Mitsubishi Electric MSC-07RV User manual

SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································3
2. PART NAMES AND FUNCTIONS······················8
3. SPECIFICATION···············································11
4. WIRING DIAGRAM ··········································13
5. REFRIGERANT SYSTEM DIAGRAM··············15
6. MICROPROCESSOR CONTROL ····················16
7. TROUBLESHOOTING······································16
8. PARTS LIST ·····················································27
Wireless type
Models
MSC-07RV - (WH) · MU-07RV -
MSC-09RV - (WH) · MU-09RV -
MSC-12RV - (WH) · MU-12RV -
MSC-07RV - (WH) · MU-07RV -
MSC-09RV - (WH) · MU-09RV -
MSC-12RV - (WH) · MU-12RV -
MSC-07RV - (WH) · MU-07RV -
MSC-09RV - (WH) · MU-09RV -
MSC-12RV - (WH) · MU-12RV -
MSC-07RV - (WH) · MUH-07RV -
MSC-09RV - (WH) · MUH-09RV -
MSC-12RV - (WH) · MUH-12RV -
MSC-07RV - (WH) · MUH-07RV -
MSC-09RV - (WH) · MUH-09RV -
MSC-12RV - (WH) · MUH-12RV -
MSC-07RV - (WH) · MUH-07RV -
MSC-09RV - (WH) · MUH-09RV -
MSC-12RV - (WH) · MUH-12RV -
Multi system type
MSC-07RV - (WH) · MUX-10RV -
MSC-09RV - (WH) · MUX-18RV -
MSC-12RV - (WH) · MUX-24RV -
Inverter controlled multi system type
· MXZ-18RV -
E2
E2E2
E2E2
E2E2
E4E4
E4E4
E4E4
E3E3
E3E3
E3E3
E2E2
E2E2
E2E2
E4E4
E4E4
E4E4
E3E3
E3E3
E3E3
E2E2
E2E2
E2E2
No. OB252
REVISED EDITION-C
SPLIT-TYPE, AIR CONDITIONERS
SPLIT-TYPE, HEAT PUMPAIR CONDITION
NOTE: • This service Manual covers only change points.
Please refer to the Service Manual OB227 REVISED
EDITION-B for unchanged contents.
• Please refer to the following service manual when the
outdoor unit is the under mentioned model.
MXZ-32SV- : OB254
MXZ-18TV- : OB280
MUX-19/20/25TV- : OB284
• Please void OB252 REVISED EDITION-B.
E1
E1
E1
MSC-07RV -
MSC-09RV -
MSC-12RV - E4
E4
E4
OB252C-1.qxp 02.4.25 11:27 AM Page 1

REVISION
Parts numbers have been partially modified.
Page Part name
E02 504 426 ➔E02 141 083REMOTE CONTROLLER HOLDER
Model
MSC-07/09/12RV- E1
MSC-07/09/12RV- E2
MSC-07/09/12RV- E2
P27
Part number
P27 REMOTE CONTROLLER E02 141 083 ➔E02 504 426
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3
TECHNICAL CHANGES
1
1
2
3
4
5
6
7
8
9
10
11
12
13
The specifications of Indoor and Outdoor fan motor.
The data of Med. and Low speed are added to Indoor fan motor
specification✼
✼The data value of indoor fan motor does not change if the indoor
unit is connected to a multi-type outdoor unit.
Remote controllers of COOL ONLY or COOL & HEAT
type are outdoor unit accessory.
Remote controller is included as an indoor unit accessory.
Two-way common remote controller
Two-way (using dip switch) remote controller
The specification of electronic control P.C. board is
compatible with remote controllers of COOL ONLY
and COOL & HEAT type.
Indoor electronic control P.C. board has changed
for two-way remote controller.
Indoor electronic control P.C. board has changed
for two-way remote controller.
Microprocessor programing flow has changed.
Electronic control P.C. board for E3 is interchangeable
with the one for E2 (except for MSC-12RV).
(New P.C. board) Indoor electronic control P.C. board has
changed.
Earth wire from the board is fixed to the electrical box with screw.
The shape of connector CN211 has changed. Indoor electronic
control P.C. board has been connected with
Power monitor, receiver P.C. board using connector.
When fan speed is set to"Auto", initial temperature difference
specitying changing fan speed has been improved in order to
reach the set temperature faster than E1, E2, and E3.
The mark of terminal block has changed. Terminal block for E4 is
interchangeable with the ones for E1, E2 and E3.
Winding resistance and shape of fan motor have changed.
Fan motor for E4 is not interchangeable with the ones for E1,
E2 and E3 except for MSC-12RV.
Fan motor rubber mount has changed because the shape of
fan motor was changed.
Circle shows the change point of the model.
Change point
No.
MSC-07RV-
E1
E2
E3 MSC-09RV-
E1
E2 E3 MSC-12RV-
E1
E2 E3
E4
E4
E4
OB252C-1.qxp 02.4.25 11:27 AM Page 3

