Mitsubishi Electric MU-GA20VB-E1 User manual

CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································3
4. NOISE CRITERIA CURVES·······························5
5. OUTLINES AND DIMENSIONS ·························6
6. WIRING DIAGRAM ············································6
7. REFRIGERANT SYSTEM DIAGRAM················7
8. PERFORMANCE CURVES································8
9. TROUBLESHOOTING······································17
10. DISASSEMBLY INSTRUCTIONS·····················20
11. PARTS LIST······················································22
12. RoHS PARTS LIST···········································24
MU-GA20VB
MU-GA25VB
MU-GA35VB
HFC
utilized
R410A
SPLIT-TYPE, AIR CONDITIONERS
Wireless type
Models
MU-GA20VB-
MU-GA20VB-
MU-GA25VB-
MU-GA25VB-
MU-GA35VB- E1
E2
E1
E2
E1
SERVICE MANUAL
OUTDOOR UNIT
Indoor unit service manual
MSC-GA• VB Series (OB385)
MSC-CA• VB Series (OB393)
No. OB386
REVISED EDITION-B
Please void OB386 REVISED EDITION-A.
Revision B:
●MU-GA20VB- and MU-GA25VB -
have been added. E2E2
NOTE:
• This service manual describes technical data of outdoor units.
• RoHS compliant products have <G> mark on the spec name plate.
For servicing of RoHS compliant products, refer to the RoHS Parts List.
OB386B.qxp 06.4.25 11:23 AM Page 1

TECHNICAL CHANGES
2
1
MU-A07YV- ➔MU-GA20VB-
1. Indication of capacity has been changed.(BTU base ➔ kW base)
2. Unit size has been changed. (W780mm x H540mm x D255mm ➔W800mm x H550mm x D285mm)
3. Outdoor fan motor has been changed. (RC6V20-AC ➔RA6V21-AC)
4. Stop valve cover has been added.
5. Outdoor fan capacitor has been changed.
6. Compressor capacitor has been changed.
MU-A09YV- ➔MU-GA25VB-
1. Indication of capacity has been changed.(BTU base ➔ kW base)
2. Unit size has been changed. (W780mm x H540mm x D255mm ➔W800mm x H550mm x D285mm)
3. Outdoor fan motor has been changed. (RC6V20-AC ➔RA6V21-AC)
4. Stop valve cover has been added.
5. Outdoor fan capacitor has been changed.
6. Compressor capacitor has been changed.
7. Compressor has been changed. (RN099VHSHT ➔RN092VHSHT)
MU-A12YV- ➔MU-GA35VB-
1. Indication of capacity has been changed.(BTU base ➔ kW base)
2. Unit size has been changed. (W780mm x H540mm x D255mm ➔W800mm x H550mm x D285mm)
3. Outdoor fan motor has been changed. (RC6V33-AC ➔RA6V33-KA)
4. Stop valve cover has been added.
5. Outdoor fan capacitor has been changed.
6. Compressor capacitor has been changed.
7. Compressor has been changed. (RN135VHSHT ➔5PS132DAH01)
8. Stop valve (Gas) has been changed from [12.7 to [9.52.
9. Fuse for compressor protection has been added.
MU-GA20VB- ➔MU-GA20VB-
MU-GA25VB- ➔MU-GA25VB-
1. Compressor has been changed. (RN092VHST ➔ KN092VDMHC)
2. Compressor capacitor has been changed.
3. Capillary tube has been changed. ([3.0x[1.4x700 ➔[3.0x[1.4x900)
E2E1
E2E1
E1E1
E1E1
E1E1
Revision A:
•11-1. PARTS LIST has been modified. (The parts No. of BACK PANEL has been changed.)
Revision B:
•MU-GA20VB- and MU-GA25VB- have been added.
E2E2
OB386B.qxp 06.4.25 11:23 AM Page 2

