Mitsubishi Electric MUH-GD80VB User manual

CONTENTS
1. TECHNICAL CHANGES ··································· 2
2. PART NAMES AND FUNCTIONS····················· 2
3. SPECIFICATION················································ 3
4. NOISE CRITERIA CURVES······························ 3
5. OUTLINES AND DIMENSIONS ························ 4
6. WIRING DIAGRAM············································ 4
7. REFRIGERANT SYSTEM DIAGRAM··············· 5
8. PERFORMANCE CURVES······························· 6
9. ACTUATOR CONTROL··································· 10
10. SERVICE FUNCTIONS·····································11
11. TROUBLESHOOTING······································11
12. DISASSEMBLY INSTRUCTIONS···················· 18
SERVICE MANUAL
Wireless type
Model
MUH-GD80VB - E1
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
HFC
utilized
R410A
OUTDOOR UNIT No. OBH514
Indoor unit service manual
MSH-GD•VB Series (OBH513)
PARTS CATALOG (OBB514)

2
TECHNICAL CHANGES
1
MUH-GD80VB - E1
1. New model
PART NAMES AND FUNCTIONS
2
Air inlet
Air outlet
(back and side)
ACCESSORIES
Drain socket
Drain cap 33
Drain cap 16
1
2
—
MUH-GD80VB
MUH-GD80VB

3
SPECIFICATION
3
Outdoor model MUH-GD80VB
Function Cooling Heating
Power supply Single phase
230 V, 50 Hz
Capacity kW 8.0 9.4
Electrical
data
Breaker capacity A 25
Running current (Total) A 14.76 15.90
Power input (Total) W 3,320 3,580
Power factor (Total) % 98
Starting current (Total) A90
Coefficient of performance (C.O.P) (Total) 2.41 2.63
Compressor
Model NN37VAAHT
Output W 2,500
Compressor motor current A 13.85 14.62
Fan
motor
Model RA6V75-AD
Fan motor current A 0.57
Dimensions W H D mm 840 850 330
Weight kg 77
Special
remarks
Dehumidification /h 4.6 -
Air flow (High/Low) /h 2,940/1,470
Sound level (High/Low) dB 55/53
Fan speed (High/Low) rpm 805/435
Fan speed regulator 2
Refrigerant filling
capacity (R410A) kg 2.40
Refrigeration oil (Model) NEO 22
NOTE: Test conditions are based on ISO 5151.
Cooling: Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C
Outdoor Dry-bulb temperature 35°C Wet-bulb temperature 24°C
Heating: Indoor Dry-bulb temperature 20°C Wet-bulb temperature 15.5°C
Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C
Indoor-Outdoor piping length: 5 m
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
55
SPL(dB(A)) LINE
High
FAN SPEED
Test conditions,
Cooling : Dry-bulb temperature 35 Wet-bulb temperature 24
Heating : Dry-bulb temperature 7 Wet-bulb temperature 6
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
NOISE CRITERIA CURVES
4
MUH-GD80VB
OUTDOOR UNIT
MICROPHONE
1m

4
30º
35º
155
90
198
40
515
299
66
34
51
330
360
850
430
500
80
121
840
Open as a rule
500 mm or more if
the front and both
sides are open
100 mm or more
200 mm or more if
there are obstacles
to both sides
Open as a rule
500 mm or more if the back,
both sides and top are open 350 mm or more
100 mm or more
Service panel
Gas refrigerant
pipe joint
Refrigerant pipe
(flared) 15.88
Liquid refrigerant
pipe joint
Refrigerant pipe
(flared) 9.52
REQUIRED SPACE
MUH-GD80VB
OUTLINES AND DIMENSIONS
5
Unit: mm
WIRING DIAGRAM
6
MUH-GD80VB

5
REFRIGERANT SYSTEM DIAGRAM
7
Unit: mm
MUH-GD80VB
Outdoor
heat
exchanger
Flared connection
Defrost
thermistor
RT61
Discharge
temperature
thermistor
RT62
Flared connection
Stop valve
Stop valve
(with service port)
Refrigerant flow in cooling
Compressor
4-way valve
Refrigerant flow in heating
Refrigerant pipe 15.88
(with heat insulator)
Capillary tube
3.6 2.4 50
Refrigerant pipe 9.52
(with heat insulator)
LEV
R.V. coil
heating ON
cooling OFF
Muffler
#100
Strainer
#100
Receiver
Muffler
Ambient
temperature
thermistor
RT63
Strainer
#100
MAX. REFRIGERANT PIPING LENGTH
Piping size O.D: mm
Refrigerant piping: m
Max. length
A
Max. height
BGas Liquid
30
MUH-GD80VB 9.52
15 15.88
Model
Indoor
unit
Outdoor unit
Max. length
A
Max. Height
difference
B
MAX. HEIGHT DIFFERENCE
ADDITIONAL REFRIGERANT CHARGE (R410A: g)
Outdoor unit
precharged
2,400
0 165 440 715 990 1,265
Refrigerant piping length (one way)
15 m10 m7 m
Model
MUH-GD80VB
20 m 25 m 30 m
Calculation: Xg = 55 g/m (Refrigerant piping length (m) - 7)