4
1
2
3
4
5
6
7
8
9
10
11
12
13
Remote controller of COOL ONLY type is outdoor unit accessory.
Remote controller is included as an indoor unit accessory.
Compressor contactor (52C) has changed. Compressor
contactor for E2,E3,E4 are interchangeable with the ones for E1.
Compressor has changed. Compressors for E3 and E4 are not
interchangeable with the ones for E1 and E2.
Compressor capacitor has changed. Due to different shape,
compressor capacitor for E4 is not interchangeable with the
ones for E1, E2 and E3.
Fuse has been removed.
Wiring diagram has changed because fuse was removed.
The shape of propeller fan has changed. The number of
propeller fan has changed from four to three. Propeller fan for E4
is not interchangeable with the ones for E1, E2 and E3.
The shape, diameter of axis and fan speed of fan motor have
changed. Fan motor for E4 is not interchangeable with the ones
for E1, E2 and E3.
Fan motor capacitor has changed. 1.5+➔ 2.0+
Fan motor capacitor for E4 is not interchangeable with the
ones for E1, E2 and E3(MU-12RV only).
Refrigerant filing capacity has changed. 0.85kg➔ 0.80kg
The method of troubleshooting for outdoor unit has changed.
The repairing procedure when outdoor unit does not stop
has been added to troubleshooting.
Circle shows that change points apply to the models.
Change point
No.
MU-07RV-
E1
E2
E3 MU-09RV-
E1
E2 E3 MU-12RV-
E1
E2 E3
E4
E4
E4
OB252C-1.qxp 02.4.25 11:27 AM Page 4

5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Remote controller of COOL & HEAT type is outdoor unit
accessory.
Remote controller is included as an indoor unit accessory.
Accumulator has been removed.
Compressor has changed.
Compressor capacitor has changed. Due to different
shape, compressor capacitor for E4 is not interchangeable
with the ones for E1,E2 and E3.
The mark of terminal block has changed. Terminal block
for E4 is interchangeable with the ones for E1, E2 and E3.
Deicer P.C. board has changed. Jumper wire of compulsory
defrosting mode has changed.
(JP607-R853➔JPDS-JPSG)
Jumper wire for defrost setting has changed.
(JPC-JPE➔JRF-JRG) (Refer to page 26.)
The defrosting intervals which are changed by setting a short
circuit are the same as E1, E2, and E3.
Deicer P.C. board for E4 is not interchangeable with the
ones for E1, E2 and E3.
Wiring diagram has changed according to the following
reasons; the shape of connectors CN711 and CN661 has
changed and R.V. coil relay (X62) has changed into SSR (SR62).
X62 has changed into SR62 in Example of Operation
time chart in HEAT operation.
Compared to E1, E2, and E3, no change has been made about
the operational condition for defrosting and tne control system of
R.V. coil (timing of switching on/off).
The shape of propeller fan has changed. The number of
propeller fan has changed from four to three. Propeller
fan for E4 is not interchangeable with the ones for E1,E2, and E3.
The shape and diameter of axis of fan motor have changed.
The shape of connector has changed.
Fan motor and connector for E4 are not interchangeable
with those for E1, E2 and E3.
Refrigerant filling capacity has changed. 0.80kg➔ 0.85kg
The method of checking serial signal error for E4 has been added.
The method of troubleshooting for outdoor unit has changed.
The method for checking thermistor has been added to
troubleshooting.
The method for checking 4-way valve has been added to
troubleshooting.
The repairing procedure when outdoor unit does not stop has
been added to troubleshooting.
Circle shows that change points apply to the models.
Change point
No.
MUH-07RV-
E1
E2
E3 MUH-09RV-
E1
E2 E3 MUH-12RV-
E1
E2 E3
E4
E4
E4
MUX-10RV -
MUX-18RV -
MUX-24RV -
MXZ-18RV - E1
E1
E1
E1 MUX-10RV -
MUX-18RV -
MUX-24RV -
MXZ-18RV - E2
E2
E2
E2
1. Remote controller is unprovided as the outdoor unit accessory.
OB252C-1.qxp 02.4.25 11:27 AM Page 5

