Mitsubishi Electric MS-A18VD-K1 User manual

CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································5
4. OUTLINES AND DIMENSIONS ·························6
5. WIRING DIAGRAM ············································7
6. REFRIGERANT SYSTEM DIAGRAM················9
7. SERVICE FUNCTIONS ····································10
8. TROUBLESHOOTING······································12
9. DISASSEMBLY INSTRUCTIONS ····················21
10. PARTS LIST······················································23
11. RoHS PARTS LIST···········································26
SPLIT-TYPE AIR CONDITIONERS
TM
MS-A18VD
MS-A24VD
MS-A30VD
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.
SERVICE MANUAL
Models
MS-A18VD-
MS-A18VD-
MS-A24VD-
MS-A24VD-
MS-A30VD-
MS-A30VD- K2
K1
K2
K1
K2
K1
No. OB400
REVISED EDITION-C
INDOOR UNIT
Outdoor unit service manual
MU-A·VD Series (OB401)
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-A18/24/30VD- .
K
Please void OB400, REVISED EDITION-B.
OB400C--1.qxp 11.7.11 9:10 AM Page 1

2
TECHNICAL CHANGES1
Indoor unit:Unit size:W1,015mmoH320mmoD190mm ➞ W1,100mmoH325mmoD258mm
Electricity receiving unit: Indoor unit ➞ Outdoor unit
Rated voltage : 220/240V ➞ 220-230-240V
Frequency
New Model
Old Model
MS-18NV -
KB
w : change
MS-A18VD -
K1
50Hz
MS-18UV -
P1
MS-18RV -
R1
w
w
w
w
w
w
Indoor unit:Unit size:W1,015mmoH320mmoD190mm ➞ W1,100mmoH325mmoD258mm
Electricity receiving unit: Indoor unit ➞ Outdoor unit
Rated voltage : 220/240V ➞ 220-230-240V
Frequency
New Model
Old Model
MS-24NV -
K1
MS-A24VD -
K1
50Hz
MS-24UV -
P1
MS-24RV -
R1
w
w
w
w
w
w
Indoor unit:Unit size:W1,100mmoH325mmoD227mm ➞ W1,100mmoH325mmoD258mm
Rated voltage : 220/240V ➞ 220-230-240V
Frequency
New Model
Old Model
MS-30SV -
K1
MS-30SV -
P1
MS-A30VD -
K1
50Hz
w
w
w
MS-A18VD - ➔MS-A18VD -
MS-A24VD - ➔MS-A24VD -
MS-A30VD - ➔ MS-A30VD -
1. Fan guard has been added.
2. Fan speed has been changed.
3. Wiring diagram has been changed.
4. FUSE (F12) has been removed. (MS-A18/24VD- )
5. “8-5.C Check of indoor electronic control P.C. board” has been changed.
K2
K2K1
K2K1
K2K1
Revision A:
• MS-A18VD- , MS-A24VD- and MS-A30VD- have been added.
K2K2K2
Revision B:
• Remote controller model “KM04B” has been added.
There are two remote controller models for “ ” and “ ”. (KP0B, KM04B)
You can use the remote controller model “KP0B” and “KM04B”.
The remote controller model “KM04B” is supplied as service parts for “ ” and “ ”.
K2K1
K2K1
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-A18/24/30VD- .
K
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3
PART NAMES AND FUNCTIONS
2
MS-A18VD
MS-A24VD
MS-A30VD
INDOOR UNIT
Grille
(When the grille is opened)
Remote controller
Operation section Display section
Front Panel
Emergency operation switch
Operation indicator lamp
Air inlet
Remote control
receiving section
Air cleaning filter
(White bellows type)
Horizontal vane
Vertical vanes
Catechin air filter
Remote control
receiving section
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OB400C

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
Indication of remote controller
model is on back.
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)
4
Installation plate
Installation plate fixing screw 4 x 25 mm
Remote controller holder
Fixing screw for 33.5 x 16 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
Air cleaning filter
Pipe cover
1
2
3
4
5
6
7
8
9
1
7
1
2
2
1
1
2
ACCESSORIES
REMOTE CONTROLLER
MS-A18VD
MS-A24VD
MS-A30VD
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5
SPECIFICATION
3
Indoor model
Function
Power supply
Air flow
(High/Med./Low)
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
Electrical data
Fan motor
Special remarks
Capacity
Cooling
Single phase
220-230-240V, 50Hz
1,100O325O258
16
5
3
10
10
KP0B / KM04B
0.33-0.34-0.35
67-69-75
—
92-88-89
0.33-0.34-0.35
RC4V40-AA
WHT-BLK 138.2
RED-BLK 159.0
774/660/552
0.30-0.30-0.31
60-60-64
—
91-87-86
0.30-0.30-0.31
RC4V32-AA
WHT-BLK 293.0
RED-BLK 146.0
42/37/33