6
PERFORMANCE CURVES
8
17.4
13.9
12.4
10.8
15.6
19.2
MUH-GD80VB
Indoor air Wet-bulb temperature
Outdoor intake air Dry-bulb temperature (°C) Outdoor intake air Dry-bulb temperature (°C)
Indoor intake air Wet-bulb temperature (°C)
Indoor intake air Wet-bulb temperature (°C)
The standard specifications apply only to the operation of the air conditioner under normal conditions, since operating condi-
tions 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 ~ 264 V, 50 Hz
(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
(5) Indoor intake air dry-bulb temperature: °CDB
(6) Outdoor intake air wet-bulb temperature: °CWB
(7) 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-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 (twice) to start the EMERGENCY COOL (HEAT) 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
}
}
Cooling
Heating
Wet and dry-bulb
thermometers
Wet and dry-bulb
thermometers
MUH-GD80VB

7
38.4
35.5
32.5
29.6
26.6
23.6
20.7
17.7
MUH-GD80VB
Indoor air Dry-bulb temperature
Outdoor intake air Wet-bulb temperature (°C) Outdoor intake air Wet-bulb temperature (°C)
Indoor intake air Dry-bulb temperature (°C)
Indoor intake air Dry-bulb temperature (°C)
NOTE: The above curves are for the heating operation without any frost.
OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT
COOL operation
Both indoor and outdoor unit are under the same temperature/humidity condition.
Air flow should be set at MAX.
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/ [Gauge])
Dry-bulb temperature Relative humidity(%)
20 50
25 60
30 70
MUH-GD80VB
Ambient temperature (˚C)
Ambient humidity (%)
18 32
70 (%)
230 V
15 20
50
25
60
30 35
5
6
7
8
9
10
11
5
6
7
8
9
10
11
Ambient temperature (˚C)
Ambient humidity (%)
18 32
70 (%)
230 V
15 20
50
25
60
30 35
10
11
12
13
14
15
16
Outdoor low pressure
Outdoor unit current(A)
(kgf/ [Gauge])(MPa[Gauge]) MUH-GD80VB
HEAT operation
Condition indoor: Dry bulb temperature 20.0°C
Wet bulb temperature 14.5°C
Outdoor: Dry bulb temperature 7,15, 20°C
Wet bulb temperature 6,12, 14.5°C
Ambient temperature (˚C)
721
230 V
5 10152025
16
17
18
19
20
Outdoor unit current(A)
MUH-GD80VB

