Mitsubishi Electric MSC-A07YV-E1 User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································3
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································5
4. NOISE CRITERIA CURVES·······························6
5. OUTLINES AND DIMENSIONS ·························7
6. WIRING DIAGRAM ············································8
7. REFRIGERANT SYSTEM DIAGRAM················8
8. MICROPROCESSOR CONTROL ······················9
9. SERVICE FUNCTIONS ····································17
10. TROUBLESHOOTING······································19
11. DISASSEMBLY INSTRUCTIONS·····················26
12. PARTS LIST······················································28
Wireless type
Models
MSC-A07YV - (WH)
MSC-A09YV - (WH)
MSC-A12YV - (WH)
E1
E1
E1
MSC-A07YV -
MSC-A09YV -
MSC-A12YV - E1
E1
E1
No. OB329
HFC
utilized
R410A
SPLIT-TYPE, AIR CONDITIONERS
SPLIT-TYPE, HEAT PUMPAIR CONDITIONERS
Indication of model name
NOTE:
•This manual describes technical data of indoor units.
•As for outdoor units MU-A07/A09/A12YV - , refer to the service manual OB330.
•As for outdoor units MUH-A07/A09/A12YV - , refer to the service manual OB331.
•As for outdoor units MUX-A10/A19/A20/A25/A26WV - , refer to the service manual OB307 REVISED
EDITION-A.
•As for outdoor units MUX-A22WV - , refer to the service manual OB318.
•As for outdoor units MXZ-A18/A26/A32WV - , refer to the service manual OB319.
E1
E1
E1
E1
E1
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3
PART NAMES AND FUNCTIONS
2
INDOOR UNIT
MSC-A07YV -
MSC-A09YV -
MSC-A12YV - E1
E1
E1
Emergency operation switch
Fan
Catechin air filter
(With deodorizer)
Air outlet
Vertical vanes
Air inlet
to Breaker
Remote control
receiving section
Display section
Air cleaning filter
(white bellows type) Front panel
Power supply cord
Panel
Horizontal vane
Operation section
(When the front panel is opened)
Remote controller
Operation indicator lamp
Remote control
receiving section
TECHNICAL CHANGES
1
MSC-A07WV- ➔MSC-A07YV-
MSC-A09WV- ➔MSC-A09YV-
MSC-A12WV- ➔MSC-A12YV-
1. Design of front panel has changed.
2. Air filter has changed to the catechin air filter.
E1E1
E1E1
E1E1
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4
ACCESSORIES
MSC-A07YV-
MSC-A09YV-
MSC-A12YV- E1
E1
E1
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller holder
Fixing screw for 33.5 o16 mm
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
Air cleaning filter
1
5
1
2
2
1
1
1
<Indoor unit>
1
2
3
4
5
6
7
8
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
ECONO COOL
STOP
START
HR.
MIN.
I FEEL COOL
DRY
PM
CLOCK
AM
RESET CLOCK
HEAT
/FAN
/
Open the front lid.
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
Signal transmitting section
Operation display section
OPERATE /STOP
(ON /OFF)button
TEMPERATURE buttons
Indication of remote controller model is
on back.
OPERATION SELECT button
FAN SPEED CONTROL button OFF-TIMER button
HR. button
MIN. button
(TIME SET button)
ON-TIMER button
RESET button
ECONO COOL button
VANE CONTROL button
CLOCK SET button
REMOTE CONTROLLER
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5
SPECIFICATION
3
Indoor model
Function
Indoor unit power supply
Air flow(High/Med. /Low )
Power outlet
Running current
Power input
Power factor
Fan motor current
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Air direction
Sound level(High/Med. /Low )
Fan speed(High/Med. /Low )
Fan speed regulator
Thermistor RT11(at 25:)
Thermistor RT12(at 25:)
Remote controller model
K/h
A
A
W
%
A
"
mm
kg
dB
rpm
k"
k"
MSC-A07YV - E1
Single phase
230V,50Hz
10
0.17
35
90
0.17
RC4V19-LA
WHT-BLK 413
BLK-RED 334
815O278O244
9
5
3
10
10
KP1A or KG3A
Cooling
474/372 /276
36/31 /25
900/750 /600
Heating
510/420 /342
36/31 /25
950/820 /700
MSC-A09YV - E1
Single phase
230V,50Hz
10
0.17
35
90
0.17
RC4V19-LA
WHT-BLK 413
BLK-RED 334
815O278O244
9
5
3
10
10
KP1A or KG3A
Cooling
474/384 /306
36/31 /25
900/770 /650
Heating
588/456 /342
39/32 /25
1,050/870 /700
MSC-A12YV - E1
Single phase
230V,50Hz
10
0.19
40
92
0.19
RC4V19-KA
WHT-BLK 316
BLK-RED 299
815O278O244
10
5
3
10
10
KP1A or KG3A
Cooling
582/444 /324
40/33 /26
930/760 /600
Heating
606/498 /396
39/33 /26
960/830 /700
Electrical data
Fan motor
Special remarks
Capacity
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NOTE: 1. Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C Heating : Indoor DB20°C
Outdoor DB35°C WB24°C OutdoorDB 7°C/WB 6°C
Indoor-Outdoor piping length 5m
2.Remote controller model KP1A and KG3A are the same in terms of specification.
