Mitsubishi Electric MS-A18WV User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················2
3. SPECIFICATION·················································4
4. NOISE CRITERIA CURVES·······························5
5. OUTLINES AND DIMENSIONS ·························6
6. WIRING DIAGRAM ············································7
7. REFRIGERANT SYSTEM DIAGRAM················8
8. MICROPROCESSOR CONTROL ······················9
9. SERVICE FUNCTIONS ····································17
10. TROUBLESHOOTING······································19
11. DISASSEMBLY INSTRUCTIONS·····················27
12. PARTS LIST······················································29
13. OPTIONAL PARTS···········································31
Wireless type
Models
MS-A18WV - (WH)
MS-A24WV - (WH)
MS-A30WV - (WH)
E1
E1
E1
No. OB325
SPLIT-TYPE, AIR CONDITIONERS
MS-A18WV -
MS-A24WV -
MS-A30WV - E1
E1
E1
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. E1E1E1
Indication of model name
OB325-1.qxp 03.12.3 1:03 PM Page 1

TECHNICAL CHANGES
2
1
PART NAMES AND FUNCTIONS
2
INDOOR UNIT
Grille
(When the grille is opened)
Remote controller
Operation section Display section
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
MS-A18WV -
MS-A24WV -
MS-A30WV - E1
E1
E1
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.
E1E1
E1E1
E1E1
ACCESSORIES
Indoor unit
1
2
3
4
5
6
7
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller holder
Fixing screw for 3o3.5 o1.6 mm (Black)
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
1
7
1
2
2
1
1
MS-A18WV-
MS-A24WV-
MS-A30WV-
E1
E1
E1
OB325-1.qxp 03.12.3 1:03 PM Page 2

REMOTE CONTROLLER
MS-A18WV -
MS-A24WV -
MS-A30WV - E1
E1
E1
3
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
ECONO COOL
STOP
START
HR.
MIN.
WIDE VANE
LONG
I FEEL COOL
DRY
PM
CLOCK
AM
RESET CLOCK
FAN
Open the front lid.
Signal transmitting section
Operation display section
OPERATE/ STOP
(ON/ OFF)button
TEMPERATURE buttons
OPERATION SELECT button
FAN SPEED CONTROL button
OFF-TIMER button
HR. button
MIN. button
(TIME SET button)
ON-TIMER button
RESET button
ECONO COOL button
VANE button
(Horizontal vane button)
CLOCK SET button
LONG button
WIDE VANE button
(Vertical vane button)
Indication of remote controller
model is on back.
OB325-1.qxp 03.12.3 1:03 PM Page 3

SPECIFICATION
4
3
Indoor model
Function
Power supply
Air flow
(High/Med. /Low )
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Fan motor current
Model
Winding
resistance(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
ww
ww
ww
ww
ww
ww
ww
NOTE: 1. Test conditions are based on JIS C 9612.
Cooling : Indoor DB27°C WB19°C
Outdoor DB35°C WB(24°C)
Indoor-Outdoor piping length 5m
2. Remote controller model KP0B and KG1D are the same in terms of specification.
wReference value
Indoor model
Function
Power supply
Air flow
(High/Med. /Low )
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Fan motor current
Model
Winding
resistance(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
ww
ww
ww
ww
ww
OB325-1.qxp 03.12.3 1:03 PM Page 4

5
NOISE CRITERIA CURVES
4
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
47
SPL(dB(A)) LINE
High
FAN SPEED
MS-A30WV- E1
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
42
SPL(dB(A)) LINE
High
FAN SPEED
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : Dry-bulb temperature 27: Wet-bulb temperature 19:
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
45
SPL(dB(A)) LINE
High
FAN SPEED
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
MS-A18WV- E1 MS-A24WV- E1
INDOORUNIT WALL
MICROPHONE
0.8m
1m
OB325-1.qxp 03.12.3 1:03 PM Page 5

OUTLINES AND DIMENSIONS
6
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
INDOOR UNIT
MS-A18WV -
MS-A24WV -
MS-A30WV - E1
E1
E1 Unit: mm
OB325-1.qxp 03.12.3 1:03 PM Page 6