8
PERFORMANCE DATA COOL operation
MSH-GD80VB: MUH-GD80VB (230V)
CAPACITY : 8.0(kW) SHF : 0.62 INPUT : 3320(W)
NOTE Q : Total capacity (kW) SHF : Sensible heat factor DB : Dry-bulb temperature
SHC : Sensible heat capacity (kW) INPUT : Total power input (W) WB : Wet-bulb temperature
OUTDOOR DB(°C)
INDOOR INDOOR 21 25 27 30
DB(°C) WB(°C) Q SHC SHF INPUT Q SHC SHF INPUT Q SHC SHF INPUT Q SHC SHF INPUT
21 18 9.40 4.14 0.44 2656 9.00 3.96 0.44 2789 8.64 3.80 0.44 2922 8.32 3.66 0.44 3054
21 20 9.80 3.14 0.32 2789 9.40 3.01 0.32 2955 9.12 2.92 0.32 3021 8.80 2.82 0.32 3154
22 18 9.40 4.51 0.48 2656 9.00 4.32 0.48 2789 8.64 4.15 0.48 2922 8.32 3.99 0.48 3054
22 20 9.80 3.53 0.36 2789 9.40 3.38 0.36 2955 9.12 3.28 0.36 3021 8.80 3.17 0.36 3154
22 22 10.20 2.45 0.24 2888 9.84 2.36 0.24 3071 9.60 2.30 0.24 3154 9.20 2.21 0.24 3287
23 18 9.40 4.89 0.52 2656 9.00 4.68 0.52 2789 8.64 4.49 0.52 2922 8.32 4.33 0.52 3054
23 20 9.80 3.92 0.40 2789 9.40 3.76 0.40 2955 9.12 3.65 0.40 3021 8.80 3.52 0.40 3154
23 22 10.20 2.86 0.28 2888 9.84 2.76 0.28 3071 9.60 2.69 0.28 3154 9.20 2.58 0.28 3287
24 18 9.40 5.26 0.56 2656 9.00 5.04 0.56 2789 8.64 4.84 0.56 2922 8.32 4.66 0.56 3054
24 20 9.80 4.31 0.44 2789 9.40 4.14 0.44 2955 9.12 4.01 0.44 3021 8.80 3.87 0.44 3154
24 22 10.20 3.26 0.32 2888 9.84 3.15 0.32 3071 9.60 3.07 0.32 3154 9.20 2.94 0.32 3287
24 24 10.72 2.14 0.20 3021 10.32 2.06 0.20 3187 10.08 2.02 0.20 3287 9.76 1.95 0.20 3453
25 18 9.40 5.64 0.60 2656 9.00 5.40 0.60 2789 8.64 5.18 0.60 2922 8.32 4.99 0.60 3054
25 20 9.80 4.70 0.48 2789 9.40 4.51 0.48 2955 9.12 4.38 0.48 3021 8.80 4.22 0.48 3154
25 22 10.20 3.67 0.36 2888 9.84 3.54 0.36 3071 9.60 3.46 0.36 3154 9.20 3.31 0.36 3287
25 24 10.72 2.57 0.24 3021 10.32 2.48 0.24 3187 10.08 2.42 0.24 3287 9.76 2.34 0.24 3453
26 18 9.40 6.02 0.64 2656 9.00 5.76 0.64 2789 8.64 5.53 0.64 2922 8.32 5.32 0.64 3054
26 20 9.80 5.10 0.52 2789 9.40 4.89 0.52 2955 9.12 4.74 0.52 3021 8.80 4.58 0.52 3154
26 22 10.20 4.08 0.40 2888 9.84 3.94 0.40 3071 9.60 3.84 0.40 3154 9.20 3.68 0.40 3287
26 24 10.72 3.00 0.28 3021 10.32 2.89 0.28 3187 10.08 2.82 0.28 3287 9.76 2.73 0.28 3453
26 26 11.04 1.77 0.16 3187 10.72 1.72 0.16 3353 10.56 1.69 0.16 3453 10.24 1.64 0.16 3552
27 18 9.40 6.39 0.68 2656 9.00 6.12 0.68 2789 8.64 5.88 0.68 2922 8.32 5.66 0.68 3054
27 20 9.80 5.49 0.56 2789 9.40 5.26 0.56 2955 9.12 5.11 0.56 3021 8.80 4.93 0.56 3154