WReference value
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6
NOISE CRITERIA CURVES
4
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
APPROXIMATE
TERESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : DB27:WB19:
Heating : DB20:WB -:
MSC-A07YV- E1 COOL
High
FUNCTIONFAN SPEED
36
HEAT
SPL(dB(A)) LINE
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
APPROXIMATE
TERESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
Test conditions.
Cooling : DB27:WB19:
Heating : DB20:WB -:
MSC-A09YV- E1 COOL
High
FUNCTIONFAN SPEED
36
HEAT 39
SPL(dB(A)) LINE
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
APPROXIMATE
TERESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
Test conditions,
Cooling : DB27:WB19:
MSC-A12YV- E1 COOL
FUNCTIONFAN SPEED
40
HEAT
High 39
SPL(dB(A)) LINE
INDOORUNIT WALL
MICROPHONE
0.8m
1m
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7
OUTLINES AND DIMENSIONS
5
MSC-A07YV -
MSC-A09YV - E1
E1
INDOOR UNIT
244
242 5
7 or more
90
110
30
149
606
278
60
815
783
Power supply cord
Lead to right 1.0m
Lead to left 0.3m
Air out
Installation plate
Insulation [28
Drain hose [16
(Connected part O,D)
Air in Liquid line [6.35-0.5m
Gas line [9.52-0.43m
Insulation [37 O.D
[21 I.D
{
Wireless remote controller
162
19
58
81.5
81.5
41
2.5
42
271
231.5
4.5
81.5 133.5
326326
Wall hole [65
Indoor unit
Installation plate
Unit: mm
MSC-A12YV - E1
INDOOR UNIT
244
242
218.5
258
81.581.5
41
42
2.5
17.5
161.5161.5
326326
5
7 or more
90
110
30
149
606
278
60
815
783
Power supply cord
Lead to right 1.0m
Lead to left 0.3m
Air out
Indoor unit
Installation plate
Wall hole [65
Installation plate
Insulation [28
Drain hose [16
(Connected part O,D)
Air in
Liquid line [6.35-0.5m
Gas line [9.52-0.43m
Insulation [37 O.D
[21 I.D
{
Wireless remote controller
162
19
58
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8
REFRIGERANT SYSTEM DIAGRAM
7
MSC-A07YV - MSC-A09YV - E1E1 MSC-A12YV - E1
INDOOR UNIT INDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
Refrigerant pipe [9.52
(with heat insulator)
Unit:mm
Refrigerant pipe [12.7
(with heat insulator)
Refrigerant pipe [6.35
(with heat insulator)
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT12
Indoor coil
thermistor
RT12
Indoor
heat
exchanger
Flared connection
Flared connection
Flared connection
Flared connection
WIRING DIAGRAM
6
MSC-A07YV - MSC-A09YV - MSC-A12YV - E1E1E1
MODELS WIRING DIAGRAM
SYMBOL
NR11
RT11
RT12
SR141
NAME NAME NAME
INDOOR FAN CAPACITOR
FUSE(3.15A)
INDOOR FAN MOTOR (INNER FUSE)
VANE MOTOR
VARISTOR
ROOM TEMPERATURE THERMISTOR
INDOOR COIL THERMISTOR
SOLID STATE RELAY
TERMINAL BLOCK
SYMBOL
C11
F11
MF
MV
SYMBOL
TB
T11 TRANSFORMER
CIRCUIT BREAKER
SR141 C11
RED
WHT
3
6
5
BRN
YLW
GRY
BLK
4
3
2
1
MF
121
CN
1
3
5
111
CN
112
CN RT12
RT11
NR11
F11
ELECTRONIC CONTROL P.C. BOARD
CN211
TAB12
CN201
3
2
1
CN202
2
1
151
CN
55
BRN
RED
BLU
WHT
BLK
BLU
BRN
TB
L
3
N
2
1
12V
TO OUTDOOR
UNIT
CONNECTING
POWER
SUPPLY
CORD
~/N 230V
50Hz
GRN/YLW
POWER MONITOR,
RECEIVER
P.C.BOARD
REMOTE
CONTROLLER
MV
FOR
MUH OR
MXZ TYPE
FOR
MU OR
MUX TYPE
12V
PE
101
CN
T11
GRN
LD103
INDOOR UNIT
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
Refrigerant pipe [6.35
(with heat insulator)
Refrigerant flow
in cooling Refrigerant flow
in cooling
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9
MICROPROCESSOR CONTROL
8
ON/OFF
FAN
TOO
WARM TOO COOL
VANE
MODE
ECONO COOL
STOP
START
HR.
