Mitsubishi MS-A18WV-E1, MS-A24WV-E1, MS-A30WV-E1 Service Manual

SERVICE MANUAL

SPLIT-TYPE, AIR CONDITIONERS

Wireless type
Models

E1

E1

E1

(WH)

(WH)

(WH)

CONTENTS

MS-A18WV ­MS-A24WV ­MS-A30WV -

No. OB325

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

Indication of model name

MS-A18WV ­MS-A24WV ­MS-A30WV -

NOTE:

This service manual describes technical data of the indoor units.
As for outdoor units MU-A18WV- , MU-A24WV- and MU-A30WV- , refer to service manual
OB326.

E1

E1

E1

9. SERVICE FUNCTIONS ····································17

10. TROUBLESHOOTING ······································19

11. DISASSEMBLY INSTRUCTIONS·····················27

12. PARTS LIST······················································29

13. OPTIONAL PARTS ···········································31

E1E1E1

1

Grille

(When the grille is opened)

Remote controller

Operation section

Display section

Operation Indicator

Emergency operation switch

Operation indicator lamp

Air inlet

Horizontal vane

Remote control

receiving section

Catechin air filter

Air cleaning filter (option)
(White bellows type)

Vertical vanes

Front panel

Remote control

receiving section

1
2
3
4
5
6
7

Installation plate
Installation plate fixing screw 4 o 25 mm
Remote controller holder
Fixing screw for 3 o 3.5 o 1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)

1
7
1
2
2
1
1

MS-A18WV­MS-A24WV­MS-A30WV-

E1
E1

E1

TECHNICAL CHANGES

MS-18RV - ➔MS-A18WV -

1. Indoor unit model has changed.

2. Rated voltage has changed. (220V-240V ➜ 230V)

3. Remote controller has changed.

• LONG MODE and WIDE MODE have been added.

4. Indoor fan motor has changed.(RA4V27-EF ➜ RC4V32-AA)

5. Indoor heat exchanger has changed.

6. Diameter of connect pipe has changed.(Liquid:[8 ➜ [6.35)

7. Air filter has changed to catechin air filter.

MS-24RV - ➔MS-A24WV -

1. Indoor unit model has changed.

2. Rated voltage has changed. (220V-240V ➜ 230V)

3. Remote controller has changed.

• LONG MODE and WIDE MODE have been added.

4. Indoor fan motor has changed.(RA4V27-EE ➜ RC4V32-AA)

5. Indoor heat exchanger has changed.

6. Diameter of connect pipe has changed.(Liquid:[8 ➜ [6.35)

7. Air filter has changed to catechin air filter.

MS-30RV - ➔MS-A30WV -

1. Diameter of connect pipe has changed.(Gas:[15.88 ➜ [12)

2. Rated voltage has changed. (220V-240V ➜ 230V)

3. Power supply cord has been added.

4. Air filter has changed to catechin air filter.

2

PART NAMES AND FUNCTIONS

E1E1

E1E1

E1E1

INDOOR UNIT

MS-A18WV ­MS-A24WV ­MS-A30WV -

ACCESSORIES

E1

E1

E1

Indoor unit

2

REMOTE CONTROLLER

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.

MS-A18WV ­MS-A24WV ­MS-A30WV -

E1

E1

E1

3

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(at20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed(High/Med. /Low )
Fan speed regulator
Thermistor RT11(at25:)
Thermistor RT12(at25:)
Remote controller model

K /h

A
A

W

A(kW)

%

A

"

mm

kg

dB

rpm

k"
k"

MS-A18WV -

E1

Cooling

Single phase

230V, 50Hz

768/642 /528

10

0.30
60
—
87

0.30

RC4V32-AA
WHT-BLK 293
BLK-RED 146

1,100O325O227

16

5

42/38 /34

1,070/920 /780

3
10
10

KP0B or KG1D

MS-A24WV -

E1

Cooling

Single phase

230V, 50Hz

768/672 /588

10

0.30
60
—
87

0.30

RC4V32-AA
WHT-BLK 293
BLK-RED 146

1,100O325O227

16

5

45/41 /37

1,070/960 /850

3
10
10

KP0B or KG1D

Electrical

data

Fan

motor

Special

remarks

Capacity

ww

ww

w

w

ww

w

w

w

w

w

w

w

w

ww

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(at20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed(High/Med. /Low )
Fan speed regulator
Thermistor RT11(at25:)
Thermistor RT12(at25:)
Thermistor RT13(at25:)
Remote controller model

K /h

A
A

W

A(kW)

%

A

"

mm

kg

dB

rpm

k"
k"
k"

MS-A30WV -

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
1,100O325O227

16

5

47/42 /37

1,280/1,130 /970

3
10
10
10

KP0B or KG1D

Electrical

data

Fan

motor

Special

remarks

Capacity

ww

w

w

ww

w

w

w

w

w

w

SPECIFICATION

NOTE: 1. Test conditions are based on JIS C 9612.

