Indoor Heat Exchanger Temperature Thermistor (Middle) Error - Fujitsu AU A36LCLU Series Service Instruction

Trouble shooting 5
INDOOR UNIT Error Method:
Indoor Heat Exchanger Temperature
Thermistor (Middle) Error
Detective Actuators:
Indoor Unit Controller PCB
Heat Exchanger Temperature Thermistor (Middle)
Forecast of Cause :
1. Connector connection failure
Check Point 1 : Check connection of connector
Check if connector is removed.
Check if connector is erroneous connection.
Check if thermistor cable is open.
>> Upon correcting the removed connector or mis-wiring, reset the power.
OK
Check Point 2 : Remove connector and check thermistor resistance value
Thermistor characteristics (Approx. value)
Temperature (°C )
Resistance value (k )
Temperature (°C )
Resistance value (k )
If Thermistor is either open or shorted, replace it and reset the power.
OK
Check Point 3 : Check voltage of Controller PCB (DC5.0V)
Make sure circuit diagram of indoor unit and check terminal voltage at thermistor (DC5.0V)
AR*C : CN7
Other Model : CN5
CN8
If the voltage does not appear, replace Controller PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When Heat Exchanger Temperature Thermistor (Middle) open or
short-circuit is detected at power ON.
2.Thermistor failure
0 5
176 134
40 45
25.6 20.8
GRAY
1 1
THERMISTOR
GRAY
( PIPE TEMP. )
2 2
BLACK
1 1
THERMISTOR
BLACK
( ROOM TEMP. )
2 2
3. Controller PCB failure
10 15 20
103 80.3 62.9
50
17.1
02-08
25 30 35
49.7 39.6 31.7