service manual no. ob385 msc-ga20vbmitsubishitech.co.uk/data/m-series/ms(c)/2005/msc-ga-vb/... ·...

SPLIT-TYPE, AIR CONDITIONERSSPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

CONTENTS

1. TECHNICAL CHANGES ····································32. PART NAMES AND FUNCTIONS······················33. SPECIFICATION·················································54. NOISE CRITERIA CURVES·······························55. OUTLINES AND DIMENSIONS ·························66. WIRING DIAGRAM ············································77. REFRIGERANT SYSTEM DIAGRAM················88. SERVICE FUNCTIONS ······································89. TROUBLESHOOTING······································11

10. DISASSEMBLY INSTRUCTIONS·····················1811. PARTS LIST······················································2012. RoHS PARTS LIST···········································2213. OPTIONAL PARTS ·························BACK PAGE

MSC-GA20VB -MSC-GA25VB -MSC-GA35VB - E1

E1

E1

SERVICE MANUAL

Wireless typeModels

INDOOR UNIT

NOTE:This service manual describes technical data of the indoor units.RoHS compliant products have mark on the spec name plate.For servicing of RoHS compliant products, refer to the RoHS PARTS LIST (RoHS compliant).

Outdoor unit service manualMU-GA•VB Series (OB386)

MUH-GA•VB Series (OB387)MUX-A•VB Series (OB384)MXZ-A•WV Series (OB319)

No. OB385REVISED EDITION-B

Revision B:• Indoor heat exchanger of MSC-GA35VB -

has been changed. E1

Please void OB385 REVISED EDITION-A.

OB385B.qxp 07.5.21 4:41 PM Page 1

2

Revision B:• Indoor heat exchanger of MSC-GA35VB - has been changed. E1

Revision A:• RoHS PARTS LIST has been added.

OB385B.qxp 07.5.21 4:41 PM Page 2

3

PART NAMES AND FUNCTIONS2

MSC-GA20VB MSC-GA25VB MSC-GA35VB

Emergency operation switch

Fan

Catechin air filter(With deodorizer)

Air outlet

Vertical vanes

Air inlet

to Breaker

Remote controlreceiving section

Display section

Air cleaning filter(option)(white bellows type)

Front panel

Power supply cord

Panel

Horizontal vane

Operation section

(When the front panel is opened)

Remote controller

Operation indicator lamp

Remote controlreceiving section

TECHNICAL CHANGES1

MSC-A07YV - ➔ MSC-GA20VB -1. Indication of capacity has been changed. (BTU base ➔ kW)2. P.C. board has been changed.3. Air cleaning filter has been changed to optional parts.4. Fan motor has been changed.5. Fan motor capacitor has been changed.6. Color of indoor unit has been changed.



E1E1

E1E1

E1E1

OB385B.qxp 07.5.21 4:41 PM Page 3

4

ACCESSORIES

MSC-GA20VBMSC-GA25VBMSC-GA35VB

Installation plate

Installation plate fixing screw 4 o 25 mm

Remote controller holder

Fixing screw for 3 3.5 o 16 mm

Battery (AAA) for remote controller

Wireless remote controller

Felt tape (Used for left or left-rear piping)

1

5

1

2

2

1

1

1

2

3

4

5

6

7

ON/OFF

FAN

TOOWARM

TOOCOOL

VANE

MODE

ECONO COOL

STOP

START

HR.

MIN.

I FEEL COOL

DRY

PMCLOCK

AM

RESET CLOCK

HEAT/FAN

/

Open the front lid.

ON/OFF TOOCOOL

PM

AM

TOOWARM

Signal transmitting section

Operation display section

OPERATE /STOP(ON /OFF) button

TEMPERATURE buttons

Indication of remote controller model is on back.

OPERATION SELECT button

FAN SPEED CONTROL buttonOFF-TIMER button

HR. buttonMIN. button

(TIME SET button)

ON-TIMER button

RESET button

ECONO COOL button

VANE CONTROL buttonCLOCK SET button

REMOTE CONTROLLER

OB385B.qxp 07.5.21 4:41 PM Page 4

5

SPECIFICATION3

Indoor modelFunction

Indoor unit power supply

Air flow(High/Med. /Low )Power outletRunning currentPower inputPower factorFan motor currentModelWinding resistance(at 20:)Dimensions WOHODWeightAir directionSound level(High/Med. /Low )Fan speed(High/Med. /Low )Fan speed regulatorThermistor RT11(at 25:)Thermistor RT12(at 25:)Remote controller model

K /hAAW%A

"

mmkg

dBrpm

k"k"

MSC-GA20VB

Single phase230V,50Hz

10 0.173590

0.17 RC4V19-JA

WHT-BLK 283 BLK-RED 188 815O278O244

95

31010

KP1A or KM04F

Cooling

474/372 /276

36/31 /25900/750 /600

Heating

510/420 /342

36/31 /25950/820 /700

MSC-GA25VB


10 0.173590

0.17 RC4V19-JA


95

31010

KP1A or KM04F

Cooling

474/384 /306

36/31 /25900/770 /650

Heating

588/456 /342

39/32 /251,050/870 /700

MSC-GA35VB


10 0.194092

0.19 RC4V19-HA


105

31010

KP1A or KM04F

Cooling

582/444 /324

40/33 /26930/760 /600

Heating

606/498 /396

39/33 /26960/830 /700

Ele

ctric

alda

taF

an

mot

orS

peci

alre

mar

ks

Capacity

w w

w w

w w w w w w w w w w

w w w w w w w w w w w

w w w w w w w w w w w w

w

w w w w

NOTE: 1. Test conditions are based on ISO 5151.Cooling : Indoor DB27°C WB19°C Heating : Indoor DB20°C

Outdoor DB35°C WB24°C Outdoor DB7°C WB6°CIndoor-Outdoor piping length 5m

W Reference value

NOISE CRITERIA CURVES4

90

80

70

60

50

40

30

20

1063 125 250 500 1000 2000 4000 8000

APPROXIMATETERESHOLD OFHEARING FORCONTINUOUSNOISE

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OC

TAV

E B

AN

D S

OU

ND

PR

ES

SU

RE

LE

VE

L, d

B r

e 0.

