Fujitsu AS*G09KXCA Series Service Instruction page 45

Trouble shooting 8
INDOOR UNIT Error Method:
Indoor Heat Ex. Thermistor Error
Detective Actuators:
Indoor unit Controller PCB
Heat exchanger (MID) Thermistor
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
Thermistor Characteristics (Rough value)
Temperature (°C )
Resistance value (k )
Temperature (°C )
Resistance value (k )
If Thermistor is either open or shorted, replace it and reset the power.
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)
BLACK
1 1
CN3
BLACK
2 2
If the voltage does not appear, replace Controller PCB and execute the check operation again.
Indicate or Display:
Indoor Unit :
Operation indicator: 4 time Flash
Timer indicator
Economy indicator: Continuous Flash
Error code : [ E : 42 ]
Detective details:
When Heat Ex. temperature thermistor open or short-circuit is detected.
-30 -25 -20
1131.9 804.5 579.6
20 25 30
62.9 49.7 39.6
Thermistor ( Pipe temp.)
: 2 time Flash
-15 -10 -5
422.9 312.3 233.2 176.0
35
40 45
31.7
25.6 20.9
02-12
0 5 10
134.2 103.3
50 55
60
11.6 10.4
17.1 14.1
15
80.3
63
DC