Fujitsu AB*G14LVTA Service Instructions Manual page 63

Trouble shooting 23
OUTDOOR UNIT Error Method:
Heat sink thermistor error
Detective Actuators:
Outdoor unit Main PCB
Heat sink temperature thermistor
Forecast of Cause :
1. Connector connection failure
Check Point 1 : Check connection of Connector
Check if connector is removed.
Check erroneous connection.
Check if thermistor cable is open.
>>Upon correcting the removed connector or mis-wiring, reset the power.
OK OK
Check Point 2 : Remove connector and check Thermistor resistance value
Check Point 2 :
Thermistor Characteristics (Approx. value)
Temperature(°C)
Resistance Value (k )
Temperature(°C)
Resistance Value (k )
If Thermistor is either open or shorted, replace it and reset the power.
OK OK
Check Point 3 :
Check Point 3 : Check voltage of Main PCB (DC5.0V)
Make sure circuit diagram of outdoor unit and check terminal voltage at Thermistor (DC5.0V)
1 2
1 2
CN25 CN26
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When the heat sink temperature thermistor open or short-circuit is
detected at power ON or while running the compressor.
2.Thermistor failure
-30 -20 -10
92.3 49.2 27.5
50 60
70
1.8 1.2 0.9
1 2 1 2 1 2
CN23 CN22 CN21
02-26
3. Main PCB failure
0 10 20
16.1 9.7 6.1
80 90 100
0.6 0.5 0.4
30 40
3.9 2.6