Mitsubishi Electric MU-A18ND-S1, MU-A18ND-S2, MU-A24ND-S1, MU-A30ND-S1, MU-A24ND-S2 Service Manual
...
SPLIT-TYPE AIR CONDITIONERS
OUTDOOR UNIT
SERVICE MANUAL
Models
Revision E:
• SPECIFICATION has been modified.
Please void OB405 REVISED EDITION-D.
No. OB405
REVISED EDITION-E
MU-A18NDMU-A18NDMU-A24NDMU-A24NDMU-A30NDMU-A30ND-
MU-A18ND
S1
S2
S1
S2
S1
S2
Indoor unit service manual
MS-A• ND Series (OB404)
CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················3
3. SPECIFICATION·················································3
4. OUTLINES AND DIMENSIONS ·························4
5. WIRING DIAGRAM ············································6
6. REFRIGERANT SYSTEM DIAGRAM ················8
7. PERFORMANCE CURVES······························10
8. TROUBLESHOOTING······································12
9. DISASSEMBLY INSTRUCTIONS ····················21
10. PARTS LIST······················································27
11. RoHS PARTS LIST···········································30
NOTE:
• This service manual describes technical data of the 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.
TM
Compressor: NH30VCD ➞ RH247NRAT
Compressor: RH277NHD
➞
RH247NRAT
Electricity receiving unit: Indoor unit ➞ Outdoor unit
Gas pipe diameter: [15.88
➞
[12.7
Rated voltage: 220V ➞ 220-230V
Frequency
New Model
Old Model
MU-18TN -
S1
w
: change
MU-A18ND -
S1
60Hz
MU-18SN -
C1
w
w
w
w
w
w
w
w
Outdoor unit:Unit size:W850mmoH605mmoD290mm ➞ W840mmoH850mmoD330mm
Outdoor unit:Unit size:W870mmoH850mmoD295mm ➞ W840mmoH850mmoD330mm
Compressor: NH38NBD
➞
PH33NPBT
Electricity receiving unit: Indoor unit ➞ Outdoor unit
Liquid refrigerant pipe diameter: [9.52
➞
[6.35
Rated voltage: 220V ➞ 220-230V
Frequency
New Model
Old Model
MU-24TN -
S1
MU-A24ND -
S1
60Hz
MU-24SN -
C2
w
w
w
w
w
w
w
w
w
w
Revision A:
• Check of solenoid valve coil has been partially modified.
Revision B:
• MU-A24ND - has been added.
S2
Revision C:
• MU-A18ND - has been added.
S2
Revision D:
• MU-A30ND - has been added.
S2
Revision E:
• SPECIFICATION has been modified.
TECHNICAL CHANGES1
MU-A30ND -
S1
New model
MU-A18ND - ➔ MU-A18ND -
• Valve cover has been added.
S2S1
MU-A24ND - ➔ MU-A24ND -
• Compressor contactor has been added.
S2S1
MU-A30ND - ➔ MU-A30ND -
• Solenoid valve and solenoid valve coil have been changed.
S2S1
2
2
2
Outdoor model
Function
Power supply
Capacity
Dehumidification
Air flow (High/Low)
Power outlet
Running current (Total)
Power input (Total)
Power factor (Total)
Starting current (Total)
Compressor motor current
Fan motor current
Model
Output
Winding
resistance (at 20:)
Model
Winding
resistance (at 20:)
Dimensions WOHOD
Weight
Sound level (High/Low)
Fan speed (High/Low)
Fan speed regulator
Refrigerant filling
capacity (R22)
Refrigeration oil (Model)
kW
R/h
K /h
A
A
W
%
A
A
A
W
"
"
mm
kg
dB
rpm
kg
cc
Cooling
Single phase
220-230V, 60Hz
2,880
58
0.66
PH33NPBT
1,500
C-R 0.84
C-S 2.09
RA6N75-BA
WHT-BLK 65.0
BLK-RED 65.4
67
54
790
1
2.20
900 (MS32N1)
Electrical
data
Compressor
Fan
motor
Special
remarks
Coefficient of performance (C.O.P) (Total)
Capacity
2,480
