. board exceeds 82 - 83°C, or temperature of P.C. board temperature thermistor on the inverter P.C. board exceeds 81 - 85°C.

•Check around outdoor unit.

•Check outdoor unit air passage.

•Refer to 9-5. "Check of outdoor fan motor".


Nonvolatile memory data — Nonvolatile memory data cannot be read properly.

•Replace the inverter P.C. board. ○ ○


Discharge temperature 5-time fl ash 2.5 seconds OFF

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

•Refer to 9-5. "Check of LEV".



DC voltage — DC voltage of inverter cannot be detected normally.

•Refer to 9-5. "How to check inverter/compressor". — ○Each phase current of

compressor 8-time fl ash 2.5 seconds OFF

Each phase current of compressor cannot be detected normally.


Overcurrent Compressor open-phase

9-time fl ash 2.5 seconds OFF 10-time fl ash 2.5 seconds OFF

Large current fl ows into intelligent power module (IPM). The open-phase operation of compressor is detected. The interphase short out occurs in the output of the intelligent power module (IPM). The compressor winding shorts out.

•Reconnect compressor connector.

•Refer to 9-5. "How to check inverter/compressor".


Stop valve (Closed valve) 14-time fl ash 2.5 seconds OFF

Closed valve is detected by compressor current.

•Check stop valve ○ ○NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (9-3.).

28

MUZ-GC50NA- C1 MUZ-GC60/71NAThe left lamp of OPERATION

INDICATOR lamp (Indoor unit)

Abnormal point(Failure mode / protection)

LED indication (Outdoor P.C. board) Condition Correspondence


functionLED 1 LED 2 OFF None (Normal) — — — — —2-time fl ash Outdoor power system Lighting Lighting 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 9-5. "How to check inverter/compressor".

• Check the stop valve. ○

3-time fl ash Discharge temperature thermistor

Lighting Once Thermistor shorts or opens during compressor running.

• Refer to 9-5. "Check of outdoor thermistors".

○Defrost thermistor 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 9-5. "Check of outdoor thermistors".

4-time fl ash Over current Once Goes out 28 A current fl ows into intelligent power module. • Reconnect compressor connector.

• Refer to 9-5. "How to check inverter/compressor."

• Check the stop valve.

—

5-time fl ash Discharge temperature Lighting Lighting Discharge temperature exceeds 116°C during operation. Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.

• Check refrigerant circuit and refrigerant amount. • Refer to 9-5. "Check of LEV". —

6-time fl ash High pressure Lighting Lighting High-pressure is detected with the high-pressure switch (HPS) during operation.


• Check the stop valve. —The outdoor heat exchanger temperature exceeds 70°C during cooling or the indoor gas pipe temperature exceeds 70°C during heating.

7-time fl ash Fin temperature 3 times Goes out The fi n temperature exceeds 87°C during operation.

• Check around outdoor unit.• Check outdoor unit air

passage.• Refer to 9-5. "Check of

outdoor fan motor".

—P.C. board temperature 4 times Goes out The P.C. board temperature exceeds 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 9-5. "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 39°C for more than 20 minutes.

• Check refrigerant circuit and refrigerant amount.

• Refer to 9-5. "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. ○

Converter 5 times Goes out A failure is detected in the operation of the converter during operation.

• 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.

NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (9-3.).

29

MUZ-GC50NA- C2

The left lamp of OPERATION INDICATOR lamp (Indoor unit)

Abnormal point(Failure mode / protection)

LED indication(Outdoor P.C. board) Condition Correspondence


function

Outdoor unit failure mode

recall function

OFF None (Normal) — — — — —



—

Overcurrent protection stop is continuously performed 3 times within 1 minute after the compressor gets started.

Reconnect connectors.Refer to 9-5. "How to check inverter/compressor".Check stop valve.

••

•○ ○

3-time fl ash2.5 seconds OFF



Thermistor shorts or opens during compressor running.

Refer to 9-5."Check of outdoor thermistors". Defective outdoor thermistors can be identifi ed by checking the blinking pattern of LED.

•

•

○ ○Defrost thermistor

Fin temperature thermistor 3-time fl ash2.5 seconds OFF

P.C. board temperature thermistor

4-time fl ash2.5 seconds OFF

Ambient temperature thermistor



Overcurrent 11-time fl ash 2.5 seconds OFF

Large current fl ows into intelligent power module.

Reconnect compressor connector.Refer to 9-5. "How to check inverter/compressor".Check stop valve.

•

•

•

— ○Compressor synchronous abnormality (Compressor start-up failure protection)


Waveform of compressor current is distorted.

Reconnect compressor connector.Refer to 9-5. "How to check inverter/compressor".

•

• — ○5-time fl ash 2.5 seconds OFF


—

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

Check refrigerant circuit and refrigerant amount.Refer to 9-5. "Check of LEV".

•

• — ○


High pressure

—

Temperature indoor coil thermistor exceeds 70°C in HEAT mode. Temperature defrost thermistor exceeds 70°C in COOL mode.

Check refrigerant circuit and refrigerant amount.Check stop valve.

•

•— ○


Fin temperature/ P.C. board temperature


Temperature of fi n temperature thermistor on the inverter P.C. board exceeds 75 ~ 80°C, or temperature of P.C. board temperature thermistor on the inverter P.C. board exceeds 70 ~ 75°C.

Check around outdoor unit.Check outdoor unit air passage.Refer to 9-5. "Check of outdoor fan motor".

•

•

•— ○


Outdoor fan motor—

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

Refer to 9-5. "Check of outdoor fan motor". Refer to 9-5. "Check of inverter P.C. board".

•— ○


Nonvolatile memory data 5-time fl ash 2.5 seconds OFF

Nonvolatile memory data cannot be read properly.

Replace the inverter P.C. board.

• ○ ○10-time fl ash 2.5 seconds OFF


—


Refer to 9-5. "Check of LEV".Check refrigerant circuit and refrigerant amount.

•

• — ○11-time fl ash 2.5 seconds OFF

DC voltage 8-time fl ash 2.5 seconds OFF

DC voltage of inverter cannot be detected normally.

Refer to 9-5. "How to check inverter/compressor".

•

— ○Each phase current of compressor


Each phase current of compressor cannot be detected normally.


