Mitsubishi Electric MS-GA50VB User manual

CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································5
4. NOISE CRITERIA CURVES·······························6
5. OUTLINES AND DIMENSIONS ·························7
6. WIRING DIAGRAM ············································8
7. REFRIGERANT SYSTEM DIAGRAM················9
8. SERVICE FUNCTIONS ····································10
9. TROUBLESHOOTING······································12
10. DISASSEMBLY INSTRUCTIONS·····················21
11. PARTS LIST······················································23
12. RoHS PARTS LIST···········································25
13. OPTIONAL PARTS···········································27
SPLIT-TYPE AIR CONDITIONERS
MS-GA50VB -
MS-GA60VB -
MS-GA80VB - E1
E1
E1
SERVICE MANUAL
Models
INDOOR UNIT
NOTE:
This service manual describes technical data of the indoor units.
RoHS compliant products have <G> mark on the spec name plate.
For servicing of RoHS compliant products, refer to the RoHS PARTS LIST (RoHS compliant).
Outdoor unit service manual
MU-GA•VB Series (OB370)
No. OB369
REVISED EDITION-D
Revision D :
• Parts numbers of indoor fan motor and motor band have been
changed.
• Some descriptions have been modified.
Please void OB369 REVISED EDITION-C.
OB369D.qxp 12.1.13 8:47 AM Page 1

2
TECHNICAL CHANGES
1
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 1,100mmoH 325mmoD 227mm ➔W1,100mmoH 325mmoD 258mm)
E1E1
E1E1
E1E1
Revision A :
• RoHS PARTS LIST has been added.
Revision B :
• Indoor heat exchanger of MS-GA80VB - has been changed.
• PARTS LIST and RoHS PARTS LIST have been changed.
E1
Use the specified refrigerant only
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the spec labels provided with our products.
We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by
failure to follow the instructions.
Revision C :
• Another type of the electronic control P.C. board (TYPE 2) has been added to the original one (TYPE 1). They are both com-
patible with MS-GA50/60/80VB- .
E1
Revision D :
• Parts numbers of indoor fan motor and motor band have been changed.
• Some descriptions have been modified.
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OB369D

3
PART NAMES AND FUNCTIONS
2
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
ACCESSORIES
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
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OB369D

4
REMOTE CONTROLLER
MS-GA50VB
MS-GA60VB
MS-GA80VB
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.
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OB369D

5
SPECIFICATION
3
Indoor model
Function
Power supply
Air flow
(High/Med./Low)
Breaker capacity
Running current
Power input
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
"
mm
kg
dB
rpm
k"
k"
MS-GA50VB
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
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
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor Dry-bulb temperature 27:Wet-bulb temperature 19:
Outdoor Dry-bulb temperature 35:Wet-bulb temperature (24:)
Indoor-Outdoor piping length : 5m
Indoor model
Function
Power supply
Air flow
(High/Med./Low)
Breaker capacity
Running current
Power input
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
"
mm
kg
dB
rpm
k"
k"
k"

MS-GA80VB
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
OB369D.qxp 12.1.13 8:47 AM Page 5
OB369D

6
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
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 MS-GA60VB
INDOOR UNIT WALL
MICROPHONE
0.8m
1m
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OB369D

7
OUTLINES AND DIMENSIONS
5
258
159
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-GA50/60VB
for MS-GA80VB
Power supply cord
Lead to right 2.0m
Lead to left 1.0m
MS-GA50VB
MS-GA60VB
MS-GA80VB
Unit: mm
OB369D.qxp 12.1.13 8:47 AM Page 7
OB369D

8
WIRING DIAGRAM
6
MS-GA50VB
MS-GA60VB
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
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
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OB369D

9
REFRIGERANT SYSTEM DIAGRAM
7
MS-GA80VB
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
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
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
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OB369D

10
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. (Refer to 9-6.)
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
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 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 has turned OFF, or the power supply has shut down.
Please conduct the above setting once again after the power has restored.
NOTE : For modification, take out the bat-
teries and press the OPERATE/
STOP (ON/ OFF) button 2 or 3
times at first.
After modification, put back the
batteries then press the RESET
button.
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OB369D

11
How to disable “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 10-1.2.)
3Solder jumper wire to JR07 on the indoor electronic control
P.C. board. (Refer to 9-6.)
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
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OB369D

12
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 turn OFF the main unit first with the remote controller, and then after
confirming the horizontal vane is closed, turn OFF the breaker and / or disconnect the power plug.
(2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
(3) When removing the 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) 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 OPERATION INDICATOR lamp is flashing ON and OFF before starting ser-
vice 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
<Incorrect> <Correct>
NOTE : 1. If the RESET button is not pressed, the remote controller may not operate correctly.
2. Do not use the leaking batteries.
MS-GA50VB
MS-GA60VB
MS-GA80VB
FAN
RESET button
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries is correct.
FAN
2Press the RESET button with a thin instrument, and
then use the remote controller.
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OB369D