15
40
0.55
RH247NRAT
1,200
C-R 1.43
C-S 2.06
RA6V60-MA
WHT-BLK 71.2
BLK-RED 89.3
850o605o290
44
54
945
1
1.40
520 (MS56)
ISO 5151
5.10
2.3
8.52
1,800
96-92
7.60
2.83
SSA 385
5.9
2.7
20( )
12.42
2,650
97
11.39
2.23
ISO 5151
6.6
3.2
15( )
10.54
2,250
97-93
9.50
2.93
SSA 385
6.6
3.2
17.52
3,700
96
16.49
1.78
ISO 5151
8.1
4.3
14.25
3,010
96-92
13.22
2.69
SSA 385
4.40
1.8
9.94
2,100
96
9.02
2.10
MU-A24ND MU-A30ND
2,880/1,380
25
78
0.66
NH44NAVT
2,000
C-R 0.62
C-S 1.40
RA6N75-AA
WHT-BLK 64.2 BLK-YLW 32.9
YLW-RED 32.7
76
55/51
790/490
2
2.40
1,300 (MS32N1)
840o850o330
S2
S1
MU-A18ND
PART NAMES AND FUNCTIONS
OUTDOOR UNIT
MU-A18ND
Air inlet
Piping
Drain hose
Air outlet
MU-A24ND MU-A30ND
Air inlet
(back and side)
3
NOTE: Test conditions are based on ISO 5151 / SSA 385
SPECIFICATION
Cooling : Indoor DB27°C WB19°C / DB29°C WB19°C
Indoor-Outdoor piping length: 5 / 7.5 m
Outdoor DB35°C WB24°C / DB46°C WB24°C
Drain outlet
3
Air outlet
OUTLINES AND DIMENSIONS4
100mm or more
350mm or more
100mm or more
100mm or more
REQUIRED SPACE
500mm or more
100
157
161
Liquid refrigerant
pipe joint
Refrigerant pipe
(Flared) [6.35
Service panel
183
500
850
30
50
20350
35
248
605
292
20
310
290
345
Air in
Air out
Drainage
3holes [33
50
90
Air in
Drainage
hole [16.2
355
74
30-
35
-
Gas refrigerant
pipe joint
Refrigerant pipe
(flared) [12.7
MU-A18ND -
S1
OUTDOOR UNIT
Unit: mm
MU-A18ND -
S2
355
Drainage
hole [16.2
Air in
20350
35
248
90
Air in
Drainage
3holes [33
Air out
605
292
20
50
183
500
850
50
74
81
290
157
30
100
REQUIRED SPACE
345
310
4
100mm or more
Service panel
Liquid refrigerant
Refrigerant pipe
30-
161
Gas refrigerant
pipe joint
Refrigerant pipe
(flared) [12.7
100mm or more
500mm or more
pipe joint
(Flared) [6.35
-
35
100mm or more
350mm or more
MU-A24ND MU-A30ND
OUTDOOR UNIT
299
66
51
34
330
850
430
515
121
500
840
40
REQUIRED SPACE
100mm or more
360
Open as a rule
80
500mm or more if the back,
both sides and top are open
155
90
198
Open as a rule
500mm or more if
the front and both
sides are open
100mm or more
200mm or more if
there are obstacles
to both sides
350mm or more
Service panel
Liquid refrigerant
pipe joint
Refrigerant pipe
(flared) [6.35(MU-A24ND)
[9.52(MU-A30ND)
30-
35-
Gas refrigerant
pipe joint
Refrigerant pipe
(flared) [15.88
5
5
R
S
2
N
L
TB2
RED
ORN
BLU
BRN
WHT
GRN/YLW
C2
RED
MF
BLACK
4
WHITE
ORANGE
321
BLK
L
N
TB1
BRN
BLU
C1
RED
C
MC
BLU
220-230V~
CONNECTING
TO INDOOR UNIT
POWER SUPPLY
220-230V ~/N 60Hz
F
BLU
DSAR
220-230V~
WHT
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.
: Connector
: Terminal block,
NOTES:
SYMBOL
C1
C2
DSAR
SYMBOL
F
MC
MF
SYMBOL
TB1
TB2
NAME
NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
FUSE (3.15A)
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER PROTECTOR)
TERMINAL BLOCK
TERMINAL BLOCK
WIRING DIAGRAM
MU-A18ND
OUTDOOR UNIT
MU-A24ND-
S1
OUTDOOR UNIT
POWER SUPPLY
~/N 220-230V 60Hz
220-230V~
220-230V~
TO INDOOR UNIT CONNECTING
SYMBOL
F
MC
MF
SYMBOL
COMPRESSOR CAPACITOR
C1
C2
DSAR
NOTES:
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
1.Use copper conductors only (For field wiring).