Cooling : Indoor DB27°C WB19°C
Indoor-Outdoor piping length 5m

2. Remote controller model KP0B and KG1D are the same in terms of specification.
w Reference value

Outdoor DB35°C WB(24°C)

4

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

NOISE CRITERIA CURVES

MS-A18WV-

E1

FAN SPEED

High

SPL(dB(A)) LINE

42

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

90

80

70

60

50

40

30

MS-A24WV-

NC-70

NC-60

NC-50

NC-40

NC-30

E1

FAN SPEED

High

SPL(dB(A)) LINE

45

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

90

80

70

NC-70

60

NC-60

50

NC-50

40

NC-40

30

NC-30

APPROXIMATE

20

THRESHOLD OF
HEARING FOR
CONTINUOUS

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

NOISE

10

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

MS-A30WV-

E1

NC-20

APPROXIMATE

20

THRESHOLD OF
HEARING FOR
CONTINUOUS

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR

NOISE

10

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

INDOORUNIT

WALL

1m

0.8m

MICROPHONE

NC-20

5

5

162

19

58

47

7.5315

255.547

2.5

98 173

98 173414.5 414.5

5225

253

791

56

1068

1100

325

Air out

Air in

Insulation [ 28

Drain hose [ 16
(Connected part O.D)

{

Liquid line [ 6.35-0.5m
Gas line [ 12-0.43m
Insulation [ 50 O.D

[ 32 I.D

Installation plate

Wall hole [ 75

Wireless remote controller

Installation plate

Indoor unit

{

Liquid line [ 9.52-0.5m
Gas line [ 12-0.43m
Insulation [ 50 O.D

[ 32 I.D

for MS-A18/A24WV

for MS-A30WV

Power supply cord
Lead to right 2.0m
Lead to left 1.0m

OUTLINES AND DIMENSIONS

MS-A18WV ­MS-A24WV ­MS-A30WV -

INDOOR UNIT

E1

E1

E1

Unit: mm

6

6

WIRING DIAGRAM

MS-A18WV ­MS-A24WV -

INDOOR UNIT

TO OUTDOOR UNIT
CONNECTING

12V

POWER
SUPPLY
CORD
~/N 230V
50Hz

PE

CIRCUIT
BREAKER

SYMBOL

C11

HIC1

NOTES:

INDOOR FAN CAPACITOR

F11

FUSE (3.15A)
DC/DC CONVERTER

MF

INDOOR FAN MOTOR (INNER FUSE)

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

E1

E1

TB

1
2
N

L

BRN
BLU

BLK
WHT

BLU

BRN

GRN/YLW

NAME

MV2

: Connector

MODELS WIRING DIAGRAM

CN202

1
2

CN201

3
2
1

TAB12

ELECTRONIC CONTROL

CN

151

15

MV2

SYMBOL

MV1

MV1
MV2

NR11

RT11

CN

102

DISPLAY
P. C. BOARD

VANE MOTOR (HORIZONTAL)
VANE MOTOR (VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMISTOR

CN
101

P. C. BOARD

33

RECEIVER
P. C. BOARD

NAME

HIC1

TRANS

F11

REMOTE
CONTROLLER

NR11

C11

SR141

SYMBOL

RT12

SR141

TB

2
1

CN112

CN

121

1
3
4

3

RT12

BLK
GRY
YLW
BRN
WHT
RED

1
2
3

MF

4
5
6

CN211

CN
111

RT11

NAME
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK

MS-A30WV -

E1

MODEL WIRING DIAGRAM

INDOOR UNIT

TO OUTDOOR
UNIT
CONNECTING

12V

POWER
SUPPLY
CORD
~/N 230V
50Hz

PE

CIRCUIT
BREAKER

TB

3
N
L

BRN
BLU

RED
BLU
BRN

MV2

CN
151

MV2

15

MV1

CN201

CN

102

DISPLAY
P. C. BOARD

3
2
1

TAB12

ELECTRONIC CONTROL

CN
101

P. C. BOARD

33

RECEIVER
P. C. BOARD

GRN/YLW

SYMBOL

C11
F11

HIC1

MF

MV1

NOTE:1. About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.

INDOOR FAN CAPACITOR
FUSE(3.15A)
DC/DC CONVERTER
INDOOR FAN MOTOR(INNER PROTECTOR)
VANE MOTOR(HORIZONTAL)

2. Use copper conductors only. (For field wiring)

3. Symbols below indicate.

/: Terminal block, : Connector

NAME

SYMBOL

MV2

NR11

RT11
RT12
RT13

NAME NAME
VANE MOTOR(VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMIST OR
INDOOR COIL THERMISTOR (MAIN)
INDOOR COIL THERMISTOR (SUB)

7

HIC1

TRANS

F11

NR11

C11

SR141

REMOTE
CONTROLLER

SYMBOL

SR141

TB

4
3
2
1

CN112

CN

121

1
3
4

3

RT13
RT12

BLK
GRY
YLW
BRN
WHT
RED

CN211

CN
111

RT11

SOLID STATE RELAY
TERMINAL BLOCK

MF

7

REFRIGERANT SYSTEM DIAGRAM

MS-A18WV -

INDOOR UNIT

Indoor
heat
exchanger

Room temperature
thermistor
RT11

E1

Indoor coil
thermistor
RT12

Distributor

Refrigerant pipe [12.7
(with heat insulator)