Overcurrent Compressor open-phase


Large current fl ows into intelligent power module (IPM).The open-phase operation of compressor is detected.The interphase short out occurs in the output of the intelligent power module (IPM).The compressor winding shorts out.

Reconnect compressor connector.Refer to 9-5. "How to check inverter/compressor".

•

•

— ○


Stop valve (Closed valve) 14-time fl ash 2.5 seconds OFF

Closed valve is detected by compressor current.

Check stop valve• ○ ○NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (9-3.).

30

9-3. TROUBLESHOOTING CHECK TABLEMUZ-GC25/35NANo. Symptom LED indication Abnormal point/

Condition Condition Correspondence

1

Outdoor unit does not operate.


Outdoor power system Overcurrent protection stop is continuously performed 3 times within 1 minute after the compressor gets started.

• Reconnect connector of compressor.


• Check stop valve.

2Outdoor thermistors Discharge temperature thermistor, fi n temperature thermistor,

defrost thermistor or P.C. board temperature thermistor shorts or opens during compressor running.

• Refer to 9-5. "Check of outdoor thermistors".

3Outdoor control system Nonvolatile memory data cannot be read properly. (When the

upper lamp of OPERATION INDICATOR lamp of the indoor unit lights up or fl ashes 7-time.)

Replace inverter P.C. board.

4 6-time fl ash 2.5 seconds OFF

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

Refer to 9-5. "How to check miswiring and serial signal error.


Stop valve / Closed valve

Closed valve is detected by compressor current. • Check stop valve.


Outdoor unit (Other abnormality)

Outdoor unit is defective. Refer to 9-2.2. "Flow chart of the detailed outdoor unit failure mode recall function".

7

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


Overcurrent protection Large current fl ows into intelligent power module. • Reconnect connector of compressor.




Discharge temperature overheat protection





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

Temperature of fi n temperature thermistor on the heat sink exceeds 82 - 83°C or temperature of P.C. board temperature thermistor on the inverter P.C.board exceeds 81 - 85°C.

• Check around outdoor unit. • Check outdoor unit air passage. • Refer to 9-5. "Check of outdoor

fan motor".


High pressure protection

Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost thermistor exceeds 70°C in COOL mode.




Compressor synchronous abnormality

The waveform of compressor current is distorted. • Reconnect connector of compressor.



Each phase current of compressor

Each phase current of compressor cannot be detected normally • Refer to 9-5. "How to check inverter/compressor".


DC voltage DC voltage of inverter cannot be detected normally. • Refer to 9-5. "How to check inverter/compressor".

14 Outdoor unit operates.


Frequency drop by current protection

Current from power outlet reaches the protection current, and compressor frequency lowers.

The unit is normal, but check the following. • Check if indoor fi lters are clogged.• Check if refrigerant is short. • Check if indoor/outdoor unit air

circulation is short cycled. 15


Frequency drop by high pressure protection

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

Frequency drop by defrosting in COOL

mode

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

16


Frequency drop by discharge temperature protection

Temperature of discharge temperature thermistor exceeds 111°C, compressor frequency lowers.


• Refer to 9-5. "Check of LEV". • Refer to 9-5. "Check of outdoor

thermistors".

17Outdoor unit operates.


Low discharge temperature protection


• Refer to 9-5. "Check of LEV". • Check refrigerant circuit and

refrigerant amount.

18


PAM protection PAM: Pulse Amplitude Modulation

The overcurrent fl ows into IGBT (Insulated Gate Bipolar transistor : TR821) or when the bus-bar voltage reaches 320 V or more, PAM stops and restarts.

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

Instantaneous power voltage drop. (Short time power failure)

When the power supply voltage is high.


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

Check if the connector of the compressor is correctly connected. Refer to 9-5. "How to check inverter/compressor".

NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 9-6.1. 2. LED is lighted during normal operation.

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

Inverter P.C. board (Parts side)

LEDFlashing

ON

OFF2.5-second OFF 2.5-second OFF

0.5-second ON 0.5-second ON

31

MUZ-GC50NA- C1 MUZ-GC60/71NANo. Symptom

Indication Abnormal point /

Condition Condition CorrespondenceLED1 (Red)

LED2 (Yellow)

1

Outdoor unit does not op-erate.

Lightning Twice


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 com-pressor connecting wire.

• Refer to 9-5. "How to check in-verter/compressor".

• Check the stop valve.

2Lightning 3 times Discharge temperature

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

• Refer to 9-5. "Check of outdoor thermistor".

3

Lightning 4 times Fin temperature ther-mistor A short or open circuit is detected in the thermistor during op-

eration.


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 op-eration.



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.

Defrost thermistor 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 9-5. "How to check mis-wiring 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.

8Lightning 11 times Communication error

between P.C. boards The communication protection stop between boards is continu-ously performed twice.

• Check the connecting wire be-tween outdoor electronic control P.C. board and power board.

9Lightning 12 times

Zero cross detecting circuit

The protection stop of the zero cross detecting circuit is con-tinuously 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 Over-current is detected after 30 minutes of compressor start-up.

• Reconnect compressor connector. • Refer to 9-5. "How to check in-

verter/compressor". • Check the stop valve. • Check the power module (PAM

module). Lock protection Over-current is detected within 30 minutes of compressor start-up.

113 times Goes out Discharge temperature

protection Discharge temperature exceeds 116°C during operation and compressor stops. Compressor can restart if discharge tem-perature thermistor reads 100°C or less 3 minutes later.

• Check the amount of gas and re-frigerant circuit.


12

4 times Goes out Fin temperature protec-tion The fi n temperature exceeds 87°C during operation. • Check around outdoor unit.

• Check outdoor unit air passage.• Refer to 9-5. "Check of outdoor

fan motor".P.C. board temperature protection The P.C. board temperature exceeds 70°C during operation.

5 times Goes out High-pressure protec-tion

High-pressure is detected with the high-pressure switch (HPS) during operation.

• Check around of gas and the re-frigerant circuit.

• Check of stop valve. 13

The outdoor heat exchanger temperature exceeds 70°C during cooling or indoor gas pipe temperature exceeds 70°C during heating.

