Fujitsu AOU24RLXFZH - Page 43

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:
Heat Exchanger (MID) thermistor is open or short is detected always.
Forecast of Cause :
1. Connector failure connection 2. Thermistor failure 3. Controller PCB failure
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
Trouble shooting 8
INDOOR UNIT Error Method:
Indoor Heat Ex. Thermistor Error
Resistance Value ( )
Temperature (°F)
31.7
95
39.6
86
49.762.9580.3103.3134.2176.0
86 7759504132
Resistance Value ( )
Temperature (°F)
17.120.925.6
122113104
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.
Indicate or Display:
Outdoor Unit : No indication
Indoor Unit : Operation lamp: 4 time Flash, Timer lamp: 2 time Flash
Economy lamp: Continuous flash.
ERROR CODE : [E : 42]
Compact wall mount circuit diagram (Connector connection)
Room Temp. Thermistor
H/E Thermistor
Wall mount circuit diagram (Direct soldering to PCB)
BLACK
BLACK
3
4
CN4
1
2
3
4
1
2
BLACK
BLACK
BLACK
BLACK
BLACK
BLACK
1
2
1
2
CN3
CN1
1
2
3
1
2
3
RED
WHITE
H/E Thermistor
Room Temp. Thermistor
Floor circuit diagram (Connector connection and Direct soldering to PCB)
BLACK
BLACK
1
2
1
2
1
2
CN3
CN1
GRAY
GRAY
H/E (MID) Thermistor
Room Temp. Thermistor
02-11
H/E (MID) Thermistor
Room Temp. Thermistor
Compact cassette circuit diagram (Connector connection)
Slim duct circuit diagram (Connector connection)
BLACK
BLACK
1
2
1
2
1 1
2 2
CN5
CN8
GRAY
GRAY
1
2
CN7
BLACK
BLACK
1
2
1
2
1 1
2 2
CN5
CN8
GRAY
GRAY
H/E (MID) Thermistor
Room Temp. Thermistor
k
k