Flared connection

Flared connection

MS-A24WV -

INDOOR UNIT

Indoor
heat
exchanger

Room temperature
thermistor
RT11

E1

Indoor coil
thermistor
RT12

Distributor

Unit:mm

Refrigerant pipe [15.88
(with heat insulator)

Flared connection

Flared connection

MS-A30WV -

INDOOR UNIT

Indoor
heat
exchanger

Indoor coil
thermistor
RT13(sub)

Room temperature
thermistor
RT11

Strainer

E1

Indoor coil
thermistor
RT12(main)

#50

Refrigerant pipe[6.35
(with heat insulator)

Refrigerant pipe [15.88
(with heat insulator)

Flared connection

Flared connection

Refrigerant pipe [6.35
(with heat insulator)

Refrigerant pipe [9.52
(with heat insulator)

Refrigerant flow in cooling

8

8

MICROPROCESSOR CONTROL

MS-A18WV - MS-A24WV - MS-A30WV -

WIRELESS REMOTE CONTROLLER

Signal transmitting section

Operation display section

OPERATE/ STOP

(ON/ OFF)button

VANE button

(Horizontal vane button)

OPERATION SELECT button

ECONO COOL button

WIDE VANE button

(Vertical vane button)

RESET button

ON/OFF

ON/OFF

I FEEL

COOL

FAN

DRY

MODE

WIDE VANE

ECONO COOL

TOO

WARM

CLOCK

TOO

WARM

FAN

VANE

LONG

RESET CLOCK

PM

AM

TOO

COOL

PM

AM

TOO

COOL

STOP

START

HR.

MIN.

E1E1E1

TEMPERATURE buttons

FAN SPEED CONTROL button

OFF-TIMER button

ON-TIMER button

HR. button

MIN. button

(TIME SET button)

CLOCK SET button

LONG button

INDOOR UNIT DISPLAY SECTION

Operation Indicator lamp

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

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

Operation Indicator

Operation stateIndication

This shows that the
air conditioner is
operating to reach
the target temperature.
Please wait until the
target temperature is
obtained.

This shows that the
room temperature is
approaching the
target temperature.

lighted
not lighted

Difference
between target
temperature
and room
temperature

Approx. 2 :
or more

Approx. 2 :
or less

Once the operation mode are set, the same operation mode
can be repeated by simply turning the 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.

8-1. “I FEEL CONTROL” ( ) OPERATION

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

controller. OPERATION INDICATOR lamp of the indoor
unit turns on with a beep tone.

(2) Select “I FEEL CONTROL” mode with the OPERATION

SELECT button.

(3) The operation mode is determined by the room tempera-

ture at start-up of the operation.

Initial room temperature

25: or more

more than 13:,

less than 25:

"I FEEL CONTROL"

"I FEEL CONTROL"

Mode

COOL mode of

DRY mode of

9

• Once the mode is fixed, the mode does not change by room temperature afterwards.

Model

COOL mode of

"I FEEL CONTROL"

DRY mode of

"I FEEL CONTROL"

Initial room temperature Initial set temperature

26: or more

25: to 26:

more than 13:, less than 25:

24:

Initial room temperature
minus 2:
Initial room temperature
minus 2:

❈1

TOO

COOL

TOO

WARM

• Under the ON-TIMER ( ) operation, mode is determined according to the room temperature at the set time the
operation starts.

• When the system is stopped on the remote controller, and restarted within 2 hours in “I FEEL CONTROL” ( ) mode,
the system operates in previous mode automatically regardless of the room temperature.

Operation timer chart
Example

Previous operation

COOL mode of
“I FEEL CONTROL”

Restart

COOL mode of
“I FEEL CONTROL”

or COOL mode

When the system is restarted after 2 hours and more, the operation mode is determined by the room temperature at
start-up of the operation.

Operation timer chart
Example

Previous operation

COOL mode of
“I FEEL CONTROL”

or COOL mode

Restart

COOL or DRY mode
of “I FEEL CONTROL”
that determined by
room temperature at
start-up of the opera­tion.

(4) The initial set temperature is decided by the initial room temperature.

❈1 When the system is restarted with the remote controller, the system operates with the previous set temperature regard-

less of room temperature at restart.
The set temperature is calculated by the previous set temperature.

(5) TEMPERATURE buttons

In “I FEEL CONTROL” ( ) mode, set temperature is decided by the microprocessor based on the room temperature.
In addition, set temperature can be controlled by TOO WARM or TOO COOL buttons when you feel too cool or too warm.
Each time the TOO WARM or TOO COOL button is pressed, the indoor unit receives the signal and emits a beep tone.

• Fuzzy control

When the TOO COOL or TOO WARM button is pressed, the microprocessor changes the set temperature, considering
the room temperature, the frequency of pressing TOO COOL or TOO WARM button and the user’s preference to heat or
cool. So this is called “Fuzzy control”, and works only in “I FEEL CONTROL” mode.
In DRY mode of “I FEEL CONTROL”, the set temperature doesn’t change.

…

…

To raise the set temperature 1~2 degrees(°C)

To lower the set temperature 1~2 degrees(°C)

10

8-1-1. COOL mode of “I FEEL CONTROL”

Difference between room
temperature and set temperature
during operation

1deg. 1.7deg.