MIN.
I FEEL COOL
DRY
PM
CLOCK
AM
RESET CLOCK
HEAT
/FAN
/
Open the front lid.
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
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 CONTROL button
CLOCK SET button
WIRELESS REMOTE CONTROLLER
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.
MSC-A07YV -
MSC-A09YV -
MSC-A12YV - E1
E1
E1
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 does not
depend on the shape of lamp.
8-1. 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 TEMPERATURE buttons (TOO WARM or TOO COOL button)to select the desired temperature.
The setting range is 16 ~ 31°C
1 deg. 1.7 deg. 3 deg.
2. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless
of thermostat’s OFF-ON.
In Auto the fan speed is as follows. Initial temperature difference
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
Fan speed Difference between room
temperature and set tem-
perature during operation
-0.3 :0.3 :
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature
Initial temperature difference Thermostat
Room temperature minus set temperature : 0.3 :or more················································ON
Room temperature minus set temperature : less than -0.3 :············································OFF
Set temperature
Difference between room
temperature and set tem-
perature during operation
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10
Compressor
Outdoor fan OFF
ON
( continuously at set speed)
Indoor fan ON
ON
OFF
② Time control
When the three conditions as follows have been satisfied for 1 hour and 45 minutes, the compressor stops for 3 minutes.
The indoor fan operates at the set speed.
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. 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
8-2. 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 temperature and determines the set tem-
perature. Set temperature is as shown on the right chart.
DRY operation will not function when the room temperature is 13°C or below.
(4) When DRY operation functions the fan speed is lower than COOL operation
except at (fan speed) Low.
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.
35
30
25
20
15
10
:
10 15 20 25 30 35
Set temperature
Initial room temperature
Set temperature and
initial room temperature in dry mode
:
2. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In Auto fan speed becomes Low.
3. The operation of the compressor and indoor / outdoor fan
<MU-A07/A09/A12YV, MUH-A07/A09/A12YV, MUX-A10/A19/A20/A22/A25/A26WV>
Compressor operates by room temperature control and time control.
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.
3. Coil frost prevention
① Temperature control
When the indoor coil thermistor RT12 reads 4°C or below(MSC-A07/A09YV) / 0°C or below(MSC-A12YV) for 5 minutes, the
coil frost prevention mode starts.
The indoor fan operates at the set speed and the compressor stops for 5 minutes.
After that, if RT12 still reads below 4°C (MSC-A07/A09YV) / 0°C (MSC-A12YV), this mode is prolonged until the RT12
reads over 4°C (MSC-A07/A09YV) / 0°C (MSC-A12YV).
-0.3 :0.3 :
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference Thermostat
Room temperature minus set temperature : 0.3 :or more················································ON
Room temperature minus set temperature : less than -0.3 :············································OFF
Set temperature
Difference between room
temperature and set tem-
perature during operation
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11
4. Coil frost prevention
The operation is as same as coil frost prevention during COOL operation.(Refer to 8-1.3.)
However when coil frost prevention works while the indoor fan is OFF, its speed becomes set speed.
