Fujitsu ARU7RLF Service Instruction page 61

Trouble shooting 22
OUTDOOR UNIT Error Method:
Heat Sink Thermistor 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
Check Point 2 : Remove connector and check Thermistor resistance value Check Point 2 :
Thermistor Characteristics (Approx. value)
Temperature(°F)
Resistance Value (k )
Temperature(°F)
Resistance Value (k )
If Thermistor is either open or shorted, replace it and reset the power.
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 Heat Sink Temperature Thermistor open or short-circuit is
detected at power ON or while running the compressor.
-22°F -4°F 14°F
92.3 49.2 27.5
122°F 140°F
158°F
1.8 1.2 0.9
1 2 1 2 1 2
CN23 CN22 CN21
02-26
32°F 50°F 68°F
16.1 9.7 6.1
176°F 194°F 212°F
0.6 0.5 0.4
86°F 104°F
3.9 2.6