Fujitsu AU*G30LRLE series Service Instruction page 41

Trouble shooting 12
OUTDOOR UNIT Error Method:
Discharge Thermistor Error
Detective Actuators:
Outdoor unit Main PCB
Discharge pipe temperature thermistor
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 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 OK
Check Point 3 : Check voltage of Main PCB (DC5.0V)
Make sure circuit diagram of outdoor unit and check terminal voltage at thermistor (DC5.0V)
BROWN
3 3
CN64 2 2
BROWN
1 1
BLUE
3 3
2 2
CN62
BLUE
1 1
BLACK
3 3
CN65 2 2
BLACK
1 1
BROWN
3 3
CN63 2 2
BROWN
1 1
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When Discharge pipe temperature thermistor open or short-circuit
is detected at power ON or while running the compressor.
2. Thermistor failure
-30 -20 -10
1013.1 531.6 292.9
30 40 50
40.0 26.3 17.8
Thermistor
(Compressor temp.)
Thermistor
(Outdoor temp.)
Thermistor
(Heat exchanger)
Thermistor
(Discharge pipe)
3. Main PCB failure
-5 0 5
221.1 168.6 129.8 100.9
60 70 80 90
8.7 6.3 4.6
12.3
02-14
10 15 20
79.1 62.5
100 120
3.4 2.0