Mitsubishi Electric MSZ-GC22VA, MSZ-GC25VA, MSZ-GC35VA, MSZ-GC22VA - E1, MSZ-GC25VA -E1 Service Manual

CONTENTS

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

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

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

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

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

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

7. REFRIGERANT SYSTEM DIAGRAM ················6

8. SERVICE FUNCTIONS ······································7

9. MICROPROCESSOR CONTROL ······················9

10. TROUBLESHOOTING······································14

11. DISASSEMBLY INSTRUCTIONS·····················26

MSZ-GC22VA ­MSZ-GC22VA ­MSZ-GC25VA ­MSZ-GC25VA ­MSZ-GC35VA ­MSZ-GC35VA -

E2

E1

E2

E1

E2

E1

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

NOTE:

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

Outdoor unit service manual
MUZ-GC·VA Series (OBH469)
MXZ-A·VA Series (OB377)
MXZ-8A140A (OC316)

SERVICE MANUAL

Wireless type
Models

No. OBH468

REVISED EDITION-B

INDOOR UNIT

PARTS CATALOG (OBB468)

Revision B:

• has been added.

E2

Please void OBH468 REVISED EDITION-A.

2

1

TECHNICAL CHANGES

MSZ-GA22VA -

➔ MSZ-GC22VA ­MSZ-GA25VA - ➔ MSZ-GC25VA ­MSZ-GA35VA - ➔ MSZ-GC35VA -

E1

E1

E1E1

E1E1

1. Indoor model has been changed.

PART NAMES AND FUNCTIONS

2

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

Air outlet

Vertical vane

Air inlet

Operation Indicator
lamp

Front panel

Catechin air filter

Horizontal vane

Remote controller

Remote control
receiving section

Emergency operation switch (E.O. SW)

Air cleaning filter
(Anti-allergy enzyme filter, option)

Line flow fan

Revision A:

• 10.TROUBLESHOOTING has been corrected.

• Color of lead wire (indoor fan motor : sensor part) of 10-5.”Trouble criterion of main parts” has been corrected.

• 10-6.”ACheck of indoor fan motor” has been corrected.

Revision B:

• has been added.

E2

MSZ-GC22VA - ➔ MSZ-GC22VA ­MSZ-GC25VA - ➔ MSZ-GC25VA ­MSZ-GC35VA - ➔ MSZ-GC35VA -

E2

E1

E2E1

E2E1

1. Panel has been changed.

3

SPECIFICATION

3

Fuse

Horizontal vane motor

Varistor

Terminal block

(F11)

(MV)

(NR11)

(TB)

T3.15AL 250V

12V DC

S10K320E3K1(ERZV14D471)

3P

Specifications and rating conditions of main electric parts

NOTE : Test conditions are based on ISO 5151

Cooling : Indoor Dry-bulb temperature 27

:Wet-bulb temperature 19:

Outdoor Dry-bulb temperature 35:

Heating : Indoor Dry-bulb temperature 20:

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

Refrigerant piping length (one way): 5m
✽1 Measured under rated operating frequency.

MSZ-GC25VA MSZ-GC35VA

Single phase

230V,50Hz

0.22
40

0.22

788O295O234

9
4

43

4

KM05B

36/29/22

Cooling

576

462/354/246

1,070

890/720/550

Heating

600

480/378/276

1,100

920/760/600

MSZ-GC22VA

Indoor model

Function

Power supply

36/29/21

Cooling

576

462/354/246

1,070

890/720/550

Heating

600

480/378/276

1,100

920/760/600

RC4V18-BA or CA

Cooling

552

444/330/234

1,110

930/740/580

Heating

570

462/354/246

1,140

960/780/600

Air flow(Super High)
Air flow(High/Med./Low)
Running current ✽1
Power input ✽1
Fan motor current ✽1
Model
Dimensions WOHOD
Weight
Air direction
Sound level (Super High)
Sound level (High/Med./Low)
Fan speed (Super High)
Fan speed (High/Med./Low)
Fan speed regulator

Remote controller model

K /h
K /h

A

W

A

mm

kg

dB(A)
dB(A)

rpm
rpm

Electrical

data

Fan motor

Special

remarks

Capacity

ACCESSORIES

1
2
3
4
5
6
7

Installation plate

Installation plate fixing screw 4 o 25 mm

Remote controller holder
Fixing screw for 3 3.5 o 1.6 mm (Black)

Battery (AAA) for remote controller

Wireless remote controller

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

1

5

1

2

2

1

1

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

4

4

NOISE CRITERIA CURVES

MSZ-GC22VA
MSZ-GC25VA

INDOOR UNIT

WALL

MICROPHONE

0.8m

1m

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

BAND CENTER FREQUENCIES, Hz

COOLING

FUNCTION

SPL(dB(A))

LINE

Super High

FAN SPEED

HEATING

Test conditions
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:

Heating : Dry-bulb temperature 20:

43

43

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

MSZ-GC35VA

90

80

70

60

50

40

30

20

10

63 125 250 500 1000 2000 4000 8000

NC-60

NC-50

NC-40

NC-30

NC-20

NC-70

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

BAND CENTER FREQUENCIES, Hz

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

COOLING

FUNCTION

SPL(dB(A))

