Fujitsu AGU12RLF Service Instruction page 33

Trouble shooting 5
INDOOR UNIT Error Method:
INDOOR UNIT
Indoor room thermistor error
Detective Actuators:
Indoor unit Controller PCB
Room 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
Check Point 2 : Check Point 2 : Check the voltage value between the terminals at Thermistor
Check Voltage at CN1 (terminal 1-2) of Controller PCB.
THERMISTOR
(PIPE)
GRAY
GRAY
BLACK
BLACK
THERMISTOR
(ROOM TEMP.)
Thermistor Characteristics (Approx. value)
Temperature
Voltage value (V)
Temperature
Voltage value (V)
If the voltage does not appear, replace Controller PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When Room Temperature Thermistor open or short-circuit is detected.
2.Thermistor failure
1 1
CN3
2 2
1
CN1
2
14°F 23°F 32°F
4.27 4.07 3.85
95°F 104°F 113°F
1.97 1.73 1.52
3. Controller PCB failure
41°F 50°F 59°F
3.61 3.34 3.06
02-08
68°F 77°F 86°F
2.78 2.50
2.23