Fujitsu AS*G09KXCA Series Service Instruction page 54

Trouble shooting 17
OUTDOOR UNIT Error Method:
Heat Ex. Liquid Outlet Thermistor Error
Detective Actuators:
Outdoor unit Main 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 )
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 Main PCB (DC5.0V)
Make sure circuit diagram of outdoor unit and check terminal voltage at thermistor (DC5.0V)
BLACK
1 1
Thermistor (PIPE temp.)
BLACK
2 2
P1
BLACK
3 3
BLACK
4 4
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Indoor Unit :
Operation indicator: 7 time Flash
Timer indicator
Economy indicator: Continuous Flash
Error code: [ E : 73 ]
Detective details:
When Heat exchanger temperature thermistor open or
short-circuit is detected at power ON or while running the compressor.
2. Thermistor failure
-30 -20 -10 -5
92.3 49.2 27.5 20.9
20 30 40 50
6.1 4.0 2.6 1.8
02-21
: 3 time Flash
3. Main PCB failure
0 5 10 15
16.1 12.4 9.7 7.7
60 70 80 90
1.3 0.9 0.7 0.5