Fujitsu AB*14LBAJ Service Instruction page 74

Trouble shooting 32
OUTDOOR UNIT Error Method:
4-way valve error
Detective Actuators:
Outdoor Unit Main PCB Circuit
Discharge Temperature Thermistor
Outdoor Temperature Thermistor
2/3 way valve thermistor
4-way valve
Forecast of Cause :
1. Connector connection failure
5. Main 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 thermistor
Isn't it fallen off the holder?
Is there a cable pinched?
>> Check characteristics of thermistor,
If defective, replace the thermistor
OK 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 about 1.4k
>>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 : Replace Main PCB
If Check Point 1- 3 do not improve the symptom, replace Main PCB.
Indicate or Display:
Refer to error code table.
Detective details:
When the following condition is detected even only one time
between 6min. - 15min. after compressor starts, compressor stops.
Cooling operation
Discharge temp. > 50degC and Outdoor temp. >15degC and
Minimum temp. of 2/3 way valve thermistor > Outdoor temp.+5degC
Heating operation
Discharge temp. > 50degC and Outdoor temp. <15degC and
Maximum temp. of 2/3 way valve thermistor < Outdoor temp.+5degC
If the same operation wiyhin 60sec is repeated 3 times,
the compressor stops permanently.
2. Thermistor failure 3. Coil failure
02-41
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4. 4-way valve failure
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