Mitsubishi Electric MSZ-GC22VA User 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
1TECHNICAL 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 o25 mm
Remote controller holder
Fixing screw for 33.5 o1.6 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
4NOISE 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 X26 Oblong hole 11 X20 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
6WIRING 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
1If the main power has been cut, the operation settings remain.
2After 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”
1Turn 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 tem-
perature 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 con-
densing 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 temper-
ature 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.
• Press VANE CONTROL
button again to return the
vane to the previously-set
position.
Pressing and holding
VANE CONTROL
button for 2 seconds
or more causes
the horizontal vane
to reverse and
move to horizontal
position.
The air conditioner starts the
cooling or drying operation
approx. 3 minutes after the
vane has moved to the hori-
zontal 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 heat-
ing 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.
2Press RESET button with tip end of ball point pen
or the like, and then use the remote controller.
1Remove 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 1to 2.
NOTE : Before installation of the horizontal vane, turn OFF the power supply.
5. How to install the horizontal vane
In procedure 2lock 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 0.5-
second interval
2.5-second OFF 3-second ON
Blinking at 0.5-
second interval
Beeps
Repeated cycle
2.5-second OFF
Blinking at 0.5-
second interval
No beep Beeps
Repeated cycle
2.5-second OFF 3-second ON
Blinking at 0.5-
second 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>
1While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller at the same time, press
RESET button.
2First, 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 thermis-
tor.
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".
3Indoor 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.