LINE

Super High

FAN SPEED

HEATING

43

43

5

OUTLINES AND DIMENSIONS

5

Unit : mm

7459

41.5

214

235

253.5

18.5

320335

155 155

21540.5

254.5

5959 225 225

2

295

53 607 128

8

100

137

119

Piping

Insulation

[35 O.D

Liquid line

[6.35 - 0.5 m (Flared connection [6.35)

Gas line

[9.52 - 0.43 m (Flared connection [9.52)

Drain hose

Insulation [28 O.D Connected part [16 O.D

11 X 26 Oblong hole

11

X 20 Oblong hole

Installation plate

Indoor unit

Wall hole

[65

Air in

Air out

Installation plate

Piping

Drain hose

19

159

58

234

5

788

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

6

6

WIRING DIAGRAM

REFRIGERANT SYSTEM DIAGRAM

7

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

Refrigerant flow in cooling
Refrigerant flow in heating

Indoor
heat
exchanger

Flared connection

Room temperature
thermistor
RT11

Flared connection

Refrigerant pipe [9.52
(with heat insulator)

Refrigerant pipe [6.35
(with heat insulator)

Indoor coil
thermistor
RT12 (main)

Indoor coil
thermistor
RT13 (sub)

Unit : mm

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

7

SERVICE FUNCTIONS

8

8-2. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION

A 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 be
modified according to the number of the indoor unit.

8-1. TIMER SHORT MODE

For service, set time can be shortened by short circuit of JPG and JPS on the electronic control P.C. board.
The time will be shortened as follows. (Refer to 10-7.)
Set time : 1-minute ➔ 1-second
Set time : 3-minute ➔ 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.)

No. 1 unit

No. 2 unit

No. 3 unit

No. 4 unit

1 unit operation

No modification

–

–

–

2 units operation

Same as at left

Solder J1

–

–

3 units operation

Same as at left

Same as at left

Solder J2

–

4 units operation

Same as at left

Same as at left

Same as at left

Solder both J1 and J2

Table 1

How to set the remote controller exclusively for particular indoor unit

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

How to modify the remote controller P.C. board

Remove batteries before modification.
The board has a print as shown below :

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.

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.

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

J2

J1

8

NOTE :

• The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the

remote controller.

• If main power is turned OFF or a power failure occurs 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 to the system that allows the units to start one by one.

JR07

Indoor electronic
control P.C. board

CN10A CN111CN151 CN112

8-3. AUTO RESTART FUNCTION

When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed
are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation
in the same mode just before the shutoff of the main power.

Operation

1

If the main power has been cut, the operation settings remain.

2 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.)

How to release “AUTO RESTART FUNCTION”

1

Turn off the main power for the unit.

2Solder the jumper wire to JR07 on the indoor electronic control P.C. board. (Refer to 10-7.)

9

MICROPROCESSOR CONTROL

9

Once the operation mode is set, the same operation mode can be repeated by simply turning OPERATE/STOP
(ON/OFF) button ON.
Indoor unit receives the signal with a beep tone.
When the system turns off, 3-minute time delay will operate to protect system from overload and compressor will not
restart for 3 minutes.

WIRELESS REMOTE CONTROLLER

Operation Indicator lamp

The operation indicator at the right side of the indoor unit indicates the operation state.

INDOOR UNIT DISPLAY SECTION

About 2 : or more
away from
set temperature

Room temperature

About 1 to 2 : from
set temperature

The unit is operating
to reach the set
temperature

The room temperature
is approaching
the set temperature

Standby mode
(only during multi
system operation)

Operation state

Indication

Lighted

Not lighted

•The following indication applies regardless of shape of the indicator.

Blinking

MSZ-GC22VA
MSZ-GC25VA
MSZ-GC35VA

ON TIMER button

CLOCK SET button

TIME SET buttons
FORWARD button
BACKWARD button

OFF TIMER button

Open the front lid.

RESET button

VANE CONTROL button

Signal transmitting section

Operation display section

Temperature buttons

OPERATE/STOP
(ON/OFF) button

FAN SPEED CONTROL button

OPERATION SELECT button

ECONO COOL button

Indication of
remote controller
model is on back

10

1. Coil frost prevention

Coil frost prevention is as same as COOL mode. (9-1.1.)

2. Low outside temperature operation

Low outside temperature operation is as same as COOL mode. (9-1.2.)

1. Cold air prevention control

When the compressor is not operating or is starting, and the temperature of indoor heat exchanger and/or the room tem­perature is low or when defrosting is being done, the indoor fan will stop or rotate in Very Low speed.

9-2. DRY ( ) OPERATION

(1) Press OPERATE/STOP(ON/OFF) button.

OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select DRY mode with OPERATION SELECT button.
(3) The set temperature is determined from the initial room temperature.

9-3. HEAT ( ) OPERATION

(1) Press OPERATE/STOP(ON/OFF) button.

OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature.

The setting range is 16 ~ 31°C.

1. Coil frost prevention

The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the coil

from frosting.

When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works.

The indoor fan operates at the set speed and the compressor stops. This mode continues until the temperature of indoor

heat exchanger rises.

2. Low outside temperature operation

When the outside temperature is lower, low outside temperature operation starts, and the outdoor fan slows or stops.

9-1. COOL ( ) OPERATION

(1) Press OPERATE/STOP(ON/OFF) button.

OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button)to select the desired temperature.

The setting range is 16 ~ 31°C.

