Fujitsu AO*G09KXCA Series, Service Instruction

Page: 45 / 110

Thermistor Characteristics (Rough value)
If Thermistor is either open or shorted, replace it and reset the power.
Detective Actuators:
Indoor unit Controller PCB
Heat exchanger (MID) Thermistor
Detective details:
When Heat Ex. temperature thermistor open or short-circuit is detected.
Forecast of Cause : 1. Connector failure connection 2. Thermistor failure 3. Controller PCB failuer
Check Point 1 : Check connection of Connector
Check if connector is loose or removed
Check erroneous connection
Check if thermistor cable is open
>>Reset Power when reinstalling due to removed connector or incorrect wiring.
OK
Check Point 2 : Remove connector and check Thermistor resistance value
OK
Check Point 3 : Check voltage of Controller PCB (DC5.0V)
Make sure circuit diagram of each indoor unit and check terminal voltage at Thermistor (DC5.0V)
If the voltage does not appear, replace Controller PCB and execute the check operation again.
DC
02-12
Trouble shooting 8
INDOOR UNIT Error Method:
Indoor Heat Ex. Thermistor Error
31.7 39.6 49.7 62.9
80.3 103.3 134.2 176.0
17.1 20.9 25.6 Resistance value (k )
Temperature (°C )
Temperature (°C )
0
40 45 50
14.1
55
5 10
1131.9
-30
804.5
-25
579.6
-20
422.9
-15
312.3
-10
233.2
-5 15
20 25 30 35
11.6
60
10.4
63
Resistance value (k )
BLACK
BLACK
1
2
CN3
1
2
Thermistor ( Pipe temp.)
Indicate or Display:
Indoor Unit :
Operation indicator: 4 time Flash
Timer indicator : 2 time Flash
Error code : [ E : 42 ]
Economy indicator: Continuous Flash