Fujitsu AB*30LBAG series Service Instruction page 54

Trouble shooting 7
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)
1 2
CN21 CN22
If the voltage does not appear, replace Main PCB.
0°C 5°C 10°C
176 135 105
70°C 80°C 90°C
8.78 6.31 4.61
1 2 1 2 1 2
CN23 CN26
Indicate or Display:
Indoor Unit : Operation LED: Blink, Timer LED: 5 times blink,
Vertical swing LED: OFF
Outdoor Unit : LED 2 times blink
Detective details:
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
81.8 64.5 41.1
100°C 120°C 140°C
3.43 1.98 1.21
1 2
CN25
07-08
40°C 50°C 60°C
26.9 18.1 12.5
160°C 180°C
0.77 0.51