Fujitsu AB Series A18LATN Service Instruction page 78

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)
For AB*A18L/ 24L
3 2 1 2 1
3 2 1 2 1
CN70 CN72
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Outdoor Unit (AB*A18L/ 24L) : LED 0.1sec ON/ 0.1sec OFF
ERROR CODE : E : 0C
Detective details:
When Discharge Pipe Temperature Thermistor open or short-circuit
is detected at power ON or while running the compressor.
0°C 5°C 10°C 15°C
169 130 101 79.1
70°C 80°C 90°C 100°C
8.70 6.27 4.60 3.43
2 1 4 3 2 1
2 1 4 3 2 1
CN73 CN71
(AB*A36L/ 45L) : LED 2 times blink
20°C 30°C 40°C
62.6 40.0 26.3
120°C 140°C
2.00 1.22
For AB*A36L/ 45L
1 2 1 2
1 2 1 2
CN24 CN21
07-10
50°C 60°C
17.8 12.3
1 2 1 2 1 2 1 2
1 2 1 2 1 2 1 2
CN22 CN23 CN26 CN25