Service Manual

SiUS041638E Check
Service Diagnosis 92
5. Check
5.1 Thermistor Resistance Check
Check No.01 Disconnect the connectors of the thermistors from the PCB, and measure the resistance of each
thermistor using a multimeter.

The room temperature thermistor is soldered on the PCB. Disconnect the connector to the
control PCB before measuring the resistance.

When the connector of indoor heat exchanger thermistor is soldered on the PCB, remove the
thermistor and measure the resistance.
Thermistor temperature
Resistance (kΩ)
°C °F
–20 –4 197.8
–15 5 148.2
–10 14 112.1
–5 23 85.60
0 32 65.93
5 41 51.14
10 50 39.99
15 59 31.52
20 68 25.02
25 77 20.00
30 86 16.10
35 95 13.04
40 104 10.62
45 113 8.707
50 122 7.176
(R25°C (77°F) = 20 kΩ, B = 3950 K)
(R21673)
(˚C)
(kΩ)
–15
0
15 30
45
150
100
50
(˚F)
5 32 59 86 113
Multimeter
Resistance range
Other thermistors
(R23371)
Multimeter
(R19752)
Room temperature
thermistor