Mitsubishi Electric MS-GA50VB E1 WH User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················2
3. SPECIFICATION·················································4
4. NOISE CRITERIA CURVES·······························5
5. OUTLINES AND DIMENSIONS ·························6
6. WIRING DIAGRAM ············································7
7. REFRIGERANT SYSTEM DIAGRAM················8
8. SERVICE FUNCTIONS ······································9
9. TROUBLESHOOTING······································11
10. DISASSEMBLY INSTRUCTIONS·····················19
11. PARTS LIST······················································21
12. OPTIONAL PARTS···········································23
Wireless type
Models
MS-GA50VB - (WH)
MS-GA60VB - (WH)
MS-GA80VB - (WH)
E1
E1
E1
No. OB369
SPLIT-TYPE, AIR CONDITIONERS
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
NOTE:
This service manual describes technical data of the indoor units.
As for outdoor units MU-GA50VB - , MU-GA60VB - and MU-GA80VB - ,
refer to service manual OB370. E1E1E1
Indication of model name
OB369-1.qxp 04.10.14 1:37 PM Page 1

TECHNICAL CHANGES
2
1
PART NAMES AND FUNCTIONS
2
INDOOR UNIT
Grille
(When the grille is opened)
Remote controller
Operation section Display section
Emergency operation switch
Operation indicator lamp
Air inlet
To Breaker
Power supply cord
Remote control
receiving section
Air cleaning filter (option)
(White bellows type)
Horizontal vane
Vertical vanes
Catechin air filter
Remote control
receiving section
Catechin air filter
Front panel
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
MS-A18WV - ➔MS-GA50VB -
MS-A24WV - ➔MS-GA60VB -
MS-A30WV - ➔MS-GA80VB -
1. Model name has been changed.
Indication of capacity has been changed. (BTU➔kW)
2. Grille design has been changed.
3. Unit size has been changed.(W 1,100aoH 325aoD 227a➔W1,100aoH 325aoD 258a)
E1E1
E1E1
E1E1
ACCESSORIES
Indoor unit
1
2
3
4
5
6
7
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller holder
Fixing screw for 3o3.5 o1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
1
7
1
2
2
1
1
MS-GA50VB -
MS-GA60VB -
MS-GA80VB -
E1
E1
E1
OB369-1.qxp 04.10.14 1:37 PM Page 2

REMOTE CONTROLLER
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
3
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
ECONO COOL
STOP
START
HR.
MIN.
WIDE VANE
LONG
I FEEL COOL
DRY
PM
CLOCK
AM
RESET CLOCK
FAN
Open the front lid.
Signal transmitting section
Operation display section
OPERATE/ STOP
(ON/ OFF)button
TEMPERATURE buttons
OPERATION SELECT button
FAN SPEED CONTROL button
OFF-TIMER button
HR. button
MIN. button
(TIME SET button)
ON-TIMER button
RESET button
ECONO COOL button
VANE button
(Horizontal vane button)
CLOCK SET button
LONG button
WIDE VANE button
(Vertical vane button)
Indication of remote controller
model is on back.
OB369-1.qxp 04.10.14 1:37 PM Page 3