14 8 times Goes out Converter protection A failure is detected in the operation of the converter during op-eration. • Replace the power board.

15

9 times Goes out Bus-bar voltage protec-tion (1)

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

• Replace the power board. Bus-bar voltage protec-tion (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 3 times within 30 seconds after the fan gets started.

• Refer to 9-5. "Check of outdoor fan motor".

17 Lighting 8 times Current sensor protec-tion

A short or open circuit is detected in the current sensor during compressor operating. • Replace the power board.

18Lighting 11 times Communication be-

tween P.C. boards pro-tection

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

• Check the connecting wire be-tween outdoor electronic control P.C. board and power board.

19Lighting 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.


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

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

LightingLED2 LED1

ON



32

No. Symptom Indication

Abnormal point / Condition Condition Correspondence

LED1 (Red) LED2 (Yellow)

20Outdoor unit

operates. Once Lighting Primary current protection The input current exceeds 15 A. These symptoms do not mean any ab-

normality 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 circu-

lation is short cycled.

Secondary current protec-tion

The current of the compressor exceeds 15 A.

21Twice Lighting High-pressure protection The indoor gas pipe temperature exceeds 45°C during heating.

Defrosting in cooling The indoor gas pipe temperature falls 3°C or below during cooling.

22

3 times Lighting Discharge temperature protection The discharge temperature exceeds 100°C during operation.

• Check refrigerant circuit and refriger-ant amount.

• Refer to 9-5. "Check of LEV". • Refer to 9-5. "Check of outdoor

thermistors".

234 times Lighting Low discharge tempera-

ture protection The frequency of the compressor is kept 80 Hz or more and the dis-charge temperature is kept under 39°C for more than 20 minutes.

• Refer to 9-5. "Check of LEV". • Check refrigerant circuit and refriger-

ant amount.

24

5 times Lighting

Cooling high-pressure protection

The outdoor heat exchanger temperature exceeds 58°C during op-eration.

This symptom does not mean any ab-normality 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 circu-

lation is short cycled.

25Outdoor unit

operates 9 times Lighting

Inverter check mode The unit is operated with emergency operation switch. -

26Lighting Lighting

Normal - -

33

MUZ-GC50NA- C2

No. Symptom LED indication Abnormal point/ Condition Condition Correspondence

1

Outdoor unit does not oper-ate.


Outdoor power sys-tem

Overcurrent protection stop is continuously performed 3 times within 1 minute after the compressor gets started, or failure of restart of compressor has repeated 24 times.

Reconnect connector of compres-sor.Refer to 9-5. "How to check in-verter/compressor".Check stop valve.

•

•

•

2Outdoor thermistors Discharge temperature thermistor, fi n temperature thermistor,

defrost thermistor, P.C. board temperature thermistor or ambi-ent temperature thermistor shorts or opens during compressor running.

Refer to 9-5. "Check of outdoor thermistors".

•

3Outdoor control sys-tem

Nonvolatile memory data cannot be read properly.

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

Replace inverter P.C. board.•


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

Refer to 9-5. "How to check mis-wiring and serial signal error.

•


Stop valve/ Closed valve

Closed valve is detected by compressor current. Check stop valve.•


Outdoor unit(Other abnormality)

Outdoor unit is defective. Refer to 9-2.2. "Flow chart of the detailed outdoor unit failure mode recall function".

•

7

'Outdoor unit stops and restarts 3 min-utes later' is repeated.


Overcurrent protec-tion

Large current fl ows into intelligent power module. Reconnect connector of compres-sor.Refer to 9-5. "How to check in-verter/compressor".Check stop valve.

•

•

•


Discharge tempera-ture overheat protec-tion


Check refrigerant circuit and refrig-erant amount.Refer to 9-5. "Check of LEV".

•

•


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

Temperature of fi n temperature thermistor on the heat sink exceeds 75 ~ 88°C or temperature of P.C. board temperature thermistor on the inverter P.C.board exceeds 72 ~ 82°C.

Check around outdoor unit.Check outdoor unit air passage.Refer to 9-5. "Check of outdoor fan motor".

•••


High pressure pro-tection

Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost thermistor exceeds 70°C in COOL mode.

Check refrigerant circuit and refrig-erant amount.Check stop valve.

•

•


Compressor syn-chronous abnormal-ity

The waveform of compressor current is distorted. Reconnect connector of compres-sor.Refer to 9-5. "How to check in-verter/compressor".

•

•


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

Refer to 9-5. "Check of outdoor fan motor.Refer to 9-5. "Check of inverter P.C. board.

•

•


Each phase current of compressor

Each phase current of compressor cannot be detected nor-mally

Refer to 9-5. "How to check in-verter/compressor".

•


DC voltage DC voltage of inverter cannot be detected normally. Refer to 9-5. "How to check in-verter/compressor".

•

15 Outdoor unit operates.


Frequency drop by current protection

Current from power outlet reaches the protection current, and compressor frequency lowers.

The unit is normal, but check the following.Check if indoor fi lters are clogged.Check if refrigerant is short.Check if indoor/outdoor unit air cir-culation is short cycled.

•••

16


Frequency drop by high pressure pro-tection

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

Frequency drop by defrosting in COOL mode

Indoor coil thermistor reads 8°C or less in COOL mode, com-pressor frequency lowers.

17


Frequency drop by discharge tempera-ture protection

Temperature of discharge temperature thermistor exceeds 111°C, compressor frequency lowers.

Check refrigerant circuit and refrig-erant amount.Refer to 9-5. "Check of LEV".Refer to 9-5. "Check of outdoor thermistors".

•

••

18Outdoor unit operates.


Low discharge tem-perature protection


Refer to 9-5. "Check of LEV".Check refrigerant circuit and refrig-erant amount.

••

19


PAM protection PAM : Pulse Amplitude Modulation

The overcurrent fl ows into IGBT (Insulated Gate Bipolar tran-sistor : TR821) or when the bus-bar voltage reaches 320 V or more, PAM stops and restarts.

This is not malfunction. PAM protec-tion will be activated in the following cases;1 Instantaneous power voltage drop.

(Short time power failure)2 When the power supply voltage is

high.


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

Check if the connector of the com-pressor is correctly connected. Refer to 9-5. "How to check in-verter/compressor".