6
COOL ONLY COOL
& HEAT TWO-WAY
REMOTE CONTROLLER
Model
MS-07/09/12RV- E1
MSH-07/09/12RV- E1
MS-07/09/12RV- E2
MSH-07/09/12RV- E2
✕✕
✕
✕
w
wWhen HEAT mode is selected
by the remote controller of
COOL & HEAT type, the unit
will operate in FAN mode.
TWO-WAY
DIP switch
✕
MS-07/09/12RV- E3
MSH-07/09/12RV- E3
MS-07/09/12RV- E4
MSH-07/09/12RV- E4 ✕
✕
Reference
COOL ONLY REMOTE CONTROLLER TWO-WAY REMOTE CONTROLLER
COOL&HEAT REMOTE CONTROLLER TWO-WAY REMOTE CONTROLLER
1. Both of COOL ONLY and COOL & HEAT remote controller are unified into a two-way remote controller.
2. FAN mode operation is available in COOL ONLY unit. In this case the set room temperature
will be displayed on the remote controller, however, the room temperature can not be controlled by remote controller button.
HEAT operation is available in only HEAT & COOL type unit.
TWO-WAY REMOTE CONTROLLER TWO-WAY DIP SWITCH REMOTE CONTROLLER
• Outlines and dimensions have been changed.
162
19
58
Wireless remote controller
MSC-07RV -
MSC-09RV -
MSC-12RV -
MU-07RV -
MU-09RV -
MU-12RV -
MUH-07RV -
MUH-09RV -
MUH-12RV - E1
E1
E1
E1
E1
E1
E1
E1
E1 MSC-07RV -
MSC-09RV -
MSC-12RV -
MU-07RV -
MU-09RV -
MU-12RV -
MUH-07RV -
MUH-09RV -
MUH-12RV - E2
E2
E2
E2
E2
E2
E2
E2
E2
MSC-07RV -
MSC-09RV -
MSC-12RV - E2
E2
E2 MSC-07RV -
MSC-09RV -
MSC-12RV - E3
E3
E3
OB252C-1.qxp 02.4.25 11:27 AM Page 6

7
Slide switch Type
The position
of the slide
switch
COOL ONLYCOOL & HEAT
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 it does not, correct the setting as shown below.
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 :
The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown
in Table 1. After modification, press the RESET button.
NOTE : For remodelling, take out the bat-
teries 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.
Table 1
• The way of remodelling individual operation of P.C Board of remote controller has changed.
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
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8
PART NAMES AND FUNCTIONS
2
ACCESSORIES
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller mounting hardware
Fixing screw for 33.5 o16 mm
Battery (AAA) for remote controller
Felt tape (Used for left or left-rear piping)
Deodorizing filter
Air cleaning filter
Wireless remote controller
Drain socket: MUH type
Drain cap: MUH type
1
1
2
1
5
1
2
2
1
1
1
<Indoor unit>
Installation plate
Installation plate fixing screw 4 o25 mm
Remote controller mounting hardware
Fixing screw for 33.5 o16 mm
Battery (AAA) for remote controller
Wireless remote controller
Felt tape (Used for left or left-rear piping)
Deodorizing filter
Air cleaning filter
Drain socket
Drain cap
1
2
1
5
1
2
2
1
1
1
1
<Indoor unit>
<Outdoor unit: MUH type><Outdoor unit>
9
0
1
1
2
3
4
5
6
7
8
0
1
1
2
3
4
5
6
7
8
9
MSC-07RV - • MU-07RV -
MSC-09RV - • MU-09RV -
MSC-12RV - • MU-12RV -
MSC-07RV - • MUH-07RV -
MSC-09RV - • MUH-09RV -
MSC-12RV - • MUH-12RV -
MSC-07RV - • MU-07RV -
MSC-09RV - • MU-09RV -
MSC-12RV - • MU-12RV -
MSC-07RV - • MUH-07RV -
MSC-09RV - • MUH-09RV -
MSC-12RV - • MUH-12RV -
MSC-07RV - • MU-07RV -
MSC-09RV - • MU-09RV -
MSC-12RV - • MU-12RV -
MSC-07RV - • MUH-07RV -
MSC-09RV - • MUH-09RV -
MSC-12RV - • MUH-12RV - E4E4
E4E4
E4E4
E4E4
E4E4
E4E4
E3E3
E3E3
E3E3
E3E3
E3E3
E3E3
E2E2
E2E2
E2E2
E2E2
E2E2
E2E2
MSC-07RV - • MU-07RV -
MSC-09RV - • MU-09RV -
MSC-12RV - • MU-12RV -
MSC-07RV - • MUH-07RV -
MSC-09RV - • MUH-09RV -
MSC-12RV - • MUH-12RV - E1E1
E1E1
E1E1
E1E1
E1E1
E1E1
• How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
NOTE : 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 re-attach the front lid. 2Press the RESET button.
OB252C-1.qxp 02.4.25 11:27 AM Page 8

