Fujitsu AB Series A18LATN, Service Instruction

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Trouble shooting 4
INDOOR UNIT
INDOOR UNIT Error Method:
Indicate or Display:
Outdoor Unit : No indication
ERROR CODE : E : 04
Detective Actuators:
Detective details:
Forecast of Cause :
Check Point 2 :
31.7
35°C
39.6
30°C
49.7 62.9 80.3 103 134 176 Resistance Value (k )
25°C 20°C 15°C 10°C 5°C 0°C
Temperature
OK OK
OK
17.1 20.8 25.6 Resistance Value (k )
50°C 45°C 40°C
Temperature
Indoor Heat Exchanger Temperature
Sensor Error
Indoor Unit Controller PCB Circuit
Heat Exchanger Temperature Thermistor
When Heat Exchanger Temperature Thermistor open or short-circuit is
detected at power ON.
1. Connector connection failure 2.Thermistor failure 3. Controller PCB 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.
Check Point 2 : Remove connector and check Thermistor resistance value
Thermistor Characteristics (Approx. value)
If Thermistor is either open or shorted, replace it and reset the power.
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)
If the voltage does not appear, replace Controller PCB.
07-07
THERMISTOR
(PIPE TEMP.)
THERMISTOR
(ROOM TEMP.)
G
R
A
Y
G
R
A
Y
B
LA
C
K
B
LA
C
K
CN5
CN7 CN8
1 2 1 2
1 2 1 2 1 2