•


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

ON



LEDFlashing →

Inverter P.C. board(Parts side)

34

9-4. TROUBLE CRITERION OF MAIN PARTSMUZ-GC25NA MUZ-GC35NA

Part name Check method and criterion Figure

Defrost thermistor (RT61) Measure the resistance with a tester.

Refer to 9-6. “Test point diagram and voltage”, 1. “Inverter P.C. board”, the chart of thermistor.

Discharge temperature thermistor (RT62)

Fin temperature thermistor (RT64)

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

Refer to 9-6. “Test point diagram and voltage”, 1. “Inverter P.C. board”, the chart of thermistor.

Compressor (MC)

Measure the resistance between terminals using a tester.(Winding temperature : -20 ~ 40°C)

Normal

GC25 GC35

U-VU-WV-W

1.58 ~ 2.03 Ω 1.43 ~ 1.84 Ω

Outdoor fan motor (MF)INNER FUSE126 +2

-2 °C CUT OFF

Measure the resistance between lead wires using a tester.(Part temperature : -20 ~ 40°C)

Color of the lead wire NormalWHT – BLK 212 ~ 272 ΩBLK – RED 234 ~ 300 Ω

R. V. coil (21S4)

Measure the resistance using a tester.(Part temperature : -20 ~ 40°C)

Normal

1.26 ~ 1.62 kΩ

Expansion valve coil (LEV)


Color of lead wire NormalWHT – RED

38 ~ 50 ΩRED – ORNYLW – BRNBRN – BLU

2 3W

UV

1

WHT RED BLK

WHTREDBLK

FUSE

LEVWHTREDORN

YLW

BRN

BLU

35

MUZ-GC50NA MUZ-GC60NA MUZ-GC71NAPart name Check method and criterion Figure

Defrost thermistor (RT61)

Ambient temperature ther-mistor (RT65)

Outdoor heat exchanger tem-perature thermistor(RT68)

Measure the resistance with a tester.

Refer to 9-6. "Test point diagram and voltage", 1. "Inverter P.C. board" or 2. "Outdoor electronic control P.C. board”, the chart of thermistor.

Discharge temperaturethermistor(RT62)

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

Refer to 9-6. "Test point diagram and voltage", 1. "Inverter P.C. board" or 2. "Outdoor electronic control P.C. board", the chart of thermistor.

Fin temperaturethermistor (RT64)

Compressor (MC)

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

NormalGC50/60NA- C1 GC50/60NA- C2 GC71

0.40 ~ 0.49 Ω 0.86 ~ 1.06 Ω 1.29 ~ 1.49 Ω

Outdoor fan motor (MF)

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

Color of lead wire NormalRED – BLK

13.4 ~ 16.4 ΩBLK – WHTWHT – RED

R. V. coil

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

NormalGC50NA- C2 GC60NA- C2 Other models

1.32 ~ 1.62 kΩ 2.6 ~ 3.3 kΩ

Linear expansion valve


Color of lead wire NormalWHT – RED

37.4 ~ 53.9 ΩRED – ORNYLW – BRNBRN – BLU

High pressure switch (HPS) GC60NA- C2

GC71NA

Pressure (MPa) Normal3.7 ± 0.15 Close

4.8+0.05 -0.1 Open

W

UVWHT

RED

BLK

LEV

WHT

RED

YLW BRN

ORN

BLU

URED

WHT

BLK

V

W

(W)

(V)

(U)

36

Check the compres-sor.

Check the voltage between terminals.

Disconnect the connector (CN61) between compressor and the intel-ligent power module (IPM).


See 9-5. “Check of compressor” .

No

See 9-5. “Check of open phase” .

Yes

Are the voltages balanced?

9-5. TROUBLESHOOTING FLOW

MUZ-GC25/35NA MUZ-GC50NA- C2

A How to check inverter/compressor

MUZ-GC50NA- C1 MUZ-GC60/71NA

Measure the voltage between each lead wire lead-ing to the compressor.U (BLK) - V (WHT)V (WHT) - W (RED)W (RED) - U (BLK)Is voltage output on right table?

Yes

No

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

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.)

Is output balanced?Yes

No

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

YesNo 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 lock60 seconds to 5 minutes: refrigerant circuit defective5 minutes or more: normal

37

B Check of open phase


● With the connector between the compressor and the intelligent power module disconnected, activate the inverter and check if the inverter is normal by measuring the balance of voltage between the terminals.

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

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

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

NOTE: 1. Output voltage varies according to power supply voltage. 2. Measure the voltage by analog type tester. 3. During this check, LED of inverter P.C. board fl ashes 9 times. (Refer to 9-6.1.)

Measure AC voltage between the lead wires at 3 points.

C Check of compressor


Refer to 9-5. “Check of compressor operation time”. Does the compressor operate continuously?

OK.

No

Yes

Refer to 9-5. “Check of compressor winding”. Is the compressor normal? Replace the compressor.No

Yes

Refer to 9-5. "Check of compressor start failure".

MUZ-GC25/35NA● Disconnect the connector (CN61) between the compressor and intelligent power module, and measure the resistance be-

tween the compressor terminals.<<Measurement point>> At 3 points BLK-WHT BLK-RED WHT-RED<<Judgement>> Refer to 9-4. 0[Ω] ················Abnormal [short] Infinite[Ω] ·······Abnormal [open]

NOTE: Be sure to zero the ohmmeter before measurement.

Measure the resistance between the lead wires at 3 points.

D Check of compressor winding

38

E Check of compressor operation time


● Connect the compressor and activate the inverter. Then measure the time until the inverter stops due to over current.

<<Operation method>> Start heating or cooling operation by pressing EMERGENCY

OPERATION switch on the indoor unit. (TEST RUN OPERATION : Refer to 6-3.)<<Measurement>> Measure the time from the start of outdoor fan running to the

stop of compressor due to overcurrent.