9
MSC-07RV - MSC-09RV - MSC-12RV - E2E2E2
Signal transmitting section
Operation display section
OPERATE /STOP
(ON /OFF)button
OPERATION SELECT button
FAN SPEED CONTROL button
ON-TIMER button
CLOCK SET button
HR. button
MIN. button
(TIME SET button)
TEMPERATURE buttons
VANE CONTROL button
OFF-TIMER button
RESET button
ON/OFF TOO
WARM TOO
COOL
HR. MIN.
CLOCK
RESET
CLOCK
MODE
FAN VANE
START STOP
ECONO COOL button ECONO COOL
I FEEL COOL DRY
HEAT/FAN
600 1 100
AM PM
REMOTE CONTROLLER
OB252C-1.qxp 02.4.25 11:27 AM Page 9

10
MSC-07RV - MSC-09RV - MSC-12RV -
MSC-07RV - MSC-09RV - MSC-12RV - E4E4E4
E3E3E3
ON/OFF
TOO
COOL
PM
AM
TOO
WARM
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.
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
REMOTE CONTROLLER
OB252C-1.qxp 02.4.25 11:27 AM Page 10

11
SPECIFICATION
3
Indoor model
Function
Indoor unit power supply
Air flow(High/Med. /Low )
Power outlet
Running current
Power input
Power factor
Starting current
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:)
Outdoor model
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Compressor motor current
Fan motor current
Model
Output
Winding
resistance(at20:)
Model
Winding
resistance(at20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity(R22)
Refrigerating oil (Model)
K/h
A
A
W
%
A
A
"
mm
kg
dB
rpm
k"
k"
kW
R/h
K/h
A
A
W
A(kW)
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
MSC-07RV - E4
Single phase
220-240V,50Hz
10
0.17
35
93.6-85.8
—
0.17
WHT-BLK 413
BLK-RED 334
850O278O191
9
5
3
10
10
MU-07RV - E4
Single phase
220-240V,50Hz
10
—
2.77-2.71
0.21-0.22
RH-130VGCT
650
C-R 4.18
C-S 5.76
RA6V23-FC
WHT-BLK 353
BLK-RED 321
780o540o255
32
44-45
710-760
1
0.80
300 (MS56 )
Cooling
474/384 /294
RC4V19-LA
36/31 /26
950/790 /640
2.2
0.8
1620-1752
2.98-2.93
645-675
98.4-96.0
19
3.24-3.10
MSC-09RV - E4
Single phase
220-240V,50Hz
10
0.17
35
RC4V19-LA
WHT-BLK 413
BLK-RED 334
850O278O191
9
5
3
10
10
MU-09RV - E4
Single phase
220-240V,50Hz
10
—
RH-140VGCT
700
C-R 4.03
C-S 5.71
RA6V23-FC
WHT-BLK 353
BLK-RED 321
780o540o255
32
44-45
710-760
1
0.80
300 (MS56 )
Cooling
474/384 /294
93.6-85.8
—
0.17
36/31 /26
950/790 /640
2.5
1.1
1620-1752
3.43-3.28
745-775
98.7-98.5
20
3.22-3.06
0.21-0.22
3.21-3.09
MSC-12RV - E4
Single phase
220-240V,50Hz
10
0.19
40
RC4V19-GA
WHT-BLK 375
BLK-RED 294
850O278O191
10
5
3
10
10
MU-12RV - E4
Single phase
220-240V,50Hz
1.6
1848-1980
10
—
96.1-91.3
35
RH-220VHAT
1050
C-R 2.13
C-S 3.91
RA6V33-DC
WHT-BLK 301
BLK-RED 332
780o540o255
34
49
810-840
1
0.88
520 (MS56)
Cooling
588/468 /360
95.7-87.7
—
0.19
39/34 /29
1020/850 /690
3.5
6.01-6.16
1270-1350
5.72-5.84
0.29-0.33
2.67-2.52
Electrical data
Fan motor
Special remarks
Compressor
Electrical data
Fan motor
Special remarks
Capacity
Coefficient of performance(C.O.P)
Outdoor unit power supply
Capacity
ww
ww
wwwwwwww
ww
ww
ww
ww ww
ww
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C
Outdoor DB35°C WB24°C
Indoor-Outdoor piping length 5m
wReference value
OB252C-1.qxp 02.4.25 11:27 AM Page 11

