Fujitsu ASU09RL2 Service Instructions Manual page 35

Trouble shooting 10
OUTDOOR UNIT Error Method:
INDOOR UNIT
Discharge temp. sensor 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
Resistance Value (k )
Temperature
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)
THERMISTOR
(PIPE)
BLACK
BLACK
BLACK
BLACK
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
-10°C -5°C 0°C
(14°F) (23°F) (32°F) (41°F)
286.3 218.6 168.6 130.9
40°C 50°C 60°C 70°C
(104°F) (122°F) (140°F) (158°F)
27.26 18.40 12.68 8.909
1 1
2 2
CN71
3 3
4 4
1 1
CN70
2 2
3 3
3. Main PCB failure
5°C 10°C 20°C 30°C
(50°F) (68°F) (86°F)
102.5 64.22 41.33
80°C 90°C 100°C
(176°F) (194°F) (212°F)
6.375 4.639 3.430
02-12
110°C 120°C
(230°F) (248°F)
2.573 1.956