Fujitsu AB F18LAT Series Service Instruction page 42

Trouble shooting 8
OUTDOOR UNIT Error Method:
INDOOR UNIT
Outdoor Discharge Pipe Temperature
Sensor Error
Detective Actuators:
Outdoor Unit Main PCB Circuit
Discharge Pipe 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)
3 2 1
3 2 1
CN70
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Outdoor Unit : LED 0.1sec ON/ 0.1sec OFF
ERROR CODE : E : 0C
Detective details:
0°C 5°C 10°C
169 130 101
70°C 80°C 90°C
8.70 6.27 4.60
2 1 2 1 4 3 2 1
2 1 2 1 4 3 2 1
CN72 CN73 CN71
When Discharge Pipe Temperature Thermistor open or short-circuit
is detected at power ON or while running the compressor.
15°C 20°C 30°C 40°C
79.1 62.6 40.0 26.3
100°C 120°C 140°C
3.43 2.00 1.22
02-11
50°C 60°C
17.8 12.3