12
Indoor model
Function
Indoor unit power supply
Air flow(High/Med. /Low )
Power outlet
Running current
Power input
Power factor
Starting current
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:)
Outdoor model
Capacity
Dehumidification
Outdoor air flow
Power outlet
Running current
Power input
Auxiliary heater
Power factor
Starting current
Compressor motor current
Fan motor current
Model
Output
Winding
resistance(at20:)
Model
Winding
resistance(at20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity(R22)
Refrigerating oil (Model)
Thermistor RT61(at0:)
K/h
A
A
W
%
A
A
"
mm
kg
dB
rpm
k"
k"
kW
R/h
K/h
A
A
W
A(kW)
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
k"
MSC-07RV - E4
Single phase
220-240V,50Hz
10
0.17
35
93.6-85.8
—
0.17
RC4V19-LA
WHT-BLK 413
BLK-RED 334
850O278O191
9
5
3
10
10
MUH-07RV - E4
Single phase
220-240V,50Hz
1620-1752
10
—
25
0.21-0.22
RH-130VGCT
650
C-R 4.18
C-S 5.76
RA6V23-FB
WHT-BLK 353
BLK-RED 321
788o540o255
33
47
710-760
1
0.85
300 (MS56)
33.18
Cooling
474/384 /294
36/31 /26
950/790 /640
2.2
0.8
3.13-3.03
675-715
98.0-98.3
2.92-2.81
3.10-2.93
Heating
504/414 /336
35/30 /26
1000/850 /710
2.5
—
2.98-2.88
645-685
98.4-99.1
2.77-2.66
3.68-3.47
MSC-09RV - E4
Single phase
220-240V,50Hz
10
0.17
35
93.6-85.8
—
0.17
RC4V19-LA
WHT-BLK 413
BLK-RED 334
850O278O191
9
5
3
10
10
MUH-09RV - E4
Single phase
220-240V,50Hz
1620-1752
10
—
25
0.21-0.22
RH-165VGCT
800
C-R 3.30
C-S 5.80
RA6V23-FB
WHT-BLK 353
BLK-RED 321
780o540o255
33
47
710-760
1
0.85
300 (MS56)
33.18
Cooling
474/384 /294
36/31 /26
950/790 /640
2.5
1.1
3.93-3.83
845-885
97.7-96.3
3.72-3.61
2.84-2.72
Heating
504/414 /336
35/30 /26
1000/850 /710
3.1
—
4.13-3.93
885-905
97.4-95.9
3.92-3.71
3.37-3.30
MSC-12RV - E4
Single phase
220-240V,50Hz
10
0.19
40
95.7-87.7
—
0.19
RC4V19-GA
WHT-BLK 375
BLK-RED 294
850O278O191
10
5
3
10
10
MUH-12RV - E4
Single phase
220-240V,50Hz
1656-1758
10
—
35
0.29-0.32
RH-220VHAT
1050
C-R 2.13
C-S 3.91
RA6V33-DB
WHT-BLK 301
BLK-RED 332
780o540o255
38
49
810-840
1
1.19
520 (MS56)
33.18
Cooling
588/468 /360
39/34 /29
1020/850 /690
3.4
1.6
5.56-5.71
1180-1260
96.5-91.9
5.27-5.39
2.79-2.62
Heating
642/516 /402
39/34 /29
1100/920 /750
4.0
—
5.76-5.91
1220-1310
96.3-92.4
5.47-5.59
3.17-2.96
Electrical data
Fan motor
Special remarks
Compressor
Electrical data
Fan motor
Special remarks
Capacity
Coefficient of performance(C.O.P)
Outdoor unit power supply
Capacity
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NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C Heating : Indoor DB20°C
Outdoor DB35°C WB24°C Outdoor DB 7°C / WB 6°C
Indoor-Outdoor piping length 5m
wReference value
OB252C-1.qxp 02.4.25 11:27 AM Page 12

13
WIRING DIAGRAM
4
MSC-07RV -
MSC-09RV -
MSC-12RV - E4
E4
E4
MODELS WIRING DIAGRAM
SYMBOL
TB
T11
SYMBOL
NR11
RT11
RT12
SR141
SYMBOL
C11
F11
MF
MV
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
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
T11
TRANS
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 220-240V
50Hz
GRN/YLW
POWER MONITOR,
RECEIVER
P.C.BOARD
REMOTE
CONTROLLER
MV
FOR
MUH OR
MXZ TYPE
FOR
MU OR
MUX TYPE
12V
PE
LD103 101
CN
GRN
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
SG79J412H01
OB252C-1.qxp 02.4.25 11:27 AM Page 13