Compressor starts

Abnormal(IPM failure)(Compressor winding short)Abnormal(Compressor lock out)(Starting defect)

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

Abnormal(Refrigerant circuit defect)(Closed valve)

Normal

0 second

1 second

2 seconds

10 seconds

10 minutes

<<Judgement>>

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 8-2. "PRE-HEAT CONTROL SETTING")

No

Yes

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

Check the refrigerant circuit.Check the stop valve.Yes

No

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

Heating part

Confi rm that 1~4 is normal.•Electrical circuit check

Contact of the compressor connector (including CN61)Output voltage of inverter P.C. board and balance of them (See 9-5. )Direct current voltage between DB61(+) and (-) on the inverter P.C.boardVoltage between outdoor terminal block S1-S2

1.2.3.4.


39


Thermistor Symbol Connector, Pin No. Board Defrost RT61 Between CN641 pin1 and pin2

Inverter P.C. boardDischarge temperature RT62 Between CN641 pin3 and pin4 Fin temperature RT64 Between CN642 pin1 and pin2 Ambient temperature (GC50) RT65 Between CN643 pin1 and pin2 Outdoor heat exchanger temperature (GC50) RT68 Between CN644 pin1 and pin3

MUZ-GC50NA- C1 MUZ-GC60/71NAThermistor Symbol Connector, Pin No. Board

Defrost RT61 Between CN661 pin 1 and pin 2 Outdoor electronic control P.C. board

Discharge temperature RT62 Between CN661 pin 3 and pin 4 Outdoor heat exchanger temperature RT68 Between CN661 pin 7 and pin 8 Ambient temperature RT65 Between CN663 pin 1 and pin 2 Fin temperature RT64 Between CN3 pin 1 and pin 2 Outdoor power board

G Check of outdoor thermistors

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

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

No

No

Is the thermistor normal? (Refer to 9-6.1. or 9-6.2.)

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

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

OK.(Cause is poor contact.)

Yes

Yes

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

H Check of R.V. coil

First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 9-4. In case CN721 is not connected or R.V. coil is open, voltage is generated between the terminal pins of the connector although any signal is not being transmitted to R.V. coil.

Check if CN721 is connected.

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

NoReplace the inverterP.C. board.

Is there 220 - 230 VAC between CN721 and on the inverter P.C. board 3

minutes after the power supply is turned ON?

Yes

Replace the 4-way valve.

Disconnect connector (CN61) between the compressor and the intelligent power module.Turn ON the power supply and press EMERGENCY OPERATION switch twice (HEAT mode).

YesReplace the inverterP.C. board.

Is there 220 - 230 VAC between CN721 and on the inverter P.C. board 3

minutes after the power supply is turned ON?

No

Replace the 4-way valve.

Unit operates HEAT mode even if it is set to COOL mode.Disconnect connector (CN61) between the compressor and the intelligent power module.Turn ON the power supply and press EMERGENCY OPERATION switch once (COOL mode).


40

MUZ-GC50NA- C1 MUZ-GC60/71NAHeating operation does not work.•

Is there voltage of 220 - 230 VAC between pin1 and pin 2 at connector CN912?

YesNo

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 discon-nect the connector CN781 in the outdoor electronic control P.C. board.3 minutes after turning ON the power supply, start EMER-GENCY OPERATION in HEAT mode.

1.

2.Turn OFF power supply of indoor and outdoor unit.

Is there voltage 12 VDC be-tween the connector CN781 pin 5 (+) and pin 3 (-)? No

Disconnect the connec-tor 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 outdoor electronic control P.C. board.

Yes

Cooling operation does not work.•

Is there voltage of 220 - 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 EMER-GENCY 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.


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.

41

I Check of outdoor fan motor

Is the resistance between each ter-minal of outdoor fan motor normal? (Refer to 9-4.)

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 and 0 VDC repeatedly?

Does the outdoor fan motor rotate smoothly?

Replace the outdoor fan motor.

Yes

Yes

No(Fixed to either 5 or 0 VDC)

No

No

Yes

MUZ-GC50/60/71NA


Check the resistance of fan motor. (Refer to 9-4.)

Is the resistance of fan motor normal?


Disconnect the connector CN771 on the power P.C. board.Disconnect the connector (CN61) between compressor and power transistor module.Turn ON the power supply and press theEMERGENCY OPERATION switch.

Does the upper lamp ofOPERATION INDICATOR lamp on the indoor unit light up?

After 3 minutes, is there voltage 220 - 230 VAC between CN771 and on the power P.C. board?


Replace the power P.C. board.

YesNo

Yes

No

MUZ-GC25/35NA

42

J Check of power supply


Is there voltage 220 - 230 VAC between the indoor terminal block S1 and S2? No

YesReplace the indoor electronic control P.C. board.

Rectify indoor/outdoor connecting wire.

Yes

If light up, OK.If fl ash, refer to 9-3.

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

Dose LED on the inverter P.C. board light up or fl ash? (Refer to 9-6.1.) No


Is there voltage 280 - 370 VDC between DB61 (+) and DB61 (–) on the inverter P.C. board?(Refer to 9-6.1.)

No

Check the electric parts in main circuit.

Yes

Yes

No

Disconnect the connector (CN61) between compressor and intelligent power module.Turn ON power supply and pressEMERGENCY OPERATION switch.

Inverter P.C. board(Solder side)

DB61

280 - 370 VDC

Is there voltage of 220 - 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 220 - 230 VAC?

Replace the noise fi lter P.C. board.

NoYes

NoYes

Is the input voltage to the power board 220 - 230 VAC? Replace the reactor.No

Yes

Is the input voltage to the outdoor electronic control P.C. board 325 VDC? Replace the power board.No


Yes

Is fuse (F64) blown? NoYes

Replace the fuse.

MUZ-GC50NA- C1 MUZ-GC60/71NA

43

K Check of LEV (Expansion valve)

MUZ-GC50NA- C1 MUZ-GC60/71NATurn 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 LEV coil.

Yes

No

No

Yes

Replace the inverter P.C. board.No

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

Expansion valve operates in full-opening direction.

OK

NOTE : After check of LEV, do the undermentioned operations. 1. Turn OFF the power supply and turn ON it again. 2. Press RESET button on the remote controller.

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

Measure each voltage between connector pins of CN724 on the inverter P.C. board.1. Pin (-) — Pin (+)2. Pin (-) — Pin (+)3. Pin (-) — Pin (+)4. Pin (-) — Pin (+)Is there about 3 ~ 5 VAC between each?NOTE: Measure the voltage by an analog

tester.

