Mitsubishi Electric SLZ Series Technical & Service Manual page 25

8-7-1. Thermistor Characteristic Graph
<Thermistor characteristic graph>
Thermistor for
lower temperature
Thermistor R =15 k" ± 3%
0
Fixed number of B=3480 ± 2%
t(˚C)Rt=15exp { 3480(
T(˚F)Rt=15exp { 3480(
32˚F [0˚C] 15 k"
50˚F [10˚C] 9.6 k"
68˚F [20˚C] 6.3 k"
77˚F [25˚C] 5.4 k"
86˚F [30˚C] 4.3 k"
104˚F [40˚C] 3.0 k"
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.
Check the fuse (FUSE) on indoor
controller board.
Wiring contact check
Contact of fan motor connector (CNMF)
Is there contact failure?
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?
Replace the indoor
controller board.
Check the operation.
Replace the defective fan motor.
TCH118
Room temperature thermistor (TH1)
Pipe temperature thermistor/liquid (TH2)
Condenser/evaporator temperature
thermistor (TH5)
1 1
) }
273+t 273
1 1
) }
T-32
273+ 273
1.8
Yes
No
(between 1 (+) and 4 (−) of the fan connector): V
DC
(between 5 (+) and 4 (−) of the fan connector): V
CC
Yes
No
OK
Complete.
Fail ▪Symptom:
▪Troubleshooting: The temporary connector of indoor controller board might be set
board and fan motor.)
Correct wiring.
board.
DC
CC
Replace the defective fan motor.
Check the operation of fan.
Fail
Replace the indoor controller board.
The fan motor does not stop when controlled to stop by the remote
controller. The fan motor runs when the breaker is turned on.
ON. Check the setting of SWE and turn OFF when it is set ON.
25
< Thermistor for lower temperature >
50
40
30
20
10
0
-20 -10 0 10 20 30 40 50
-4 -14 32 50 68 86 104 122 (°F)
Temperature
310–340 V DC
15 V DC
OK
Complete.
(°C)