4-Way Valve Error - Fujitsu ASU 9RLF1 Service Instruction

Trouble shooting 18
INDOOR UNIT Error Method:

4-way valve error

Detective Actuators:
Indoor unit Controller PCB
Heat Ex. temperature thermistor
Room temperature thermistor
4-way valve
Forecast of Cause :
1. Connector connection 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 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 OK
Check Point 3 : Check the solenoid coil and 4-way valve
[ Solenoid coil ]
Remove CN501(9RLFW1), CN30(12RLFW1) from PCB and check the resistance value of coil.
Resistance value is 1.22k
>> 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 OK
Check Point 4 : Check the voltage of 4-way valve
Check the voltage CN501(9RLFW1), CN30(12RLFW1) of Main PCB.
Check if AC187V(AC208V-10%) - 253V(AC230V+10%) appears at CN 30 or CN500 of Main PCB.
[ Heating operation ]
>> If it is not voltage, Replace Main PCB.
[ Cooling operation ]
>> If it is voltage, Replace Main PCB.
OK OK
Check Point 4 : Replace Controller PCB
If Check Point 1- 3 do not improve the symptom, replace Controller PCB.
Indicate or Display:
Refer to error code table.
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.] > 20°F ( 10°C )
Heating operation
[Indoor heat exchanger temp.] - [room temp.] < -20°F ( -10°C )
If the same operation is repeated 5 times,
the compressor stops permanently.
2. Thermistor failure
1.49k (at 68°F).
3. Coil failure
02-21
4. 4-way valve failure