2. High pressure protection

The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the con­densing pressure from increasing excessively.
When the temperature of indoor heat exchanger becomes too high, the high pressure protection works.
The indoor fan operates following the cold air prevention control. This mode continues until the temperature of indoor
heat exchanger falls.

3. Defrosting

Defrosting starts when the temperature of outdoor heat exchanger becomes too low.
The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.
This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.

9-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION

Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.

Mode selection

(1) Initial mode

When unit starts the operation with AUTO operation from off;

• If the room temperature is higher than the set temperature, operation starts in COOL mode.

• If the room temperature is equal to or lower than the set temperature, operation starts in HEAT mode.

(2) Mode change

COOL mode changes to HEAT mode when about 15 minutes have passed with the room temperature 2 degrees
below the set temperature.
HEAT mode changes to COOL mode when about 15 minutes have passed with the room temperature 2 degrees
above the set temperature.

NOTE 1

If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is operating
in (AUTO), cannot change over to the other operating mode (COOL HEAT) and becomes a state of standby.
Refer to NOTE 2 “FOR MULTI SYSTEM AIR CONDITIONER”.

11

(3) Positioning

To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the selected
angle.
Confirming of standard position is performed in the following cases:
(a) When the operation starts or finishes (including timer operation).
(b) When the test run starts.
(c) When standby mode (only during multi system operation) starts or finishes.

9-5. AUTO VANE OPERATION

1. Horizontal vane

(1) Vane motor drive

These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approx. 12V) transmitted from indoor microprocessor.

(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.

(4) VANE AUTO ( ) mode

In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room temper­ature distribution.

Horizontal

position

In COOL and DRY operation

In HEAT operation

Vane angle is fixed to Horizontal position.

Vane angle is fixed to Angle 4.

(6) Dew prevention

During COOL or DRY operation with the vane angle at Angle 2 ~ 4 when the compressor cumulative operation time

exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.

(5) STOP (operation OFF) and ON TIMER standby

In the following cases, the horizontal vane returns to the closed position.
(a) When OPERATE/STOP (ON/OFF) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON TIMER is ON standby.

NOTE 2
FOR MULTI SYSTEM AIR CONDITIONER

OUTDOOR UNIT : MXZ series

Multi system air conditioner can connect two or more indoor units with one outdoor unit.

•Unit won’t operate in case the total capacity of indoor units exceeds the capacity of outdoor units. Do not connect
indoor units beyond the outdoor unit capacity.
Operation indicator lamp flashes as shown in the figure below.

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

•When indoor unit 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

flowng may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.

OPERATION INDICATOR

Not lighted

Blinking

Lighted

12

To change the air

flow direction

When to use this function?

Use this function if you don’t
want the air from the indoor
unit to blow directly onto your
body.

• Depending on the shape of
the room, the air may blow
directly onto your body.

• Pr es s VANE CONTROL
bu tt on again to return the

vane to the previously-set
position.

Pressing and holding
VANE CONTROL
button for 2 s ec on ds
or m or e cau se s
the horizontal vane
to reverse and
move to horizontal
position.

The air conditioner starts the
cooling or dr ying operat ion
appr ox. 3 minutes after the
vane has moved to the hori­zontal position.

• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the cool or dry
operation in approx.
3 minutes.

The air conditioner starts heat­ing operation approx. 3 minutes
after the vane has moved to the
horizontal position.

• Sometimes the area
around your feet may not
warm. To warm the area
around the feet, set the
horizontal vane to
(AUTO) or the downward­ blowing position.

• When VANE CONTROL
button is pressed again,
the vane returns to the
previously-set position
and the air conditioner
starts the heat operation
in approx. 3 minutes.

COOL/DRY

HEAT

NOTE :

• If you make the air flow not to blow directly onto your body by pressing VANE CONTROL button,
the compressor stops for 3 minutes even during the operation of the air conditioner.

• The air conditioner operates with Very Low speed until the compressor turns on again.

(9) To change the air flow direction not to blow directly onto your body.

Horizontal

position

(10) ECONO COOL ( ) operation (ECONOmical operation)

When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 2°C higher.
Also the horizontal vane swings in various cycle.
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher, the air
conditioner can keep comfort. As a result, energy can be saved.
ECONO COOL operation is cancelled when ECONO COOL button is pressed once again or VANE CONTROL
button is pressed or change to other operation mode.

9-6. TIMER OPERATION

1. How to set the time

(1) Check that the current time is set correctly.

NOTE : Timer operation will not work without setting the current time. Initially “AM0:00” blinks at the current time display

of TIME MONITOR, so set the current time correctly with CLOCK SET button.

How to set the current time

(a) Press the CLOCK set button.

(b) Press the TIME SET buttons ( and ) to set the current time.

• Each time FORWARD button ( ) is pressed, the set time increases by 1minute, and each time BACK
WARD button ( ) is pressed, the set time decreases by 1minute.

• Pressing those buttons longer, the set time increases / decreases by 10 minutes.

(c) Press the CLOCK set button.
(2) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(3) Set the time of timer.

ON timer setting

(a) Press ON TIMER button( ) during operation.

(b) Set the time of the timer using TIME SET buttons ( and ) .

w

OFF timer setting

(a) Press OFF TIMER button ( ) during operation.

