Mitsubishi Electric City Multi PEFY-WP20VMA-E, Technical & Service Manual, Page: 17 / 32

[
VII
Troubleshooting ]
- 11 - HWE1114A GB
VII
Troubleshooting
[1] Troubleshooting
1. Check methods
1. Component and check points
(1) Thermistor
Œ
Room temperature thermistor (TH21)
Œ
Water inlet thermistor (TH22)
Œ
Water outlet thermistor (TH23)
Disconnect the connector and measure the resistance between terminals with a volt meter.
(Ambient temperature 10°C - 30°C)
1) Thermistor characteristic graph
(2) Fan motor (CNMF)
Refer to the page on "DC fan motor (fan motor/indoor control board)."
(3) Drain-up mechanism
Measure the resistance between the terminals with a tester.
(coil temperature 20°C)
Normal Abnormal
4.3k - 9.6k Open or short
(Refer to the thermistor characteristic graph below.)
Low-temperature thermistor
Œ
Room temperature thermistor (TH21)
Œ
Water inlet pipe thermistor (TH22)
Œ
Water outlet thermistor (TH23)
Œ
Drain sensor (DS)
Œ
Thermistor R
0
= 15 k 3%
Œ
Multiplier of B = 3480 k 2%
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 (°C)
(B) Resistance (k)
Normal Abnormal
340 Open or short
Rt = 15 exp { 3480( ) }
1
273+t
1
273
0
10
20
30
40
50
-20 -10 0 10 20 30 40 50
(A)
(B)
1
3