27 22 10.20 4.49 0.44 2888 9.84 4.33 0.44 3071 9.60 4.22 0.44 3154 9.20 4.05 0.44 3287
27 24 10.72 3.43 0.32 3021 10.32 3.30 0.32 3187 10.08 3.23 0.32 3287 9.76 3.12 0.32 3453
27 26 11.04 2.21 0.20 3187 10.72 2.14 0.20 3353 10.56 2.11 0.20 3453 10.24 2.05 0.20 3552
28 18 9.40 6.77 0.72 2656 9.00 6.48 0.72 2789 8.64 6.22 0.72 2922 8.32 5.99 0.72 3054
28 20 9.80 5.88 0.60 2789 9.40 5.64 0.60 2955 9.12 5.47 0.60 3021 8.80 5.28 0.60 3154
28 22 10.20 4.90 0.48 2888 9.84 4.72 0.48 3071 9.60 4.61 0.48 3154 9.20 4.42 0.48 3287
28 24 10.72 3.86 0.36 3021 10.32 3.72 0.36 3187 10.08 3.63 0.36 3287 9.76 3.51 0.36 3453
28 26 11.04 2.65 0.24 3187 10.72 2.57 0.24 3353 10.56 2.53 0.24 3453 10.24 2.46 0.24 3552
29 18 9.40 7.14 0.76 2656 9.00 6.84 0.76 2789 8.64 6.57 0.76 2922 8.32 6.32 0.76 3054
29 20 9.80 6.27 0.64 2789 9.40 6.02 0.64 2955 9.12 5.84 0.64 3021 8.80 5.63 0.64 3154
29 22 10.20 5.30 0.52 2888 9.84 5.12 0.52 3071 9.60 4.99 0.52 3154 9.20 4.78 0.52 3287
29 24 10.72 4.29 0.40 3021 10.32 4.13 0.40 3187 10.08 4.03 0.40 3287 9.76 3.90 0.40 3453
29 26 11.04 3.09 0.28 3187 10.72 3.00 0.28 3353 10.56 2.96 0.28 3453 10.24 2.87 0.28 3552
30 18 9.40 7.52 0.80 2656 9.00 7.20 0.80 2789 8.64 6.91 0.80 2922 8.32 6.66 0.80 3054
30 20 9.80 6.66 0.68 2789 9.40 6.39 0.68 2955 9.12 6.20 0.68 3021 8.80 5.98 0.68 3154
30 22 10.20 5.71 0.56 2888 9.84 5.51 0.56 3071 9.60 5.38 0.56 3154 9.20 5.15 0.56 3287
30 24 10.72 4.72 0.44 3021 10.32 4.54 0.44 3187 10.08 4.44 0.44 3287 9.76 4.29 0.44 3453
30 26 11.04 3.53 0.32 3187 10.72 3.43 0.32 3353 10.56 3.38 0.32 3453 10.24 3.28 0.32 3552
31 18 9.40 7.90 0.84 2656 9.00 7.56 0.84 2789 8.64 7.26 0.84 2922 8.32 6.99 0.84 3054
31 20 9.80 7.06 0.72 2789 9.40 6.77 0.72 2955 9.12 6.57 0.72 3021 8.80 6.34 0.72 3154
31 22 10.20 6.12 0.60 2888 9.84 5.90 0.60 3071 9.60 5.76 0.60 3154 9.20 5.52 0.60 3287
31 24 10.72 5.15 0.48 3021 10.32 4.95 0.48 3187 10.08 4.84 0.48 3287 9.76 4.68 0.48 3453
31 26 11.04 3.97 0.36 3187 10.72 3.86 0.36 3353 10.56 3.80 0.36 3453 10.24 3.69 0.36 3552
32 18 9.40 8.27 0.88 2656 9.00 7.92 0.88 2789 8.64 7.60 0.88 2922 8.32 7.32 0.88 3054
32 20 9.80 7.45 0.76 2789 9.40 7.14 0.76 2955 9.12 6.93 0.76 3021 8.80 6.69 0.76 3154
32 22 10.20 6.53 0.64 2888 9.84 6.30 0.64 3071 9.60 6.14 0.64 3154 9.20 5.89 0.64 3287
32 24 10.72 5.57 0.52 3021 10.32 5.37 0.52 3187 10.08 5.24 0.52 3287 9.76 5.08 0.52 3453
32 26 11.04 4.42 0.40 3187 10.72 4.29 0.40 3353 10.56 4.22 0.40 3453 10.24 4.10 0.40 3552