3deg.

1. Indoor fan speed control

Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In AUTO the fan speed is as follows.

Initial temperature difference Fan Speed
Room temperature minus set temperature : 1.7 degrees or more
Room temperature minus set temperature : Between 1 and 1.7 degrees
Room temperature minus set temperature : less than 1 degree

2. Coil frost prevention

① Temperature control

When the indoor coil thermistor RT12 reads 0°C or below(MS-A18WV) /3°C or below(MS-A24WV)/ RT12 or RT13
reads -1°C or below (MS-A30WV), the coil frost prevention mode starts immediately.

However, the coil frost prevention doesn’t work for 5 minutes since the compressor has started.

The indoor fan operates at the set speed and the compressor stops for 5 minutes.
After that, if RT12 still reads below 0°C(MS-A18WV)/ 3°C(MS-A24WV)/ RT12 or RT13 still reads below-1°C (MS­A30WV) this mode prolonged until the RT12 reads over 0°C(MS-A18WV)/ 3°C(MS-A24WV) / RT12 or RT13 still reads­over-1°C(MS-A30WV).

② Time control

When the three conditions as follows have been satisfied for 1 hour and 45 minutes, compressor stops for 3 minutes.
a. Compressor has been continuously operating.
b. Indoor fan speed is Low or Med.
c. Room temperature is below 26°C.
When compressor stops, the accumulated time is cancelled and when compressor restarts, time counting starts from the
beginning.
Time counting also stops temporarily when the indoor fan speed becomes High or the room temperature exceeds
26°C. However, when two of the above conditions (b.and c.) are satisfied again. Time accumulation is resumed.

Operation chart

Example

Compressor

OFF

ON

Outdoor fan

··························High

················Med.

······························Low

ON

OFF

(continuously at set speed)

Indoor fan

ON

NOTE : As for outdoor fan speed control and discharge temperature protection, refer to service manual for outdoor

unit.

8-1-2. DRY mode of “I FEEL CONTROL”

The system for dry operation uses the same refrigerant circuit as the cooling circuit.
The compressor and the indoor fan are controlled by the room temperature.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease.

1. Indoor fan speed control

Indoor fan operates at the set speed by FAN SPEED CONTROL button.
However, in AUTO fan operation, fan speed becomes Low.

2. The operation of the compressor and indoor/ outdoor fan

Compressor operates by room temperature control and time control.
Set temperature is controlled to fall 2°C from initial room temperature.
Indoor fan and outdoor fan operate in the same cycle as the compressor.

•When the room temperature is 23°C or over:

When the thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

•When the room temperature is under 23°C.

When the thermostat is ON, the compressor repeats 2 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.

11

Operation time chart

Example

ON

ON

Thermostat

Indoor fan

Outdoor fan
Compressor

3. Coil frost prevention

• The operation is as same as coil frost prevention during COOL mode of “I FEEL CONTROL”.

• Indoor fan operates at the set speed and the compressor stops for 5 minutes, because protection(Coil frost
prevention) has the priority.
However, when coil frost prevention works while the compressor is not operating, it’s speed becomes Low.

NOTE : As for outdoor fan speed control, refer to service manual for outdoor unit.

OFF

OFF

OFF

ON

ON

8 min.

OFF

OFF

ON

ON

3 min.

OFF

4 min.

OFF

ON

ON

OFF

1 min.

8-2. 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 the OPERATION

SELECT button.

(3) Press the TEMPERATURE buttons.

(TOO WARM or TOO COOL button) to select
the desired temperature.
The setting range is 16 ~ 31°C.
✻ Indoor fan continues to operate regardless of

thermostat’s OFF-ON at set speed.

✻ Coil frost prevention is as same as COOL

mode of “I FEEL CONTROL”.

8-3. 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 the OPERATION

SELECT button.

(3) The microprocessor reads the room tempera-

ture and determines the set temperature. Set
temperature is as shown on the right chart.
Thermostat (SET TEMP.)does not work.
The other operations are same as DRY mode of
“I FEEL CONTROL”.

(4) DRY operation will not function when the room

temperature is 13°C or below.

8-4. FAN( d )OPERATION

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

OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone.
(2) Select FAN mode with the OPERATION SELECT button.
(3) Select the desired fan speed. When AUTO, it becomes Low.

Only indoor fan operates. Outdoor unit does not operate.

12

8-5. INDOOR FAN MOTOR CONTROL

AUTO

Horizontal

12

34 5

Middle Downward Swing

(1) Rotational frequency feedback control

The indoor fan motor is equipped with a rotational frequency sensor, and outputs signal to the microprocessor to
feedback the rotational frequency. Comparing the current rotational frequency with the target rotational frequency
(High, Med., Low), the microprocessor controls SR141 and adjusts fan motor electric current to make the current rota­tional frequency close to the target rotational frequency. With this control, when the fan speed is switched, the rotational
frequency changes smoothly.

Rotational frequency

High

Med.

Low

(2) Fan motor lock-up protection

When the rotational frequency feedback signal has not output for 12 seconds, (or when the microprocessor cannot
detect the signal for 12 seconds) the fan motor is regarded locked-up. Then the electric current to the fan motor is shut
off. 3 minutes later, the electric current is applied to the fan motor again. During the fan motor lock-up, the OPERATION
INDICATOR Indicator lamp flashes on and off to show the fan motor abnormality. (Refer to page 21.)

