Fujitsu ASU12RL2, AOU12RL2, AOU09RL2 manual Check Point 2 Check each thermistor

Trouble shooting 17 INDOOR UNIT Error Method:

4-way valve error

Indicate or Display:

Refer to error code table.

Detective Actuators:

Indoor unit Controller PCB Heat Ex. temperature thermistor Room temperature thermistor 4-way valve

Detective details:

When the indoor heat exchanger temperature is compared with the room temperature, and either following condition is detected continuously two times, the compressor stops.

Cooling or Dry operation

[Indoor heat exchanger temp.] - [Room temp.] > 10degC (20°F) Heating operation

[Indoor heat exchanger temp.] - [room temp.] < - 10degC (-20°F)

If the same operation is repeated 5 times, the compressor stops permanently.

Forecast of Cause :

1.	Connector connection failure 2. Thermistor failure 3. Coil failure 4. 4-way valve failure
5.	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.

OK

Check Point 2 : Check each thermistor

Isn’t it fallen off the holder?

Is there a cable pinched?

>>Check characteristics of thermistor (Refer to Trouble shooting 5, 6), If defective, replace the thermistor

OK

Check Point 3 : Check the solenoid coil and 4-way valve

[ Solenoid coil ]

Remove CN30 from PCB and check the resistance value of coil. Resistance value is 1.88k 2.29k(at 20°C (68°F)).

>> If it is Open or abnormal resistance value, replace Solenoid Coil.

[ 4-way valve ]

Check each piping temperature,

and the location of the valve by the temperature difference.

>>If the value location is not proper, replace 4-way valve.

OK

Check Point 4 : Replace Controller PCB

If Check Point 1- 3 do not improve the symptom, replace Controller PCB.

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