9
NOTE Q : Total capacity (kW) SHF : Sensible heat factor DB : Dry-bulb temperature
SHC : Sensible heat capacity (kW) INPUT : Total power input (W) WB : Wet-bulb temperature
PERFORMANCE DATA COOL operation
MSH-GD80VB: MUH-GD80VB (230V)
CAPACITY : 8.0(kW) SHF : 0.62 INPUT : 3320(W)
OUTDOOR DB(°C)
INDOOR INDOOR 35 40 43
DB(°C) WB(°C) Q SHC SHF INPUT Q SHC SHF INPUT Q SHC SHF INPUT
21 18 7.84 3.45 0.44 3254 7.20 3.17 0.44 3453 6.92 3.04 0.44 3519
21 20 8.24 2.64 0.32 3386 7.68 2.46 0.32 3552 7.40 2.37 0.32 3652
22 18 7.84 3.76 0.48 3254 7.20 3.46 0.48 3453 6.92 3.32 0.48 3519
22 20 8.24 2.97 0.36 3386 7.68 2.76 0.36 3552 7.40 2.66 0.36 3652
22 22 8.72 2.09 0.24 3519 8.16 1.96 0.24 3718 7.88 1.89 0.24 3785
23 18 7.84 4.08 0.52 3254 7.20 3.74 0.52 3453 6.92 3.60 0.52 3519
23 20 8.24 3.30 0.40 3386 7.68 3.07 0.40 3552 7.40 2.96 0.40 3652
23 22 8.72 2.44 0.28 3519 8.16 2.28 0.28 3718 7.88 2.21 0.28 3785
24 18 7.84 4.39 0.56 3254 7.20 4.03 0.56 3453 6.92 3.88 0.56 3519
24 20 8.24 3.63 0.44 3386 7.68 3.38 0.44 3552 7.40 3.26 0.44 3652
24 22 8.72 2.79 0.32 3519 8.16 2.61 0.32 3718 7.88 2.52 0.32 3785
24 24 9.20 1.84 0.20 3652 8.64 1.73 0.20 3818 8.40 1.68 0.20 3901
25 18 7.84 4.70 0.60 3254 7.20 4.32 0.60 3453 6.92 4.15 0.60 3519
25 20 8.24 3.96 0.48 3386 7.68 3.69 0.48 3552 7.40 3.55 0.48 3652
25 22 8.72 3.14 0.36 3519 8.16 2.94 0.36 3718 7.88 2.84 0.36 3785
25 24 9.20 2.21 0.24 3652 8.64 2.07 0.24 3818 8.40 2.02 0.24 3901
26 18 7.84 5.02 0.64 3254 7.20 4.61 0.64 3453 6.92 4.43 0.64 3519
26 20 8.24 4.28 0.52 3386 7.68 3.99 0.52 3552 7.40 3.85 0.52 3652
26 22 8.72 3.49 0.40 3519 8.16 3.26 0.40 3718 7.88 3.15 0.40 3785
26 24 9.20 2.58 0.28 3652 8.64 2.42 0.28 3818 8.40 2.35 0.28 3901
26 26 9.68 1.55 0.16 3785 9.12 1.46 0.16 3951 8.84 1.41 0.16 4034
27 18 7.84 5.33 0.68 3254 7.20 4.90 0.68 3453 6.92 4.71 0.68 3519
27 20 8.24 4.61 0.56 3386 7.68 4.30 0.56 3552 7.40 4.14 0.56 3652
27 22 8.72 3.84 0.44 3519 8.16 3.59 0.44 3718 7.88 3.47 0.44 3785
27 24 9.20 2.94 0.32 3652 8.64 2.76 0.32 3818 8.40 2.69 0.32 3901
27 26 9.68 1.94 0.20 3785 9.12 1.82 0.20 3951 8.84 1.77 0.20 4034
28 18 7.84 5.64 0.72 3254 7.20 5.18 0.72 3453 6.92 4.98 0.72 3519
28 20 8.24 4.94 0.60 3386 7.68 4.61 0.60 3552 7.40 4.44 0.60 3652
28 22 8.72 4.19 0.48 3519 8.16 3.92 0.48 3718 7.88 3.78 0.48 3785
28 24 9.20 3.31 0.36 3652 8.64 3.11 0.36 3818 8.40 3.02 0.36 3901
28 26 9.68 2.32 0.24 3785 9.12 2.19 0.24 3951 8.84 2.12 0.24 4034
29 18 7.84 5.96 0.76 3254 7.20 5.47 0.76 3453 6.92 5.26 0.76 3519
29 20 8.24 5.27 0.64 3386 7.68 4.92 0.64 3552 7.40 4.74 0.64 3652
29 22 8.72 4.53 0.52 3519 8.16 4.24 0.52 3718 7.88 4.10 0.52 3785
29 24 9.20 3.68 0.40 3652 8.64 3.46 0.40 3818 8.40 3.36 0.40 3901
29 26 9.68 2.71 0.28 3785 9.12 2.55 0.28 3951 8.84 2.48 0.28 4034
30 18 7.84 6.27 0.80 3254 7.20 5.76 0.80 3453 6.92 5.54 0.80 3519
30 20 8.24 5.60 0.68 3386 7.68 5.22 0.68 3552 7.40 5.03 0.68 3652
30 22 8.72 4.88 0.56 3519 8.16 4.57 0.56 3718 7.88 4.41 0.56 3785
30 24 9.20 4.05 0.44 3652 8.64 3.80 0.44 3818 8.40 3.70 0.44 3901
30 26 9.68 3.10 0.32 3785 9.12 2.92 0.32 3951 8.84 2.83 0.32 4034
31 18 7.84 6.59 0.84 3254 7.20 6.05 0.84 3453 6.92 5.81 0.84 3519
31 20 8.24 5.93 0.72 3386 7.68 5.53 0.72 3552 7.40 5.33 0.72 3652
31 22 8.72 5.23 0.60 3519 8.16 4.90 0.60 3718 7.88 4.73 0.60 3785
31 24 9.20 4.42 0.48 3652 8.64 4.15 0.48 3818 8.40 4.03 0.48 3901
31 26 9.68 3.48 0.36 3785 9.12 3.28 0.36 3951 8.84 3.18 0.36 4034
32 18 7.84 6.90 0.88 3254 7.20 6.34 0.88 3453 6.92 6.09 0.88 3519
32 20 8.24 6.26 0.76 3386 7.68 5.84 0.76 3552 7.40 5.62 0.76 3652
32 22 8.72 5.58 0.64 3519 8.16 5.22 0.64 3718 7.88 5.04 0.64 3785
32 24 9.20 4.78 0.52 3652 8.64 4.49 0.52 3818 8.40 4.37 0.52 3901
32 26 9.68 3.87 0.40 3785 9.12 3.65 0.40 3951 8.84 3.54 0.40 4034