SPECIFICATION
4
3
Indoor model
Function
Power supply
Air flow
(High/Med. /Low )
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Fan motor current
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed(High/Med. /Low )
Fan speed regulator
Thermistor RT11(at 25:)
Thermistor RT12(at 25:)
Remote controller model
K/h
A
A
W
A(kW)
%
A
"
mm
kg
dB
rpm
k"
k"
MS-GA50VB - E1
Cooling
Single phase
230V, 50Hz
768/642 /528
10
0.30
60
—
87
0.30
RC4V32-AA
WHT-BLK 293
BLK-RED 146
1,100O325O258
16
5
42/38 /34
1,070/920 /780
3
10
10
KM04B
MS-GA60VB - E1
Cooling
Single phase
230V, 50Hz
768/672 /588
10
0.30
60
—
87
0.30
RC4V32-AA
WHT-BLK 293
BLK-RED 146
1,100O325O258
16
5
45/41 /37
1,070/960 /850
3
10
10
KM04B
Electrical data
Fan motor
Special remarks
Capacity
ww
ww
ww
ww
ww
ww
ww
ww
ww
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C
Outdoor DB35°C WB(24°C)
Indoor-Outdoor piping length : 5m
wReference value
Indoor model
Function
Power supply
Air flow
(High/Med. /Low )
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Fan motor current
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed(High/Med. /Low )
Fan speed regulator
Thermistor RT11(at 25:)
Thermistor RT12(at 25:)
Thermistor RT13(at 25:)
Remote controller model
K/h
A
A
W
A(kW)
%
A
"
mm
kg
dB
rpm
k"
k"
k"
MS-GA80VB - E1
Cooling
Single phase
230V, 50Hz
960/822 /684
10
0.34
69
—
88
0.34
RC4V40-AA
WHT-BLK 138.2
BLK-RED 159.0
1,100O325O258
16
5
47/42 /37
1,280/1,130 /970
3
10
10
10
KM04B
Electrical data
Fan motor
Special remarks
Capacity
ww
ww
ww
ww
ww
ww
OB369-1.qxp 04.10.14 1:37 PM Page 4

5
NOISE CRITERIA CURVES
4
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
47
SPL(dB(A)) LINE
High
FAN SPEED
MS-GA80VB - E1
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
42
SPL(dB(A)) LINE
High
FAN SPEED
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
45
SPL(dB(A)) LINE
High
FAN SPEED
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
MS-GA50VB - E1 MS-GA60VB - E1
INDOORUNIT WALL
MICROPHONE
0.8m
1m
OB369-1.qxp 04.10.14 1:37 PM Page 5

OUTLINES AND DIMENSIONS
6
5
258
162
19
58
47
7.5
315
255.547
2.5
98 173
98 173414.5 414.5
5
253
791
56
1068
1100
325
Air out
Air in
Insulation [28
Drain hose [16
(Connected part O.D)
Installation plate
Wall hole [75
Wireless remote controller
Installation plate Indoor unit
{
Liquid line [6.35-0.5m
Gas line [12-0.43m
Insulation [50 O.D
[32 I.D
{
Liquid line [9.52-0.5m
Gas line [12-0.43m
Insulation [50 O.D
[32 I.D
for MS-GA50VB
for MS-GA60/GA80VB
Power supply cord
Lead to right 2.0m
Lead to left 1.0m
INDOOR UNIT
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1 Unit: mm
OB369-1.qxp 04.10.14 1:37 PM Page 6

