Fujitsu AMUG24LMAS Service Manual page 75

Troubleshooting 20
Outdoor unit heat-exchanger liquid
temperature sensor error
Detective actuators:
Heat-exchanger liquid temperature thermistor
Detective details:
Heat-exchanger outlet or middle temperature
thermistor short or open detected
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 thermistor
Thermistor characteristics check (Disconnect thermistor from PCB and check.)
(PARTS INFORMATION 7)
OK
Check Point 3 : Check voltage of main PCB (DC5.0V)
Main PCB (CN65:1-3) voltage value = 5V (AOU24/30RGLX)
Main PCB (CN62:2-3) voltage value = 5V (AOUG36/48LMAS1)
Disconnect thermistor from main PCB, and check voltage.
AOU24RGLX
AOU30RGLX
If voltage does not appear, replace main PCB,
and execute check operation again.
AOUG36LMAS1
AOUG48LMAS1
1 2 3
1 2 3
CN65
Indicate or Display:
Indoor unit
Operation lamp: 7 times Flash,
Timer lamp
Wired remote control
Error code : [E : 73]
Outdoor unit (AOUG36/48LMAS1)
Mode Error
2
: Light OFF
1 2 3
1 2 3
CN62
03-27
: 3 times Flash
A B C D E
7
3
: Light ON n : n times blinking
DC
F