Mitsubishi Electric SLZ-KF25VA2 Technical & Service Manual page 27

8-7-1. Thermistor Characteristic Graph
Thermistor for
lower temperature
Thermistor R =15 kΩ ± 3%
0
Fixed number of B=3480 ± 2%
1
Rt=15exp { 3480(
273+t
0˚C 15 kΩ
10˚C 9.6 kΩ
20˚C 6.3 kΩ
25˚C 5.2 kΩ
30˚C 4.3 kΩ
40˚C 3.0 kΩ
8-7-2. DC Fan Motor (Fan Motor/Indoor Controller Board)
Check method of DC fan motor (fan motor/indoor controller circuit board)
Notes
1
· High voltage is applied to the connector (CNMF) for the fan motor. Pay attention to the service.
· Do not pull out the connector (CNMF) for the motor with the power supply on.
(It causes trouble of the indoor controller circuit
Self check
2
Symptom : The indoor fan cannot rotate.
Indoor controller board fuse check
Wiring contact check
Contact of fan motor connector (CNMF)
Is there contact failure?
No
Power supply check (Remove the connector (CNMF))
Measure the voltage in the indoor controller circuit
TEST POINT
1 : V
TEST POINT
2 : V
Is the voltage normal?
No
Replace the indoor
controller board.
Check the operation.
Fail
Replace the fan motor.
OCH616
•Room temperature thermistor (TH1)
•Pipe temperature thermistor/liquid (TH2)
•Condenser/evaporator temperature
thermistor (TH5)
1
) }
273
Yes
(between 1 (+) and 4 (−) of the fan connector): V
DC
(between 5 (+) and 4 (−) of the fan connector): V
CC
Yes
OK
END
board and fan motor.)
Wiring recovery
board.
DC
CC
Replace the fan motor.
Check the operation of fan.
Fail
Replace the indoor controller board.
27
< Thermistor for lower temperature >
50
40
30
20
10
0
−20 −10 0 10 20 30 40 50
Temperature (:)
310–340 V DC
15 V DC
OK
END