Mitsubishi Electric Mr.SLIM PLA Series Service Manual page 30

9-6-1. Thermistor
<Thermistor Characteristic graph>
Thermistor for
lower temperature
Thermistor R =15k' ± 3%
0
Fixed number of B=3480 ± 2%
Rt=15exp { 3480(
273+t
0: 15k'
10: 9.6k'
20: 6.3k'
25: 5.4k'
30: 4.3k'
40: 3.0k'
9-6-2. DC Fan motor (Fan motor/Indoor controller board)
Check method of DC fan motor (fan motor / indoor controller circuit board)
Notes
· 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
Symptom : The indoor fan cannot rotate.
Indoor controller board fuse check
Is the fuse normal?
Yes
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
: V (between 1 (+) and 4 (-) of the fan connector): V
DC
TEST POINT
: V (between 5 (+) and 4 (-) of the fan connector): V
CC
Is the voltage normal?
No
Replace indoor
controller board
Check the operation
NG
Replace the fan motor.
OCH529
Room temperature thermistor (TH1)
Pipe temperature thermistor/liquid (TH2)
Condenser/evaporator temperature
thermistor (TH5)
1 1
) }
273
Is the resistance
between the terminals of
drain pump normal?
Replace the drain pump.
Yes
Wiring recovery
board.
Yes
Replace indoor controller board.
OK
END
board and fan motor.)
No
DC 310~340 V
DC
DC 15 V
CC
Replace the fan motor.
Check the operation of fan.
NG
30
< Thermistor for lower temperature >
50
40
30
20
10
0
-20 -10 0 10 20 30 40 50
Temperature ( )
Replace the fan motor.
Replace the indoor controller board.
OK
END