K/h
A
W
A(kW)
%
A
"
mm
kg
dB
rpm
k"
k"
k"
972/828/684
45/41/37
1,220/1,070/910 1,280/1,130/970
1,220/1,070/910 1,280/1,130/9701,010/880/760 1,070/920/780
—10
MS-A18VD - K1 MS-A18VD - K2 MS-A24VD - K1 MS-A24VD - K2 MS-A30VD - K1 MS-A30VD - K2
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 : 5 m
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6
OUTLINES AND DIMENSIONS4
Unit: mm
MS-A18VD MS-A24VD MS-A30VD
INDOOR UNIT
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 [16-0.43m
Insulation [50 O.D
[32 I.D
for MS-A18VD
for MS-A30VD
for MS-A24VD
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OB400C

7
WIRING DIAGRAM
5
MS-A18VD - MS-A24VD - K1K1
INDOOR UNIT
220-230-240V~ BLK
GRY
YLW
BRN
WHT
RED
MF
3
SR141 4
3
1
CN
121
C11
HIC1
MV1
151
CN
MV2
15
RT12
112
CN
CN211
NR11
ELECTRONIC CONTROL P.C. BOARD
F11
1
2
3
CN201
MV2
CN
101
CN
102
DISPLAY
P.C. BOARD RECEIVER P.C. BOARD
REMOTE
CONTROLLER
33
3
452C/
X11
F12 BLU
BLU
GRN/YLW
N
2
220-230-240V~
TO OUTDOOR
UNIT
CONNECTING
BRN
L
TB
BLU 2
1
WHT BLU
RT11
111
CN
NOTE:1. About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2. Use copper conductors only. (For field wiring)
3. Symbols below indicate.
/: Terminal block, : Connector
SYMBOL
SR141
TB
52C/X11
SYMBOL
MV1
MV2
NR11
RT11
RT12
SYMBOL
C11
F11
F12
HIC1
MF
NAME NAME NAME
INDOOR FAN CAPACITOR
FUSE(3.15A)
THERMAL FUSE (93:)
DC/DC CONVERTER
INDOOR FAN MOTOR(INNER PROTECTOR)
HORIZONTAL VANE MOTOR
VERTICAL VANE MOTOR
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
COMPRESSOR CONTACTOR
MS-A18VD - MS-A24VD - K2K2
INDOOR UNIT
220-230-240V~ BLK
GRY
YLW
BRN
WHT
RED
MF
3
SR141 4
3
1
CN
121
C11
HIC1
MV1
151
CN
MV2
15
RT12
112
CN
CN211
NR11
ELECTRONIC CONTROL P.C. BOARD
F11
1
2
3
CN201
MV2
CN
101
CN
102
DISPLAY
P.C. BOARD RECEIVER P.C. BOARD
REMOTE
CONTROLLER
33
3
4X11
GRN/YLW
N
2
220-230-240V~
TO OUTDOOR
UNIT
CONNECTING
BRN
L
TB
BLU
WHT
RT11
111
CN
NOTE:1. About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2. Use copper conductors only. (For field wiring)
3. Symbols below indicate.
/: Terminal block, : Connector
SYMBOL
TB
X11
SYMBOL
MV2
NR11
RT11
RT12
SR141
SYMBOL
C11
F11
HIC1
MF
MV1
NAME NAME NAME
INDOOR FAN CAPACITOR
FUSE(T3.15AL250V)
DC/DC CONVERTER
INDOOR FAN MOTOR(INNER PROTECTOR)
HORIZONTAL VANE MOTOR
VERTICAL VANE MOTOR
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
CONTACTOR
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OB400C

8
MS-A30VD
INDOOR UNIT
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
220-230-240V~
3
N
2BRN
1
2
3
CN201
12V
TO OUTDOOR
UNIT
CONNECTING
GRN/YLW
MV2
BLU
RED
CN
101
CN
102
DISPLAY
P.C. BOARD RECEIVER P.C. BOARD
REMOTE
CONTROLLER
33
TAB12
TB
NOTE:1. About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2. Use copper conductors only. (For field wiring)
3. Symbols below indicate.
/: Terminal block, : Connector
SYMBOL
SR141
TB
SYMBOL
MV2
NR11
RT11
RT12
RT13
SYMBOL
C11
F11
HIC1
MF
MV1
NAME NAME NAME
INDOOR FAN CAPACITOR
FUSE (T3.15AL250V)
DC/DC CONVERTER
INDOOR FAN MOTOR (INNER PROTECTOR)
HORIZONTAL VANE MOTOR
VERTICAL VANE MOTOR
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR (MAIN)
INDOOR COIL THERMISTOR (SUB)
SOLID STATE RELAY
TERMINAL BLOCK
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OB400C