8-3. FAN ( ) OPERATION <MU-A07/A09/A12YV, MUX-A10/A19/A20/A22/A25/A26WV>
(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.
8-4. HEAT ( ) OPERATION <MUH-A07/A09/A12YV, MXZ-A18/A26/A32WV>
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with the OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature.
The setting range is 16 ~ 31°C.
2. Indoor fan speed control
(1) Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In Auto the fan speed is as follows.
Set temperature minus room temperature: 1.7 degrees or more·············································· High
Set temperature minus room temperature: Between 1 and 1.7 degrees·································· Med.
Set temperature minus room temperature: less than 1 degree················································· Low
Initial temperature difference Fan speed
Difference between room
temperature and set tem-
perature during operation
Operation time chart
Example
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
OFFOFF
(2) Cold air prevention control
1When the compressor is not operating,
(1) if the temperature of indoor coil thermistor RT12 is 0°C or less, the fan stops.
(2) if the temperature of indoor coil thermistor RT12 is more than 0°C, the fan operates at Very Low.
2When the compressor is operating,
(1) if the temperature of RT12 is 22°C or more, the fan operates at set speed.
(2) if the temperature of RT12 is less than 22°C and
(1) if the temperature of room temperature thermistor RT11 is 15°C or less, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is more than 15°C, the fan operates at Very Low.
NOTE : If the temperature of RT12 reads from 18°C to 22°C at the air conditioner stating and also after defrosting,
this control works.
Released
Cold Air Prevention 18:22:
Fan speed
Set speed
Very Low or stop
-0.3 deg.
0.3 deg.
Set temperature
Difference between room
temperature and set tem-
perature during operation
1. Thermostat control
Thermostat is ON or OFF by difference between room temperature and set temperature.
Initial temperature difference Thermostat
Room temperature minus set temperature : less than -0.3 :··············································ON
Room temperature minus set temperature : 0.3 :or more·················································OFF
1 deg. 1.7 deg. 3 deg.
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12
(3) Warm air control.
When the following any condition of 1(a. ~ c.) and the condition of 2are satisfied at the same time, warm air control
works.
1a.) When outdoor unit starts operating in HEAT mode.
b.) When cold air prevention has been released.
c.) When defrosting has been finished
2When the temperature of indoor coil thermistor RT12 is less than 37°C.
When warm air control works, the fan speed changes as follows to blow out warm air gradually.
Gradation of fan speed in initial
The upper limit of the fan speed in MANUAL is the set speed.
The upper limit of the fan speed in AUTO is the speed decided by indoor fan speed control.(Refer to 8-4.2.(1).)
When the temperature of RT12 has been 37°C or more, or when the set speed has been changed, this control is
released and the fan speed is the set speed.
NOTE: As for high pressure protection, defrosting and R.V. coil control, refer to service manual for outdoor unit.
<Time condition> <Indoor fan speed>
less than 2 minutes Low
2 minutes to 4 minutes Med.
more than 4 minutes High
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
HEAT mode of
"I FEEL CONTROL"
Initial room temperature
MUH &MXZ type
25: or more
23:or more,
less than 25:
less than 23:
MU & MUX type
25: or more
more than13:,
less than 25:
8-5. “I FEEL CONTROL” ( ) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on
with a beep tone.
(2) Select “I FEEL CONTROL”( ) mode with the OPERA-
TION SELECT button.
(3) The operation mode is determined by the initial room tem-
perature at start-up of the operation, as shown on the
right table.
Example
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 set time the opera-
tion 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.
Restart
COOL mode of
“I FEEL CONTROL”
Example
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 or DRY or
HEAT mode of “I FEEL
CONTROL” that deter-
mined by room tem-
perature at start-up of
the operation.
Operation time chart
Operation time chart
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13
Mode
COOL mode of
"I FEEL CONTROL"
DRY mode of
"I FEEL CONTROL"
HEAT mode of
"I FEEL CONTROL"
Initial room temperature Initial set temperature
26:
26: or more
25: or more,
less than 26:
23:or more,
less than25:
24:
Initial room temperature
minus 2:
Initial room temperature
minus 2:
❈1
more than 13:,
less than 25:
26: or more
25: or more,
less than 26:
less than 23:
MU & MUX type MUH & MXZ type
❈1 When the system is restarted with the remote controller, the system operates with the previous set temperature regard-
less of the room temperature at restart.