14
MODELS WIRING DIAGRAM
OUTDOOR UNIT
SYMBOL
TB1,TB2
21S4
52C
SYMBOL
MF
NR61
RT61
SR61, SR62
T61
SYMBOL
C1
C65
DSAR
F61
MC
NAME NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
FUSE(2A)
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER FUSE)
VARISTOR
DEFROST THERMISTOR
SOLID STATE RELAY
TRANSFORMER
TERMINAL BLOCK
R.V. COIL
COMPRESSOR CONTACTOR
SR61
SR62
MF
21S4
CN721
2
1
3
CN661
MC
52C
CN711
C65
T61
F61
NR61
~/N
PE
N
L
TB1
N
3
TB2
INDOOR UNIT
CONNECTING
FROM
12V WHT
RED
1
3
2BLK
RT61
CN730
R
C
S
WHT
3
RED
BLK
C1
4
DEICER P.C.BOARD
RED
BRN
BLK
DSAR
BRN
BLU
POWER SUPPLY
CIRCUIT BREAKER
BLU
GRN/YLW
220-240V
50Hz
TAB20
MUH-07RV -
MUH-09RV -
MUH-12RV - E4
E4
E4
MODELS WIRING DIAGRAM
OUTDOOR UNIT
MU-07RV -
MU-09RV -
MU-12RV - E4
E4
E4
NOTE:1. About the indoor side electric wiring refer to the indoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3. Symbols below indicate.
/: Terminal block, : Connector
NOTE:1. About the indoor side electric wiring refer to the indoor unit electric wiring diagram for servicing.
2.Use copper conductors only. (For field wiring)
3. Symbols below indicate.
/: Terminal block, : Connector
CIRCUIT BREAKER
POWER SUPPLY
~/N
220-240V
50Hz
12V
GRN/YLW
TB2
RED
WHT
BLK
WHT
BLU 3
2
1
RED MF
C2
MC
C1
SR
C
N
2
FROM
INDOOR UNIT
CONNECTING
WHT
BLU
BLK
RED
WHT
52C
TB1
WHT
BLK
52C
PE
L
1
NO COM
DSAR
BRN
BRN
SYMBOL
52C
SYMBOL
MC
MF
TB1,TB2
SYMBOL
C1
C2
DSAR
NAME NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER FUSE)
TERMINAL BLOCK
COMPRESSOR CONTACTOR
VG79B132H01
SG79B111H01
OB252C-1.qxp 02.4.25 11:27 AM Page 14

15
REFRIGERANT SYSTEM DIAGRAM
5
Unit:mm
MSC-12RV - MSC-12RV - E4E3 MUH-12RV - MUH-12RV - E4E3
INDOOR UNIT OUTDOOR UNIT
(with heat insulator)
(with heat insulator)
Refrigerant pipe [12.7 4-way valve
Muffler
Stop valve
(with service port)
Strainer
Refrigerant pipe [6.35
Stop valve
Capillary tube
[3.0x[1.6x700
Check
valve
Refrigerant flow in cooling
Refrigerant flow in heating
Defrost
thermistor
RT61 Outdoor
heat
exchanger
Room temperature
thermistor
RT11
Indoor coil
thermistor
RT12
Capillary tube
[3.0x[1.8x300
Flared connection
Flared connection
Compressor
Indoor
heat
exchanger
R.V. coil
heating ON
cooling OFF
MSC-07RV - MSC-07RV -
MSC-09RV - MSC-09RV - E4E3
E4E3 MUH-07RV - MUH-07RV -
MUH-09RV - MUH-09RV - E4E3
E4E3
INDOOR UNIT OUTDOOR UNIT
Indoor
heat
exchanger
Room temperature
thermistor
RT11
(with heat insulator)
Refrigerant pipe [9.52
Muffler
4-way valve
Defrost
thermistor
RT61
Strainer
Outdoor
heat
exchanger
Capillary tube
[3.0x[1.4x800 (2 pcs)
Capillary tube
[3.0x[1.6x600(MUH-07)
[3.0x[1.6x400(MUH-09)
Capillary tube
[3.0x[1.4x600(MUH-07)
[3.0x[1.4x550(MUH-09)
Check valve
Strainer
Refrigerant pipe [6.35
(with heat insulator) Refrigerant flow in cooling
Refrigerant flow in heating
Unit:mm
Stop valve
(with service
port)
Indoor coil
thermistor
RT12
R.V. coil
heating ON
cooling OFF
Capillary tube
[3.0x[1.4x500(2pcs)
Flared connection
Flared connection
Compressor
Stop valve
Strainer
OB252C-1.qxp 02.4.25 11:27 AM Page 15