0002

MIC

RO

BA

R

BAND CENTER FREQUENCIES, Hz

Test conditions,Cooling : DB27: WB19:Heating : DB20: WB -:

MSC-GA20VBCOOLING

High

FUNCTIONFAN SPEED

36HEATING

SPL(dB(A)) LINE

90

80

70

60

50

40

30

20

1063 125 250 500 1000 2000 4000 8000


NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OC

TAV

E B

AN

D S

OU

ND

PR

ES

SU

RE

LE

VE

L, d

B r

e 0.

0002

MIC

RO

BA

R


Test conditions.Cooling : DB27: WB19:Heating : DB20: WB -:

MSC-GA25VBCOOLING

High

FUNCTIONFAN SPEED

36

HEATING 39

SPL(dB(A)) LINE

OB385B.qxp 07.5.21 4:41 PM Page 5

6

OUTLINES AND DIMENSIONS5

MSC-GA20VB MSC-GA25VB

244

242 5

7 or

mor

e

90

11030149606

278

60

815

783

Power supply cordLead to right 1.0mLead to left 0.3m

Air out

Installation plate

Insulation [28

Drain hose [16(Connected part O,D)

Air in

Liquid line [6.35-0.5mGas line [9.52-0.43mInsulation [37 O.D [21 I.D

{


162

1958

81.581.5

41 2.5

42

271

231.

5

4.581.5 133.5

326326

Wall hole [65

Indoor unit

Installation plate

Unit: mm

90

80

70

60

50

40

30

20

1063 125 250 500 1000 2000 4000 8000


NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OC

TAV

E B

AN

D S

OU

ND

PR

ES

SU

RE

LE

VE

L, d

B r

e 0.

0002

MIC

RO

BA

R


Test conditions.Cooling : DB27: WB19:Heating : DB20: WB -:

MSC-GA35VBCOOLING

FUNCTIONFAN SPEED

40

HEATINGHigh

39

SPL(dB(A)) LINE

INDOOR UNITWALL

MICROPHONE

0.8m

1m

OB385B.qxp 07.5.22 7:48 AM Page 6

7

MSC-GA35VB

244

242

218.

5

258

81.581.5

41 422.5

17.5

161.5161.5

326326

5

7 or

mor

e90

11030149606

278

60

815

783

Power supply cordLead to right 1.0mLead to left 0.3m

Air out

Indoor unit

Installation plate

Wall hole [65

Installation plate

Insulation [28

Drain hose [16(Connected part O,D)

Liquid line [6.35-0.5mGas line [9.52-0.43mInsulation [37 O.D [21 I.D

{


162

1958

Air in

WIRING DIAGRAM6


SYMBOL

NR11

RT11

RT12

SR141

NAME NAME NAME

INDOOR FAN CAPACITOR

FUSE(3.15A)

INDOOR FAN MOTOR (INNER FUSE)

VANE MOTOR

VARISTOR

ROOM TEMPERATURE THERMISTOR

INDOOR COIL THERMISTOR

SOLID STATE RELAY

TERMINAL BLOCKSYMBOL

C11

F11

MF

MV

TRANSFORMER

SYMBOL

TB

T11

MF

123456

125CNCN

109

5

REMOTECONTROLLER

23

POWER MONITORRECEIVER P.C.BOARD

GRN

LD103

PE

12V

FORMU ORMUX TYPE

FOR MUH ORMXZ-A TYPE

MV

GRN/

YLW

POWERSUPPLYCORD~/N 230V50Hz

TO OUTDOORUNITCONNECTING

12V

1

2

N

3

L

BRN

BLU

BLK

WHT

BLU

RED

BRN

5

CN151

12

CN202123

CN201

LD105

CN211

ELECTRONIC CONTROL P.C. BOARD

F11

T11

NR11

RT11

RT12CN112CN111

531

CN121

BLKGRYYLWBRN

3

WHTRED

C11SR141

CIRCUIT BREAKER

TB

NOTE:1. About the outdoor side electric wiring, refer to the outdoor unit electric wiring diagram for servicing.2. Use copper conductors only. (For field wiring)3. Symbols below indicate./: Terminal block, : Connector

Unit: mm

OB385B.qxp 07.5.21 4:41 PM Page 7

REFRIGERANT SYSTEM DIAGRAM

8

7

SERVICE FUNCTIONS8

8-2. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATIONA maximum of 4 indoor units with wireless remote controllers can be used in a room.In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must bemodified according to the number of the indoor unit.

8-1. TIMER SHORT MODEFor service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.The time will be shortened as follows. (Refer to 9-6.)

Set time : 1 minute ➔ 1-secondSet time : 3 minutes ➔ 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is

shortened by short circuit of JPG and JPS.)

How to modify the remote controller P.C. boardRemove batteries before modification. The board has a print as shown below :

NOTE : For modification, take out the batteries and press the OPERATE/STOP(ON/OFF) button twice or 3 times at first. After modification, put back the batteries then press the RESET button.