(b) Set the time of the timer using TIME SET buttons ( and ).

w

w Each time FORWARD button ( ) is pressed, the set time increases by 10 minutes; each time BACKWARD but-

ton ( ) is pressed, the set time decreases by 10 minutes.

START

STOP

NOTE : When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat

off, this control doesn’t work in the indoor unit.

(8) Cold air prevention in HEAT operation

The horizontal vane position is set to Upward.

(7) SWING ( ) mode

By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically.

13

EMERGENCY OPERATION switch (E.O. SW)

Operation mode COOL HEAT

Set temperature

24:

24:

Fan speed Medium Medium

Horizontal vane Auto Auto

The operation mode is indicated by the Operation
Indicator lamp on the indoor unit as following

Not lighted

Lighted

Operation Indicator lamp

EMERGENCY HEAT

EMERGENCY COOL

STOP

9-7. EMERGENCY/TEST OPERATION

In case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the right side of the
indoor unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of the
remote controller run down. The unit will start and OPERATION INDICATOR lamp will light.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan runs at High
speed and the system is in continuous operation (The thermostat does not work).
After 30 minutes of test run operation, the system shifts to EMERGENCY COOL / HEAT MODE with a set temperature of
24°C. The fan speed shifts to Med..

In the test run or emergency operation, the horizontal vane operates in VANE AUTO ( ) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter, normal operation will start.

NOTE : Do not press EMERGENCY OPERATION switch during normal operation.

2. To release the timer

To release ON timer, press ON TIMER button ( ).
To release OFF timer, press OFF TIMER button( ).
TIMER is cancelled and the display of set time disappears.

START

STOP

PROGRAM TIMER

(Example 1) The current time is 8:00 PM.

The unit turns off at 11:00 PM, and on at 6:00 AM.

• OFF timer and ON timer can be used in combination. The timer of the set time that is reached first will operate first.

• “ ” and “ ” display shows the order of OFF timer and ON timer operation.

(Example 2) The current time is 11:00 AM.

The unit turns on at 5:00 PM, and off at 9:00 PM.

NOTE : If the main power is turned off or a power failure occurs while ON/OFF timer is active, the timer setting

is cancelled. As these models are equipped with an auto restart function, the air conditioner starts operating with

timer cancelled when power is restored.

14

10

TROUBLESHOOTING

3. Troubleshooting procedure

1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.
To make sure, check how many times the abnormality indication is flashing on and off before starting service work.

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

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

bursting and discoloration.

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

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.

NOTE : 1. If RESET button is not pressed, the remote controller may not operate correctly.

2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.
This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by

the battery replacement.

10-1. Cautions on troubleshooting

1. Before troubleshooting, check the following:

1) Check the power supply voltage.

2) Check the indoor/outdoor connecting wire for mis-wiring.

2. Take care of the following during servicing

1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, 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 P.C. board.

3) When removing the 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.

Housing point

Lead wiring

MSZ-GC22VA MSZ-GC25VA MSZ-GC35VA

RESET button

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

2 Press RESET button with tip end of ball point pen

or the like, and then use the remote controller.

1 Remove the front lid and insert batteries.

Then reattach the front lid.

1

Lock

2

If horizontal vane is not installed correctly, all of the operation indicator lamps will blink.
In this case, install the horizontal vane correctly by following the procedures 1 to 2.

NOTE : Before installation of the horizontal vane, turn OFF the power supply.

5. How to install the horizontal vane

In procedure

2

lock the
stoppers until they click
into place.

15

Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though LED indication listed on the troubleshooting check table (10-4.) disappears, the memorized failure details
can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.

10-2. Failure mode recall function

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

Operational procedure

Yes

(Blinks)

No

(OFF)

Yes

No

Releasing the failure mode recall function

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.

W2. Blinking pattern when the indoor unit is abnormal:

W3.Blinking pattern when the outdoor unit is abnormal:

ON

OFF

Beeps

Repeated cycle Repeated cycle

ON

OFF

No beep Beeps

Repeated cycle

2.5-second OFF

Blinking at 0.5­second interval

2.5-second OFF 3-second ON

Blinking at 0.5­second interval

Beeps

Repeated cycle

2.5-second OFF

Blinking at 0.5­second interval

No beep Beeps

Repeated cycle

2.5-second OFF 3-second ON

Blinking at 0.5­second interval

Repeated cycle

Beeps

Does upper lamp of OPERATION INDICATOR
lamp on the indoor unit blink at the interval of 0.5
seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing
as the blinking of upper lamp of
OPERATION INDICATOR lamp. W2

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

Setting up the failure mode recall function

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

The indoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the indoor unit
failure mode table(10-2.2.).
Make sure to check at least two consecutive blinking cycles. W2

Turn ON the power supply.
<

Preparation of the remote controller

>

1 While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller at the same time, press
RESET button.
2 First, release RESET button.
And release the other two buttons after all LCD in operation display section of the

remote controller is displayed after 3 seconds.

Deleting the memorized abnormal condition

1After repairing the unit, recall the failure mode again according to
"Setting up the failure mode recall function" mentioned above.
2Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature is displayed)
with the remote controller headed towards the indoor unit.

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

mentioned above.

Repair the defective parts.