16
MICROPROCESSOR CONTROL
6
6-1. 11-1. COOL ( ) OPERATION
1. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regard-
less of thermostat’s OFF-ON.
In Auto the fan speed is as follows.
MSC-07RV - MU-07RV - MUH-07RV -
MSC-09RV - MU-09RV - MUH-09RV -
MSC-12RV - MU-12RV - MUH-12RV - E4E4E4
E4E4E4
E4E4E4
1 deg. 1.7 deg. 3 deg.
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
1 deg. 1.7 deg. 4 deg.
Initial temperature difference
Room temperature minus set temperature : 2 degrees or more································High
Room temperature minus set temperature : Between 1 and 2 degrees····················Med.
Room temperature minus set temperature : less than 1 degree································Low
Fan speed Difference between room
temperature and set tem-
perature during operation
MSC-07RV - MSC-07RV - MSC-07RV -
MSC-09RV - MSC-09RV - MSC-09RV -
MSC-12RV - MSC-12RV - MSC-12RV - E3E2E1
E3E2E1
E3E2E1
MSC-07RV -
MSC-09RV -
MSC-12RV - E4
E4
E4
2 deg.
TROUBLESHOOTING
7
Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)
7-1. Trouble criterion of main parts
Part name
Indoor fan
motor(MF)
INNER FUSE
136I3 CUT OFF
Motor part
Check method and criterion Figure
Normal Abnormal
Open or
short-circuit
396 ~ 430Ω
WHT-BLK
BLK-RED 320 ~ 348Ω
RED
BLK
YLW
GRY
BRN
WHT
FUSE
Outdoor fan
motor(MF)
INNER FUSE
163I3 CUT OFF
Measure the resistance between the terminals with a tester.
(Coil wiring temperature –10°C ~ 40°C)
Normal
MU-07/09RV- E4
311 ~ 381 Ω
283 ~ 347 Ω
265 ~ 325 Ω
292 ~ 359 Ω
WHT-BLK
BLK-RED
WHTRED
BLK
MAIN
AUX.
FUSE
Abnormal
Open or short-circuit
MU-12RV- E4
Normal
MUH-07/09RV-
E4
311 ~ 381 Ω
283 ~ 347 Ω
265 ~ 325 Ω
292 ~ 359 Ω
WHT-BLK
BLK-RED
Abnormal
Open or short-circuit
MUH-12RV-
E4
MSC-07/09RV- E4 MSC-12RV- E4
396 ~ 430Ω
320 ~ 348Ω
MUH-07RV -
MUH-09RV -
MUH-12RV - E4
E4
E4
MU-07RV -
MU-09RV -
MU-12RV - E4
E4
E4
MSC-07RV -
MSC-09RV -
MSC-12RV - E4
E4
E4
Color of
lead wire
Color of
lead wire
Color of
lead wire
OB252C-1.qxp 02.4.25 11:27 AM Page 16

17
Check of indoor fan motor
A
Check of remote controller and receiver P.C. board
B
Repair or replace the indoor fan motor.
Are lead wires connected?
Re-connect the lead wires.
Is soldered point of the connector
correctly soldered?
Re-solder it.
Is resistance 0 (short circuit) or ∞(open circuit)?
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.
Yes ( 0 or ∞)
Yes
No
Yes
No
Turn OFF the power supply.
Check connector CN211 visually.
Disconnect lead wires from connector CN211 on indoor electronic control P.C. board.
Measure resistance between lead wires No.1 and No.5 and then No.3 and No.5.
Yes
Replace the batteries.
Turn on a radio to AM and press switch on
the remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
Replace the remote controller.
• Re-install the unit away from lights.
• Attach a filter on receiving part.
Switch on the remote controller.
Is LCD display on the remote con-
troller displayed?
Remove batteries, then set them back and
press the RESET button. Check if the unit
operates with the remote controller.
Yes
Does the unit operate with the
remote controller?
Yes
Ok
No
(not clear)
Yes
No
No
Yes
Measure the voltage between receiver P.C. board connector CN302
No.3(–)and No.5(+) when the remote controller button is pressed.
Is the voltage approx. 4V DC? Replace the indoor electronic control
P.C. board.
Replace the receiver P.C. board.
No(5V or 0V DC)
No
wCheck the remote controller is exclusive for this air conditioner.
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.
Turn ON the power supply. Stop it if the unit oper-
ate. Insert screwdriver into air outlet to rotate
indoor fan motor slowly for 1 revolution or over, and
measure voltage No.2(+) and No.3(-) on CN121.
No
(others)
Replace the indoor electronic control P.C. board.
Does voltage repeat 0V DC and 5V DC?
Yes
No
MSC-07/09/12RV- , ,
E3E2E1
MSC-07/09/12RV- E4
OB252C-1.qxp 02.4.25 11:27 AM Page 17