3
PART NAMES AND FUNCTIONS
2
Air outlet
Drain outlet
Piping
Drain hose
( )
Air inlet
back : MU-GA20VB
MU-GA25VB
back and side : MU-GA35VB
OUTDOOR UNIT
MU-GA20VB
MU-GA25VB
MU-GA35VB
SPECIFICATION
3
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(at 20:)
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity (R410A)
Refrigeration oil (Model)
kW
R/h
K/h
A
A
W
A(kW)
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
MU-GA20VB - E1
Single phase
230V,50Hz
2.3
0.9
1,800
10
3.17
715
–
98
21
2.76
0.245
3.22
RN092VHSHT
600
C-R 3.87
C-S 6.14
RA6V21-AC
WHT-BLK 366
BLK-RED 274
800o550o285
31
45
745
1
0.60
350 (NEO22 )
MU-GA20VB - E2
Single phase
230V,50Hz
2.3
0.9
1,800
10
3.17
715
–
98
15.5
2.76
0.245
3.22
KN092VDMHC
650
C-R 3.62
C-S 5.40
RA6V21-AC
WHT-BLK 366
BLK-RED 274
800o550o285
27
45
745
1
0.60
350 (NEO22 )
Compressor
Electrical data
Fan motor
Special remarks
Capacity
Coefficient of performance(C.O.P)
Outdoor unit power supply
Outdoor model
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C
Outdoor DB35°C WB24°C
Indoor-Outdoor piping length : 5m
OB386B.qxp 06.4.25 11:23 AM Page 3

4
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(at 20:)
Model
Winding
resistance(at 20:)
Dimensions WOHOD
Weight
Sound level
Fan speed
Fan speed regulator
Refrigerant filling
capacity (R410A)
Refrigeration oil (Model)
kW
R/h
K/h
A
A
W
A(kW)
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
MU-GA25VB - E2
Single phase
230V,50Hz
10
KN092VDMHC
650
C-R 3.62
C-S 5.40
RA6V21-AC
WHT-BLK 366
BLK-RED 274
800o550o285
27
45
745
1
0.60
350 (NEO22 )
2.5
1.1
1,800
3.40
775
–
99
15.5
2.99
0.245
3.23
MU-GA25VB - E1
Single phase
230V,50Hz
10
RN092VHSHT
600
C-R 3.87
C-S 6.14
RA6V21-AC
WHT-BLK 366
BLK-RED 274
800o550o285
31
45
745
1
0.60
350 (NEO22 )
2.5
1.1
1,800
3.40
775
–
99
21
2.99
0.245
3.23
MU-GA35VB - E1
Single phase
230V,50Hz
1.7
10
5PS132DAH01
900
C-R 2.80
C-S 5.43
RA6V33-KA
WHT-BLK 215
BLK-RED 307
800o550o285
30
49
855
1
0.70
350 (RB68A)
3.45
1,902
5.02
1,120
–
97
21
4.50
0.33
3.08
Compressor
Electrical data
Fan motor
Special remarks
Capacity
Coefficient of performance(C.O.P)
Outdoor unit power supply
Outdoor model
NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C
Outdoor DB35°C WB24°C
Indoor-Outdoor piping length : 5m
OB386B.qxp 06.4.25 11:23 AM Page 4

5
NOISE CRITERIA CURVES
4
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
APPROXIMATE
THRESHOLD 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 :DB35:WB24:
MU-GA35VB
COOL
FUNCTION
49
SPL(dB(A)) LINE
OUTDOOR UNIT
MICROPHONE
1m
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
APPROXIMATE
THRESHOLD 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:
MU-GA20VB
MU-GA25VB COOL
FUNCTION
45
SPL(dB(A)) LINE
OB386B.qxp 06.4.25 11:23 AM Page 5