MODELS WIRING DIAGRAM
MODEL WIRING DIAGRAM
7
WIRING DIAGRAM
6
MS-GA50VB -
MS-GA60VB - E1
E1
INDOOR UNIT
12V BLK
GRY
YLW
BRN
WHT
RED
3
SR141 4
3
1
CN
121
C11
HIC1
MV1
2
1
CN112
151
CN
MV2
15
RT12
RT11
111
CN
CN211
NR11
ELECTRONIC CONTROL
P. C. BOARD
F11
LBRN
1
2
3
CN201
MV2
CN
101
CN
102
DISPLAY
P. C. BOARD RECEIVER
P. C. BOARD
REMOTE
CONTROLLER
33
TAB12
GRN/YLW
N
TB 2
1
2
1
CN202
TO OUTDOOR UNIT
CONNECTING BLK
WHT
BLU
BRN
BLU
1.About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3.Symbols below indicate. : Connector
: Terminal block
NOTES:
SYMBOL
C11
F11
HIC1
MF
NAME
INDOOR FAN CAPACITOR
FUSE (3.15A)
DC/DC CONVERTER
INDOOR FAN MOTOR (INNER FUSE)
SYMBOL
MV1
MV2
NR11
RT11
NAME
VANE MOTOR (HORIZONTAL)
VANE MOTOR (VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMISTOR
SYMBOL
RT12
SR141
TB
NAME
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
MF
1
2
3
4
5
6
PE CIRCUIT
BREAKER
POWER
SUPPLY
CORD
~/N 230V
50Hz
INDOOR UNIT
12V
TO OUTDOOR
UNIT
CONNECTING
BRN
BLU
GRN/YLW
BLK
GRY
YLW
BRN
WHT
RED
MF
3
SR141 4
3
1
CN
121
C11
HIC1
MV1
RT13
4
3
2
1
CN112
151
CN
MV2
15
RT12
RT11
111
CN
CN211
NR11
ELECTRONIC CONTROL
P. C. BOARD
F11
3
N
LBRN
1
2
3
CN201
MV2
BLU
RED
CN
101
CN
102
DISPLAY
P. C. BOARD RECEIVER
P. C. BOARD
REMOTE
CONTROLLER
33
TAB12
TB
PE CIRCUIT
BREAKER
POWER
SUPPLY
CORD
~/N 230V
50Hz
1.About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3.Symbols below indicate. : Connector
: Terminal block
NOTES:
SYMBOL
SR141
TB
SYMBOL
MV2
NR11
RT11
RT12
RT13
SYMBOL
C11
F11
HIC1
MF
MV1
NAME NAME NAME
INDOOR FAN CAPACITOR
FUSE(3.15A)
DC/DC CONVERTER
INDOOR FAN MOTOR(INNER PROTECTOR)
VANE MOTOR(HORIZONTAL)
VANE MOTOR(VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR (MAIN)
INDOOR COIL THERMISTOR (SUB)
SOLID STATE RELAY
TERMINAL BLOCK
MS-GA80VB - E1
OB369-1.qxp 04.10.14 1:37 PM Page 7

REFRIGERANT SYSTEM DIAGRAM
8
7
MS-GA80VB - E1
INDOOR UNIT
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT13(sub)
Flared connection
Refrigerant pipe [15.88
(with heat insulator)
Refrigerant pipe [9.52
(with heat insulator)
Indoor coil
thermistor
RT12(main)
Strainer
#50
Refrigerant flow in cooling
MS-GA50VB - E1
INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [12.7
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12
Refrigerant pipe [6.35
(with heat insulator)
Distributor
MS-GA60VB - E1
INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [15.88
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12
Refrigerant pipe [6.35
(with heat insulator)
Distributor
Unit:mm
OB369-1.qxp 04.10.14 1:37 PM Page 8

9
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.
How to modify the remote controller P.C. board
Remove batteries before modification.
The board has a print as shown below :
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.
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.)
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.
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
NOTE : For remodelling, take out the bat-
teries and press the
OPERATE/STOP(ON/OFF)button
twice or 3 times at first.
After finish remodelling, put back
the batteries then press the
RESET button.
Remote controller model : KM04B
J2
J1
Table 1
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
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 accepts 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 has turned off, or the power supply has shut down.
Please conduct the above setting once again after the power has restored.
OB369-1.qxp 04.10.14 1:37 PM Page 9

10
How to release “AUTO RESTART FUNCTION”
1Turn off the main power for the unit.
2Pull out the electronic control P.C. board, the receiver P.C.
board and the display P.C. board. (Refer to page 19.)
3Solder jumper wire to JR07 on the indoor electronic control
P.C. board. (Refer to page 18.)
JR07
IC152
CN151
CN112
CN111
CN121
SW1
IC101
RA102
C11
CN201
CN211
TAB12
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.)
NOTE
•The operation settings are memorized when 10 seconds have passed after the remote controller 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 appliances 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.
When the indoor unit is controlled with the remote controller, the operation mode, set temperature, and the fan speed are
memorized by the indoor electronic control P.C.board. The “AUTO RESTART FUNCTION” sets to work the moment power
has restored after power failure.Then, the unit will restart automatically. However if the unit is operated in “I FEEL CON-
TROL” mode before power failure, the operation is not memorized. In “I FEEL CONTROL” mode, the operation is decided
by the initial room temperature.
8-3. AUTO RESTART FUNCTION
OB369-1.qxp 04.10.14 1:37 PM Page 10