High

time

8-6. 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 changes as follows by pressing the VANE button.

(3) Positioning

The vane is once pressed to the vane stopper below to confirm the standard position and then set to the desired angle.
Confirming of standard position is performed in case of follows.
(a) When the OPERATE/STOP (ON/OFF) button is pressed. (POWER ON/OFF)
(b) When the vane control is changed from AUTO to MANUAL.
(c) When the SWING is finished.
(d) When the test run starts.
(e) When the power supply turns ON.

(4) VANE AUTO ( ) mode

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

① In COOL and DRY operation

➁ In FAN operation

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

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

(6) Dew prevention

During COOL or DRY operation at Vane Angle 4 or 5 when the compressor cumulative operation time of compressor
exceeds 1 hour, the vane angle automatically changes to Angle 1 for dew prevention.

(7) SWING MODE ( )

By selecting SWING mode with the VANE button, the horizontal vane swings vertically. The remote controller displays
“”.

13

Vane angle is fixed to Angle 1.

Vane angle is fixed to Angle 4.

COOL / DRY FAN

Fan speed : Faster
Solid arrow : When the LONG mode is used.
Dotted arrow : When the LONG mode is not used.

(8) ECONO COOL ( ) operation (ECONOmical operation)

When the ECONO COOL button is pressed in COOL mode, set temperature is automatically set 2°C higher than that in
COOL mode.
Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger(Tp(w 1)).
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher than that
in COOL mode, the air conditioner can keep comfort. As a result, energy can be saved.
ECONO COOL operation is cancelled when the ECONO COOL button is pressed once again or VANE button is pressed
or LONG button is pressed or change to other operation mode.

NOTE : ECONO COOL operation does not work in COOL mode of “I FEEL CONTROL”.

SWING operation

w 1 Tp : • Value of RT12 (MS-A18/A24WV)

• Minimum value of indoor coil thermistor (main) RT12 and indoor coil thermistor (sub) RT13 (MS-A30WV)

In swing operation of ECONO COOL operation mode, the initial air flow direction is adjusted to “Horizontal”.
According to the temperature of indoor coil thermistor Tp

(w 1) at starting of this operation, next downward blow time is

decided. Then when the downward blow has been finished, next horizontal blow time is decided.
For initial 10 minutes the swing operation is performed in table G~H for quick cooling.
Also, after 10 minutes when the difference of set temperature and room temperature is more than 2:, the swing opera­tion is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.

Temperature of Tp(w 1)

A

B
C
D

E

F
G

H

15°C or less
15°C to 17°C

17°C to 18°C

18°C to 20°C

20°C to 21°C
21°C to 22°C
22°C to 24°C

more than 24°C

Downward blow time

(sec.)

2
5
8

11
14
17

20
23

Horizontal blow time

(sec.)

23
20
17
14
11

8

5
2

(9) LONG MODE ( )

By pressing the LONG button indoor fan speed becomes faster than setting fan speed on the remote controller, and the
horizontal vane moves to the position for LONG mode. The remote controller displays “ ”. LONG mode is cancelled

when the LONG button is pressed once again or the VANE button is pressed or ECONO COOLbutton is pressed in
COOL mode.

• In the following example, the vertical vane is set to (front.).

14

2. Vertical vane

About 100-

Horizontal AIR FLOW blowing range

(1) Vane motor drive

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

(2) The vertical vane angle and mode change as follows by pressing the WIDE VANE button.

23

45SWING

61

(3) Positioning

The vane is once pressed to the vane stopper to confirm the standard position and then set to the desired angle.
Confirming of standard position is performed in case of follows.
(a) When the OPERATE/STOP(ON/OFF) button is pressed (POWER ON/OFF).
(b) When the SWING is started or finished.
(c) When the power supply turns ON.

(4) SWING MODE ( )

By selecting SWING mode with the WIDE VANE button, the vertical vane swings horizontally. The remote controller dis­plays “ ”. The vane moves right and left in the width of Angle 4 repeatedly.

(5) WIDE MODE ( )

By selecting WIDE mode with the WIDE VANE button, indoor fan speed becomes faster than setting fan speed on the
remote controller (W). The remote controller displays “ ”.

W Indoor fan speed becomes faster than setting fan speed on the remote controller even when or is

selected.

8-7. TIMER OPERATION

1. How to set the timer

(1) Press OPERATE/STOP (ON/OFF) button to start the air conditioner.
(2) 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.

(3) Press ON/OFF TIMER buttons to select the operation.

“ON-TIMER” button... AUTO START operation (ON timer)
“OFF-TIMER” button... AUTO STOP operation (OFF timer)

(4) Press HR. and MIN. button to set the timer. Time setting is 10-minute units.

HR. and MIN. button will work when “ ” or “ ” mark is flashing.
These marks disappear in 1 minute.
After setting the ON timer, check that OPERATION INDICATOR lamp of the indoor unit lights.

NOTE1 : Be sure to place the remote controller at the position where its signal can reach the air conditioner even during

TIMER operation, or the set time may deviate within the range of about 10 minutes.