(5) TEMPERATURES 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)
(4) The initial set temperature is decided by the initial room temperature.
8-5-1. COOL mode of “I FEEL CONTROL”
1. Thermostat control
Thermostat control is as same as COOL OPERATION.(8-1.1.)
2. Indoor fan speed control
Indoor fan speed control is as same as COOL OPERATION.(8-1.2.)
3. Coil frost prevention
Coil frost prevention is as same as COOL OPERATION.(8-1.3.)
8-5-2. DRY mode of “I FEEL CONTROL”
1. Thermostat control
Thermostat control is as same as DRY OPERATION.(8-2.1.)
2. Indoor fan speed control
Indoor fan speed control is as same as DRY OPERATION.(8-2.2.)
3. The operation of the compressor and indoor/outdoor fan
The operation of the compressor and indoor/outdoor fan is as same as DRY OPERATION.(8-2.3.)
4. Coil frost prevention
Coil frost prevention is as same as DRY OPERATION.(8-2.4.)
8-5-3. HEAT mode of “I FEEL CONTROL” <MUH-A07/A09/A12YV, MXZ-A18/A26/A32WV>
1. Thermostat control
Thermostat control is as same as HEAT OPERATION.(8-4.1.)
2. Indoor fan speed control
Indoor fan speed control is as same as HEAT OPERATION.(8-4.2.)
NOTE: As for high pressure protection, defrosting and R.V. coil control, refer to service manual for outdoor unit.
TOO
COOL
TOO
WARM
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14
High High
Med. Low
1In COOL and DRY operation
2In HEAT operation
<MUH-A07/A09/A12YV, MXZ-A18/A26/A32WV>
Vane angle is fixed to Angle 1.
Vane angle is fixed to Angle 4.
8-6. 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 rotational 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 is 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 min-
utes later, the electric current is applied to the fan motor again. During the fan motor lock-up, the OPERATION INDICA-
TOR lamp flashes on and off to show the fan motor abnormality. (Refer to page 21.)
8-7. AUTO VANE OPERATION
(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 CONTROL 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.
(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 vane angle to make the optimum room-temper-
ature distribution.
2In FAN operation
<MU-A07/A09/A12YV,
MUX-A10/A19/A20/A22/A25/A26WV>
(5) Dew prevention
During COOL or DRY operation at Vane Angle 4 or 5 when the cumulative operation time of compressor exceeds 1
hour, the vane angle automatically changes to Angle 1 for dew prevention.
(6) SWING MODE ( )
By selecting SWING mode with the VANE CONTROL button, the horizontal vane swings vertically. The remote controller
displays “ ”.
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15
(7) Cold air prevention in HEAT operation <MUH-A07/A09/A12YV, MXZ-A18/A26/A32WV>
When any of the following conditions occurs in HEAT operation, the horizontal vane angle changes to Angle 1 automat-
ically to prevent cold air blowing on users.
① Compressor is not operating.
➁ Defrosting is performed.
➂ Indoor coil thermistor RT12 reads 24:or below.
➃ Indoor coil thermistor RT12 temperature is raising from 24°C or below, but it does not exceed 28:.
Set position
Angle 1
Released
Cold air prevention 24:28:
Indoor coil thermistor
RT12 temperature
NOTE : If the temperature of RT12 reads from 24°C to 28°C at the air conditioner stating , this control works.
8-8. 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 or OFF TIMER buttons to select the operation.
“ ” button... AUTO START operation (ON timer)
“ ” button... AUTO STOP operation (OFF timer)
Horizontal vane
Temperature of indoor
coil thermistor RT12
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
(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(RT12).
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 CONTROL but-
ton is pressed or operation mode is changed.
NOTE : ECONO COOL operation does not work in COOL mode of “I FEEL CONTROL”.
SWING operation
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 RT12 at starting of this operation, next downward blow time is
decided. Then when the downward blow has been finished, next upward blow time is decided.
For initial 10 min. the swing operation is performed in table G~H for quick cooling.
Also, after 10 min. when the difference of set temperature and room temperature is more than 2 degrees, the swing
operation is performed in table D~H for more cooling.
The air conditioner repeats the swing operation in various cycle as follows.
A
H
G
F
E
D
C
B
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16
EMERGENCY OPERATION switch
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.
