Fujitsu AU G18LVLB Series Service Instruction page 70

Trouble shooting 26
OUTDOOR UNIT Error Method:
Compressor Thermistor Error
Detective Actuators:
Compressor temperature thermistor
Forecast of Cause :
1. Connector connection failure, open
2. Thermistor failure
3. Main PCB failure
Check Point 1 : Check the connector connection and cable open
Connector connection state check
Cable open check
OK
Check Point 2 : Check the thermistor
Thermistor characteristics check (Disconnect the thermistor from the PCB and check.)
* For the thermistor characteristics, refer to the "Service Parts Information 8".
OK
Check Point 3 : Check voltage of Main PCB (DC5.0V)
Main PCB (CN146:3-4) voltage value = 5V
Remove the thermistor from Main PCB, check the voltage.
Compressor temperature thermistor (CN146:3-4)
If the voltage do not appear, replace Main PCB
the check operation again.
Indicate or Display:
Indoor Unit : Operation lamp: 7 time Flash,
Timer lamp: 2 time Flash
Economy lamp : Continuous flash.
ERROR CODE : [E : 72]
Detective details:
Compressor temperature thermistor short detected
Compressor thermistor open detected
1 2 3 4
1 2 3 4
CN146
, and execute
Outdoor unit :
POWER
MODE
DC
02-31
PUMP LOW
DOWN NOISE
ERROR
(L1) (L2) (L3) (L4)
7 2
2
PEAK
CUT
(L5) (L6)