Indoor Unit Heat Ex. Sensor Error - Fujitsu ASU 9RLF Service Instructions Manual

Trouble shooting 6
INDOOR UNIT Error Method:
INDOOR UNIT

Indoor unit Heat Ex. sensor error

Detective Actuators:
Indoor unit Controller PCB
Heat Ex. 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
Check Point 3 : Check voltage of Controller PCB (DC5.0V)
Make sure circuit diagram of indoor unit and check terminal voltage at Thermistor (DC5.0V)
THERMISTOR
(PIPE)
BLACK
1 1
BLACK
2 2
CN4
BLACK
3 3
BLACK
4 4
THERMISTOR
(ROOM TEMP.)
If the voltage does not appear, replace Controller PCB.
Indicate or Display:
Outdoor Unit : No indication
Indoor Unit
ERROR CODE : [E : 42]
Detective details:
When Heat Ex. Temperature Thermistor open or short-circuit is detected.
2.Thermistor failure
-30°C -20°C -10°C
1131.9 579.6 312.3
30°C 40°C 50°C
39.6 25.6 17.1
02-10
: Operation lamp: 4 times Flash, Timer lamp: 2 times Flash
Economy lamp: Continuous flash.
3. Controller PCB failure
-5°C 0°C 5°C
233.2 176.0 134.2
60°C 63°C
11.6 10.4
10°C 20°C
103.3 62.9