J2

J1


Indoorheatexchanger

Room temperaturethermistorRT11

Refrigerant pipe [9.52(with heat insulator)

Unit:mm

Indoor coilthermistorRT12

Flared connection

Flared connection

Refrigerant pipe [6.35(with heat insulator)

Refrigerant flow in cooling

Remote controller model : KP1A

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9

The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1.After modification, press the RESET button.

Table 1

No. 1 unitNo. 2 unitNo. 3 unitNo. 4 unit

1 unit operationNo modification

–––

2 units operationSame as at left

Solder J1––

3 units operationSame as at leftSame as at left

Solder J2–

4 units operationSame as at leftSame as at leftSame as at left

Solder both J1 and J2

How to set the remote controller exclusively for particular indoor unitAfter you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as theremote controller for the indoor unit.The indoor unit only accepts the signal from the remote controller that has been assigned to the indoor unit once they areset.The setting will be cancelled if the breaker has turned OFF, or the power supply has shut down.Please conduct the above setting once again after the power has restored.

Slide switchType

The position of the slide switch

COOL ONLYCOOL & HEAT

8-3. REMOTE CONTROLLER (How to set the type)This remote controller setting needs to be switched according to the type of air conditioner (COOL & HEAT or COOLONLY).If the setting is incorrect, the air conditioner does not operate normally. Therefore, check if the setting corresponds to the type of air conditioner. If not, correct the setting as shown below.

Remote controller model : KM04F

J1 J2

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10

NOTE• The operation settings are memorized when 10 seconds have passed after the remote controller was operated.• If main power is cut while AUTO START/STOP timer is active, the timer setting is cancelled.• If the unit has been off with the remote controller before power failure, the auto restart function does not work as the

power button of the remote controller is off.• To prevent breaker off due to the rush of starting current, systematize other home appliance not to turn ON at the same

time.• When some air conditioners are connected to the same supply system, if they are operated before power failure, the

starting current of all the compressors may flow simultaneously at restart.Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current by adding system that allows the units to start one by one.

1. MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER The indoor units for MU & MUX type and MUH & MXZ typeare common specifications. Set switch according to thetype of outdoor unit. The units are set for MUH & MXZ type when they are shipped from the factory.

How to release “AUTO RESTART FUNCTION”! Turn OFF the main power for the unit. @ Pull out the electronic control P.C. board, and change switch(SW2-1) on the indoor electronic control P.C. board as

following figures.

SW2-1 sets the AUTO RESTART FUNCTION ON / OFF.SW2-2 switches over the MU & MUX type / MUH & MXZ type. When the units are shipped from the factory, SW2 is as follows. SW2-1: AUTO RESTART FUNCTION ON SW2-2: MUH & MXZ type }

SW2

FRONT

12

12

IC101

CN

151

SW1

CN

112C

N121

L101C

N201

F11

CN202

C11CN211

SW2

LD105

Operation! If the main power (230V AC) has been cut, the operation settings remain.@ After the power is restored, the unit restarts automatically according to the memory. (However, it takes at least 3

minutes for the compressor to start running.)

8-4. MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER AND AUTO RESTART FUNCTION

2. AUTO RESTART FUNCTIONWhen the indoor unit is controlled with the remote controller, the operation mode, set temperature, and the fan speed are memorized by the indoor electronic control P.C.board. The “AUTO RESTART FUNCTION” sets to work the momentpower has restored after power failure.Then, the unit will restart automatically. However if the unit is operated in “IFEEL CONTROL” mode before power failure, the operation is not memorized. In “I FEEL CONTROL” mode, the opera-tion is decided by the initial room temperature. “AUTO RESTART FUNCTION” is ON when the units are shipped fromthe factory.

1 21 2

1 2 SW2 SW21 2

Outdoor unit MUH & MXZ type

Set 2 switch downside.

Outdoor unit MU & MUX type

Set 2 switch upside.

NOTE:•If the indoor-outdoor connecting wire is incorrectly connected on the terminal block, the unit does not operate normally.

•If a ground is incorrect, it may cause an electric shock.

How to switch over MU & MUX TYPE / MUH & MXZ TYPE! Turn OFF the main power for the unit.@ Pull out the electronic control P.C. board, and change

switch(SW2-2) on the indoor electronic control P.C. boardaccording to the type of outdoor unit as following figures.

1 2 SW2 SW21 2

1 21 2

AUTO RESTART FUNCTION ON

Set 1 switch downside.

AUTO RESTART FUNCTION OFF

Set 1 switch upside.

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11

TROUBLESHOOTING9

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) 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.3) When troubleshooting, refer to 9-2. “Instruction of troubleshooting” and 9-3. “Troubleshooting check table”.

Lead wiring Housing point

9-1. Cautions on troubleshooting1. Before troubleshooting, check the following:

1) Check the power supply voltage.2) Check the indoor/outdoor connecting wire for mis-wiring.

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. 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 electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the

components.4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.


4. How to replace batteries Weak batteries may cause the remote controller malfunction.In this case, replace the batteries to operate the remote controller normally.

NOTE1 : If the RESET button is not pressed, the remote controller may not operate correctly.

Insert the negative pole of the batteries first.Check if the polarity of the batteries is correct.

HEAT/FAN/

RESET button

HEAT/FAN/

1 Remove the front lid and insert batteries.Then reattach the front lid.

2 Press the RESET button.

NOTE2 : INFORMATION FOR MULTI SYSTEM AIR CONDITIONER (OUTDOOR UNIT : MXZ-A14WV MXZ-A18WV MXZ-A26WV MXZ-A32WV )

Multi system air conditioner (Outdoor unit MXZ-A14WV MXZ-A18WV MXZ-A26WV MXZ-A32WV) can connect two ormore indoor units with one outdoor unit. According to the capacity, two or more units can operate simultaneously.

