25
9-6-1. Thermistor
<Thermistor Characteristic graph>
Room temperature thermistor (TH1)
Pipe temperature thermistor/liquid (TH2)
Condenser/evaporator temperature
thermistor (TH5)
Thermistor R
0
=15k
± 3%
Fixed number of B=3480 ± 2%
t( )Rt=15exp { 3480( ) }
0
10
20
25
30
40
Thermistor for
lower temperature
1
273+t
1
273
0
10
20
30
40
50
-20 -10 0 10 20 30 40 50
-4 -14 32 50 68 86 104122 °F
Temperature
Resistance (k
)
<Thermistor for lower temperature>
1
273+
1
273
T-32
1.8
°C
9-6-2. DC Fan motor (fan motor/indoor controller circuit board)
Notes
· High voltage is applied to the connecter (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 turn around.
Yes
NG
Wiring contact check
Contact of fan motor connector (CNMF)
Power supply check (Remove the connector (CNMF))
Measure the voltage in the indoor controller circuit
board.
TEST POINT
: V
DC
(between 1 (+) and 4 (-) of the fan connector): V
DC
DC294~325V
TEST POINT
: V
CC
(between 5 (+) and 4 (-) of the fan connector): V
CC
DC15V
Wiring recovery
Replace indoor controller board.
Replace the fan motor
Replace the fan motor.
Is the voltage normal?
Is there contact failure?
No
No
Yes
Check the operation
END
OK
Check the operation
END
OK
NG
Check method of DC fan motor (fan motor/indoor controller circuit board)
Replace indoor controller board.