18
Check of indoor electronic control P.C. board
C
Check the both “parts side” and “pattern
side” of indoor electronic control P.C.
board visually.
Replace the fuse.
Is fuse(F11) blown?
Be sure to check both fuse
and varistor in any case.
Replace the fan
motor.
Replace the indoor
electronic control
P.C. board.
Is winding
resistance of
fan motor 0 "?
Is winding
resistance of
vane motor 0 "?
No
Yes
Replace the vane
motor.
No
Yes
Yes
Is varistor(NR11) burnt?
Replace the varistor.
Yes
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C. board and turn ON the power supply.
No
No
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up
by pressing the EMERGENCY OPERATION switch?
Yes
No
Be sure to check both resistances.
Turn OFF the
power supply. Turn OFF the
power supply.
The unit doesn’t operate with the remote controller.
Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch.
OB252C-1.qxp 02.4.25 11:27 AM Page 18

19
Check of outdoor unit
D
Compressor and / or outdoor fan motor doesn’t operate.
Yes
Is there 220-240V AC
between 1–2on the outdoor
terminal block (TB2)?
Compressor
doesn't operate.
Operate the unit in COOL mode by pressing the
EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.
Outdoor fan motor
doesn't operate.
Check the power supply, and
rectify the connecting wire.
Check the indoor electronic
control P.C. board, and rectify
the indoor and outdoor
connecting wire.
Start
No
No
Yes Is there 220-240V AC between L–N
on the outdoor terminal block (TB1)?
Is the switch SW2-2on the
indoor electronic control
P.C. board set to MU type?
No Change the switch SW-2-2
on the indoor electronic control
P.C. board to MU type.
Yes
Is there 220-240V AC between L–N
on the outdoor terminal block (TB1)?
Is there 12V DC between
1–2on the outdoor
terminal block (TB2)?
No
Check the indoor electronic
control P.C. board, and rectify
the indoor and outdoor
connecting wire.
Yes
Is there 220-240V AC between COM
on the compressor contactor (52C) and
Non the outdoor terminal block (TB1)?
Yes
Check the compressor and
compressor contactor, and
rectify the connecting wire.
Replace the compressor
contactor (52C).
No
Yes
Is there 220-240V AC between COM
on the compressor contactor (52C) and
Non the outdoor terminal block(TB1)?
Yes
Check the outdoor fan motor
and outdoor fan capacitor,
and rectify the connecting wire.
No Check the power supply, and
rectify the connecting wire.
Replace the compressor
contactor (52C).
No
E1 E2 E3
MU-07/09/12RV- , ,
Is fuse "F" (2A) blown?
No
Replace the fuse "F" (2A).
Yes
<MU-07/09/12RV>
OB252C-1.qxp 02.4.25 11:27 AM Page 19

20
Check of outdoor unit
D
Compressor and / or outdoor fan motor doesn’t operate.
Yes
Compressor
doesn't operate.
Yes Yes
Is there 220-240V AC between
3 on the compressor contactor
(52C) and Non the outdoor
terminal block (TB1)?
Operate the unit in COOL or HEAT mode by pressing the
EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.
Outdoor fan motor
doesn't operate.
No
Rectify the indoor and
outdoor connecting wire.
Rectify the connecting wire.
Check the compressor and compressor
capacitor, and rectify the connecting wire.
Start
Yes
Is there 220-240V AC between 4
on the compressor contactor (52C) and
TAB20 on the deicer P.C. board?
Is there 220-240V AC between L–N
on the outdoor terminal block (TB1)?
Replace the
deicer P.C. board.
Replace the
deicer P.C. board.
No
No
Yes Yes
No
Check the outdoor fan motor
and rectify the connecting
wire.
Is there 220-240V AC between 4 on
the compressor contactor (52C) and
TAB 20 on the deicer P.C. board?
Replace the
deicer P.C. board.
No
Yes
Rectify the indoor and
outdoor connecting wire.
Rectify the connecting wire.
Is there 220-240V AC between L–N
on the outdoor terminal block (TB1)?
No
No
Is the switch SW2-2on the
indoor electronic control
P.C. board set to MUH type?
No Change the switch SW-2-2
on the indoor electronic control
P.C. board to MUH type.
Yes
+–
Is there 5V DC between J8 –J9
(MUH-07/09/12RV- , , )/
J205 –J101 (MUH-07/09/12RV- )
on the deicer P.C. board?
+
–
E1 E2 E3 E4
+–
Is there 5V DC between J8 –J9
(MUH-07/09/12RV- , , )/
J205 –J101 (MUH-07/09/12RV- )
on the deicer P.C. board?
+
–
E1 E2 E3 E4
<MUH-07/09/12RV>
OB252C-1.qxp 02.4.25 11:27 AM Page 20