MODELS WIRING DIAGRAM
MODEL WIRING DIAGRAM
7
WIRING DIAGRAM
6
MS-A18WV -
MS-A24WV - E1
E1
INDOOR UNIT
12V BLK
GRY
YLW
BRN
WHT
RED
3
SR141 4
3
1
CN
121
C11
HIC1
TRANS
MV1
2
1
CN112
151
CN
MV2
15
RT12
RT11
111
CN
CN211
NR11
ELECTRONIC CONTROL
P. C. BOARD
F11
LBRN
1
2
3
CN201
MV2
CN
101
CN
102
DISPLAY
P. C. BOARD RECEIVER
P. C. BOARD
REMOTE
CONTROLLER
33
TAB12
GRN/YLW
N
TB 2
1
2
1
CN202
TO OUTDOOR UNIT
CONNECTING BLK
WHT
BLU
BRN
BLU
1.About the outdoor side electric wiring refer to the outdoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3.Symbols below indicate. : Connector
: Terminal block
NOTES:
SYMBOL
C11
F11
HIC1
MF
NAME
INDOOR FAN CAPACITOR
FUSE (3.15A)
DC/DC CONVERTER
INDOOR FAN MOTOR (INNER FUSE)
SYMBOL
MV1
MV2
NR11
RT11
NAME
VANE MOTOR (HORIZONTAL)
VANE MOTOR (VERTICAL)
VARISTOR
ROOM TEMPERATURE THERMISTOR
SYMBOL
RT12
SR141
TB
NAME
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
MF
1
2
3
4
5
6
PE CIRCUIT
BREAKER
POWER
SUPPLY
CORD
~/N 230V
50Hz
INDOOR UNIT
12V
TO OUTDOOR
UNIT
CONNECTING
BRN
BLU
GRN/YLW
BLK
GRY
YLW
BRN
WHT
RED
MF
3
SR141 4
3
1
CN
121
C11
HIC1
TRANS
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
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
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
MS-A30WV - E1
OB325-1.qxp 03.12.3 1:03 PM Page 7

REFRIGERANT SYSTEM DIAGRAM
8
7
MS-A30WV - E1
INDOOR UNIT
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT13(sub)
Flared connection
Refrigerant pipe [15.88
(with heat insulator)
Refrigerant pipe [9.52
(with heat insulator)
Indoor coil
thermistor
RT12(main)
Strainer
#50
Refrigerant flow in cooling
MS-A18WV - E1
INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [12.7
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12
Refrigerant pipe[6.35
(with heat insulator)
Distributor
MS-A24WV - E1
INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [15.88
(with heat insulator)
Flared connection
Flared connection
Indoor coil
thermistor
RT12
Refrigerant pipe [6.35
(with heat insulator)
Distributor
Unit:mm
OB325-1.qxp 03.12.3 1:03 PM Page 8

9
MICROPROCESSOR CONTROL
8
WIRELESS REMOTE CONTROLLER
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
Initial room temperature
25:or more
more than 13:,
less than 25:
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.
MS-A18WV - MS-A24WV - MS-A30WV - E1E1E1
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
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)
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
FAN
Signal transmitting section
Operation display section
OPERATE/ STOP
(ON/ OFF)button
TEMPERATURE buttons
lighted
not lighted
Approx. 2 :
or more
Difference
between target
temperature
and room
temperature
Approx. 2 :
or less
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.
Operation stateIndication
Operation Indicator
Operation Indicator lamp
The operation indicator at the right side of the indoor
unit indicates the operation state.
INDOOR UNIT DISPLAY SECTION
• The following indication applies regardless of
shape of the indicator.
OB325-1.qxp 03.12.3 1:03 PM Page 9