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

Judgment of indoor/outdoor abnormality

Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit. W1

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

The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the
outdoor unit failure mode table (Refer to outdoor unit service manual.)
Make sure to check at least two consecutive blinking cycles. W3

W1. Regardless of normal or abnormal condition,
a short beep is emitted once the signal is
received.

16

2. Indoor unit failure mode table

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

12-time flash

2.5-second OFF

Replace the indoor electronic control
P.C. board.

Indoor control system

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

11-time flash

2.5-second OFF

Refer to 10-6.A "Check of indoor fan
motor".

Indoor fan motor

The rotational frequency feedback signal is
not sent out for 12-seconds after indoor fan
motor is opeated.

2-time flash

2.5-second OFF

Refer to the characteristics of the main
indoor coil thermistor, the sub indoor coil
thermistor (10-7.).

Indoor coil thermistor

The indoor coil thermistor short or open
circuit is detected every 8 seconds during
operation.

3-time flash

2.5-second OFF

Refer to 10-6.D "How to check mis-wiring
and serial signal error".

Serial signal

The serial signal from outdoor unit is
not received for 6 minutes.

1-time flash
every 0.5-second

Refer to the characteristics of the room
temperature thermistor (10-7.).

Room temperature
thermistor

The room temperature thermistor short
or open circuit is detected every 8 seconds
during operation.

Not lighted —Normal —

Upper lamp of OPERATION

INDICATOR lamp

Correspondence

Abnormal point

(Failure mode)

Condition

17

Start

Indoor unit
operates.
Outdoor unit
doesn't
operate.

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

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

Outdoor unit
operates only
in Test Run
operation.

w

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

w

Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.

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

Check room
temperature
thermistor.
Refer to 10-7.
"Test point
diagram and
voltage".

Refer to
"How to check
inverter/
compressor".

Refer to 10-6.B
"Check of
remote controller
and indoor
electronic control
P.C. board".

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

2. Refer to 10-6.C
"Check of indoor
P.C. board and indoor
fan motor".

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

Refer to
"Check of
R.V. coil".

Refer to outdoor unit service manual.

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

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

w

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

Upper lamp
Flash on and off
at 0.5-second
intervals
Cause:
Indoor/
Outdoor unit

• Mis-wiring
or trouble
of serial signal

Upper

lamp
2-time flash
Cause:
Indoor unit

• Trouble of
room temp­ erature/
indoor coil
thermistor

Upper

lamp
3-time flash
Cause:
Indoor unit

• Trouble of
indoor fan
motor

Upper

lamp
5-time flash
Cause:
Outdoor unit

• Outdoor
power
system
abnormality

Upper

lamp
6-time flash
Cause:
Outdoor unit

• Trouble of
thermistor
in outdoor
unit

Upper

lamp
7-time flash
Cause:
Outdoor unit

• Trouble of
outdoor
control
system

Refer to 10-6.
D "How to
check of
mis-wiring
and serial
signal error

".

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

• The horizontal
vane is not
installed
correctly.

Refer to 10-6.
E "Check of
installation of
the horizontal
vane".

Check room
temperature
thermistor
and indoor
coil thermis­tor.
Refer to 10-7.
"Test point
diagram and
voltage".

Refer to 10-6.
A "Check of
indoor fan
motor".

Refer to
"How to check
inverter/
compressor".

Refer to
"Check of
outdoor
thermistors".

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

Upper

lamp
14-time flash
Cause:
Outdoor unit

• Other
abnormality

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

Upper

lamp
4-time flash
Cause:
Indoor unit

• Trouble of
indoor unit
control
system

Replace the
indoor
electronic
control
P.C. board.

10-3. Instruction of troubleshooting

18

No.

1

2

5

6

SymptomOperation indicator lamp

Condition

Correspondence

Upper lamp flashes.

0.5-second ON

0.5-second OFF

Mis-Wiring
or serial
signal

Outdoor
power
system

Outdoor
thermistors

Outdoor
control
system

Indoor coil
thermistor

The serial signal from the outdoor unit is not
received for 6 minutes.

It consecutively occurs 3 times that the
compressor stops for overcurrent protection or
start-up failure protection within 1 minute after
start-up.

The outdoor thermistors short or open circuit
during the compressor operation.

It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the
outdoor electronic control P.C. board.

• Refer to "Check of outdoor
thermistor".

Refer to outdoor unit service
manual.

• Refer to "How to check of

inverter/compressor".

Refer to outdoor unit service
manual.

• Check the stop valve.

• Replace the inverter P.C.

board or the outdoor
electronic control P.C. board.
Refer to outdoor unit service
manual.

• Refer to 10-6.D "How to check

mis-wiring and serial signal

error".

3

Indoor fan
motor

7

Abnormal

point

Room
temperature
thermistor

Upper lamp flashes.
2-time flash

2.5-second OFF

The indoor coil or the room temperature
thermistor is short or open circuit.

• Refer to 10-7.the

characteristics of indoor coil
thermistor, and the room
temperature thermistor.

Upper lamp flashes.
3-time flash

2.5-second OFF

The rotational frequency feedback signal is
not emitted during the indoor fan operation.

• Refer to 10-6.A "Check of

indoor fan motor".

Indoor unit
and outdoor
unit do not
operate.

Upper lamp flashes.
5-time flash

2.5-second OFF

Upper lamp flashes.
6-time flash

2.5-second OFF

Other
abnormality

An abnormality other than above mentioned is
detected.

