Fujitsu AO G24KATA Series Service Instruction page 52

Trouble shooting 23
OUTDOOR UNIT Error Method:
Heat Ex. Outlet / Middle Temp.
Thermistor Error
Detective Actuators:
Heat exchanger Outlet / Middle 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 P1 :1-2 voltage value =5V
Main PCB P10:1-2 voltage value =5V
Remove the thermistor from Main PCB, check the voltage.
1 2 3 4
1 2 3 4
P1
If the voltage does not appear, replace Main PCB,
and execute the check operation again.
Indicate or Display:
Error code : 73
Detective details:
Heat exchanger outlet temperature thermistor short or open detected
Heat exchanger middle temperature thermistor short or open detected
1 2 3
1 2 3
P10
02-24
Outdoor unit : No indication
DC