Outdoor Thermistor Error - Fujitsu ASU 9RLF Service Instructions Manual

Trouble shooting 13
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)
AOU9RLFW
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 : LED 0.1sec ON/ 0.1sec OFF
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 8.0
AOU12RLFW, 15RLS
THERMISTOR
(PIPE)
1 1
2 2
CN61
3 3
4 4
THERMISTOR
(DISCHARGE)
THERMISTOR
(OUTDOOR)
1 1
CN62
2 2
3 3
02-17
: Operation lamp: 7 times Flash, Timer lamp: 4 times Flash
Economy lamp: Continuous flash.
3. Main PCB failure
-10°C -5°C 0°C 5°C
62.3 46.6 35.2 26.9
35°C 40°C 45°C 50°C
6.4 5.2 4.2
BLACK
1 1
BLACK
2 2
CN71
BROWN
3 3
BROWN
4 4
BLACK
1 1
CN70
2 2
BLACK
3 3
10°C
20.7
55°C
3.5 2.8