2.Since the indoor and outdoor unit connecting wires have polarity, connect them according to the numbers (2,N,L).
3.Symbols below indicate.
: Terminal block, : Connector
NAME
BLU
F
GRN/YLW
BLU
BRN
BLU
C1
BLU
WHT
ORN
C2
RED
4
3
2
1
RED
BLK
BLK
WHT
ORN
RED
S
C
MC
R
MF
WHT
N
N
L
2
TB1
PE
TB2
L
BRN
DSAR
FUSE(3.15A)
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER PROTECTOR)
NAME NAME
SYMBOL
TB1
TB2
TERMINAL BLOCK
TERMINAL BLOCK
6
SYMBOL
C1
C2
DSAR
F61
LEV
MC
MF
SYMBOL
NR61
RT62
RT63
SR61
SR62
TB1
TB2
SYMBOL
T61
X52
X63
21S2
52C
NAME
DEICER
P.C. BOARD
2
N
3
N
L
12V
WHT
BLU
RED
BLU
WHT
WHT
T61
YLW
BLK
WHT
RED
BLU
TB2
5
CN730
YLW
BLK
WHT
1
52C
2
RED
C2
ORN
A1 A2BLU
52C
DSAR
WHT
C1
BLK
S
C
R
MC
BLU
NR61
3
1
TB1
GRN/YLW
BRN
SR62
SR61
F61
TAB52
COM
NO
X52
CN711
CN724
CN662
6
MF
RT62 RT63
123
21
ORN
RED
3456
LEV
COM
NO
X63
3
2
1
CN722
X52
PE
220-230V~
TO INDOOR UNIT CONNECTING
POWER SUPPLY
~/N 220-230V 60Hz
X63
21S2
NAME NAME
COMPRESSOR CAPACITOR
OUTDOOR FAN CAPACITOR
SURGE ABSORBER
FUSE(3.15A)
EXPANSION VALVE COIL
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER PROTECTOR)
VARISTOR
DISCHARGE TEMPERATURE THERMISTOR
AMBIENT TEMPERATURE THERMISTOR
SOLID STATE RELAY
SOLID STATE RELAY
TERMINAL BLOCK
TERMINAL BLOCK
TRANSFORMER
CONTACTOR
SOLENOID VALVE COIL RELAY
SOLENOID VALVE COIL
COMPRESSOR CONTACTOR
NOTES:
1.Use copper conductors only (For field wiring).
2.Since the indoor and outdoor unit connecting wires have polarity, connect them according to the numbers (3,N,2).
3.Symbols below indicate.
: Terminal block, : Connector
MU-A24ND-
OUTDOOR UNIT
S2
TB1
L
N
PE
POWER SUPPLY
~/N 220-230V 60Hz
GRN/YLW
TB2
2
220-230V~
220-230V~
TO INDOOR UNIT CONNECTING
SYMBOL
COMPRESSOR CAPACITOR
C1
OUTDOOR FAN CAPACITOR
C2
DSAR
NOTES:
SURGE ABSORBER
1.Use copper conductors only (For field wiring).
2.Since the indoor and outdoor unit connecting wires have polarity, connect them according to the numbers (2,N,L).
3.Symbols below indicate.