• Check the stop valve.

• Confirm the abnormality in

detail using the failure mode
recall function for outdoor
unit.

8

4

Upper lamp flashes.
4-time flash

2.5-second OFF

Indoor
control
system

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

• Replace the indoor electronic

control P.C. board.

Outdoor
control
system

It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the
outdoor electronic control P.C. board.

• Check the blinking pattern of
the LED on the inverter P.C.
board or the outdoor
electronic
control P.C. board.

9

Outdoor unit
does not
operate.

Upper lamp lights up

Upper lamp flashes.
7-time flash

2.5-second OFF

Upper lamp flashes.
14-time flash

2.5-second OFF

10-4. Troubleshooting check table

Not lighted

Blinking

OPERATION INDICATOR

Lighted

Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and the following detection method has detected an abnormality (the first
detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with
OPERATION INDICATOR lamp flashing.

19

10-5. Trouble criterion of main parts

MSZ-GC22VA MSZ-GC25VA MSZ-GC35VA

Measure the voltage power ON.

Figure

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

BLK

BLK
RED

BLK

BLK

ROTOR

BLK

RED

WHT

GRY

YLW

BRN

MAIN

AUX.

FUSE

Motor part

Sensor part

Measure the resistance between the terminals with a tester.
(Part temperature 10˚C ~ 30˚C)

BRN – YLW

BRN – GRY

Normal

4.5 ~ 5.5V

(When fan revolved one time)

0V➔5V➔0V

(Approx.)

Color of lead wire

Part name Check method and criterion

Indoor fan motor (MF)
INNER FUSE
BA : 135i3: CUT OFF
CA : 140i2: CUT OFF

Measure the resistance with a tester.

Refer to 10-7."Test point diagram and voltage",
"2.Indoor electronic control P.C. board", the chart of thermistor.

Room temperature
thermistor (RT11)

Indoor coil thermistor
(RT12, RT13)

Vane motor (MV)

Normal

RED-BLK

235 " ~ 255 "

Color of the lead wire

WHT – BLK

BLK – RED

Normal

RC4V18-BA

273 " ~ 296 "
295 " ~ 320 "

Color of lead wire

RC4V18-CA

308 " ~ 334 "
295 " ~ 320 "

OPERATION INDICATOR

OPERATION INDICATOR

No.

1

SymptomOperation indicator lamp

Condition

Correspondence

Abnormal

point

0.5-second ON

0.5-second OFF

The electricity is not conducted to the interlock
switch (Fan) of the horizontal vane.

• Refer to 10-6.E "Check of
installation of the horizontal
vane".

Indoor unit
and outdoor
unit do not
operate.

Attachment
of the
horizontal
vane

All lamps flash at the same time.

No.

SymptomOperation indicator lamp

Condition

Correspondence

Abnormal

point

1

MXZ type

Operation
mode
setting

Outdoor unit
operates but
indoor unit
does not
operate.

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

• Unify the operation mode.
Refer to outdoor unit service
manual.

2.5-second OFF

Upper lamp lights and lower lamp flashes.

20

Check of remote controller and indoor electronic control P.C. board

B

Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller.

wCheck if the remote controller is exclusive for this air conditioner.

Yes

Replace the batteries. (Refer to 10-1.4.)

Is noise heard from radio?

Are there any fluorescent lights of

inverter or rapid-start type within
the range of 1m?

Replace the indoor electronic
control P.C. board.
(including the receiver)

Replace the remote controller.

● Reinstall the unit away from lights.

● Attach a filter on receiving part.

Press OPERATE/STOP(ON/OFF) button on the remote controller.

Is LCD display on the the remote
controller visible?

Remove the batteries, then set them back
and press RESET button. (Refer to 10-

1.4.) Check if the unit operates with the
remote controller.

Yes

Does the unit operate with the
remote controller?

Yes

OK

No

(not clear)

Yes

No

No

No

Check of indoor fan motor

A

When OPERATION INDICATOR lamp flashes 3-time. Indoor fan does not operate.

10-6. Troubleshooting flow

CN211

Indoor power P.C.board

Fuse (F11)

Indoor terminal
P.C.board

Varistor
(NR11)

CN121

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

Yes ( 0 or ∞ )

No

Yes

No

Turn OFF the power supply.
Check connector CN211 visually.

Disconnect the lead wires from connector CN211 on indoor power P.C. board.
Measure the resistance between lead wires No.1 and No.4 and then No.4 and No.7.

Turn ON the power supply. Rotate indoor fan slowly for 1 revo­lution or over with a screwdriver etc. from air outlet, and mea­sure the voltage No.2(+) and No.1(-) on CN121.

No

(others)

Replace the indoor power / terminal P.C. board
and the indoor electronic control P.C. board.

Does the voltage repeat 0V DC and 5V DC?

Yes

No

Are lead wires connected?

Reconnect the lead wires.

Resolder it.

Replace the indoor fan motor.

Are soldered points of the

connector correctly soldered to

indoor power P.C. board?

Yes

Turn ON a radio to AM and press
OPERATE/STOP(ON/OFF) button on the remote controller.

21

The unit does not operate with the remote controller.
Also, OPERATION INDICATOR lamp does not light up by pressing EMERGENCY OPERATION switch.

Check of indoor P.C. board and indoor fan motor

C

Yes

No

w. Please replace the fuse after removing
the indoor terminal P.C. board from the electrical box.