9
REFRIGERANT SYSTEM DIAGRAM
6
MS-A18VD
INDOOR UNIT
Unit : mm
Indoor
heat
exchanger
Flared connection
RT11
Room
temperature
thermistor
Distributor
Flared connection
Refrigerant pipe
[12.7
(with heat insulator)
Refrigerant pipe
[6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Strainer
#50
MS-A24VD
INDOOR UNIT
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant flow in cooling
Refrigerant pipe
[15.88
(with heat insulator)
Refrigerant pipe
[6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Strainer
#50
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
MS-A30VD
INDOOR UNIT
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10
SERVICE FUNCTIONS
7
MS-A18VD
MS-A24VD
MS-A30VD
7-2. 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.
7-1. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.
The time will be shortened as follows. (Refer to 8-6.)
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.
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 finish modification, put
back the batteries then press
the RESET button.
Remote controller model : KP0B
Remote controller model : KM04B
J2
J1
J2
J1
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OB400C

11
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
CONTROL” mode before power failure, the operation is not memorized. In “I FEEL CONTROL” mode, the operation is
decided by the initial room temperature.
How to disable “AUTO RESTART FUNCTION”
1Turn off the main power for the unit.
2Pull out the indoor electronic control P.C. board and the display P.C. board.(Refer to 9-1.2.)
3Solder the Jumper wire or the RESISTOR 220"to the RESISTOR JR07 on the indoor electronic control P.C.board.
(Refer to 8-6.)
7-3. AUTO RESTART FUNCTION
Operation
1If the main power has been cut, the operation settings remain.
2After the power is restored, the unit automatically resumes the same operation as the memory has recorded.
However, it takes the compressor at least 3 minutes to get started.
NOTE:
•The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the remote
controller.
•If the 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.
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 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.
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12
TROUBLESHOOTING8
8-1. 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 unit first with the remote controller, and then after confirm-
ing the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel and the electronic
control P.C. board.
3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
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 OPERATION INDICATOR lamp is flashing on and off before starting service
work.
2) Before servicing that the connector and terminal are connected properly.
3) When the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the
components for bursting and discolouration.
4) When troubleshooting, refer to 8-2. and 8-3.
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
<Incorrect>
Housing point
<Correct>
MS-A18VD
MS-A24VD
MS-A30VD
RESET button
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries is correct.
2Press the RESET button with a thin instrument,
and then use the remote controller.
NOTE: 1. If the RESET button is not pressed, the remote controller may not operate correctly.
2. Do not use the leaking batteries.
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OB400C

13
Start
Indoor unit
operates.
Outdoor unit
does not
operate.
Indoor unit
does not receive
the signal from
remote controller.
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
Outdoor unit
operates
in only Test
Run operation.
w
Indoor unit
operates when
EMERGENCY
OPERATION
switch is pressed.
Indoor unit
does not operate
when
EMERGENCY
OPERATION
switch is pressed.
Check room
temperature
thermistor.
Refer to 8-6.
"Test point
diagram and
voltage".
Refer to
"Check of
outdoor unit".
Refer to 8-5. B
"Check of
remote controller
and receiver
P.C. board".

