Troubleshooting; Check Methods - Mitsubishi Electric CITY MULTI PEFY Series Technical And Service Manual

[ VII Troubleshooting ]
VII Troubleshooting

[1] Troubleshooting

1. Check methods

1. Component and check points
(1) Thermistor
Inlet air temperature thermistor (TH21)
Liquid pipe thermistor (TH22)
Gas pipe thermistor (TH23)
Outdoor air temperature thermistor (TH24)
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
Thermistor R = 15 kΩ 3%
0
Multiplier of B = 3480 kΩ 2%
Rt = 15 exp { 3480(
273+t
0°C 15kΩ
10°C 9.6kΩ
20°C 6.3kΩ
25°C 5.2kΩ
30°C 4.3kΩ
40°C 3.0kΩ
(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
HWE1804A
Abnormal
Open or short
50
1
1
) }
273
40
30
20
10
Normal
1-6 2-6
White-Red Yellow-Red
(150Ω)
(E) Yellow
(F) White
0
-20 -10 0 10 20 30
Temperature(°C)
3-6 4-6
Orange-Red Blue-Red
10%
- 14 -
40 50
Abnormal
Open or short
GB