NOTE2 : Reset the timer in the following cases, or the set time may deviate and other malfunctions may occur.

• Apower failure occurs.

•The circuit breaker functions.

15

EMERGENCY OPERATION switch

Press once <Cool>

Press again <Stop>

OPERATION INDICATOR lamp

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

2. Cancel

PM

AM

PM

PM

TIMER setting can be cancelled with the ON/OFF TIMER buttons.
To cancel the ON timer, press the “ON-TIMER” button.
To cancel the OFF timer, press the “OFF-TIMER” button.
TIMER is cancelled and the display of set time disappears.

PROGRAM TIMER

• The OFF timer and ON timer can be used in combination.

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

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

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

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

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

NOTE : TIMER setting will be cancelled by power failure or breaker functioning.

8-8. EMERGENCY-TEST OPERATION

In case of test run operation or emergency operation, use the EMERGENCY OPERATION switch on the front of the
indoor unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of remote
controller run down. The unit will start and the OPERATION INDICATOR lamp will light.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan speed runs at
High speed and the system is in continuous operation. (The thermostat is ON.)
After 30 minutes of test run operation the system shifts to EMERGENCY COOL MODE with a set temperature of 24°C.
The fan speed shifts to Med. speed.
The coil frost prevention works even in emergency operation.

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

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

16

9

SERVICE FUNCTIONS

MS-A18WV ­MS-A24WV ­MS-A30WV -

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9-1. 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.)

9-2. 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 :

Remote controller model : KP0B

J2

Remote controller model : KG1D

Remote controller model : KG1D

J1

J2

J1

J2

NOTE : 1. For remodelling, take out the

batteries 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.

2. Remote controller model KG1D
and KP0B are the same in
terms of specification.

J1

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.

17

JR07

IC152

CN151

CN112

CN111

CN121

SW1

IC101

RA102

C11

CN201

CN211

TAB12

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.

9-3. AUTO RESTART FUNCTION

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 FEELCON­TROL” 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 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 27.)

3Solder jumper wire to the RESISTOR JR07 on the indoor

electronic control P.C. board. (Refer to page 26.)

Operation

1If the main power (230V AC) 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

NOTE

for the compressor to start running.)

•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

18

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.

10

Lead wiring

Housing point

TROUBLESHOOTING

MS-A18WV ­MS-A24WV ­MS-A30WV -

E1
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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 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 the flow chart on page 20 and the check table on page 21.

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.
1 Remove the front lid and insert batteries.

Then reattach the front lid.

2 Press the RESET button with tip end of ball point

pen or the like, and then use the remote controller.

FAN

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

RESET button

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

FAN

19

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
"Test point
diagram and
voltage" on
page 26.

Refer to
"Check of
outdoor unit".

Refer to B
"Check of
remote controller
and receiver
P.C. board"
on page 23.

MS-A30WV

Flash on and
off at 0.5­second
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-A30WV

6-time flash
Cause:
Outdoor unit

• Trouble of
thermistor
in outdoor
unit

MU-A30WV

7-time flash
Cause:
Outdoor unit

• Trouble of
outdoor
control
system

Refer to D
"How to
check
mis-wiring
(When
outdoor unit
doesn't work)"
on page 25.

Check room
temperature
thermistor
and indoor
coil thermis­tor.
Refer to
"Test point
diagram and
voltage"
on page 26.

Refer to A
"Check of
indoor fan
motor"
on page 23.

Refer to
"Check of
outdoor
thermistor".

Replace the
deicer
P.C. board.

MU-A30WV

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 OB326.

1. Check indoor /
outdoor
connecting wire.

2. Refer to C
"Check of indoor
electronic control
P.C. board"
on page 24.

Outdoor unit
doesn't
stop even
if indoor unit
stops.

Refer to
"Check of
outdoor unit".

10-2. Instruction of troubleshooting

20

1. Troubleshooting check table

Operation Indicator

flashing

No.

1

2

4

5

6

SymptomOperation indicator lamp Detection method

Checkpoint

0.5-second ON

0.5-second OFF

MS-A30WV

Mis-Wiring

MU-A30WV

Outdoor
thermistor

MU-A30WV

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 OB326.

• Check the deicer P.C. board.

Refer to service manual
OB326.

• Refer to D "How to check
mis-wiring " on page 25.

3

Indoor fan
motor

7

MU-A30WV

Low
discharge
tempera­ture
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
thermistor on page 26.

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 A "Check of

indoor fan motor" on page 23.

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
OB326.

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

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

· 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.

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.

21

Part name

Figure

Check method and criterion

Indoor fan motor(MF)

MS-A18/A24WV

INNER FUSE
145: CUT OFF

MS-A30WV

INNER
PROTECTOR
135i 5: OPEN

Color of

lead wire
WHT – BLK
BLK – RED

Abnormal

Open or

short-circuit

MS-A18/A24WV

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-A30WV
133 " ~ 144 "
152 " ~ 165 "

Normal

MS-A18/A24WV

MS-A30WV

YLW

GRNORN

BRN

RED

ROTOR

MAIN

AUX.

