Fujitsu AGU12RLF Service Instruction page 42

Trouble shooting 12
OUTDOOR UNIT Error Method:
INDOOR UNIT
Discharge thermistor error
Detective Actuators:
Outdoor unit Main PCB
Discharge pipe temperature thermistor
Forecast of Cause :
1. Connector connection 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 (°F)
Resistance Value (k )
Temperature (°F)
Resistance Value (k )
If Thermistor is either open or shorted, replace it and reset the power.
OK OK
Check Point 3 : Check voltage of Main PCB (DC5.0V) Check Point 3 :
Make sure circuit diagram of outdoor unit and check terminal voltage at Thermistor (DC5.0V)
AOU9 / 12RLFF
THERMISTOR
(PIPE)
BLACK
BLACK
BROWN
BROWN
THERMISTOR
(DISCHARGE)
THERMISTOR
(OUTDOOR)
BLACK
BLACK
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When Discharge pipe temperature thermistor open or short-circuit
is detected at power ON or while running the compressor.
2.Thermistor failure
14°F 23°F 32°F 41°F
292.9 221.1 168.6 129.8
140°F 158°F 176°F 194°F
12.3 8.7 6.3
AOU15RLFF
THERMISTOR
(PIPE)
1 1
2 2
CN71
3 3
4 4
THERMISTOR
(DISCHARGE)
THERMISTOR
(OUTDOOR)
1 1
CN70
2 2
3 3
3. Main PCB failure
50°F 68°F 86°F
40.0
100.9 62.5
212°F 230°F 248°F
4.6 3.4 2.6 2.0
BLACK
1 1
BLACK
2 2
BROWN or BLACK
3 3
BROWN or BLACK
4 4
BLACK
1 1
2 2
BLACK
3 3
02-17
104°F 122°F
26.3 17.8
CN61
CN62