27
OCHT669
8-7-2. DC Fan Motor (Fan Motor/Indoor Controller Board)
Check the fuse (FUSE) on indoor
controller 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
board and fan motor.)
Self check
Symptom : The indoor fan cannot rotate.
1
2
Wiring contact check
Contact of fan motor connector (CNMF)
Fail
Power supply check (Remove the connector (CNMF))
Measure the voltage in the indoor controller circuit
board.
TEST POINT
1
: V
DC
(between 1 (+) and 4 (
−
) of the fan connector): V
DC
310–340 V DC
TEST POINT
2
: V
CC
(between 5 (+) and 4 (
−
) of the fan connector): V
CC
15 V DC
Correct wiring.
Replace the indoor controller board.
Replace the defective fan motor.
Replace the indoor
controller board.
Replace the defective fan motor.
Is the voltage normal?
Is there contact failure?
No
Yes
Yes
No
Check the operation of fan.
Complete.
Complete.
Fail
OK
OK
Check the operation.
Check method of DC fan motor (fan motor/indoor controller circuit board)
8-7-1. Thermistor Characteristic Graph
▪Symptom: The fan motor does not stop when controlled to stop by the remote
controller. The fan motor runs when the breaker is turned on.
▪Troubleshooting: The temporary connector of indoor controller board might be set
ON. Check the setting of SWE and turn OFF when it is set ON.
<Thermistor characteristic graph>
Room temperature thermistor(TH1)
Pipe temperature thermistor/liquid(TH2)
Condenser/evaporator temperature
thermistor(TH5)
Thermistor R
0
=15 k
"
± 3%
Fixed number of B=3480
± 2%
T(˚F)Rt=15exp { 3480(
) }
30˚F
15.8 k
"
50˚F
9.6 k
"
70˚F
6.0 k
"
80˚F
4.8 k
"
90˚F
3.9 k
"
100˚F 3.2 k
"
Thermistor for
lower temperature
1
273+
1
273
T-32
1.8
0
10
20
30
40
50
0
-20
20
40
60
80
100 120
< Thermistor for lower temperature >
Temperature (°F)
Resistance (k
"
)
