Check; Thermistor Resistance Check - Daikin FTKN09NMVJU Service Manual

Check

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 multimeter.
91
Thermistor temperature
Room temperature
°C °F
thermistor
–20 –4
–15 5
–10 14
–5 23
0 32
5 41
10 50
15 59
20 68
25 77
30 86
35 95
40 104
45 113
50 122
Room temperature thermistor
(kΩ)
50
25
0
–15 0 15
5 32 59
When the room temperature thermistor is soldered on a PCB, remove the PCB from the control
PCB to measure the resistance.
When the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the
thermistor and measure the resistance.
Resistance (kΩ)
Other thermistors
73.4
57.0
44.7
35.3
28.2
22.6
18.3
14.8
12.1
10.0
8.2
6.9
5.8
4.9
4.1
(R25°C (77°F) = 10 kΩ, (R25°C (77°F) = 20 kΩ,
B = 3435 K)
(kΩ)
150
100
50
45 –15
30 (˚C)
(˚F) 5
86 113
Resistance range
197.8
148.2
112.1
85.60
65.93
51.14
39.99
31.52
25.02
20.00
16.10
13.04
10.62
8.707
7.176
B = 3950 K)
Other thermistors
0 45
15 30 (˚C)
32 59 86 113 (˚F)
Room temperature
thermistor
Multimeter
Multimeter
(R19751)
SiUS041501E
(R21673)
(R20505)
Service Diagnosis