Daikin FDMQ12RVJU, Service Manual

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Check SiUS091601EA
181 Part 6 Service Diagnosis
Note(s)
8. Check
8.1 Thermistor Resistance Check
Check No.01
Measure the resistance of each thermistor using multimeter.
The resistance values are defined by below table.
If the measured resistance value does not match the listed value, the thermistor must be replaced.
 Disconnect the connector of thermistor ASSY from the PCB to measure the resistance between
the pins using multimeter.
 To check the thermistor soldered on a PCB, disconnect the PCB from other PCB/parts, and
measure the resistance between the both ends of soldered thermistor.
R6000680
When replacing the defective thermistor(s), replace the thermistor as ASSY.
Thermistor
FTX09/12/15
NMVJU
FTX18/24UVJU
FVXS series
FDMQ series
Indoor
Unit
R1T Room temperature thermistor B A —
R2T Indoor heat exchanger thermistor A A —
R1T Suction air thermistor — — A
R2T Middle thermistor — — A
R3T Liquid pipe thermistor A A A
Outdoor
Unit
R1T Outdoor air temperature thermistor A A A
R2T Outdoor heat exchanger thermistor A A A
R3T Discharge pipe thermistor A A A
Multimeter
Resistance range
Thermistor ASSY Soldered thermistor
Multimeter
R(25°C / 77°F) = 10 k
:
, B = 3435 K
R(25°C / 77°F) = 20 k
:
, B = 3950 K
Thermistor
temperature
–20
–15
–10
–5
0
5
10
15
20
25
30
35
40
45
R(25°C / 77°F) = 10 k
:
B = 3435 K
Type B
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
R(25°C / 77°F) = 20 k
:
B = 3950 K
Type A
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 50
–4
5
14
23
32
41
50
59
68
77
86
95
104
113
122
°C °F
(˚C)
(k Ω )
–15
0 15 30
45
150
100
50
(˚F) 5 32 59 86 113
(˚C)
(˚F)
50
25
0
–15
5 32 59 86 113
0 15 30 45
(k Ω )