PM
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.
PM
PM
Press once <Cool>
Press again <Heat>
Press once again <Stop>
wHeat is available only in MUH-A07/A09/A12YV and
MXZ-A18/A26/A32WV.
2. Cancel
TIMER setting can be cancelled with the ON or OFF TIMER buttons. (“ ” or “ ”)
To cancel the ON timer, press the “ ” button.
To cancel the OFF timer, press the “ ” button.
TIMER is cancelled and the display of set time disappears.
OPERATION INDICATOR lamp
(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.
8-9. 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 [/ HEAT<MUH-A07/A09/A12YV, MXZ-
A18/A26/A32WV>] MODE with a set temperature of 24°C. The fan speed shifts to Med. speed.
The coil frost prevention works even in emergency operation [, and defrosting<MUH-A07/A09/A12YV, MXZ-
A18/A26/A32WV> too].
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 once again
(MU-A07/A09/A12YV, MUX-A10/A19/A20/A22/A25/A26WV)/once or twice (MUH-A07/A09/A12YV, MXZ-A18/A26/A32WV)
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.
• The following indication does not depend on the
shape of lamp.
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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.
9-1. TIMER SHORT MODE
For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.
The time will be shortened as follows. (Refer to page 25.)
Set time : 1 minute ➔ 1-second
Set time : 3 minutes ➔ 3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by short circuit of JPG and JPS.)
How to modify the remote controller P.C. board
Remove batteries before modification. The board has a print as shown below :
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 KP1A
and KG3A are the same in
terms of specification.
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.
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
MSC-A07YV -
MSC-A09YV -
MSC-A12YV - E1
E1
E1
Remote controller model : KP1A J2
J1
Remote controller model : KG3A J2
J1
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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18
NOTE
•The operation settings are memorized when 10 seconds have passed after the remote controller was operated.
•If main power is cut 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 appliance 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 system that allows the units to start one by one.
1. MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER
The indoor units for MU & MUX type and MUH & MXZ type
are common specifications. Set switch according to the
type of outdoor unit. The units are set for
MUH & MXZ type when they are shipped from the factory.
How to release “AUTO RESTART FUNCTION”
! Turn off the main power for the unit.
@ Pull out the electronic control P.C. board, and change switch(SW2-1) on the indoor electronic control P.C. board as
following figures.
SW2-1 sets the AUTO RESTART FUNCTION ON / OFF.
SW2-2 switches over the MU & MUX type / MUH & MXZ type.
When the units are shipped from the factory, SW2 is as follows.
SW2-1:AUTO RESTART FUNCTION ON
SW2-2:MUH & MXZ type
}
12
12
SW2
FRONT
IC101
SW2
CN151
SW1
CN112
CN121
L101
CN201
F11
TAB12
CN202
C11
CN211
Operation
! If the main power (230V AC) has been cut, the operation settings remain.
@ After 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.)
9-4. MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER AND AUTO RESTART FUNCTION
2. 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
FEEL CONTROL” mode before power failure, the operation is not memorized. In “I FEEL CONTROL” mode, the opera-
tion is decided by the initial room temperature. “AUTO RESTART FUNCTION” is ON when the units are shipped from
the factory.
1 2
1 2
1 2 SW2 SW2
1 2
Outdoor unit
MUH & MXZ type
Set 2 switch downside.
Outdoor unit
MU & MUX type
Set 2 switch upside.
NOTE:•If the indoor-outdoor connecting wire is incorrectly
connected on the terminal block, the unit does not
operate normally.
•If a ground is incorrect, it may cause an electric shock.
How to switch over MU & MUX TYPE / MUH & MXZ TYPE
! Turn off the main power for the unit.
@ Pull out the electronic control P.C. board, and change
switch(SW2-2) on the indoor electronic control P.C. board
according to the type of outdoor unit as following figures.
1 2 SW2 SW2
1 2 1 2
1 2
AUTO RESTART
FUNCTION ON
Set 1 switch downside.
AUTO RESTART
FUNCTION OFF
Set 1 switch upside.
Slide switch Type
The position
of the slide
switch
COOL ONLYCOOL & HEAT
9-3. REMOTE CONTROLLER (How to set the type)
This remote controller setting needs to be switched according to the type of air conditioner (COOL & HEAT or COOL
ONLY).