10
PERFORMANCE DATA HEAT operation
MSH-GD80VB: MUH-GD80VB (230V)
CAPACITY : 9.4(kW) INPUT : 3580(W)
NOTE Q :Total capacity (kW) INPUT:Total power input (W) DB: Dry-bulb temperature
ACTUATOR CONTROL
9
MUH-GD80VB
9-1. R.V. COIL CONTROL
OUTDOOR WB(°C)
INDOOR -10 -5 0 5 10 15 20
DB(°C) Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT
15 5.92 2327 7.14 2792 8.37 3150 9.59 3401 10.81 3616 11.94 3723 13.16 3795
21 5.64 2506 6.77 2971 7.99 3294 9.12 3544 10.34 3723 11.47 3831 12.64 3974
26 5.08 2685 6.30 3150 7.43 3473 8.65 3723 9.87 3902 11.00 4010 12.22 4117

11
SERVICE FUNCTIONS
10
10-1. COMPULSORY DEFROSTING MODE FOR SERVICE
By short circuit of the connector JPG1 and R871 on the outdoor deicer P.C. board, defrosting mode can be accomplished
regardless of the defrost interval restriction. (Refer to 11-4.)
Defrost thermistor RT61 must read below -3°C.
10-2. CHANGE IN DEFROST SETTING
<JRF> When the JRF wire of the deicer P.C. board is cut, the defrost interval time will be changed.
<JRG> When the JRG wire of the deicer P.C. board is cut, the defrost temperature will be changed.
(Refer to 11-4.)
Jumper wire
JRF
JRG
Model Change point
Defrost interval time changes from 40 minutes to 15 minutes.
Defrost start temperature does not change.(-3.0 )
Defrost finish temperature changes from 13 to 15 .
MUH-GD80VB
MUH-GD80VB
TROUBLESHOOTING
11
11-1. 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 turn OFF the main unit first with the remote controller, 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 com-
ponents.
(4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
MUH-GD80VB
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 OPERATION INDICATOR lamp is flashing ON and OFF before starting serv-
ice work.
(2) Before servicing check that the connector and terminal are connected properly.
(3) If the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the compo-
nents for bursting and discoloration.
Lead wiring Housing point

12
11-2. TROUBLE CRITERION OF MAIN PARTS
MUH-GD80VB
Part name FigureCheck method and criterion
Measure the resistance between the terminals with a tester.
(Part temperature –10°C ~ 40°C)
Compressor (MC)
INNER
PROTECTOR
160± 5°C OPEN
90±10°C CLOSE
Normal
Terminal
C – R
C – S
0.56 Ω~ 0.71 Ω
1.43 Ω~ 1.76 Ω
R.V. coil (21S4)
LEV (Expansion valve)
Measure the resistance between the terminals with a tester.
(Part temperature –10°C ~ 40°C)
Normal
2.673 kΩ~ 3.268 kΩ
Color of lead wire
WHT – RED
RED – ORN
YLW – BRN
BRN – BLU
Normal
41.0 Ω~ 49.0 Ω
Measure the resistance with a tester.
(Part temperature : –10°C ~ 40°C)
Measure the resistance with a tester.
(Part temperature –10°C ~ 40°C)
Discharge temperature
thermistor (RT62)
Ambient temperature
thermistor (RT63)
Measure the resistance with a tester.
Before measurement, hold the thermistor with your hands to warm it up.
(Part temperature 0°C ~ 40°C)
Measure the resistance with a tester.
(Part temperature –10°C ~ 40°C)
Defrost thermistor
(RT61)
Reference value
Measure the resistance between the terminals with a tester.
(Part temperature –10°C ~ 40°C)
Color of
lead wire
WHT – BLK
BLK – YLW
YLW – RED
55 Ω~ 68 Ω
49 Ω~ 61 Ω
22 Ω~ 29 Ω
Normal
Outdoor fan motor (MF)
INNER
PROTECTOR
135± 5°C OPEN
( 83±15°C CLOSE )
Refer to 11-4. "Test point diagram and voltage", "Outdoor deicer P.C. board",
the chart of thermistor.
Refer to 11-4. "Test point diagram and voltage", "Outdoor deicer P.C. board",
the chart of thermistor.
Refer to 11-4. "Test point diagram and voltage", "Outdoor deicer P.C. board",
the chart of thermistor.
RED ORN WHT
YLW
BLK
MAIN
AUX.1AUX.2
C
P
P~
BLK
R
MAIN
AUX.
RED
S
C
WHT
LEV
: INNER PROTECTOR
P

13
Check of outdoor unit
Compressor and/or outdoor fan motor doesn’t operate.
11-3. TROUBLESHOOTING FLOW
Is there 230 V AC to
between on the
outdoor terminal block?
No Check the outdoor power supply
and connection of wiring.
Yes
Compressor
does not operate.
Yes
3 minutes after the power
supply turns ON, is there
230 V AC between A1-A2 on
the compressor contactor
(52C)?
Operate the unit in
COOL or HEAT mode by
pressing the EMERGENCY
OPERATION switch.
Outdoor fan motor
does not operate.
No Rectify the connecting
wire.
Rectify the connecting
wire.
Rectify the connecting
wire.
Check the compressor.
Refer to 11-2.
Replace the compressor
contactor (52C).
Turn ON the power supply.
Yes
Is there 230 V AC between
2/T1 on the compressor
contactor (52C) and on the
outdoor terminal block?
Yes
Replace the
deicer P.C. board.
Replace the
deicer P.C. board.
No
Yes
No
No
No
Yes
Yes Yes
Operate the unit in
COOL or HEAT mode by
pressing the EMERGENCY
OPERATION switch.
No
Check the outdoor fan
motor. Refer to 11-2.
Yes
Replace the
deicer P.C. board.
Replace the
deicer P.C. board.
No
No
Is there 5 V DC between
J101 - J401 on the deicer
P.C. board?
+
Is there 5 V DC between
J101 - J401 on the deicer
P.C. board?
+

