Fujitsu AS*A09LKC Service Instructions Manual page 31

Trouble shooting 7
OUTDOOR UNIT Error Method:
Outdoor Heat Exchanger Temperature
Thermistor Error
Detective Actuators:
Outdoor Unit Inverter PCB
Heat Exchanger Temperature Thermistor
Forecast of Cause :
1. Connector connection failure
Check Point 1 : Check connection of connector
Check if connector is removed.
Check if connector is 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
Thermistor characteristics (Approx. value)
Temperature (°C )
Resistance value (k )
If Thermistor is either open or shorted, replace it and reset the power.
OK OK
Check Point 3 : Check voltage of Inverter PCB (DC5.0V)
Make sure circuit diagram of outdoor unit and check terminal voltage at thermistor (DC5.0V)
AO*R09LKC
BLACK
1 1
BLACK
2 2
BLACK
3 3
BLACK
4 4
BLACK
1 1
2 2
BLACK
3 3
If the voltage does not appear, replace Controller PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When Heat Exchanger Temperature Thermistor (Out) open or
short-circuit is detected at power ON or while running the compressor.
2. Thermistor failure
-10 -5 0 5
27.8 21.0 16.1 12.4
THERMISTOR
( HEAT EXCHANGER )
THERMISTOR
( DISCHARGE PIPE )
THERMISTOR
( OUTDOOR TEMP. )
02-09
3. Inverter PCB failure
10
15 20 25
9.63 7.56 5.98 4.77
AO*R12LKC
BLACK
1 1
BLACK
2 2
BLACK
3 3
BLACK
4 4
BLACK
1 1
2 2
BLACK
3 3
35
30
3.84 3.11
THERMISTOR
( HEAT EXCHANGER )
THERMISTOR
( DISCHARGE PIPE )
THERMISTOR
( OUTDOOR TEMP. )