11
TROUBLESHOOTING
9
9-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
(1) Check the power supply voltage.
(2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
(1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main unit, and then after
confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
(2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
(3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the com-
ponents.
(4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
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 electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discolouration.
(4) When troubleshooting, refer to 9-2. and 9-3..
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.
1Remove the front lid and insert batteries.
Then reattach the front lid.
Lead wiring Housing point
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
FAN
RESET button
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries are correct.
FAN
2Press the RESET button with tip end of ball point
pen or the like, and then use the remote controller.
OB369-1.qxp 04.10.14 1:37 PM Page 11

12
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't receive
the signal from
remote controller.
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
Outdoor unit
operates in
only Test Run
operation.
Outdoor unit
doesn't
operate
even in
Test Run
operation.
Indoor unit
operates, when
the EMERGENCY
OPERATION
switch is pressed.
Indoor unit
doesn't operate,
when the
EMERGENCY
OPERATION
switch is pressed.
Check room
temperature
thermistor.
Refer to 9-6.
"Test point
diagram and
voltage".
Refer to
"Check of
outdoor unit".
Refer to 9-5. B
"Check of
remote controller
and receiver
P.C. board".
MS-GA80VB
Flash on and
off at 0.5-
second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
2-time flash
Cause:
Indoor unit
• Trouble of
room temp-
erature/
indoor coil
thermistor
3-time flash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
MU-GA80VB
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
MU-GA80VB
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Refer to 9-5.
D "How to
check
mis-wiring
(When
outdoor unit
doesn't
work)".
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to 9-6.
"Test point
diagram and
voltage".
Refer to 9-5.
A"Check of
indoor fan
motor".
Refer to
"Check of
outdoor
thermistor".
Replace the
deicer
P.C. board.
MU-GA80VB
10-time flash
Cause:
Outdoor unit
• Trouble of
low discharge
temperature
protection
Refer to
"Check of
LEV".
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
As for outdoor unit, refer to service manual OB370.
1. Check indoor /
outdoor
connecting wire.
2. Refer to 9-5. C
"Check of indoor
electronic control
P.C. board".
Outdoor unit
doesn't
stop even
if indoor unit
stops.
Refer to
"Check of
outdoor unit".
9-2. Instruction of troubleshooting
OB369-1.qxp 04.10.14 1:37 PM Page 12

13
9-3. Troubleshooting check table
• The following indication applies regardless of shape of the indicator.
Operation Indicator Lighted
Not lighted
Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
NOTE : When the indoor unit has started operation and the above 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 the
OPERATION INDICATOR lamp flashing.
No.
1
2
4
5
6
SymptomOperation indicator lamp Detection method
Checkpoint
0.5-second ON
0.5-second OFF
MS-GA80VB
Mis-Wiring
MU-GA80VB
Outdoor
thermistor
MU-GA80VB
Outdoor
control
system
Indoor coil
thermistor
3 minutes after power supply turns ON, when
serial signal is not received.
<Thermistor short>
Thermistors are abnormal when they short
after compressor start-up.
<Thermistor open>
Thermistors are abnormal when they open
after compressor start-up.
However, discharge temperature thermistor is
abnormal when open circuit is detected more
than 10 minutes after compressor start-up.
When it cannot properly read data in the
nonvolatile memory of the deicer P.C. board,
outdoor unit stops.
• Check the deicer P.C.
board.
• Reconnect the connector.
Refer to "Check of outdoor
thermistor". Refer to service
manual OB370.
• Check the deicer P.C. board.
Refer to service manual
OB370.
• Refer to 9-5. D"How to check
mis-wiring ".
3Indoor fan
motor
7
MU-GA80VB
Low
discharge
tempera-
ture
protection
When discharge temperature has been 50:
or less on cool operation.
Abnormal
point
Outdoor unit
does not
operate.
Room
temperature
thermistor
2-time flash
2.5-second OFF
Detect Indoor coil/room temperature
thermistor short or open circuit every 8
seconds during operation.
• Refer to the characteristics of
main indoor coil thermistor,
sub indoor coil thermistor,
and room temperature on
page 18.
3-time flash
2.5-second OFF
Indoor fan repeats
12 seconds ON
and 3minutes OFF.
When the indoor
fan breaks, the
fan keeps stopping.
When rotational frequency feedback signal is
not emitting during 12-second indoor fan
operation. • Refer to 9-5. A"Check of
indoor fan motor".
4-time flash
2.5-second OFF
Indoor
control
system
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate. • Check the indoor electronic
control P.C. board.
6-time flash
2.5-second OFF
• Refer to "Check of LEV".
• Check refrigerant circuit and
refrigerant amount.
Refer to service manual
OB370.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
7-time flash
2.5-second OFF
10-time flash
2.5-second OFF
· Flashing of the OPERATION INDICATOR lamp (on the left-hand side) indicates possible
abnormalities.
· The OPERATION INDICATOR lamp (on the left-hand side) is lighted during normal operation.
OB369-1.qxp 04.10.14 1:37 PM Page 13