Properly fi x the LEV coil to the expansion valve.

Replace the LEV coil.

Replace the expansion valve.

Is LEV coil properly fi xed to the expansion valve?

Does the resistance of LEV coil have the characteristics?(Refer to 9-4.)

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

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 except the set temperature in operation display section of the remote controller is displayed after 3 seconds.

Yes

No

No

Yes

NoYes

Yes


44

Check the outdoor fan motor. (Refer to 9-5. .)

Is the fuse (F901) blown on the in-verter P.C. board?

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

Operate the outdoor unit by starting EMERGENCY OPERATION.

Check the LED indication on the in-verter P.C. board.Does the LED fl ash 10 times?


Check the corresponding parts following LED indication.(Refer to 9-3.)

YesNo

Yes(10-time fl ash)

No

MUZ-GC50NA- C2

L Check of inverter P.C. board

45

M How to check miswiring and serial signal error

Replace the indoor power P.C. board and the indoor terminal P.C. board

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 upper lamp of OPERATION INDICA-TOR lamp light up? <Confi rmation of the power to the indoor unit>

YesNo

Is serial signal error indicated 6 minutes later?

YesNo

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

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.


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-second-ON quick blinking"? 3

Yes

No(Lighted or not lighted)


2

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

Turn OFF the power supply.Remove the short-circuit between out-door terminal block S2 and S3.Turn ON the power supply.Is there amplitude of 10 to 20 V DC between indoor terminal block S2 and S3? <Confi rmation of serial signal>Is there rated voltage between indoor terminal block S1 and S2?<Confi rmation of power voltage>

Yes

No

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

YesReplace the indoor/outdoor connecting wire.

Is there 2 VDC or less between CN10A (+) and JPG (GND)(-) on the indoor electronic control P.C. board?

No

NoYes

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

Yes

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

•

•

•

A


B

Yes

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

•

•No

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.

Is there 2VDC or less between CN10A (+) and JPG (GND)(-) on the indoor electronic control P.C. board?

Is there 2 VDC or less between CN10A (+) and JPG (GND)(-) on the indoor electronic control P.C. board?

Replace the indoor elec-tronic control P.C. board.

No Yes No

Yes

MUZ-GC25/35NA

46

MUZ-GC50/60/71NA

Turn OFF the power supply.

Is there rated voltage in the power supply?

YesNo


Check the power supply.

Is there rated voltage between outdoor termi-nal block S1 and S2? No Check the wiring.

Press EMERGENCY OPERATION switch once.

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

YesNo

Is serial signal error indicated 6 minutes later?Yes

No

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

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

B1. Miswiring may damage indoor electronic control P.C. board

during the operation. Be sure to confi rm the wiring is correct before the operation

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.


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-second-ON quick blinking"? 3

Yes

No(Lighted or not lighted)


22. Be careful to 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



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

•

•

•

A


B

Yes

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

•

•No

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

No

No



No

Replace the indoor electronic control P.C. board.

Yes

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

Yes

47

MUZ-GC60NA- C2 MUZ-GC71NA

N Check of HPS

1. Disconnect the connector CN681 in the outdoor 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.


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.

48

O Electromagnetic noise enters into TV sets or radios

YesIs the unit earthed?

No Earth the unit.

Yes

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

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 1 m, or is the distance between the TV sets or radios and the outdoor unit within 3 m?

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 anten-na 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 wir-ing 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 following before asking for service.1. Devices affected by the electromagnetic noise TV sets, radios (FM/AM broadcast, shortwave)2. Channel, frequency, broadcast station affected by the electromagnetic noise3. Channel, frequency, broadcast station unaffected by the electromagnetic noise4. Layout of ; indoor/outdoor unit of the air conditioner, indoor/outdoor wiring, earth wire, antennas, wiring from antennas, receiver5. Electric fi eld intensity of the broadcast station affected by the electromagnetic noise6. Presence or absence of amplifi er such as booster7. 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.

49

-20 -10 0 10 20 30 400

10

20

30

40

50

60

70

80

90

100

Temperature(°C)

Defrost thermistor(RT61)

Temperature(°C)

Discharge temperature thermistor(RT62)

0 10 20 30 40 50 60 70 80 90 100 110 1200

100

200

300

400

500

600

700

0 10 20 30 40 50 60 70 800

20

40

60

80

100

120

140

160

180

200

Temperature(°C)

Fin temperature thermistor(RT64)

Res

ista

nce(

k )

Res

ista

nce(

k )

Res

ista

nce(

k )

1. Inverter P.C. boardMUZ-GC25NA MUZ-GC35NA

9-6. TEST POINT DIAGRAM AND VOLTAGE

Back side of unit

Output to drive outdoor fan motor (CN771)

Fin

tem

pera

ture

ther

mis

tor/R

T64

(CN

642)

Dis

char

ge te

mpe

ratu

re

ther

mis

tor/R

T62

(CN

641)

Def

rost

ther

mis

tor/R

T61

(CN

641)

LEVconnector(CN724)

DB61220-230V AC

Jum

per w

ire fo

r cha

nge

in d

efro

st s

ettin

g (J

S)

Front side of unit

DB61280V ~ 370VDC

Smoothing capacitor(C62)


Output to drivecompressor(LDW,LDV,LDU)

LED monitorlamp

R.V.coil(CN721)

(+) (-)

Fuse(F701)

Fuse(F801)

Jum

per w

ire fo

r pre

-hea

t co

ntro

l set

ting

(JK

)

Varistor(NR61)Varistor

(NR63)

Varistor(NR62)

50

-20 -10 0 10 20 30 400

10

20

30

40

50

60

70

80

90

100

Temperature( )

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

Temperature( )

Discharge temperature thermistor(RT62)

0 10 20 30 40 50 60 70 80 90 100 110 1200

100

200

300

400

500

600

700

0 10 20 30 40 50 60 70 800

20

40

60

80

100

120

140

160

180

200

Temperature( )

Fin temperature thermistor(RT64)

Res

ista

nce(

k )

Res

ista

nce(

k )

Res

ista

nce(

k )

MUZ-GC50NA- C2

Back side of unit

Fin

tem

pera

ture

ther

mis

tor /

RT6

4(C

N64

2)