14
After 3 minutes, does the unit
operate in HEAT mode? Ok
No
Replace the
deicer P.C. board.
Yes
Yes
No
Replace the R.V. coil.
Disconnect the TAB52 on the deicer P.C. board.
Turn ON the power supply and operate the indoor unit in COOL mode
by pressing the EMERGENCY OPERATION switch.
Is there 230 V AC between
CN721 – on the deicer
P.C. board?
Check of outdoor unit
After 30 seconds,
does compressor stop?
No
Yes
Is there 230 V AC between
A1-A2 on the compressor
contactor (52C)?
Replace the
deicer P.C. board.
Yes
Turn OFF the power supply.
After 30 seconds, turn ON the power supply again.
Operate the unit in COOL or HEAT mode by
pressing the EMERGENCY OPERATION switch.
Operate the unit for 1 minute or more and stop it by
pressing the EMERGENCY OPERATION switch again.
Ok
No
After 30 seconds, does
outdoor fan motor stop?
Replace the
deicer P.C. board.
Yes
Ok
No
Is there 230 V AC between
2/T1 on the compressor
contactor (52C) and on the
outdoor terminal block?
Yes
Replace the
compressor contactor (52C).
No Rectify the connecting
wire.
Compressor and/or outdoor fan motor doesn’t stop.
Unit operates HEAT mode even if it is set to COOL mode.
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
Check of R.V. coil
C
After 3 minutes, does the unit
operate in COOL mode? OK
Yes
Yes
No
Replace the
deicer P.C. board
No
Replace the R.V. coil.
Disconnect the TAB52 on the deicer P.C. board.
Turn ON the power supply and operate the indoor unit in HEAT mode
by pressing the EMERGENCY OPERATION switch.
Is there 230 V AC between
CN721 – on the deicer
P.C. board?
Unit operates COOL mode even if it is set to HEAT mode.
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.

15
How to check mis-wiring
D
1. Turn OFF the power supply (indoor/outdoor unit) and disconnect indoor/outdoor
connecting wire on indoor side.
2. Short-circuit terminal block - by lead wire.
3.
Turn ON the power supply (indoor unit) and press EMERGENCY OPERATION switch once.
During EMERGENCY OPERATION, is there
10 V DC between both ends of R601 on the
deicer P.C. board? (Refer to 11-4.)
(By tester, the stylus is between 5 ~10 V.)
Refer to indoor unit
service manual.
Start
No
No
Is there 20 V DC between both ends of
R132 on the indoor electronic control P.C.
board ?
( By tester, the stylus is between 0 ~ 20 V. )
• Turn ON the power supply. (indoor/outdoor unit)
• Press EMERGENCY OPERATION switch once.
Is this mis-wiring, poor contact,
or wire disconnection?
Correct them.
Replace the indoor electronic
control P.C. board.
Is there 230 V AC between -
on the outdoor terminal block?
No Check the outdoor power supply
and connection of wiring.
Is there 5 V DC between J101 + -J401 - on the deicer P.C.
board?(Refer to 11-4.)
Yes
No Replace the deicer P.C. board.
Yes
No Make the wiring between CN730
on the deicer P.C. board and
outdoor terminal block correct.
(Refer to 11-4.)
Replace the deicer P.C. board.
Yes
Yes
Yes
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
on OPERATION INDICATOR
lamp on indoor unit.
Short circuit of JPG and JPS on the indoor electronic control
P.C. board enables self -check to be displayed in 3 seconds.
• Turn OFF the power supply. (indoor unit)
• Connect indoor/outdoor connecting
wire.
Turn ON the power supply. (outdoor unit)
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit doesn’t operate.

16
Measure
resistance
between CN661
and .
Measure
resistance
between CN662
and .
No
Yes
Replace the
thermistor.
Measure
resistance
between CN662
and .
Connect CN661 and
CN662.
Turn ON the power
supply and press
the EMERGENCY
OPERATION
switch.
Does the resistance
of thermistor have the
characteristics
on 11-4?
No
Yes
Does the unit operate
10 minutes or more?
Replace the deicer P.C.
board.
OK .
It probably had contact failure of the connectors.
Turn OFF the
power supply.
Discharge temperature
thermistor(RT62)
Ambient temperature
thermistor(RT63)
Defrost thermistor(RT61)
When OPERATION INDICATOR lamp flashes 6-time.
Thermistors in the outdoor unit are abnormal.
Check of outdoor thermistor
F
Check of LEV (Expansion valve)
E
Replace the
LEV.
With remote controller set toward the indoor unit, press
OPERATE/STOP (ON/OFF) button and confirm one
beep tone.
LEV operates in full-opening
direction.
Is LEV properly fixed to
the expansion valve?
OK
Do you hear the expansion
valve "click, click·······"?
Do you feel the expansion
valve vibrate on touching it?
Does the resistance of LEV have
the characteristics on 11-2?
No
Yes
Yes
Yes
No
No Properly fix the LEV to the
expansion valve.
Replace the
deicer P.C. board.
NOTE : After check of LEV, do the undermentioned operations.
1. Turn OFF the power supply and turn ON again.
2. Press the RESET button on the remote controller.
Turn ON the power supply.
During pressing both the OPERATION SELECT
button and the TOO COOL button on the
remote controller at the same time,
press the RESET button.
First, release the RESET button.
And release the other two buttons since all LCD
in operation display section of the remote controller
is displayed after 3 seconds.
AMPM
CLOCK
°C
AMPM
When OPERATION INDICATOR lamp flashes 10-time.
Heating/Cooling doesn't operate.
Disconnect the connectors CN661 and/or CN662 from the deicer P.C. board.
(Check the characteristics of each thermistor.)