14
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
Part name Figure Check method and criterion
Indoor fan motor(MF)
MS-GA50/GA60VB
INNER FUSE
145:CUT OFF
MS-GA80VB
INNER
PROTECTOR
135i5:OPEN
Color of
lead wire
WHT – BLK
BLK – RED
Abnormal
Open or
short-circuit
MS-GA50/GA60VB
282 "~ 305 "
141 "~ 152 "
Measure the resistance with a tester.
(Part temperature 10˚C ~ 30˚C)
Normal
8 k"~ 20 k"Abnormal
Open or short-circuit
Room temperature
thermistor(RT11)
Indoor coil thermistor
(RT12(main), RT13(sub))
Horizontal vane
motor(MV1)
Vertical vane
motor(MV2)
Motor part
Sensor part
Measure the resistance between the terminals with a tester.
(Part temperature 10˚C ~ 30˚C)
Color of lead wire
BRN – YLW
YLW – GRY
Abnormal
Remain 0V or 5V
Normal
4.5 ~ 5.5V
Measure the voltage power ON.
(When fan revolved one time)
0V➔5V➔0V
(Approx.)
Normal
282 "~ 306 "Abnormal
Open or short-circuit
Measure the resistance between the terminal with a tester.
(Part temperature 10°C ~ 30°C)
BLK
RED
WHT
GRY
YLW BRN
MAIN
AUX
FUSE
BLK
RED
WHT
GRY
YLW BRN
MS-GA80VB
133 "~ 144 "
152 "~ 165 "
Normal
MS-GA50/GA60VB
MS-GA80VB
YLW
GRNORN
BRN
RED ROTOR
MAIN
AUX.
P
:INNER PROTECTOR
P
9-4. Trouble criterion of main parts
OB369-1.qxp 04.10.14 1:37 PM Page 14

