Fujitsu AU*A12LALN Service Instruction page 98

( For AU*A36L/ 45L )
Trouble shooting 29
OUTDOOR UNIT Error Method:
Heat Sink Temperature Sensor Error
Detective Actuators:
Outdoor Unit Main PCB Circuit
Heat Sink Temperature Thermistor
Forecast of Cause :
1. Connector connection failure 2.Thermistor failure 3. Main PCB 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
Resistance Value (k )
Temperature
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)
For AU*A36L/ 45L
1 2 1 2
1 2 1 2
CN24 CN21
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Outdoor Unit : LED 8 times blink
ERROR CODE : No indication
Detective details:
When Heat Sink Temperature Thermistor open or
short-circuit is detected at power ON or while running the compressor.
-10°C -5°C 0°C
27.8 21.0 16.1
35°C 40°C 45°C
3.11 2.53 2.08
1 2 1 2 1 2 1 2
1 2 1 2 1 2 1 2
CN22 CN23 CN26 CN25
5°C 10°C 15°C 20°C
12.4 9.63 7.56 5.98
50°C 60°C 70°C 80°C
1.71 1.19 0.840 0.606
07-31
25°C 30°C
4.77 3.84
90°C 100°C
0.446 0.333
DC