OUTLINES AND DIMENSIONS
6
5
WIRING DIAGRAM
6
OUTDOOR UNIT
MU-GA20VB MU-GA25VB
C2
C1
WHT
POWER SUPPLY ~/N 230V 50Hz
CIRCUIT
BREAKER
BLU
BRN
WHT
RED
BLU
WHT
BLK
RED
12V TO INDOOR UNIT CONNECTING
WHT
BLK
DSAR
52C
TB2
2
1
C
R
S
GRN/YLW
PE
N
LBRN
TB1
COM
52C
NO
MC
1
3
2BLK
RED
WHT
MF
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
10
69
800
302.5
500 Bolt pitch for installation
150
22.3
Handle
550
280
164.5
99.5
170.5
23 Service panel
Service port
285
344.5
44
400
Air in
Air out
Air in
(MU-GA35VB)
17.5
Bolt pitch for
installation
304~325
40
Liquid refrigerant pipe joint
Refrigerant pipe (flared) [6.35
Gas refrigerant pipe joint
Refrigerant pipe (flared) [9.52
43-
35-
2 holes 10X21
REQUIRED SPACE Basically open 100mm or more
without any obstruction in front
and on both sides of the unit.
350mmor more
200mmor more
100mm or more
100mm or more
Open two sides of left,
right, or rear side.
Drain hole [42
Unit: mm
OUTDOOR UNIT
MU-GA20VB MU-GA25VB MU-GA35VB
SYMBOL
TB2
52C
SYMBOL
MC
MF
TB1
SYMBOL
C1
C2
DSAR
NAME NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
COMPRESSOR(INNER PROTECTOR)
TERMINAL BLOCK
COMPRESSOR CONTACTOR
OUTDOOR FAN MOTOR(INNER FUSE)
TERMINAL BLOCK
OB386B.qxp 06.4.25 11:23 AM Page 6

7
REFRIGERANT SYSTEM DIAGRAM
7
MU-GA20VB
MU-GA25VB
MU-GA35VB
OUTDOOR UNIT
Outdoor
heat
exchanger
Capillary tube
[3.0x[1.4x700 (MU-GA20VB-, MU-GA25VB-)
[3.0x[1.4x900 (MU-GA20VB-, MU-GA25VB-)
[3.0x[1.4x450 (MU-GA35VB) E2E2
E1E1
Strainer
#100
Refrigerant pipe [6.35
(with heat insulator) Refrigerant flow in cooling
Unit:mm
Stop valve
(with service port)
Compressor
Flared connection
Flared connection
Muffler
Refrigerant pipe [9.52
(with heat insulator)
OUTDOOR UNIT
MU-GA35VB
PE
N
L
TB1
1
2
TB2
C1
C2
WHT
CIRCUIT
BREAKER
WHT
51C
41
BRN
F
BLU
BRN
WHT
RED
BLU
WHT
BLK
RED
POWER SUPPLY ~/N 230V 50Hz
12V TO INDOOR UNIT CONNECTING
WHT
BLK
DSAR
52C
C
R
S
GRN/YLW
BRN
COM
52C
NO
MC
1
3
2BLK
RED
WHT
MF
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
SYMBOL
51C
52C
SYMBOL
MC
MF
TB1
TB2
SYMBOL
C1
C2
DSAR
F
NAME NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
FUSE (T20AL250V)
OVERLOAD RELAY
COMPRESSOR CONTACTOR
COMPRESSOR
OUTDOOR FAN MOTOR (INNER FUSE)
TERMINAL BLOCK
TERMINAL BLOCK
Stop valve
OB386B.qxp 06.4.25 11:23 AM Page 7