Am

bien

t tem

pera

ture

th

erm

isto

r /R

T65

(CN

643)

Dis

char

ge te

mpe

ratu

re

ther

mis

tor /

RT6

2(C

N64

1)

Def

rost

ther

mis

tor

/RT6

1(C

N64

1)

LEV

con

nect

or (C

N72

4)

DB61DC 260 - 300 V

Front side of unit

AC 220 - 230 V


Output to drive com-pressor(LDU,LDV,LDW)

(+)(-)

Fuse (F701)250 V 3.15 A



Fuse (F801)250 V 3.15 A

Fuse (F901)250 V 3.15 A

R.V.coil(CN721)220 - 230 VAC

Jum

per w

ire fo

r cha

ngin

g de

frost

set

ting

(JS

)

Out

put t

o dr

ive

outd

oor

fan

mot

or (C

N93

2)

AC 220 -230 V

Out

door

hea

t exc

hang

erte

mpe

ratu

re th

erm

isto

r /R

T68(

CN

644)

Jum

per w

ire fo

r pre

-hea

t co

ntro

l set

ting

(JK

)

Sig

nal o

f ou

tdoo

r fan

m

otor

(CN

931)

51

2. Outdoor electronic control P.C. boardMUZ-GC50NA- C1 MUZ-GC71NAMUZ-GC60NA

LED 1

LED 2

CN801310V DC

~370V DC

Input

( (CN

932

20-9

0V A

C

GN

D5V

5V D

Cpu

lse

wav

e

( To fa

nm

otor

Def

rost

ther

mis

tor (

RT6

1)D

isch

arge

tem

pera

ture

ther

mis

tor (

RT6

2)O

utdo

or h

eat e

xcha

nger

te

mpe

ratu

re th

erm

isto

r (R

T68)

( ((+)

(–)

(+)

Rush

curre

nt re

lay (–

)R

.V. c

oil (

–)

( 12V

DC

15V

15V

(+)

(–)

CN

931

(C

N66

1

CN

701

Sig

nal t

rans

mis

sion

(To

pow

er b

oard

)5V

DC

pul

se w

ave

(+)

(–)

(

GN

DC

N70

2S

igna

l rec

eptio

n(F

rom

pow

er b

oard

)5V

DC

pul

se w

ave

GND

(pow

er b

oard

)

CN

781

CN

795

12V

DC

puls

e w

ave

LEV

(

(

( ( (

-20 -10 0 10 20 30 40

100

90

80

70

60

50

40

30

20

10

0

0 10 20 30 40 50 60 70 80

200

180

160

140

120

100

80

60

40

20

0

Res

ista

nce

(k )

Res

ista

nce

(k )

Temperature (°C)

Temperature (°C)

Defrost thermistor (RT61)Ambient temperature thermistor (RT65)Outdoor heat exchanger temperature thermistor (RT68)Fin temperature thermistor (RT64)

0 10 20 30 40 50 60 70 80 90 100 110 120

700

600

500

400

300

200

100

0

Res

ista

nce

(k

)

Temperature (°C)

Discharge temperature thermistor (RT62)

F801 FUSE

3.15A/250V

( Ambi

ent t

empe

ratu

reth

erm

isto

r (R

T65)

CN

663

Serial signal 5 - 10 VDC

CN601

220 - 230 VAC Input

High pressure switch

MUZ-GC60NA- C2

MUZ-GC71NACN681

( (

(

52

{CN912R.V. coil 220-230V AC

220-230V ACInput

220-230V ACOutput

{

CN901To electroniccontrol P.C. board

MUZ-GC50NA- C1 MUZ-GC60NA MUZ-GC71NA

F64 FUSE2A/250V

F911 FUSE1A/250V

3. Noise filter P.C. board

CN902To powerboard {

CN903To powerboard

{CN61220-230V AC Output

NR64 VARISTOR

53

MUZ-GC50NA- C1 MUZ-GC60NA MUZ-GC71NA4. Outdoor power board

310-370V DCOutput (Red)

(White)

Connect to the compressorVoltage among phases: 5V to 180V

Connect to the earth

CN5Primary current detection(Connect to the noise filter)

CN2Connect to the controller board(+)1-5(–): Signal transmission (To electronic control P.C. board) 5V DC pulse wave(+)2-5(–): Zero cross signal 3-4 : Not used(+)6-5(–): 15V(+)7-5(–): 15V

(+)

(–)

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

)

CN3Fin temperature thermistor RT64

1

3

54

10-1. MUZ-GC25NA MUZ-GC35NANOTE : Turn OFF power supply before disassembling.

OPERATING PROCEDURE PHOTOS1. Removing cabinet and panels

(1) Remove the screw fixing the service panel. (Photo 2.)(2) Pull down the service panel and remove it. (Photo 2.)(3) Disconnect the power supply and indoor/outdoor connect-

ing wire.(4) Remove the screws fixing the top panel. (Photo 1.)(5) Remove the top panel. (Photo 1.)(6) Remove the screws fixing the cabinet. (Photo 1.)(7) Remove the cabinet.(8) Remove the screws fixing the back panel.(9) Remove the back panel.

Photo 2

Photo 1

Screws of the cabinet

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

Slide the sleeve.Pull the terminal while pushing the lockinglever.

Hold the sleeve, and pull out the terminal slowly.

Connector

Sleeve

Locking lever

Service panel

Screws of the top panel


Screw of theservice panel

Direction to remove

<"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.

HooksHooks

10 DISASSEMBLY INSTRUCTIONS

55

OPERATING PROCEDURE PHOTOS2. Removing the inverter assembly, inverter P.C. board

(1) Remove the cabinet and panels. (Refer to 1.)(2) Disconnect the earth wires (Photo 3.), the lead wire to the

reactor and the following connectors;<Inverter P.C. board>CN641 (Defrost thermistor and discharge temperature

thermistor)CN721 (R.V. coil)CN771 (Fan motor)CN724 (LEV)

(3) Disconnect the compressor connector (CN61).(4) Remove the screws fixing the relay panel. (Photo 3.)(5) Remove the inverter assembly. (Photo 4.)(6) Remove the inverter P.C. board from the inverter assem-

bly.