MS-A30VD
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-A30VD
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
MU-A30VD
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Refer to
8-5. D
"How to
check
mis-wiring
(When
outdoor unit
does not work)".
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to 8-6.
"Test point
diagram and
voltage".
Refer to
8-5. A
"Check of
indoor fan
motor".
Refer to
"Check of
outdoor
thermistor".
Replace the
deicer
P.C. board.
MU-A30VD
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
control
system
Replace the
indoor
electronic
control
P.C. board.
1. Check indoor /
outdoor
connecting wire.
2. Check of outdoor
fuse.
(MU-A18/A24VD )
3. Refer to 8-5. C
"Check of indoor
electronic control
P.C. board".
MU-A24VD-K2
MU-A30VD
Outdoor unit
does not
stop even
if indoor unit
stop.
Indoor unit
operates.
Outdoor unit
does not operate
normally.
MU-A30VD
Outdoor unit
repeats start
and stop.
Refer to outdoor unit service manual.
"Test Run operation" means the operation within 30 minutes after EMERGENCY OPERATION switch is pressed.w
MU-A30VD
Outdoor unit
does not operate
even inTest
Run operation.
w
Refer to
"Check of
outdoor unit".
Refer to
"Check of
solenoid
valve coil".
8-2. Instruction of troubleshooting
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14
8-3. Troubleshooting check table
• 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 the OPERATION INDICATOR lamp flashing.
No.
1
2
4
5
6
SymptomIndication Condition
Remedy
0.5-second ON
0.5-second OFF
Mis-Wiring
Outdoor
thermistors
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.
Nonvolatile memory data cannot be read
properly on deicer P.C.board.
• Shortage of refrigerant
• Replace the deicer P.C.
board.
Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
• Replace the deicer P.C.
board.
Refer to outdoor unit service
manual.
• Refer to 8-5.D"How to check
mis-wiring ".
3Indoor fan
motor.
7
Low
discharge
temperature
protection
Discharge temperature has been 50:or less
for 20 minutes.
Abnormal
point
Outdoor unit
does not
operate.
Room
tempera-
ture
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,
sub indoor coil thermistor,
and room temperature
thermistor on 8-6.
3-time flash
2.5-second OFF
Indoor fan
motor repeats
12 seconds
ON and 3
minutes OFF.
When the
indoor fan
motor breaks,
the fan keeps
stopping.
Rotational frequency feedback signal is not
emitting during 12-second indoor fan
operation.
• Refer to 8-5.A"Check of
indoor fan motor".
4-time flash
2.5-second OFF
Indoor
control
system
Nonvolatile memory data cannot be read
properly on indoor electronic control P.C.
board.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
• Replace 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 unit service
manual.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
MS-A30VD
MU-A30VD
MU-A30VD
MU-A30VD
7-time flash
2.5-second OFF
10-time flash
2.5-second OFF
Operation Indicator Lighted
Not lighted
· Flashing of the OPERATION INDICATOR lamp (the left-hand side lamp) indicates
possible abnormalities.
· The OPERATION INDICATOR lamp (the left-hand side lamp) is lighting during
normal operation.
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15
Room
temperature
thermistor (RT11)
8-4. Trouble criterion of main parts
MS-A18VD
MS-A24VD
MS-A30VD
Part name
Indoor coil
thermistor
(RT12(main), RT13(sub))
Check method and criterion
Measure the resistance with a tester.
(Part temperature 10°C ~ 30°C)
Refer to 8-6. “Test point diagram and voltage”, “Indoor electronic control P.C.
board”, for the chart of thermistor.
Figure
Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)
Indoor fan
motor (MF)
INNER
PROTECTOR
135i 5:OPEN
86i15:CLOSE
Motor part
Sensor part
Measure the voltage Power ON.
MAIN
AUX.
BLK REDWHT
PP:INNER PROTECTOR
Horizontal vane
motor(MV1)
Vertical vane
motor(MV2)
Measure the resistance between the RED terminals and other ones.
(Winding temperature10°C ~ 30°C)
ORN
BLUYLW
RED
PNK ROTOR
282 ~ 306 "
Normal
Color of lead wire
WHT - BLK
BLK - RED
MS-A18VDNormal
282 ~ 304 "
MS-A24/30VD
132 ~ 144 "
141 ~ 152 "152 ~ 166 "
Color of lead wire
BRN - YLW
YLW - GRY
Normal
4.5 ~ 5.5 V
(When fan revolved one time)
0V➔5V➔0V
(Approx.)
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16
Yes
BBCheck of remote controller and receiver P.C. board
w Check if the remote controller is exclusive for this air conditioner.
Replace the batteries
(Refer to 8-1.4.).
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.1(+) and No.3(-) when
the remote controller button is pressed (Refer to 8-6.).
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.
Switch on the remote controller.
Is LCD display on the remote con-
troller visible?
Remove batteries, then set them back and
press the RESET button.
Check if the unit operates with remote con-
troller.
Yes
Does the unit operate with remote
controller?
Yes
OK
No
(not clear)
Yes
No
No
No (5V or 0 VDC)