P

:INNER PROTECTOR

P

2. Trouble criterion of main parts

MS-A18WV ­MS-A24WV ­MS-A30WV -

E1

E1

E1

22

When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.

A

Check of indoor fan motor

Turn OFF the power supply.
Check connector CN211 visually.

No

Reconnect the lead wires.

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

Repair or replace the indoor fan motor.

Yes

Yes ( 0 or ∞ )

Is soldered point of the connector
correctly soldered?

Yes

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

No

(others)

voltage between No.2(+) and No.3(-) on CN121.

No

Does voltage repeat 0V DC and 5V DC?

Replace the indoor electronic control P.C. board.

No

Resolder it.

Yes

Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote con­troller.

Check of remote controller and receiver P.C. board

B

w Check if the remote controller is exclusive for this air conditioner.

Switch on the remote controller.

Is LCD display on the the remote
controller visible?

Yes

Remove the batteries, then set them back
and press the RESET button. Check if the
unit operates with the remote controller.

Does the unit operate with the
remote controller?

Yes

OK

No
(not clear)

No

Replace the batteries.(Refer to page 19.)

Turn on a radio to AM and press switch on

the remote controller.

Is noise heard from radio?

Yes

Are there any fluorescent lights of

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

No

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?

No(5V or 0V DC)

No

Yes

Yes

Replace the remote controller.

● Reinstall the unit away from lights.

● Attach a filter on receiving part.

Replace the indoor electronic control P.C.
board.

Replace the receiver P.C. board.

23

The unit doesn’t operate with the remote controller. Also, the OPERATION INDICATOR lamp doesn’t light up by press­ing the EMERGENCY OPERATION switch.

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.

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.

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

Yes

Turn OFF the
power supply.

Be sure to check both resistance.

Replace the vane
motor.

Is winding
resistance of
vane motor 0 "?

Is winding
resistance of
fan motor 0 "?

Replace the fan
motor.

Yes

Yes

Turn OFF the
power supply.

No

No

No

Replace the fuse.

Is fuse(F11) blown?

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

Is varistor(NR11) burnt?

Replace the varistor.

Varistor (NR11)

Fuse (F11)

Indoor electronic
control P.C. board

Yes

No

Replace the indoor
electronic control
P.C. board.

No

Yes

24

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-3 of 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 OB326.

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-A30WV) 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

w Short 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.

How to check mis-wiring

D

MS-A30WV

25

TEST POINT DIAGRAM AND VOLTAGE

Indoor coil thermistor(RT12(main), RT13(sub))

Room temperature thermistor (RT11)

Resistance(k")

MS-A18WV - MS-A24WV - MS-A30WV ­Indoor electronic control P.C. board

Fuse (F11)
250V AC 3.15A

R132

E1E1E1

Fan motor power supply

Power supply input

}

230V AC

5V DC

}

+

Room temperature ther­mistor(RT11)

Indoor coil
thermistor(RT12(main))

Receiver P.C. board

Release of “Auto restart function”
Solder jumper wire to JR07.
(Refer to page 18.)

+

}

12V DC

MS-A30WV

Indoor coil
thermistor(RT13(sub))

Emergency operation
switch

Timer short mode point
(JPS, JPG)
(Refer to page 17.)

26

11

DISASSEMBLY INSTRUCTIONS

<"Terminal with lock mechanism" Detaching points>

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.

(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector is a terminal

Sleeve

with lock mechanism

1Slide the sleeve.
2Pull the terminal while

Locking lever

pushing the locking
lever.

MS-A18WV - MS-A24WV - MS-A30WV ­INDOOR UNIT

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.

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

Connector

E1E1E1

Photo 1

Front panel

Screws

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.

27

Photo 2

R.L holder

Screws of the ground wire

Screw of
the termi­nal block

Receiver
P.C.
board

Fan motor
connectors

Vane motor
connector

Indoor
electronic
control
P.C. board

Screw of
the electri-

cal cover

Screw of the
V.A. clamp

OPERATING PROCEDURE

PHOTOS

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.

Photo 5

Screws of the
vane motor

Photo 3

Photo 4

Screws of the ground wire

Vane motors

Screw of the
electrical cover

Screw of the
electrical box

Screws
of the
vane
motor

Vane 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.

Photo 8

Hole
cover

Photo 6

Screws fix­ing the left
side of the
heat
exchanger

Photo 7

Indoor
coil
thermistor

Water cut

28

Screws fixing the fan motor

12

E02 817 620
E02 819 620
E02 179 667
E02 138 666
E02 151 667
E02 527 667

INDOOR HEAT EXCHANGER
INDOOR HEAT EXCHANGER
UNION (GAS)
UNION (GAS)
UNION (LIQUID)
UNION (LIQUID)

{12.7
{15.88
{6.35

{9.52

10

11

12

1

1
1

1

1

1

1

1

1

PARTS LIST

MS-A18WV - (WH)
MS-A24WV - (WH)
MS-A30WV - (WH)

E1

E1

E1

12-1. INDOOR UNIT STRUCTURAL PARTS

1

2

3

4

CATCH

5

SCREW
CAP

6

7

12-2. INDOOR UNIT HEAT EXCHANGER

10

8
Optional

parts
(See page

31.)

