Fujitsu AGU12RLF Service Instruction page 44

Trouble shooting 14
OUTDOOR UNIT Error Method:
Outdoor thermistor error
Detective Actuators:
Outdoor unit Main PCB
Outdoor 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 Point 3 : Check voltage of Main PCB (DC5.0V)
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 Outdoor temperature thermistor open or short-circuit is
detected at power ON or while running the compressor.
2.Thermistor failure
-4°F 5°F 14°F 23°F
115.2 84.2 62.3 46.6
95°F 104°F 113°F 122°F
6.4 5.2 4.2
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
32°F 41°F 50°F
20.7
35.2 26.9
131°F
3.5 2.8
BLACK
1 1
BLACK
2 2
BROWN or BLACK
3 3
BROWN or BLACK
4 4
BLACK
1 1
2 2
BLACK
3 3
02-19
68°F 86°F
12.6 8.0
CN61
CN62