10
Previous operation
COOL mode of
“I FEEL CONTROL”
or COOL mode
• Once the mode is fixed, the mode does not change by room temperature afterwards.
• 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.
Previous operation
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.
Restart
COOL mode of
“I FEEL CONTROL”
Restart
COOL or DRY mode
of “I FEEL CONTROL”
that determined by
room temperature at
start-up of the opera-
tion.
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
(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)
TOO
COOL
TOO
WARM
Operation timer chart
Example
Operation timer chart
Example
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11
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.
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.
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 ··························High
Room temperature minus set temperature : Between 1 and 1.7 degrees ················Med.
Room temperature minus set temperature : less than 1 degree ······························Low
8-1-1. COOL mode of “I FEEL CONTROL”
Difference between room
temperature and set temperature
during operation
1deg. 1.7deg. 3deg.
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 (MS-
A30WV) this mode prolonged until the RT12 reads over 0°C(MS-A18WV)/ 3°C(MS-A24WV) / RT12 or RT13 still reads-
over-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.
Compressor
Outdoor fan OFF
ON
(continuously at set speed)
Indoor fan ON
ON
OFF
Operation chart
Example
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.
OB325-1.qxp 03.12.3 1:03 PM Page 11

12
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.
Operation time chart
Example
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.
Thermostat
Indoor fan
Outdoor fan
Compressor
ON
8 min. 1 min.
4 min.
3 min.
ON
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OB325-1.qxp 03.12.3 1:03 PM Page 12

13
High
Rotational frequency
High
time
Med. Low
8-5. INDOOR FAN MOTOR CONTROL
(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 rota-
tional frequency close to the target rotational frequency. With this control, when the fan speed is switched, the rotational
frequency changes smoothly.
(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.)
AUTO
Horizontal
1234 5
Middle Downward Swing
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.
① In COOL and DRY operation
➁ In FAN operation
Vane angle is fixed to Angle 1.
Vane angle is fixed to Angle 4.
(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.
(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
“”.
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14
(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 COOL button is pressed in
COOL mode.
• In the following example, the vertical vane is set to (front.).
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(w1)).
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
w1 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(w1) 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 opera-
tion is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
Temperature of Tp(w1)
more than 24°C
5
2
Downward blow time
(sec.)
22°C to 24°C
21°C to 22°C
20°C to 21°C
18°C to 20°C
17°C to 18°C
15°C to 17°C
15°C or less
5
8
11
14
17
20
23
Horizontal blow time
(sec.)
20
17
14
11
8
2
23
A
H
G
F
E
D
C
B
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15
61 23 45SWING
2. Vertical vane
(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.
(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 dis-
plays “ ”. 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 “ ”.
WIndoor 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.
• A power failure occurs.
•The circuit breaker functions.
About 100-
Horizontal AIR FLOW blowing range
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16
EMERGENCY OPERATION switch
Press once <Cool>
Press again <Stop>
OPERATION INDICATOR lamp
• The following indication applies regardless of
shape of the indicator.
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.
2. Cancel
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
(Example 1) The current time is 8:00 PM.
The unit turns off at 11:00 PM, and on at 6:00 AM.
• 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 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.
PM
AM
PM
PM
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17
SERVICE FUNCTIONS
9
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 :
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.)
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-A18WV -
MS-A24WV -
MS-A30WV - E1
E1
E1
Remote controller model : KP0B J2
J1
Remote controller model : KG1D
J2
J1
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.
Remote controller model : KG1D J2
J1
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18
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.)
JR07
IC152
CN151
CN112
CN111
CN121
SW1
IC101
RA102
C11
CN201
CN211
TAB12
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
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.
9-3. AUTO RESTART FUNCTION
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.
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19
TROUBLESHOOTING
10
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.
1Remove the front lid and insert batteries.
Then reattach the front lid.
Lead wiring Housing point
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
MS-A18WV -
MS-A24WV -
MS-A30WV - E1
E1
E1
FAN
RESET button
Insert the negative pole
of the batteries first.
Check if the polarity of
the battereis is correct.
FAN
2Press the RESET button with tip end of ball point
pen or the like, and then use the remote controller.
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20
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 0.5-
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-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 thermis-
tor.
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
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