17
11-4. TEST POINT DIAGRAM AND VOLTAGE
MUH-GD80VB
Outdoor deicer P.C. board
Varistor
(NR62)
Fuse
T3.15AL250V
Defrost
interval
time short
pin(JPG1,
R871)
(Refer to
10-1.)
}
12 V DC
Jumper wire for
change in defrost
setting (JRF, JRG)
(Refer to 10-2.)
}
5 V
DC
+
+
CN661 -
Defrost ther-
mistor (RT61)
(Refer to
11-3. )
Temperature (°C)
Discharge temperature thermistor (RT62)
Resistance (kΩ)
0 102030405060708090100110120
0
100
200
300
400
500
600
700
800
900
Defrost thermistor (RT61)
Ambient temperature thermistor (RT63)
-20 -10 0 10 20 30 40
0
10
20
30
40
50
60
70
80
90
100
Temperature (°C)
Resistance (kΩ)
CN662 -
Discharge tem-
perature thermistor
(RT62)
(Refer to 11-3. )
CN662 -
Ambient temperature
thermistor (RT63)
(Refer to 11-3. )
LEV
connector
(CN724)
Fan motor
connector
(CN711)
Varistor
(NR61)
CN730 -
230 V AC
}
(Refer to
11-3. or
11-3. .)
}
R601 10 V DC
(Refer to 11-3. .)
(Refer to
11-3. or
11-3. .)
J101
J401
+
}R.V. coil
(CN721)

OPERATING PROCEDURE PHOTOS
18
DISASSEMBLY INSTRUCTIONS
12
MUH-GD80VB
(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector has the
locking mechanism.
Slide the sleeve.
Pull the terminal while
pushing the locking
lever.
Hold the sleeve, and
pull out the terminal
slowly.
The terminal which has the locking mechanism can be detached as shown below.
There are two types ( Refer to (1) and (2)) of the terminal with locking mechanism.
The terminal without locking mechanism can be detached by pulling it out.
Check the shape of the terminal before detaching.
<"Terminal with locking mechanism" Detaching points>
Connector
Sleeve
Locking lever
1.Removing the cabinet
(1) Remove the screws of the service panel.
(2) Remove the screws of the top panel.
(3) Remove the screw of the valve cover.
(4) Remove the service panel.
(5) Remove the top panel.
(6) Remove the valve cover.
(7) Remove the screws of the cabinet.
(8) Remove the cabinet.
(9) Remove the screws of the back panel.
(10) Remove the back panel.
Photo 2
Photo 1
Photo 3
Screw of the top panel
Screws of the cabinet
Screws
of the
cabinet
Screws
of the
top
panel
Screws
of the
cabinet
Screw of the service panel
Screw
of the
valve
cover
Screw of the motor support
Screws of the back panel
Screws
of the
back
panel

OPERATING PROCEDURE PHOTOS
19
2. Removing the deicer P.C. board
(1) Remove the service panel and the cabinet.
(2) Disconnect all the connectors and the terminals on the
deicer P.C. board.
(3) Remove the deicer P.C. board.
Photo 4 Deicer P.C. board
Screws
of the
relay
panel Screws of the
relay panel
Terminal
blocks
Photo 6
Suction
pipe
Discharge pipe
Terminal cover
3. Removing the propeller and the outdoor fan motor
(1) Remove the cabinet. (Refer to 1.)
(2) Remove the propeller nut and the propeller.
NOTE: Loose the propeller in the rotating direction for
removal.
When attaching the propeller, align the mark on the
propeller and the motor shaft cut section.
Set the propeller fan in position by using the cut on
the shaft and the mark on the propeller.
(3) Remove the clamp of outdoor fan motor lead wire and
disconnect the outdoor fan motor connector.
(4) Remove the screws fixing the outdoor fan motor.
(5) Remove the outdoor fan motor.
Photo 5
Screws of the outdoor fan motor
Screws of the outdoor fan motor
Propeller
nut
4. Removing the compressor
(1) Remove the cabinet. (Refer to 1.)
(2) Remove the relay panel.
(3) Remove the soundproof felt.
(4) Remove the terminal cover on the compressor.
(5) Disconnect lead wires from the compressor.
(6) Recover gas from the refrigerant circuit.
NOTE:
Recover gas from the pipes until the pressure gauge shows
0 kg/cm2(0 MPa).
(7) Disconnect the welded part of the discharge pipe.
(8) Disconnect the welded part of the suction pipe.
(9) Remove nuts fixing the compressor.
(
10
)Remove the compressor.
Propeller
Compressor nuts

New publication, effective Apr. 2008
Specifications subject to change without notice.
Copyright 2008 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD
Distributed in Apr. 2008. No.OBH514 6
Made in Japan
HEAD OFFICE: TOKYO BLDG.,2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN