Fujitsu ASYG07KMTA Service Manual page 81

Trouble shooting 17
OUTDOOR UNIT Error Method:
Outdoor Thermistor Error
Detective Actuators:
Outdoor unit Main PCB
Outdoor 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:
Outdoor Unit : No indication
Indoor Unit
ERROR CODE : [E : 74 ]
Detective details:
When Outdoor temperature thermistor open or short-circuit is
detected at power ON or while running the compressor.
2.Thermistor failure
-30°C -25°C -20°C -15°C
224.3 159.7 115.2 84.2
15°C 20°C 25°C 30°C
16.1 12.6 10.0
1 1
2 2
P1
3 3
4 4
1 1
P5
2 2
3 3
02-20
: Operation lamp: 7 time Flash, Timer lamp: 4 time Flash
Economy lamp: Continuous flash.
3. Main PCB failure
-10°C -5°C 0°C
62.3 46.6 35.2
35°C 40°C 45°C
8.0 6.4 5.2 4.2
5°C 10°C
20.7
26.9
50°C 55°C
3.5 2.8