15
Yes
Yes
Check of indoor fan motor
A
Check of remote controller and receiver P.C. board
B
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.
Repair or replace the indoor fan motor.
Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board.
Measure resistance between lead wires No.1 and No.4 and then No.3 and No.4.
Are lead wires connected?
Reconnect the lead wires.
Is soldered point of the connector
correctly soldered? Resolder it.
Is resistance 0 (short circuit) or ∞(open circuit)?
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.
Replace the batteries.(Refer to page 11.)
Turn on a radio to AM and press switch on
the remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
Measure the voltage between receiver P.C. board connector CN301 No.2(+) and No.1(-) when the remote
controller button is pressed.
Is the voltage approx. 4V DC? Replace the indoor electronic control P.C.
board.
Replace the receiver P.C. board.
Replace the remote controller.
● Reinstall the unit away from lights.
● Attach a filter on receiving part.
Yes ( 0 or ∞)No
(others)
Yes
No
Yes
No
Switch on the remote controller.
Is LCD display on the the remote
controller visible?
Remove the batteries, then set them back
and press the RESET button. 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(5V or 0V DC)
No
Turn OFF the power supply.
Check connector CN211 visually.
wCheck if the remote controller is exclusive for this air conditioner.
Turn ON the power supply. Stop it if the unit operate.
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure
voltage between No.2(+) and No.3(-) on CN121.
Replace the indoor electronic control P.C. board.
Does voltage repeat 0V DC and 5V DC?
Yes
No
9-5. Troubleshoot flow
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16
Check of indoor electronic control P.C. board
C
Check the both “parts side” and “pattern
side” of indoor electronic control P.C.
board visually.
Replace the fuse.
Is fuse(F11) blown?
Replace the fan
motor.
Replace the indoor
electronic control
P.C. board.
Is winding
resistance of
fan motor 0 "?
Is winding
resistance of
vane motor 0 "?
No
Replace the vane
motor.
Yes
Yes
Is varistor(NR11) burnt?
Replace the varistor.
Yes
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C.board and turn ON the power supply.
No
No
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up
by pressing the EMERGENCY OPERATION switch?
Yes
No
Yes
Turn OFF the
power supply. Turn OFF the
power supply.
Varistor (NR11)
Indoor electronic
control P.C. board
Fuse (F11)
No
The unit doesn’t operate with the remote controller. Also, the OPERATION INDICATOR lamp doesn’t light up by press-
ing the EMERGENCY OPERATION switch.
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17
How to check mis-wiring
D
1. Turn OFF the power supply (indoor/ outdoor unit) and disconnect indoor and outdoor
connecting wire at the terminal block 3 of the indoor unit.
2. Short-circuit terminal block N-3of indoor unit by lead wire.
3. Turn ON the power supply (indoor unit) and press once EMERGENCY OPERATION switch.
During EMERGENCY OPERATION, is there
10V DC between both ends of R601 on the
deicer P.C. board?
(By tester, the stylus is between 5 ~10V.)
As for outdoor unit, refer to service manual OB370.
Start
No
No
Is there 20V DC between both ends of
R132 on the indoor electronic control P.C.
board ?
( By tester, the stylus is between 0 ~ 20V. )
• Turn ON the power supply. (indoor/ outdoor unit)
• Press once EMERGENCY OPERATION switch.
Is this mis-wiring, poor contact,
or wire disconnection?
Make them sure.
Replace the indoor electronic
control P.C. board.
Is there 230V AC between L-N
on the outdoor terminal block? No Check the outdoor power supply
and connection of wiring.
Yes No Replace the deicer P.C. board.
Yes
No Make the wiring between CN730
on the deicer P.C. board and
outdoor terminal block correct.
Replace the deicer P.C. board.
Yes
Is there 5V DC between J101 + -J401 -
(MU-GA80VB) on the deicer P.C. board?
Yes
Yes
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
on OPERATION INDICATOR
lamp on indoor unit.w
wShort circuit of JPG and JPS on the indoor electronic control
P.C. board enables self -check to be displayed in 3 seconds.
• Turn OFF the power supply. (indoor unit)
• Disconnect the lead wire that terminal
block N-3 of the indoor unit is
short-circuited.
• Connect ON indoor/ outdoor connecting
wire.
Turn ON the power supply. (outdoor unit)
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit doesn’t operate.