Photo 3

Photo 4 (Inverter assembly)

Photo 5

3. Removing R.V. coil (1) Remove the cabinet and panels. (Refer to 1.)(2) Remove the R.V. coil. (Photo 5.)

4. Removing the discharge temperature thermistor and defrost thermistor(1) Remove the cabinet and panels. (Refer to 1.)(2) Pull out the discharge temperature thermistor from its hold-

er. (See Photo 6.)(3) Pull out the defrost thermistor from its holder. (Photo 5.)

Defrostthermistor

R.V. coil

Screws of the earth wires

Screws of therelay panel

Heat sinkInverterP.C. board

56

OPERATING PROCEDURE PHOTOS5. Removing outdoor fan motor

(1) Remove the cabinet and panels. (Refer to 1.)(2) Disconnect the connectors for outdoor fan motor.(3) Remove the propeller nut. (Photo 7.)(4) Remove the propeller. (Photo 7.)(5) Remove the screws fixing the fan motor. (Photo 7.)(6) Remove the fan motor.

Photo 6

Photo 7

Photo 8

6. Removing the compressor and 4-way valve(1) Remove the cabinet and panels. (Refer to 1.)(2) Remove the inverter assembly. (Refer to 2.)(3) Recover gas from the refrigerant circuit.

NOTE: Recover gas from the pipes until the pressure gauge shows 0 MPa (0 kg/cm2).

(4) Detach the welded part of the suction and the discharge pipe connected with compressor.

(5) Remove the nuts of compressor legs.(6) Remove the compressor.(7) Detach the welded part of pipes connected with 4-way

valve. (Photo 8.)

Propeller Screws of the outdoor fan motor

Welded parts of 4-way valve


57

10-2. MUZ-GC50NA MUZ-GC60NA MUZ-GC71NANOTE : These photos are MUZ-GC71NA. Other models

are almost the same as MUZ-GC71NA. Turn OFF power supply. before disassembling.

OPERATING PROCEDURE PHOTOS1. 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 connect-

ing 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 3

Photo 1

Photo 2

Screw of the top panel



Screw of the motor support

Set screws of the back panel

Screws of the back panel



Screw of the service panel

Screw of the valve cover

Set screws of the back panel

58

OPERATING PROCEDURE PHOTOSMUZ-GC50NA- C1 MUZ-GC60/712. 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 thermis-

tor and outdoor heat exchanger temperature ther-mistor)

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 assem-

bly.

Photo 4 (MUZ-GC50NA- C1 MUZ-GC60/71)

Photo 5 (MUZ-GC50NA- C2 )

Photo 6 (Inverter assembly : MUZ-GC50NA- C2 )

MUZ-GC50NA- C2

3. Removing the inverter assembly, inverter P.C. board(1) Remove the cabinet and panels. (Refer to 1.)(2) Disconnect the lead wire to the reactor and the following

connectors; <Inverter P.C. board>

CN721 (R.V.coil)CN932 (Fan motor)CN641 (Defrost thermistor and discharge temperature ther-

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

(3) Remove the compressor connector (CN61).(4) Remove the screws fixing the relay panel. (Photo 5)(5) Remove the inverter assembly. (Photo 6)(6) Remove the screw of the earth wire and screw of the

T.B.support. (Photo 6)(7) Remove the screw of the PB fixture.(8) Remove the relay panel from the PB support.(9) Remove the inverter P.C. board from the inverter assembly.

Screws of the relay panel

Screws of the power board assembly

Heat sink Inverter P.C. board

Screw of the earth wire

T.B.support

Screw of the T.B.support

Screws of the relay panel

Screws of the reactor

Hook of the PB support PB support

Hook of the PB support Relay panel

Screw of the PB fixture

59

OPERATING PROCEDURE PHOTOS4. 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;

MUZ-GC50NA- C1 MUZ-GC60/71<Noise filter P.C. board>CN912 (R.V. coil)

MUZ-GC50NA- C2

<Inverter P.C. board>CN721 (R.V. coil)

(4) Remove the R.V. coil. (Photo 11)

Photo 7

Photo 8

5. Removing the defrost thermistor, discharge tempera-ture thermistor, outdoor heat exchanger temperature thermistor and ambient temperature thermistor(1) Remove the top panel, cabinet and service panel. (Refer to


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

tor and outdoor heat exchanger temperature ther-mistor)

CN663 (Ambient temperature thermistor)(4) Pull out the defrost thermistor from its holder. (Photo 8)(5) Pull out the discharge temperature thermistor from its hold-

er. (Photo 7)(6) Pull out the outdoor heat exchanger temperature thermistor

from its holder. (Photo 8)(7) Pull out the ambient temperature thermistor from its holder.

(Photo 8)

6. Removing outdoor fan motor(1) Remove the top panel, cabinet and service panel. (Refer to


MUZ-GC50NA- C1 MUZ-GA60/71<Electronic control P.C. board>CN931 and CN932 (Fan motor)

MUZ-GC50NA- C2

<Inverter 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.

Photo 9Propeller

Screws of the outdoor fan motor

Defrostthermistor



Ambient tem-peraturethermistor

60

OPERATING PROCEDURE PHOTOS7. 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/cm2 (0 MPa).(5) Detach the welded part of the suction and the discharge

pipe connected with compressor. (Photo 11)(6) Remove the compressor nuts.

(7) Remove the compressor.(8) Detach the welded part of 4-way valve and pipe. (Photo 10)

Photo 10

Photo 11

8. 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 5,12)

Photo 12 (MUZ-GC50NA- C1 MUZ-GC60/71)

Welded parts of 4-way valve

Welded part of the dis-charge pipe

R.V. coil

Welded part of the suction pipe

Screws of the reactor

61

62

63

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

Copyright 2007 MITSUBISHI ELECTRIC ENGINEERING CO.,LTDDistributed in Aug. 2008. No. OBH482 REVISED EDITION-C 6Distributed in Jun. 2008. No. OBH482 REVISED EDITION-B 6Distributed in Nov. 2007. No. OBH482 REVISED EDITION-A 6Distributed in Mar. 2007. No. OBH482 6Made in Japan

New publication, effective Aug. 2008Specifications subject to change without notice.

TM

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