Fujitsu AUXB04GALH Service Manual page 122

Trouble shooting 44
OUTDOOR UNIT Error Method:
Outdoor Temp Sensor Error<TH3>
Detective Actuators:
Outdoor temperature thermistor
Forecast of Cause :
1. Connector connection defective, open
2. Thermistor defective
3. Main PCB defective
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 17".
OK
Check Point 3 : Check voltage of Main PCB (DC5.0V)
Main PCB (CN144:1-3) voltage value = 5V
Remove the thermistor from Main PCB, check the voltage.
CN144
Outdoor temperature sensor (CN144:1-3)
If the voltage does not appear, replace Main PCB and set up orignal address. If the voltage does not appear, replace Main PCB and set up orignal address.
Indicate or Display:
E. 74.1
Outdoor Unit : E. 74. 1
Indoor Unit
Error Code
Detective details:
Outdoor temperature thermistor short or open detected
1 2 3
1 2 3
: Operation LED 9 times Flash, Timer LED 15 Times Flash,
Filter LED Continuous Flash.
: 74
DC
04-52