Troubleshooting; Check Methods - Mitsubishi Electric City Multi PFFY-P20VLRMM-E 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
4.3k - 9.6k
(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)
Thermistor R = 15 k
0
Multiplier of B = 3480 k
Rt = 15 exp { 3480(
0°C 15k
10°C 9.6k
20°C 6.3k
25°C 5.2k
30°C 4.3k
40°C 3.0k
(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
LEV
(C)
4
(B)
5
(A)
6
(A) Brown
(B) Red
(C) Blue
HWE07170
Abnormal
Open or short
3%
2%
1
1
) }
273+t 273
(°C)
(k )
1-5 2-6
White-Red Yellow-Brown
150 k
(D) Orange
(E) Yellow
(F) White
50
40
30
20
10
0
-20 -10 0 10 20
(A)
Normal
3-5
Orange-Red Blue-Brown
10%
- 11 -
30 40 50
Abnormal
4-6 Open or short
GB