No
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but does not operate with the remote controller.
Yes
AACheck of indoor fan motor Turn OFF the power supply.
Check connector CN211 visually.
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? Is soldered point of the connector
correctly soldered?
Resolder it.
Yes
No
No Yes
Reconnect the lead wires.
Repair the indoor fan motor.
Is resistance 0 (short circuit) or ∞(open circuit)?
Yes ( 0 or ∞)No
(others)
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 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
8-5. Troubleshooting flow
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor does not operate.
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17
Check of indoor electronic control P.C. board
C
Indoor electronic
control P.C. board
Varistor (NR11)
Indoor electronic
control P.C. board
Fuse (F11)
Check both “parts side” and “pattern
side” of the indoor electronic control P.C.
board visually.
Replace the fuse.
Is fuse(F11) blown?
Replace the fan
motor.
Is the winding
resistance of
fan motor 0 "?
Is the winding
resistance of
vane motor 0 "?
No
Yes
Replace the vane
motor.
No
Yes
Yes
Is varistor(NR11) burnt?
Replace the varistor.
No
Yes
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C. board and turn ON the power supply.
No
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up by
pressing the EMERGENCY OPERATION switch?
Yes
No
Turn OFF the
power supply. Turn OFF the power supply.
Replace the indoor
electronic control
P.C. board.
Measure the
resistance
between
CN201 1on
the indoor
electronic control
P.C. board and N
on the terminal
block with a tester.
Is resistance
approximately 0"?
Replace the fuse (F12).
No
Yes
(∞)
CN201
1
2
L
N
F12
Terminal
block
2
MS-A18/24VD - K1
1
2
3
MS-A18/24VD - K2
MS-A30VD
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 and disconnect only terminal block 3of indoor/ outdoor
connecting wire on indoor side.
2. Short-circuit terminal block N-3by lead wire.
3. Turn ON the power supply and press EMERGENCY OPERATION switch once.
When EMERGENCY OPERATION
is operated, is there 10V DC between both
ends of R601 on the deicer P.C. board?
However the stylus of a tester would be
between 5 ~10V.
Start
No
No
Is there 1V DC detected between both ends
of PS132 on the indoor electronic control P.C.
board ?
However, the stylus of a tester would be
between 0 and 20V.
• Turn ON the power supply.
• Press EMERGENCY OPERATION switch once.
Is this mis-wiring, poor contact,
or wire disconnection?
Make them sure.
Replace the indoor electronic
control P.C. board.
Is there 220-230-240V AC between L-N
on the outdoor terminal block? No Check the outdoor power supply
and connection of wiring.
Is there 5V DC between J101 + -J401 - ?
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
Yes
Yes
When the unit has mis-wiring, in 3 minutes,
OPERATION INDICATOR lamp on indoor unit
flash on and off at 0.5 second intervals. 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.
• Disconnect the lead wire that terminal
block N-3is short-circuited.
•
Connect ON indoor/ outdoor connecting wire.
Turn ON the power supply.
Refer to outdoor unit service manual .
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
MS-A30VD
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19
8-6. Test point diagram and voltage
MS-A18VD MS-A24VD MS-A30VD
Indoor electronic control P.C.board
Fan motor power supply
220-230-240 VAC(CN211)
Fuse (F11)
T3.5AL250V
}Power supply input
220-230-240 VAC
+}5 VDC
Indoor coil
thermistor (RT12 (main))
Timer short mode point
(JPS, JPG)
(Refer to 7-1.)
Emergency operation
switch
+
}
12 VDC
Indoor coil thermistor
(RT12 (main), RT13 (sub))
Room temperature thermistor (RT11)
Temperature (:)
Resistance (k")
Room temperature
thermistor (RT11)
MS-A30VD
Indoor coil
thermistor (RT13 (sub))
To disable “Auto restart function”,
solder the Jumper wire or the
Resistor 220"to the Resistor
JR07. (Refer to 7-3.)
Varistor (NR11)
CN121
Vane motor
power supply
(CN151)
CN301
PS132
MS-A30VD
wThere are 2 types of electronic control P.C. boards
(TYPE1/TYPE2).
They are both compatible with MS-A18/24/30VD.
TYPE 1
Receiver P.C. board
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20
+
}
}
Resistance (k )
+
{
Fan motor power supply
(CN211)
Fuse (F11)
T3.15AL250V
220-230-240 VAC
5 VDC
Indoor coil thermistor
(RT12 (main))
MS-A30VD
Indoor coil thermistor
(RT13 (sub))
Timer short
mode point
(JPS, JPG)
(Refer to 7-1.)
Emergency
operation
switch
CN121
Room temperature
thermistor (RT11)
PS132
MS-A30VD
To disable “Auto restart
function”, solder jumper
wire to JR07.
(Refer to 7-3.)
Vane motor
power supply
(CN151)
12 VDC
Indoor coil thermistor
(RT12 (main), RT13 (sub))
Room temperature thermistor (RT11)
Power supply input
MS-A18VD MS-A24VD MS-A30VD
Indoor electronic control P.C.board
TYPE 2
Receiver P.C. board
CN301
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