13
Start
Indoor unit
operates.
Outdoor unit
does not
operate.
Indoor unit
does not receive
the signal from
remote controller.
Indoor unit
operates.
Outdoor unit
does not operate
normally.
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
Outdoor unit
operates only
in Test Run
operation.w
Outdoor unit
does not
operate
even in
Test Run
operation.w
Indoor unit
operates when
the EMERGENCY
OPERATION
switch is pressed.
Indoor unit
does not 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
does not
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.
Refer to outdoor unit service manual.
1. Check indoor /
outdoor
connecting wire.
2. Refer to 9-5. C
"Check of indoor
electronic control
P.C. board".
Outdoor unit
does not
stop even
if indoor unit
stops.
Refer to
"Check of
outdoor unit".
w"Test Run operation" means the operation within 30 minutes after EMERGENCY OPERATION switch is pressed.
9-2. Instruction of troubleshooting
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OB369D

14
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 Condition
Remedy
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.
It cannot properly read data in the nonvolatile
memory of the deicer P.C.board.
• Check the deicer P.C.
board.
• Reconnect the connector.
Refer to "Check of outdoor
thermistor". Refer to outdoor
service manual.
• Check the deicer P.C. board.
Refer to outdoor service
manual.
• Refer to 9-5.D"How to check
mis-wiring ".
3Indoor fan
motor
7
MU-GA80VB
Low
discharge
tempera-
ture
protection
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
indoor coil thermistor, and
room temperature thermistor
(9-6.).
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.
Rotational frequency feedback signal is not
emitted for 12-second after indoor fan motor is
operated. • Refer to 9-5. A"Check of
indoor fan motor".
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.
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 outdoor service
manual.
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.
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15
MS-GA50VB
MS-GA60VB
MS-GA80VB
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
MS-GA50/GA60VB
282 "~ 305 "
141 "~ 152 "
Measure the resistance with a tester.
(Part temperature 10˚C ~ 30˚C)
Refer to 9-6."Test point diagram and voltage",
"Indoor electronic control P.C.board", for the chart of thermistor.
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
Normal
4.5 ~ 5.5V
Measure the voltage power ON.
(When fan revolved one time)
0V➔5V➔0V
(Approx.)
Normal
282 "~ 306 "
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
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16
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 does not 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 does not operate with the remote controller.
Replace the batteries (Refer to 9-1.4.).
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.1(+) and No.3(-) when the remote
controller button is pressed (Refer to 9-6.).
Is the voltage approximately 4 VDC? 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
Is LCD display on the remote con-
troller 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 0 VDC)
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 0 VDC and 5 VDC?
Yes
No
9-5. Troubleshooting flow
Turn ON a radio to AM and press
OPERATE/ STOP (ON/ OFF) button on
the remote controller.
Press OPERATE/ STOP (ON/ OFF)
button on the remote controller.
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17
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 does not operate with the remote controller. Also, the OPERATION INDICATOR lamp does not light up by
pressing the EMERGENCY OPERATION switch.
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18
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 EMERGENCY OPERATION switch once .
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.)
Refer to outdoor unit service manual.
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 EMERGENCY OPERATION switch once .
Is this mis-wiring, poor contact,
or wire disconnection?
Correct them.
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 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 does not operate.
MS-GA80VB
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19
9-6. Test point diagram and voltage
MS-GA50VB MS-GA60VB MS-GA80VB
Indoor electronic control P.C. board
Fan motor power supply
(CN211)
Fuse (F11)
T3.15AL250V
}Power supply input
230 VAC
+}5 VDC
Indoor coil
thermistor (RT12 (main))
Timer short mode point
(JPS, JPG)
(Refer to 8-1.)
Emergency operation
switch
+
}
12 VDC
Indoor coil thermistor
(RT12 (main), RT13 (sub))
Room temperature thermistor (RT11)
Resistance (k")
Room temperature
thermistor (RT11)
To disable “Auto restart function”,
solder the jumper wire to JR07.
(Refer to 8-3.)
MS-GA80VB
Indoor coil
thermistor (RT13 (sub))
R132
Receiver P.C. board
CN301
wThere are 2 types of electronic control P.C. boards
(TYPE1/TYPE2).
They are both compatible with MS-GA50/60/80VB.
TYPE 1
CN121
Vane motor power
supply (CN151)
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20
+
}
}
Resistance(k )
+
{
Fuse (F11)
12 VDC
Fan motor power supply
(CN211)
5 VDC
Vane motor
power supply
(CN151)
CN121
Emergency
operation
switch
Power supply input
230 VAC
Indoor coil thermistor
(RT12 (main))
MS-GA80VB
Indoor coil
thermistor (RT13 (sub))
Timer short mode
point (JPS, JPG)
(Refer to 8-1.)
Room temperature
thermistor (RT11)
R132
To disable “Auto restart
function”, solder the
jumper wire to JR07.
(Refer to 8-3.)
Indoor coil thermistor
(RT12 (main), RT13 (sub))
Room temperature thermistor (RT11)
CN301
TYPE 2
Receiver P.C. board
MS-GA50VB MS-GA60VB MS-GA80VB
Indoor electronic control P.C. board
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