: Terminal block, : Connector
NAME
N
L
SYMBOL
F
MC
MF
BRN
4
C1
C2
BLU
WHT
ORN
RED
1
RED
BLK
4
3
2
1
52C
BLK
WHT
ORN
RED
BLU
BRN
F
BLU BLU
DSAR
BRN
BLU
WHT
56
52C
NAME NAME
FUSE(3.15A)
COMPRESSOR(INNER PROTECTOR)
OUTDOOR FAN MOTOR(INNER PROTECTOR)
S
MC
R
MF
SYMBOL
MU-A30ND
C
TB1
TB2
52C
WHT
TERMINAL BLOCK
TERMINAL BLOCK
COMPRESSOR CONTACTOR
OUTDOOR UNIT
7
REFRIGERANT SYSTEM DIAGRAM6
Refrigerant pipe
{6.35
(with heat insulator)
Refrigerant pipe
{12.7
(with heat insulator)
Compressor
Outdoor heat
exchanger
Flared
connection
Strainer
#100
Stop Valve
(with service port)
Stop Valve
Capillary tube
[3.0 x [1.8 x 400
MU-A18ND
OUTDOOR UNIT
Unit : mm
MU-A24ND
OUTDOOR UNIT
Refrigerant pipe
[15.88
(with heat insulator)
Flared connection
Flared connection
Refrigerant pipe
[6.35
(with heat insulator)
Stop valve
(with service port)
Accumulator
Stop valve
Capillary tube
[3.0 x [2.0 x 550
Compressor
Strainer
#100
Refrigerant flow in cooling
Outdoor
heat
exchanger
8
Outdoor
heat
exchanger
Flared connection
Discharge
temperature
thermistor
RT62
Flared connection
Stop valve
Stop valve
(with service port)
Capillary tube
[3.6 x [2.4 x 50
Refrigerant flow in cooling
Compressor
Refrigerant pipe
[15.88
(with heat insulator)
Refrigerant pipe
[9.52
(with heat insulator)
Strainer
#100
Strainer
#100
Accumulator
Ambient
temperature
thermistor
RT63
Capillary tube
[4.0 x [2.4 x 200
Capillary tube
[4.0 x [2.4 x 100
LEV
(Expansion valve)
Solenoid valve
[4.2 x [3.0 x 50
MU-A30ND
Model
Piping size O.D : mm
Refrigerant piping : m
Max. length AMax. Height
difference
B
Gas
Liquid
30
MU-A18ND
MU-A24ND
MU-A30ND
{15.88
{6.35
{9.52
15
{12.7
Indoor
unit
Outdoor unit
Max. length
A
Max. Height
difference
B
Model
Outdoor unit precharged
Refrigerant piping length (one way)
15m
120
20m
195
30m
345
7m
0
10m
45
2,200
1,400
2,400
MU-A18ND
MU-A30ND
MU-A24ND
OUTDOOR UNIT
Unit : mm
MAX.REFRIGERANT PIPING LENGTH and MAX.HEIGHT DIFFERENCE
ADDITIONAL REFRIGERANT CHARGE(R22 : g)
NOTE : Calculation : Xg=15g/m ✕ (Refrigerant piping length (m)-7)
9
PERFORMANCE CURVES7
Indoor intake air WB temperature (:)
Outdoor intake air DB temperature (:)
Indoor intake air WB temperature (:)
Outdoor intake air DB temperature (:)
MS-A30ND
MU-A30ND
MS-A24ND
MU-A24ND
MS-A18ND
MU-A18ND
9.9
9.1
8.3
7.5
6.7
5.9
12.5
11.4
10.3
9.3
8.3
7.3
18.6
16.8
15.1
13.5
12.0
10.5
Wet and dry-bulb
thermometers
Wet-and dry-bulb
thermometers
MU-A18ND MU-A24ND MU-A30ND
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
provided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.
(1) GUARANTEED VOLTAGE
198 ~ 253V, 60Hz
(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 following chart 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/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 the 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.
INDOOR UNIT OUTDOOR UNIT
10
0.8
0.7
0.6
0.5
0.4
0.3
15
18
20
50
60
70
25
30
32
8.0
7.0
6.0
5.0
4.0
3.0
35(:)
(%)
OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
18
50
60
70
32
35(:)
(%)
15 20 25 30
4.0
5.0
6.0
7.0
8.0
8.0
7.0
6.0
5.0
4.0
3.0
18
50 70
32
(:)
(%)
15 20 25 30 35
0.3
0.4
0.5
0.6
0.7
0.8
COOL operation
① Both indoor and outdoor units are under the same temperature/humidity condition.
Dry-bulb temperature (:)
Relative humidity (%)
20 50
25 60
30 70
➁ Air flow should be set at MAX.
3 The 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])
(kgf/F [Gauge])(MPa [Gauge])
Outdoor low pressure
MU-A18ND
Outdoor unit current (A)
MU-A18ND
Ambient temperature (˚C)/Ambient humidity (%) Ambient temperature (˚C)/Ambient humidity (%)
(kgf/F [Gauge])(MPa [Gauge])
Outdoor low pressure
Ambient temperature (˚C)/Ambient humidity (%) Ambient temperature (˚C)/Ambient humidity (%)
MU-A24ND
10.0
9.0
8.0
7.0
Outdoor unit current (A)
6.0
5.0
11
MU-A24ND
18
15
20
50
25
60
32
30
35(:)
70
(%)
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