Yes

No

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

OPERATION switch?

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

Measure the resistance of the vane motor coil.
Refer to 10-5.

Measure the resistance
Refer to 10-5 of indoor fan motor.

Short circuit:
Replace the indoor fan motor.

Short circuit:
Replace the vane motor and the indoor
electronic control P.C. board.

Turn OFF the power supply.
Check both “parts side” and “pattern
side” of the indoor terminal P.C.
board visually.

Replace the varistor(NR11) and fuse(F11). w

Are the varistor (NR11) burnt
and the fuse (F11) blown?

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

No

Yes

No

Is the fuse (F11) blown only?

Yes

No

Is the resistance normal?

Is the approx. 5VDC between 5V (+)
and JPG(GND) (–) of the indoor
electronic control P.C.board? Is there
approx. 9V to 13VDC between 12V (+)
and JPG (GND) (–) of the indoor
electronic control P.C. board.

Measure the resistance of
indoor fan motor.
Refer to 10-5.

Replace the fuse (F11). w

Replace the fuse (F11) and the indoor fan motor. w

Is the resistance
approx. 4'?

Measure the resistance of cement
resistor R111 on the indoor power
P.C. board.

Replace the indoor fan motor.

Yes

Connect the connector or repair
disconnection.

Yes

No

Are connector CN10A on
the indoor electronic control
P.C. board or lead wires
disconnected?

No

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

Replace the indoor power / terminal P.C. board
and the indoor fan motor.

Yes

JPG (GND)

12VDC

5VDC

CN10A

CN211

Indoor power P.C.board

Indoor electronic
control P.C.board

Fuse (F11)

Indoor terminal
P.C.board

Varistor
(NR11)

R111

22

How to check mis-wiring and serial signal error

D

Is there rated voltage in
the power supply?

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

W1. Mis-wiring may damage indoor P.C. board during the

operation.
Be sure to confirm the wiring is correct before the
operation starts.

W3. Be sure to check this within 3 minutes after turning ON.

After 3 minutes, LED blinks 6 times. Even when
the inverter P.C.board or the outdoor electronic control
P.C.board is normal, LED blinks 6 times after 3 minutes.
(Except for outdoor unit of multi system type)

(Lighted or
not lighted)

No

Yes

No

Yes

Yes

No

Yes

No

Yes

W2 Be careful to the residual
voltage of smoothing capacitor.

No

No

Yes

No

Yes

Yes

Turn OFF the power supply.

Turn ON the power supply.

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

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

Press EMERGENCY OPERATION switch once.

Check the power
supply.

A

Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not mis-wiring.

Short-circuit outdoor terminal block S2 and
S3.
W1

B

Turn ON the power supply.

Check the wiring.

Correct them.

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

No

No

No

Yes

Yes

Yes

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

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

No

Replace the
indoor/outdoor
connecting wire.

Is serial signal
error indicated
6 minutes later?

Yes

No

· Turn OFF inverter-controlled lighting
equipment.

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

· Press EMERGENCY OPERATION
switch.

B

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

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

A

Is serial signal error indicated 6 minutes later?

Is there 2V DC or less between CN10A3(+)
and JPG(GND)(–) on the indoor electronic
control P.C. board?

Is there 2V DC or less between
CN10A4(+) and JPG(GND)(–)
on the indoor electronic control
P.C. board?

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

Is there 2V DC or less between
CN10A4(+) and JPG(GND)(–)
on the indoor electronic control
P.C. board?

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"? W3

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

Replace the indoor
electronic control P.C. board.

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

• When OPERATION INDICATOR lamp flashes ON and OFF every 0.5-seconds.
Outdoor unit does not operate.

23

Check of installation of the horizontal vane

E

Replace the
indoor electronic
control P.C. board.

Replace the
interlock switch(Fan).

Is the stopper of the horizontal vane
locked to the indoor unit correctly?

Yes

No

Is there resistance 0 "?

Relock the stopper of the
horizontal vane to the indoor unit.
(Refer to 10-1.5.)

Yes

Are all lamps flashing?

Yes

No(∞)

No

OK

Turn ON the
power supply.

To check the continuity of the interlock switch
(Fan), measure the resistance of connector 1 - 2
connected to CN1R1 on the indoor
electronic control P.C. board.

Turn OFF the
power supply.

Turn OFF the
power supply.

When All lamps flash ON and OFF every 0.5-second.
Indoor unit and outdoor unit do not operate.

24

Electromagnetic noise enters into TV sets or radios

F

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

No

No

No

Yes

Yes

No

No

Yes

Yes

Yes

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

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

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

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

Even if all of the above conditions are fulfilled, the electromagnetic noise may enter, depending on
the electric field strength or the installation condition (combination of specific conditions such as
antennas or wiring).
Check the followings before asking for service.

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

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

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

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

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

6.Presence or absence of amplifier such as booster

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

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

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

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

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

After checking the above, consult the service representative.

Is the unit earthed?

Earth the unit.

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

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

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

25

Room temperature thermistor (RT11)
Indoor coil thermistor (RT12, RT13)

Temperature (:)

Resistance (k")

MSZ-GC22VA MSZ-GC25VA MSZ-GC35VA

1. Indoor power P.C. board, Indoor terminal P.C. board

10-7. Test point diagram and voltage

Timer short mode
point JPG JPS
(Refer to 8-1.)