8
Piping size O.D : mm Length of connecting pipe : m
Model Refrigerant piping : m
Max. length
A
20
25
Max. height
B
10
Indoor unit
Gas 0.43
Liquid 0.5
Liquid
6.35
Gas
9.52
Outdoor unit
Gas 0
Liquid 0
MU-GA20VB
MU-GA25VB
MU-GA35VB
Indoor
unit
Max. Height
B Outdoor unit
Refrigerant Piping
Max. length
A
Model Refrigerant piping length (one way)
Outdoor unit precharged
600
700
25m
360
7m
0
10m
60
15m
160
20m
260
Calculation : Xg=20g/m x(A-7)m
MU-GA20VB
MU-GA25VB
MU-GA35VB
MAX. HEIGHT DIFFERENCE
ADDITIONAL REFRIGERANT CHARGE(R410A : g)
MAX. REFRIGERANT PIPING LENGTH
PERFORMANCE CURVES
8
The standard data contained in these specifications apply only to the operation of the air conditioner under normal conditions,
since operating conditions vary according to the areas where these units are installed. The following information has been pro-
vided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.
(1) GUARANTEED VOLTAGE
198~264V
(2) AIR FLOW
Air flow should be set at MAX.
(3) MAIN READINGS
(1) Indoor intake air wet-bulb temperature : °CWB
(2) Indoor outlet air wet-bulb temperature : °CWB
(3) Outdoor intake air dry-bulb temperature : °CDB
(4) Total input: W
Indoor air wet/dry-bulb temperature difference on the left side of the chart on next page shows the difference between the
indoor intake air wet/dry-bulb temperature and the indoor outlet air wet/dry-bulb temperature for your reference at service.
How to measure the indoor air wet-bulb/dry-bulb temperature difference
1. Attach at least 2 sets of wet-and dry-bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets
of wet-and dry-bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air
speed is high.
2. Attach at least 2 sets of wet-and dry-bulb thermometers to the outdoor air intake.
Cover the thermometers to prevent direct rays of the sun.
3. Check that the air filter is cleaned.
4. Open windows and doors of room.
5. Press the EMERGENCY OPERATION switch once to start the EMERGENCY COOL MODE.
6. When system stabilizes after more than 15 minutes, measure temperature and take an average temperature.
7. 10 minutes later, measure temperature again and check that the temperature does not change.
}
Cooling
MU-GA20VB MU-GA25VB MU-A35VB
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9
8-2.OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
COOL operation
①Both indoor and outdoor unit are under the same temperature/humidity condition.
➁Air flow should be set at MAX.
Dry-bulb temperature Relative humidity(%)
20 50
25 60
30 70
③The unit of pressure has been changed to MPa on the international system of units(SI unit system).
The conversion factor is : 1(MPa[Gauge]) =10.2(kgf/ff[Gauge] )
INDOOR UNIT OUTDOOR UNIT
Wet-and dry-bulb
thermometers Wet-and dry-bulb
thermometers
MSC-GA20VB
MU-GA20VB
MU-GA35VB
MSC-GA35VB
MU-GA25VB
MSC-GA25VB
8.5
7.8
7.1
6.4
5.8
5.1
9.6
8.8
8.0
7.2
6.5
5.7
11.0
10.0
9.1
8.2
7.4
6.5
8-1.CAPACITY AND THE INPUT CURVES
18 32
230V
15 20
50 25 60 30 70(%)
35(:)
0.7
0.8
0.9
1.0
1.1
1.2
1.3
7
8
9
10
11
12
13
15 20
50 25 60 30 70(%) 35(:)
1
2
4
3
18 32
230V
Outdoor low pressure
Ambient temperature(˚C) Ambient humidity(%) Ambient temperature(˚C) Ambient humidity(%)
MU-GA20VB MU-GA20VB
Outdoor unit current (A)
(kgf/F[Gauge])(MPa[Gauge])
OB386B.qxp 06.4.25 11:23 AM Page 9

10
18 32
230V
15 20
50 25 60 30
70(%)
35(:)
3
4
5
6
18 32
230V
15 20
50 25 60 30 70(%)
35(:)
0.7
0.8
0.9
1.0
1.1
1.2
1.3
7
8
9
10
11
12
13
Outdoor low pressure
Outdoor unit current (A)
15 20
50 25 60 30 70(%) 35(:)
1
2
4
3
18 32
230V
18 32
230V
15 20
50 25 60 30 70(%)
35(:)
0.6
0.7
0.8
0.9
1.0
1.1
1.2
6
7
8
9
10
11
12
MU-GA25VB MU-GA25VB
Outdoor low pressure
Outdoor unit current (A)
(kgf/F[Gauge])(MPa[Gauge])
(kgf/F[Gauge])(MPa[Gauge])
Ambient temperature(˚C) Ambient humidity(%) Ambient temperature(˚C) Ambient humidity(%)
Ambient temperature(˚C) Ambient humidity(%) Ambient temperature(˚C) Ambient humidity(%)
MU-GA35VB MU-GA35VB
OB386B.qxp 06.4.25 11:23 AM Page 10