Fujitsu ARYG72LHTA Service Instruction page 60

Trouble shooting 23
OUTDOOR UNIT Error Method:
Heat Ex. Outlet Temp.
Thermistor Error
Detective Actuators:
Heat exchanger liquid temperature
thermistor
Forecast of Cause :
1. Connector connection defective, 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 (CN147:1-2) voltage value = 5V
Remove the thermistor from Main PCB, check the voltage.
Heat exchanger outlet temperature thermistor
If the voltage do not appear, If the voltage do not appear, replace Main PCB
the check operation again.
Indicate or Display:
Error code : 73
Detective details:
Heat exchanger outlet temperature thermistor short or open detected
1 2 3 4
1 2 3 4
CN147
(CN147:1-2)
, and execute
Outdoor unit :
PUMP
POWER
DOWN
ERROR
MODE (L1)
2
2
DC
02-24
LOW PEAK
NOISE CUT
(L2) (L3) (L4) (L5) (L6)
7 3
7 3