Troubleshooting; Check Methods - Mitsubishi Electric City Multi PEFY-M20VMA-A Technical & Service Manual

[ VII Troubleshooting ]
VII Troubleshooting

[1] Troubleshooting

1. Check methods

1. Component and check points
(1) Thermistor
Room temperature thermistor (TH21)
Liquid pipe thermistor (TH22)
Gas pipe thermistor (TH23)
Disconnect the connector and measure the resistance between terminals with a tester.
(Ambient temperature 10°C - 30°C)
Normal
4.3kΩ - 9.6kΩ
(Refer to the thermistor characteristic graph below.)
1) Thermistor characteristic graph
Low-temperature thermistor
Room temperature thermistor (TH21)
Liquid pipe thermistor (TH22)
Gas pipe thermistor (TH23)
Drain sensor (DS)
Thermistor R = 15 kΩ±3%
0
Multiplier of B = 3480 kΩ±2%
Rt = 15 exp { 3480(
0°C 15kΩ
10°C 9.6kΩ
20°C 6.3kΩ
25°C 5.2kΩ
30°C 4.3kΩ
40°C 3.0kΩ
(A) Temperature
(B) Resistance
(2) Fan motor (CNMF)
Refer to the page on "DC fan motor (fan motor/indoor control board)."
(3) Linear expansion valve
Disconnect the connector, and measure the resistance between terminals with a tester.
Refer to the next page for details.
CN60
(F)
1
(E)
2
(D)
3
M
(C)
4
LEV
(A)
6
(A) Red
(C) Blue
(D) Orange
HWE19070
Abnormal
Open or short
1 1
) }
273+t 273
(°C)
(kΩ)
1-6 2-6
White-Red Yellow-Red
(150Ω) ±10%
(E) Yellow
(F) White
50
40
30
20
10
0
-20 -10 0 10
(A)
Normal
3-6
Orange-Red Blue-Red
- 23 -
20 30 40 50
Abnormal
4-6 Open or short
GB