•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and theother for heating, the operation mode of the indoor unit that operates earlier is selected. The other indoor units thatwill start the operation later cannot operate, indicating as shown in the figure below. In this case, please set all theindoor units to the same operation mode.

•When indoor units starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes(max. 10 minutes) to blow out the warm air.

•In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant flowingmay be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.

lighted

flashing

Operation Indicator

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12

9-2. Instruction of troubleshooting

Start

Indoor unit operates.Outdoor unit doesn't operate.

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

Indoor unit operates.Outdoor unitdoesn't operatenormally.

OPERATIONINDICATORlamp on theindoor unit is flashing on and off.

Outdoor unit operates only in Test Run operation.w2

Outdoor unit doesn't operate even in Test Run operation.w2

Indoor unit operates,when theEMERGENCY OPERATION switch ispressed.

Indoor unit doesn't operate,when the EMERGENCY OPERATION switch ispressed.

Check room temperature thermistor.Refer to 9-6. "Test point diagram and voltage".

MUH-GA20/GA25/GA35VB MUX-2A28/2A59/3A60/3A63/2A70/4A73VBRefer to "Check of outdoor unit".

Refer to 9-5.B "Check of remotecontroller and receiver P.C. board".

MUH-GA20/GA25/GA35VBMXZ-A14/A18/A26/A32WVFlash on and off at 0.5-second intervalsCause: Indoor/Outdoor unit• Mis-wiring or trouble of serial signal

2-time flash Cause:Indoor unit• Trouble of room temperature/ indoor coil thermistor

3-time flash Cause:Indoor unit• Trouble of indoor fan motor

6-time flash Cause: Outdoor unit• Trouble of thermistor in outdoor unit

7-time flash Cause: Outdoor unit• Trouble of outdoor control system

Check room temperature thermistor and indoor coil thermis-tor.Refer to 9-6."Test point diagram and voltage".

Refer to 9-5.A "Check of indoor fan motor".

4-time flash Cause:Indoor unit• Trouble of indoor unit control system

Replace theindoor electronic control P.C. board.

MUH-GA20/GA25/GA35VBMXZ-A14/A18/A26/A32WVRefer to "Check of outdoor thermistor" and others.

MUH-GA20/GA25/GA35VBMXZ-A14/A18/A26/A32WVReplace the deicer P.C. board and others.

Refer to 9-5. D "How to check mis-wiring and serial signal error (When outdoor unit doesn't work)".W1

1. Check indoor / outdoor connecting wire.2. Refer to 9-5. C "Check of indoor electronic control P.C. board".

Outdoor unit doesn't stop even if indoor unit stops.

Unit doesn't operate normaloperation in COOL or HEAT mode.

MU-GA20/GA25/GA35VBCheck of wiring diagram of outdoor unit".MUH-GA20/GA25/GA35VB Refer to "Check of outdoor unit".

MUH-GA20/GA25/GA35VB MXZ-A14/A18/A26/A32WVRefer to "Check of R.V. coil" and others.

W1. When the power is turned off and turned on again, the indication shows “the trouble of mis-wiring”.

Refer to outdoor unit service manual.

Indoor unit operates.But indoorunit doesn'tblow out cool air.

MUX-2A28/2A59/3A60/3A63/2A70/4A73VB Refer to "Check of indoor/outdoorunits' connectionand outdoor unit".

w2."Test Run operation" means the operation within 30 minutes after EMERGENCY OPERATION switch is pressed.

10-time flash Cause: Outdoor unitMXZ type• Outdoor refrigerant system abnormality

MXZ typeRefer tooutdoor refrigerant system related items.

MXZ type5-time flash Cause: Outdoor unit• Outdoor power system abnormality

Refer to"Check of inverter/ compressor" and "Check of power supply".


OB385B.qxp 07.5.21 4:41 PM Page 12

13

9-3. Troubleshooting check table

Operation Indicator· Flashing of the OPERATION INDICATOR lamp (on the left-hand side) indicates possible abnormalities.· The OPERATION INDICATOR lamp (on the left-hand side) is lighting during normal operation.

flashing• The following indication does not depend on the shape of lamp.

❈ Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.Self check table

No.

1

2

5

7

8

SymptomOperation indicator lamp Detection method Checkpoint

0.5-second ON

0.5-second OFF

MUH or MXZ typeMis-wiring or Serial signal

MUH or MXZ typeDefrostthermistor

MUH or MXZ typeOutdoorcontrolsystem error

When the defrost thermistor shorts or opens after the compressor start-up.

When it cannot properly read data in the non-volatile memory of outdoor electronic control P.C. board.

When the operation mode of each indoor unit is differently set to COOL(includes DRY) and HEAT at same time, the operation mode of indoor unit that has operated at first has the priority.

● Check outdoor DEICER P.C. board and others.● Check resistance of thermistor.● Reconnect connector. Refer to outdoor unit service

manual.

● Check outdoor DEICER P.C. board and others.


● Unify the operation mode.

● Check switch SW2-2.(MU & MUX type or MUH & MXZ type)● Check wiring (visual check and conductivity check).● Check indoor electronic control P.C.board.● Check outdoor DEICER P.C. board and others.● Check electrical parts.

● Check resistance of thermistor.● Reconnect connector.● Check indoor electronic control P.C.board.

3

Indoor coil thermistor

Room temperature thermistor

9

MXZ typeOutdoor refrigerant system error

When the compressor operation has been in-terrupted by LEV protection continuously 5 minutes, the compressor stops operation.

Abnormal point

Outdoor unit does not run.






2-time flash

2.5-second OFF

When serial signal from outdoor unit stops for 4 to 5 seconds.

Detect Indoor coil/room temperature thermis-tor short or open circuit every 8 seconds dur-ing operation.

3-time flash

2.5-second OFF

Indoor fan motor repeats 12 sec-onds ON and 3 minutes OFF.When the indoor fan motor breaks, the fan keeps stopping.

When rotational frequency feedback pulse signal is not emit during 12-second indoor fan operation.

When the compressor operation is continuously three times interrupted by over current protection within 1 minute after start-up , it stops operation.

● Disconnect connector CN211 and check connector CN121 2-3 to make sure rotational frequency feedback signal of 1.5V or over exists.● Check indoor electronic control P.C. board.● Check indoor fan motor.● Reconnect connector.

● Check the inverter output.● Check the compressor.

Indoor fan motor

6-time flash

2.5-second OFF

● Refer to "Check of LEV".● Check refrigerant circuit and refrigerant amount.● Check outdoor electronic control P.C. board. Refer to outdoor unit service

manual.

6

5-time flash

2.5-second OFF

Operation IndicatorMXZ typeOperation mode setting

LightedFlashing

Outdoor unit operates but indoor unit does not run.

4

4-time flash

2.5-second OFF

Indoor control system

When it cannot properly read data in the nonvolatile memory of indoor electronic control P.C. board.

Outdoor unit does not operate.

● Replace the indoor electronic control P.C. board.

7-time flash

2.5-second OFF

10-time flash

2.5-second OFF

MXZ type Outdoor power system

2.5-second OFF

OB385B.qxp 07.5.21 4:41 PM Page 13

14

AA Check of indoor fan motor

Is soldered point of the connector correctly soldered?

Is resistance 0 (short circuit) or ∞ (open circuit)?

Yes ( 0 or ∞ )

Yes

NoYesNo

Turn OFF the power supply.Check connector CN211 visually.

Disconnect lead wires from connector CN211 on indoor electronic control P.C. board.Measure resistance between lead wires No.1 and No.5, then No.3 and No.5.

When OPERATION INDICATOR lamp flashes 3-time.Indoor fan motor doesn’t operate.

Turn ON the power supply. Stop it if the unit operates.Insert screwdriver into air outlet to rotate indoor fanmotor slowly for 1 revolution or over, and measure volt-age No.2(+) and No.3(-) on CN121.

No(others)

Replace the indoor electronic control P.C. board.

Does voltage repeat 0V DC and 5V DC?

Yes

No

Are lead wires connected?Reconnect the lead wires. Resolder it.

Repair or replace the indoor fan motor.

Measure the resistance between the terminals with a tester.(Coil wiring temperature10°C ~ 30°C)

Room temperaturethermistor (RT11)

9-4. Trouble criterion of main parts

Part name

Indoor coilthermistor (RT12)

Indoor fanmotor (MF)INNER FUSE136i3°CCUT OFF

Mot

or p

art

Sen

sor

part

Check method and criterion

Measure the resistance with a tester.(Part temperature 10°C ~ 30°C)

Measure the voltage Power ON.

Figure

8kΩ ~ 20kΩ

NormalAbnormal

Open or short-circuit

271 ~ 295ΩWHT-BLKBLK-RED

BRN-YLW

YLW-GRY

Normal

4.5 ~ 5.5V

Abnormal

Remain 0V or 5V(When fan revolved one time)0V➔ 5V➔ 0V

(Approx.)

MSC-GA20/GA25VB

180 ~ 196Ω

RED

BLK

YLW

FUSE

GRY

BRN

WHT


Normal Abnormal

Open or short-circuit

MSC-GA20/GA25/GA35VB


Vane motor(MV)

Measure the resistance between the terminals with a tester.(Part temperature10°C ~ 30°C)

Normal Abnormal

Open or short-circuit240 ~ 260Ω

RED

YLW

BRN

ORN GRN

ROTOR


Color oflead wire

215 ~ 233ΩMSC-GA35VB

305 ~ 331Ω

Color oflead wire

9-5. Troubleshooting flow

OB385B.qxp 07.5.21 4:41 PM Page 14

15

BB Check of remote controller and receiver P.C. board

Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.

Yes

Replace the batteries. (Refer to 9-1-4.)

Turn ON a radio to AM and press switchon the remote controller.

Is noise heard from radio?

Are there any fluorescent lights ofinverter or rapid-start type withinthe range of 1m?

Replace the remote controller.

• Reinstall the unit away from lights.• Attach a filter on receiving part.

Switch on the remote controller.

Is LCD display on the remote con-troller displayed?

Remove batteries, then set them back and press the RESETbutton. Check if the unit operates with the remote controller.

Yes

Does the unit operate with theremote controller?

Yes

OK

No

(not clear)

Yes

No

No

Yes

Measure the voltage between receiver P.C. board connector CN302No.3(–) and No.5(+) when the remote controller button is pressed.

Is the voltage approx. 4V DC?Replace the indoor electronic controlP.C. board.

Replace the power monitor, receiver P.C. board.

No(5V or 0V DC)

No

wCheck the remote controller is exclusive for this air conditioner.

CC Check of indoor electronic control P.C. board

Check the both “parts side” and “pattern side” of indoor electronic control P.C. board visually.

Replace the fuse.

Is fuse (F11) blown?

Be sure to check both fuse and varistor in any case.

Replace the fan motor.


Is winding resistance of fan motor 0 "?

Is winding resistance of vane motor 0 "?

No

Yes

Replace the vane motor.

No

Yes

Yes

Is varistor (NR11) burnt?

Replace the varistor.

Yes

Turn OFF the power supply.Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P.C. board and turn ON the power supply.

No

Does the unit operate with the remote controller?Does the OPERATION INDICATOR lamp light up by pressing the EMERGENCY OPERATION switch?

Yes

No

Be sure to check both resistances.

Turn OFF the power supply.

Turn OFF the power supply.

No

The unit doesn’t operate with the remote controller.Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.

OB385B.qxp 07.5.21 4:41 PM Page 15

16

DD How to check mis-wiring and serial signal error

Serial signal error is indicated.(0.5-sec. ON, 0.5-sec. OFF)

1. Turn OFF the power supply(indoor / outdoor unit) and disconnect indoor and outdoor connecting wire on indoor side.2. Short-circuit between indoor terminal block N and 3.3. Turn ON the power supply(indoor unit) and press once EMERGENCY OPERATION switch.

During EMERGENCY OPERATION, is there 10V DC between both ends of R601?(By tester, the stylus is between 5 ~10V)

Start

Turn OFF the power supply(indoor/outdoor unit).

No

NoIs there 20V DC between both ends of R132 on indoor electronic control P.C. board ?( By tester, the stylus is between 0 ~ 20V. )

•Turn OFF the power supply(indoor unit).•Connect indoor and outdoor connecting wire.

Is the outdoor unit "MUH" type?

•Turn ON the power supply(indoor/outdoor unit).•Press once EMERGENCY OPERATION switch.•3 min. later, check the self-check result displayed on OPERATION INDICATOR lamp on indoor unit. w 2

Is this mis-wiring, poor contact, or disconnection of wire?Correct them.


Turn ON the power supply(outdoor unit).

Is there 230V AC between outdoor terminalblock L-N (TB1)?

No Check the outdoor power supply, power supply cord and connection.

Yes

Turn ON the power supply(indoor unit).

NoReplace the deicer P.C. board.

Yes

No Correct the wiring between CN730 on the deicer P.C. board and outdoor terminal block.

Replace the deicer P.C. board.

Yes

Yes

Yes

Set the switch(SW2-2) on the indoor electronic control P.C. board to MU or MUX type. w1

Yes

Does the unit operate? OKYes

No

NoRefer to the "Instruction of troubleshooting."

w 2 Short circuit of JPG and JPS on the indoor electronic control P.C. board enables self-check to be displayed in 3 seconds.

w 1 Set the switch(SW2-2) on indoor electronic control P.C. board to MU or MUX type, when the outdoor unit is MU or MUX type. If the setting is MUH or MXZ type, the unit does not work.

Is there 5V DC between J205 + –J101 - on the deicer P.C. board?


When OPERATION INDICATOR lamp flashes 0.5-second intervals or 1-time.Outdoor unit does not operate.

OB385B.qxp 07.5.21 4:41 PM Page 16

17

MSC-GA20VBMSC-GA25VBMSC-GA35VBIndoor electronic control P.C. board

CN302

Indoor coil thermistor (RT12)Room temperature thermistor (RT11)

Temperature (:)

Res

ista

nce

(k"

)

SW2(Refer to 8-4.)1sets the Auto restart

function ON/OFF.2switches over MU&MUX type/

MUH & MXZ type.

Power supply input230V AC

Varistor(NR11)

Fuse F11 250V AC 3.15A

Room temperaturethermistor RT11Indoor coilthermistor RT12

Timer short modepoint JPG, JPS(Refer to 8-1.)

Emergencyoperation switch

}

} Indoor fan motor 230V AC}

5V DC

+–

{12V DC +– }

Safety device offan by horizontalvane CN1R1

R132

J23J33

J33

J12

Power monitor, receiver P.C. board

9-6. Test point diagram and voltage

OB385B.qxp 07.5.21 4:41 PM Page 17

18

DISASSEMBLY INSTRUCTIONS10


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

1Slide the sleeve.2Pull the terminal while pushing the locking lever.

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

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

Connector

Sleeve

Locking lever

OPERATING PROCEDURE PHOTOS

1. Removing the front panel(1) Remove the screw caps of the front panel.

Remove the screws.(2) Pull the panel down to your side slightly and unhook the

catches at the top.

2. Removing the electronic control P.C. board and thepower monitor, receiver P.C. boardNOTE : In case of removing only indoor electronic control

P.C. board, work (3) is not necessary.(1) Remove the front panel. (Refer to 1.)(2) Remove the power monitor, receiver P.C. board holder

from the bottom of electrical box.(3) Open the power monitor, receiver P.C. board holder and

remove the power monitor, receiver P.C. board.(4) Remove the screw of the electrical cover and the electrical

cover.(5) Remove the screw of the V.A. clamp and the V.A. clamp.(6) Remove the screw of the cord clamp and the cord clamp.(7) Remove the screw of the terminal block.(8) Remove the screw of the earth wire.(9) Pull out indoor electronic control P.C. board slightly.(10) Disconnect all (except CN101) the connectors on the elec-

tronic control P.C. board.(11) Remove the electronic control P.C. board.(12) Disconnect the connector of power monitor, receiver P.C.

board (CN101) on the electronic control P.C. board.

Photo 2

Photo 1

Terminal blockfixing screw

Screw of the V.A.clamp

Indoor electroniccontrol P.C. board

Screws of the front panel

Screw of theearth wire

Power monitor, receiver P.C. board holder

Screw of theelectrical cover

Cord clamp fixingscrew

OB385B.qxp 07.5.21 4:41 PM Page 18

19

OPERATING PROCEDURE PHOTOS

3. Removing the electrical box(1) Remove the front panel. (Refer to 1.)(2) Remove the electrical cover. (Refer to 2.)(3) Remove the V.A. clamp. (Refer to 2.)(4) Remove the cord clamp. (Refer to 2.)(5) Remove the terminal block. (Refer to 2.)(6) Remove the screw of earth wire. (Refer to 2.)(7) Disconnect the connector of the indoor coil thermistor

(CN112), the fan motor connector (CN211 and CN121) andthe vane motor connector (CN151) on the electronic con-trol P.C. board.

(8) Remove the fan motor lead wire and indoor coil thermistorfrom the electrical box.

(9) Remove the lead wire of vane motor from the bottom of electrical box.

(10) Remove the screw fixing the electrical box, remove the electrical box.

4. Removing the nozzle assembly and the vane motor(1) Remove the front panel. (Refer to 1.)(2) Remove the electrical box. (Refer to 3.)(3) Pull out the drain hose from the nozzle assembly, remove

the nozzle assembly.(4) Remove the screws of the vane motor, disconnect the

vane motor connector.(5) Remove the vane motor.

5. Removing the indoor fan motor and the line flow fan (1) Remove the front panel. (Refer to 1.)(2) Remove the electrical box. (Refer to 3.)(3) Pull out the drain hose from the nozzle assembly, remove

the nozzle assembly. (Refer to 4.)(4) Remove the screw of the lead cover and lead cover.(5) Release the hooks to open the motor band slightly.(6) Loosen the hexagon socket set screw from the line flow

fan.(7) Remove the screws fixing the motor bed, remove the fan

motor with motor band and the motor bed.(8) Remove the screws fixing the left side of the heat

exchanger.(9) Lift the left side of the heat exchanger.(10) Remove the line flow fan.

Photo 5

Photo 3

Photo 4

Photo 7

Screw of theelectrical box

Drain hose

Screws of theleft side of theheat exchanger

Screws of the vane motor

Screws of the motorbed

Photo 6

Indoor coil thermistorconnector

Fan motor connector

Vane motor connector

Hooks of themotor band

Screw of the leadcover

Hexagon socket set screw

OB385B.qxp 07.5.21 4:41 PM Page 19

20

PARTS LIST (non-RoHS compliant)11

1

2345

6

7

8

E02 763 234E02 764 234E02 959 000E02 763 067E02 959 010E02 408 142E02 763 100E02 764 100E02 763 975E02 408 970E02 751 970

BOXBOXPANEL ASSEMBLYSCREW CAPFRONT PANELCATCHCATECHIN AIR FILTERCATECHIN AIR FILTERCORNER BOX (RIGHT)INSTALLATION PLATEINSTALLATION PLATE

Symbol

in Wiring

Diagram

Q'ty/unit

1

12122

11

Including No.3,4,52PCS/SET

2PCS/SET1PCE/SET1PCE/SET

RemarksPart No.No. Part Name MSC-GA20VB-E1

11212

21

1

1

12122

11

11

11

11

E02 749 426E02 527 083

910

REMOTE CONTROLLERREMOTE CONTROLLER HOLDER

MSC-GA25VB-E1

MSC-GA35VB-E1

KP1A, KM04F

1 (W)

72

4


3

8 (W)

11-2. ACCESSORY AND REMOTE CONTROLLER

11-1. INDOOR UNIT STRUCTURAL PARTS


5 6 (W)

10


9

Optional parts(See 13. Optional parts.)

(W) These figures show about MSC-GA35VB.

OB385B.qxp 07.5.21 4:41 PM Page 20

21

Part No.No. Part Name

20

21

22

INDOOR HEAT EXCHANGERINDOOR HEAT EXCHANGERUNION(GAS)UNION(GAS)UNION(LIQUID)

1

1

1

1

11

{9.52{9.52{6.35

1

1

1

E02 001 504E02 661 702E02 A59 235E02 781 040E02 781 041E02 127 382E02 829 385E02 763 034E02 815 468E02 962 452E02 963 452E02 964 452E02 749 303E02 151 308E02 749 333E02 691 375E02 749 300E02 751 300E02 749 307E02 749 302E02 408 509E02 751 509E02 749 385

123456789

10

11121314

15

1617

18

19

SLEEVE BEARINGDRAIN HOSENOZZLE ASSEMBLYVANE UPPER VANE LOWER FUSEVARISTORVANE CRANK SETPOWER MONITOR, RECEIVER P.C. BOARDELECTRONIC CONTROL P.C.BOARDELECTRONIC CONTROL P.C.BOARDELECTRONIC CONTROL P.C.BOARDVANE MOTORROOM TEMPERATURE THERMISTORMOTOR BANDTERMINAL BLOCKINDOOR FAN MOTOR(RC4V19- )INDOOR FAN MOTOR(RC4V19- )INDOOR COIL THERMISTORLINE FLOW FANBEARING MOUNTBEARING MOUNTVARISTOR

3.15A

AUTO RESTARTAUTO RESTARTAUTO RESTART

3P

F11NR11

MVRT11

TBMFMF

RT12

NR12

111111111

1

11111

111

1

1111111111

11111

111

1

111111111

11111

111

11

Symbolin WiringDiagram

Q'ty/unit

RemarksMSC-GA20VB-E1

MSC-GA25VB-E1

MSC-GA35VB-E1

Including fan motor rubber mount 2PCS/SETIncluding fan motor rubber mount 2PCS/SET

E02 A59 620E02 964 620E02 151 666E02 815 666E02 151 667

11-3. INDOOR UNIT ELECTRICAL PARTSAND FUNCTIONAL PARTS

20 (W)

21

22

10

12

4

2

5

11

15

3

1718 16

14

6 87

11-4. INDOOR UNIT HEAT EXCHANGER

11-3. INDOOR UNIT ELECTRICAL PARTS AND FUNCTIONAL PARTS



1

13

9

Part number that is circled is not shown in the illustration.

(W) This figure shows MSC-GA35VB.

PARTS LIST (non-RoHS compliant)

OB385B.qxp 07.5.21 4:41 PM Page 21

22

ROHS PARTS LIST (RoHS compliant)12

1

2345

6

7

8

GGGGGGGGGGG

GG

E12 763 234E12 764 234E12 959 000E12 763 067E12 959 010E12 408 142E12 763 100E12 764 100E12 763 975E12 408 970E12 751 970

BOXBOXPANEL ASSEMBLYSCREW CAPFRONT PANELCATCHCATECHIN AIR FILTERCATECHIN AIR FILTERCORNER BOX (RIGHT)INSTALLATION PLATEINSTALLATION PLATE

Symbol

in Wiring

Diagram

Q'ty/unit

1

12122

11

Including No.3,4,52PCS/SET

2PCS/SET1PCE/SET1PCE/SET

RemarksPart No.No.

Ro

HS

Part Name MSC-GA20VB-E1

11212

21

1

1

12122

11

11

11

11

E12 749 426E12 527 083

910

REMOTE CONTROLLERREMOTE CONTROLLER HOLDER

MSC-GA25VB-E1

MSC-GA35VB-E1

KP1A, KM04F

1 (W)

72

4


3

8 (W)




5 6 (W)

10


9

(W) These figures show about MSC-GA35VB.

Optional parts(See 13. Optional parts.)

OB385B.qxp 07.5.21 4:41 PM Page 22

23

Part No.No.

RoH

S

Part Name

20

2122

GGGG

INDOOR HEAT EXCHANGERINDOOR HEAT EXCHANGERUNION(GAS)UNION(LIQUID)

1

11

111

{9.52{6.35

1

11

E12 001 504E12 897 702E12 A59 235E12 781 040E12 781 041E12 A49 382E12 829 385E12 763 034E12 815 468E12 962 452E12 963 452E12 964 452E12 749 303E12 151 308E12 749 333E12 691 375E12 749 300E12 751 300E12 749 307E12 A59 302E12 408 509E12 751 509E12 749 385

123456789

10

11121314

15

1617

18

19

GGGGGGGGGGGGGGGGGGGGGGG

SLEEVE BEARINGDRAIN HOSENOZZLE ASSEMBLYVANE UPPER VANE LOWER FUSEVARISTORVANE CRANK SETPOWER MONITOR, RECEIVER P.C. BOARDELECTRONIC CONTROL P.C.BOARDELECTRONIC CONTROL P.C.BOARDELECTRONIC CONTROL P.C.BOARDVANE MOTORROOM TEMPERATURE THERMISTORMOTOR BANDTERMINAL BLOCKINDOOR FAN MOTOR(RC4V19- )INDOOR FAN MOTOR(RC4V19- )INDOOR COIL THERMISTORLINE FLOW FANBEARING MOUNTBEARING MOUNTVARISTOR

3.15A

AUTO RESTARTAUTO RESTARTAUTO RESTART

3P

F11NR11

MVRT11

TBMFMF

RT12

NR12

111111111

1

11111

111

1

1111111111

11111

111

1

111111111

11111

111

11

Symbolin WiringDiagram

Q'ty/unit

RemarksMSC-GA20VB-E1

MSC-GA25VB-E1

MSC-GA35VB-E1

Including fan motor rubber mount 2PCS/SETIncluding fan motor rubber mount 2PCS/SET

E12 A59 620E12 964 620E12 151 666E12 151 667

12-3. INDOOR UNIT ELECTRICAL PARTSAND FUNCTIONAL PARTS

20 (W)

21

22

10

12

4

2

5

11

15

3

1718 16

14

6 87


12-3. INDOOR UNIT ELECTRICAL PARTS AND FUNCTIONAL PARTS



1

13

9

Part number that is circled is not shown in the illustration.

(W) This figure shows MSC-GA35VB.

ROHS PARTS LIST (RoHS compliant)

OB385B.qxp 07.5.21 4:55 PM Page 23

OPTIONAL PARTS13

CC Copyright 2005 MITSUBISHI ELECTRIC ENGINEERING CO.,LTDDistributed in May 2007. No.OB385 REVISED EDITION-B 6Distributed in May 2006. No.OB385 REVISED EDITION-A 6Distributed in Jan. 2005. No.OB385 6Made in Japan

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

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

Air cleaning filter(White bellows type)

AIR CLEANING FILTER● AIR CLEANING FILTER removes fine dust of 0.01 micron from air by means of static electricity.● Normal life of AIR CLEANING FILTER is 4 months. However, when it becomes dirty, replace it as soon as possible.● Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet.● DO NOT reuse AIR CLEANING FILTER even if it is washed.● DO NOT remove or attach AIR CLEANING FILTER during unit operation.

Model Part No.

MAC-1300FTMSC-GA20VBMSC-GA25VBMSC-GA35VB

OB385B.qxp 07.5.21 4:41 PM Page 24

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