Room temperature thermistor RT11 (CN111)

Indoor coil thermistor RT12, RT13(CN112)

Vane motor (CN151)

Connector to
Indoor power P.C. board
(CN10A)

12V DC

5V DC

Release of Auto restart function
Solder the Jumper wire to JR07
(Refer to 8-3.)

Emergency operation
switch (E.O.SW) (SW1)

2. Indoor electronic control P.C. board

Indoor terminal P.C. board Indoor power P.C. board

w Please replace the fuse after removing the indoor terminal P.C. board from the electrical box.

Fuse (F11)(w)

Varistor (NR11)

Terminal
block

Connector to indoor electronic
control P.C. board (CN20A)

5VDC

12VDC GND

Indoor fan motor
(CN211)
230V AC

R111

}

CN121

GND

Interlock switch (FAN)(CN1R1)

26

11

DISASSEMBLY INSTRUCTIONS

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

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

1Slide the sleeve.
2Pull the terminal while

pushing the locking
lever.

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

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

<"Terminal with locking mechanism" Detaching points>

Connector

Sleeve

Locking lever

MSZ-GC22VA MSZ-GC25VA MSZ-GC35VA

OPERATING PROCEDURE

PHOTOS

Photo 1

1. Removing the panel

(1) Remove the screw caps of the panel. Remove the screws.
(2) Hold the lower ends part of the panel and pull it slightly

toward you, and then remove the panel by pushing it
upward.

Screws of the panel

27

3. Remove the indoor power P.C. board, the indoor ter­minal P.C. board, and the electrical box

(1) Turn the breaker OFF.
(2) Remove the panel (Refer to 1) and the corner box.
(3) Remove the screw of V.A. clamp, and then the indoor/out-

door connecting wire.

(4) Remove the earth wire connected to the indoor heat

exchanger from the electrical box.

(5) Unhook first the lower, then the upper catches of the elec-

trical box, and pull out the electrical box.

(6) Remove the screw of the electrical cover and remove the

electrical cover.

(7) Disconnect all the connectors on the indoor power P.C.

board and unhook all lead wires.

(8) Remove the screw of terminal block on the indoor terminal

P.C. board.

(9) Remove the indoor power P.C. board and the indoor termi-

nal P.C. board.

OPERATING PROCEDURE PHOTOS

Lower catch

Indoor terminal
P.C. board

Photo 3

2. Removing the indoor electronic control P.C. board

and the room temperature thermistor

(1) Turn the breaker OFF.
(2) Remove the panel (Refer to 1) and the corner box.
(3) Open the indoor electronic control P.C. board holder (to

right side), and disconnect connectors of the indoor coil
thermistor (CN112), vane motor (CN151), interlock switch
(CN1R1) and connector (CN10A) to the indoor power P.C.
board on the indoor electronic control P.C. board.

(4) Unhook the catches of the indoor electronic control P.C.

board holder from the nozzle and the electrical box (right
side).

(5) Remove the room temperature thermistor from the hook of

the indoor electronic control P.C. board holder.

(6) Open the back side of the indoor electronic control P.C.

board holder, and remove the indoor electronic control P.C.
board.

(7) Remove the room temperature thermistor from the indoor

electronic control P.C. board.

Photo 2

V.A. clamp

Indoor electronic control
P.C. board holder

Screw of the
electrical cover

Terminal block

Indoor power
P.C. board

Catch of indoor electronic
control P.C. board holder

Catch of indoor electronic
control P.C. board holder

Upper catch

Electrical box

OPERATING PROCEDURE PHOTOS

4. Removing the vane motor

(1) Turn the breaker OFF.
(2) Remove the panel (Refer to 1) and the corner box.
(3) Remove the indoor electronic control P.C. board

holder(Refer to 2).

(4) Remove the screws of vane motor and remove the vane

motor.

(5) Disconnect the connector from vane motor.

5. Removing the indoor fan motor, the indoor coil ther­mistor, and the line flow fan

(1) Remove the panel (Refer to 1) and the corner box.
(2)

Remove the indoor electronic control P.C. board holder (Refer to

2) and the electrical box (Refer to 3) .

(3)

Remove

the drain hose from the nozzle assembly, and

remove the nozzle assembly.
(4) Loosen the screw fixing the line flow fan.
(5) Remove the screws fixing the motor bed. Lift the right side

of motor bed a little, and pull right to remove the fan motor

together with motor band/bed.
(6) Remove the indoor coil thermistor from the heat exchanger
(w) Install the indoor coil thermistor in its former position when

assembling it.

(Refer to Photo 7)

(7) Remove the screws fixing the left side of the heat exchang-

er.
(8) Lift the left side of the heat exchanger, and pull out the line

flow fan to the lower-left.

Photo 6

Photo 4

Screws of the vane motor

Screws of the motor bed

Photo 5

Screws of the line flow fan

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

C

Copyright 2006 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD

Distributed in Aug. 2007. No. OBH468 REVISED EDITION-B 6
Distributed in Feb. 2007. No. OBH468 REVISED EDITION-A 6
Distributed in Dec. 2006. No. OBH468 6
Made in Japan

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

Photo 7

Indoor coil
thermistor(sub)
RT13

Indoor coil
thermistor(main)
RT12