If the setting is incorrect, the air conditioner does not operate normally. Therefore, check if the setting corresponds to the
type of air conditioner. If not, correct the setting as shown below.
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19
TROUBLESHOOTING
10
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) 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 discoloration.
3) When troubleshooting, refer to the flow chart on page 20 and the check table on page 21.
Lead wiring Housing point
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 unit, and then after con-
firming the horizontal vane is closed, turn off the breaker and/or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
MSC-A07YV -
MSC-A09YV -
MSC-A12YV - E1
E1
E1
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.
NOTE1 : If the RESET button is not pressed, the remote controller may not operate correctly.
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries are correct.
HEAT
/FAN
/
RESET button
HEAT
/FAN
/
1Remove the front lid and insert batteries.
Then reattach the front lid.
2Press the RESET button.
NOTE2 : INFORMATION FOR MULTI SYSTEM AIR CONDITIONER
(OUTDOOR UNIT : MXZ-A18WV- MXZ-A26WV- MXZ-A32WV- )
Multi system air conditioner (Outdoor unit MXZ-A18WV- MXZ-A26WV- MXZ-A32WV- ) can connect two or
more indoor units with one outdoor unit.
According to the capacity, two or more units can operate simultaneously.
•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and the
other for heating, the operation mode of the indoor unit that operates earlier is selected. The other indoor units that
will start the operation later cannot operate, indicating as shown in the figure below. In this case, please set all the
indoor units to the same operation mode.
•When indoor units starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes
(max. 10 minutes) to blow out the warm air.
•In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant flowing
may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.
E1E1E1
E1E1E1
lighted
flashing
Operation Indicator
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20
10-2. Instruction of troubleshooting
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 25.
MUH-A07/A09/A12YV
MUX-A19/A20/A22/
A25/A26WV
Refer to
"Check of
outdoor unit".
Refer to B
"Check of
remote
controller
and receiver
P.C. board"
on page 23.
MUH-A07/A09/A12YV
MXZ-A18/A26/A32WV
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
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to
"Test point
diagram and
voltage"
on page 25.
Refer to A
"Check of
indoor fan
motor"
on page 22.
MUH-A07/A09/A12YV
MXZ-A18/A26/A32WV
Refer to
"Check of
outdoor
thermistor"
and others.
MUH-A07/A09/A12YV
MXZ-A18/A26/A32WV
Replace the
deicer
P.C. board
and others.
MUH-A07/A09/A12YV
MXZ-A18/A26/A32WV
1-time flash
Cause:
Outdoor /
Indoor unit
• Trouble of
serial signal
Refer to D "How to check
mis-wiring and serial signal
error (When outdoor unit
doesn't work)" on page 24.
W1
1. Check indoor /
outdoor
connecting wire.
2. Refer to C
"Check of indoor
electronic control
P.C. board"
on page 23.
Outdoor unit
doesn't
stop even
if indoor unit
stops.
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
MU-A07/A09/A12YV
Check of wiring
diagram of
outdoor unit".
MUH-A07/A09/A12YV
Refer to
"Check of
outdoor unit".
MUH-A07/A09/A12YV
MXZ-A18/A26/A32WV
Refer to
"Check of
R.V. coil" and
others.
W1.<The case of the trouble of the serial signal>
When the power is turned off and then turned on again, the indication shows “the trouble of mis-wiring”.
As for outdoor unit MU type, refer to service manual OB330.
As for outdoor unit MUH type, refer to service manual OB331.
As for outdoor unit MUX type, refer to service manual OB307 REVISED EDITION-A or OB318.
As for outdoor unit MXZ type, refer to service manual OB319.
Indoor unit
operates.
But indoor
unit doesn't
blow out
cool air.
MUX-A10/A19/A20/
A22/A25/A26WV
Refer to
"Check of
indoor/outdoor
units' connection
and outdoor
unit".
10-time flash
Cause:
Outdoor unit
MXZ type
• Outdoor
refrigerant
system
abnormality
MXZ type
Refer to
outdoor
refrigerant
system
related items.
MXZ type
5-time flash
Cause:
Outdoor unit
• Outdoor
power
system
abnormality
Refer to
"Check of
inverter/
compressor"
and "Check
of power
supply".
MSC-A07YV -
MSC-A09YV -
MSC-A12YV - E1
E1
E1
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