Fujitsu ASYG09KMCB Service Instruction page 44

Troubleshooting 12
Outdoor unit heat-exchanger sensor error
OUTDOOR UNIT Error Method:
Detective actuators:
Outdoor unit main PCB
Heat exchanger 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 : Check Point 2 : Remove connector and check Thermistor resistance value
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)
THERMISTOR
(PIPE)
BLACK
BLACK
BLACK
BLACK
THERMISTOR
(DISCHARGE)
THERMISTOR
(OUTDOOR)
BLACK
BLACK
If the voltage does not appear, replace main PCB.
Detective details:
When Heat exchanger temperature thermistor open or
short-circuit is detected at power ON or while running the compressor.
-10°C -5°C 0°C 5°C
27.21 20.80 16.05 12.47
60°C 70°C 80°C
1.213 0.8531 0.6115
1 1
2 2
P1
3 3
4 4
1 1
P5
2 2
3 3
10°C 20°C 30°C
3.947
9.775 6.129
02-16
40°C 50°C
2.606 1.759