MS-GA80VB
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18
9-6. Test point diagram and voltage
MS-GA50VB - MS-GA60VB - MS-GA80VB -
Indoor electronic control P.C. board E1E1E1
Fan motor power supply
Fuse (F11)
250V AC 3.15A
}Power supply input
230V AC
+}5V DC
Indoor coil
thermistor(RT12(main))
Timer short mode point
(JPS, JPG)
(Refer to page 9.)
Emergency operation
switch
+
}
12V DC
Indoor coil thermistor(RT12(main), RT13(sub))
Room temperature thermistor (RT11)
Resistance(k")
Room temperature ther-
mistor(RT11)
Release of “Auto restart function”
Solder jumper wire to JR07.
(Refer to page 10.)
MS-GA80VB
Indoor coil
thermistor(RT13(sub))
R132
Receiver P.C. board
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19
DISASSEMBLY INSTRUCTIONS
10
MS-GA50VB - MS-GA60VB - MS-GA80VB -
INDOOR UNIT E1E1E1
(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector is a terminal
with lock mechanism
1Slide the sleeve.
2Pull the terminal while
pushing the locking
lever.
1Hold the sleeve, and
pull out the terminal
slowly.
In case of terminal with lock mechanism, detach the terminal as shown below.
There are two types ( Refer to (1) and (2)) of the terminal with lock mechanism.
The terminal with no lock mechanism can be removed by pulling it out.
Check the shape of the terminal and work.
<"Terminal with lock mechanism" Detaching points>
Connector
Sleeve
Locking lever
OPERATING PROCEDURE PHOTOS
1. Removing the front panel
(1) Remove the screw caps of the front panel.
Remove the screws.
(2) Pull the panel down to your side slightly and unhook the
catches at the top.
Photo 1
Photo 2
Front panel
Screw of the
V.A. clamp
Indoor
electronic
control
P.C. board
Vane motor
connector
Fan motor
connectors
Screws of the ground wire
Screws
Screw of
the electri-
cal cover
R.L holder Screw of
the termi-
nal block
Receiver
P.C.
board
2. Removing the electronic control P.C. board, the receiver
P.C. board and the display P.C. board
(1) Remove the front panel. (Refer to 1.)
(2) Remove the screw of the electrical cover.
Remove the electrical cover.
(3) Remove the screws of the V.A. clamp.
Remove the V.A. clamp.
(4) Remove the screw of the terminal block.
(5) Remove the screws of the ground wire.
(6) Disconnect all the connectors and all the lead wires on the
electronic control P.C. board.
(7) Remove the R.L holder.
(8) Remove the electronic control P.C. board.
(9) Open the R.L holder, remove the receiver P.C. board and
the display P.C. board.
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20
OPERATING PROCEDURE PHOTOS
Photo 4
Photo 6
Vane motors
Indoor
coil
thermistor
Photo 3
3. Removing the electrical box
(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Disconnect the connector of the indoor coil thermistor.
(4) Disconnect the motor connector (CN211 and CN121) and
the vane motor connector (CN151) on the electronic
control P.C. board.
(5) Remove the screws of ground wire.
(6) Remove the fan motor lead wire and indoor coil thermistor
from the electrical box.
(7) Remove the lead wire of vane motor from the bottom of
electrical box.
(8) Remove the screw fixing the electrical box and remove the
electrical box.
4. Removing the vane motor
(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical cover. (Refer to 2.)
(3) Remove the lead wire of vane motor. (Refer to 3.)
(4) Remove the R.L. holder.
(5) Pull out the drain hose from the nozzle assembly and
remove the nozzle assembly.
(6) Remove the screws of the vane motor and disconnect the
connector.
(7) Remove the vane motor.
Screws fixing the fan motor
5. Removing the line flow fan and the indoor fan motor
(1) Remove the front panel. (Refer to 1.)
(2) Remove the electrical box. (Refer to 3.)
(3) Pull out the drain hose from the nozzle assembly and
remove the nozzle assembly.
(4) Remove the water cut.
(5) Slide the hole cover and remove the hole cover.
(6) Remove the hexagon socket set screw from the line flow
fan.
(7) Remove the screws fixing the fan motor and remove the
fan motor. (Be careful not to drop the fan motor because it
is heavy.)
(8) Remove the screws fixing the left side of the heat
exchanger.
(9) Lift the left side of the heat exchanger.
(
10 ) Remove the line flow fan.
Screws fix-
ing the left
side of the
heat
exchanger
Screws
of the
vane
motor
Screws of the
vane motor
Vane motor
Screw of the
electrical box
Screws of the ground wire
Photo 5
Photo 7
Photo 8
Hole
cover
Water cut
Screw of the
electrical cover
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