11

12

12-1. INDOOR UNIT STRUCTURAL PARTS

Part number that is circled is not shown in the illustration.

No.

E02 527 970

1

E02 527 234

2

E02 527 000

3

E02 408 142

4

E02 527 067

5

E02 527 010

6

E02 534 100

7

E02 527 975

8

E02 528 007

9

INSTALLATION PLATE
BOX (WH)
FRONT PANEL ASSEMBLY(WH)
CATCH
SCREW CAP (WH)
GRILLE (WH)
CATECHIN AIR FIL TER
CORNER BOX RIGHT
LAMP PANEL

Part Name

12-2. INDOOR UNIT HEAT EXCHANGER

Symbol

in Wiring

WV -

Diagram

MS-A18

E1

WV -

(WH)

1
1
1
4
3
1
2
1
1

Q'ty/unit

MS-A24

E1

WV -

(WH)

1
1
1
4
3
1
2
1
1

MS-A30

E1

(WH)

1
1
1
4
3
1
2
1
1

RemarksPart No.

Including No.4,5,6

4PCS/ SET
3PCS/ SET

29

E02 527 302
E02 408 509
E02 001 504
E02 408 702
E02 527 235
E02 527 040
E02 527 041
E02 127 382
E02 817 385
E02 527 034
E02 817 300
E02 527 300
E02 448 303
E02 408 303
E02 817 333
E02 527 333
E02 528 329
E02 527 468
E02 817 452
E02 818 452
E02 819 452
E02 527 308
E02 817 375
E02 819 375
E02 408 311
E02 527 307
E02 528 034
E02 529 034

1
2
3
4
5
6
7
8
9

10
11
12

13
14
15

16

17

18
19

20
21

22

LINE FLOW FAN
BEARING MOUNT
SLEEVE BEARING
DRAIN HOSE
NOZZLE (WH)
VANE UPPER (WH)
VANE LOWER (WH)
FUSE
VARISTOR
VANE CRANK SET
INDOOR FAN MOTOR ASSEMBLY
INDOOR FAN MOTOR ASSEMBLY
VANE MOTOR (VERTICAL)
VANE MOTOR (HORIZONTAL)
MOTOR BAND
MOTOR BAND
DISPLAY P.C. BOARD
RECEIVER P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
ELECTRONIC CONTROL P.C. BOARD
ROOM TEMPERATURE THERMISTOR
TERMINAL BLOCK
TERMINAL BLOCK
INDOOR COIL THERMISTOR
INDOOR COIL THERMISTOR
VANE MOTOR SUPPORT SET(RIGHT)
VANE MOTOR SUPPORT SET(LEFT)

Symbol

in Wiring

Diagram

Q'ty/unit

3.15A

RIGHT & LEFT
UP & DOWN

RemarksPart No.

No.

Part Name

F11

NR11

MF

MF
MV2
MV1

RT11

TB

TB

RT12

RT12, RT13

1
1
1
1
1
1
1
1
1
1
1

2
1
1

1
1

1

1
1

1

1
1

1
1
1
1
1
1
1
1
1
1

1
2
1

1
1
1

1
1

1

1
1
1

1
1
1
1
1
1
1
1
1
1
1

2
1
1

1
1
1

1
1

1

1
1

MS-A18

WV -

(WH)

E1

MS-A24

WV -

(WH)

E1

MS-A30

WV -

(WH)

E1

RC4V32 ­Including RUBBER MOUNT

AUTO RESTART
Including No.16
AUTO RESTART
Including No.16
AUTO RESTART
Including No.16

RC4V40 ­Including RUBBER MOUNT

MS-A18WV - (WH)

23
24

E02 527 426
E02 527 083

REMOTE CONTROLLER
REMOTE CONTROLLER HOLDER

1
1

1
1

1
1

MS-A24WV - (WH)
MS-A30WV - (WH)

E1

E1

E1

12-3. INDOOR UNIT FUNCTIONAL PARTS AND

ELECTRICAL PARTS

12-4. ACCESSORY AND

REMOTE CONTROLLER

1

20

19

23 24

2

3

SLEEVE
BEARING

4

12

11

ROOM

18

TEMPERATURE
THERMISTOR

5
6

14

13

10

7

FUSE

8

VARISTOR

9

15

16

17

12-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS

Part numbers that are circled are not shown in the illustration.

12-4. ACCESSORY AND REMOTE CONTROLLER

30

13

,

Air cleanig filter (White bellows type)

Model Part No.

MAC-1700FT

MS-A18WV-

E1

MS-A24WV-

E1

MS-A30WV-

E1

OPTIONAL PARTS

AIR CLEANING FILTER

● AIR CLEANING FILTER removes fine dust of 0.01 micron from air by means of static electricity.

● Normal life of AIR CLEANING FILTER is 4 months. However, when it becomes dirty, replace it as soon as possible.

● Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet.

● DO NOT reuse AIR CLEANING FILTER even if it is washed.

● DO NOT remove or attach AIR CLEANING FILTER during unit operation.

31

HEAD OFFICE: MITSUBISHI DENKI BLDG.,2-2-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN

CC

Copyright 2003 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Dec. 2003. No.OB325 6
Made in Japan

New publication, effective Dec. 2003
Specifications subject to change without notice.