Fujitsu ASU18RLB Service Instructions Manual page 46

Trouble shooting 19
OUTDOOR UNIT Error Method:
4 Way Valve Error
Detective Actuators:
Indoor unit Controller PCB
Heat Ex. temperature thermistor
Room temperature thermistor
4-way valve
Main PCB
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 miss-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 CN500 from PCB and check the resistance value of coil.
Resistance value is 1.88k
>> 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 CN500 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 5 : Replace Controller PCB
If Check Point 1- 4 do not improve the symptom, replace Controller PCB.
Indicate or Display:
Outdoor Unit : No indication
Indoor Unit
ERROR CODE : [E : 99]
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.] > 40°F(20°C)
Heating operation
[Indoor heat exchanger temp.] - [room temp.] < - 40°F(-20°C)
If the same operation is repeated 5 times,
the compressor stops permanently.
2. Thermistor failure
6. Controller PCB failure
2.29k at 68°F (20°C).
: Operation lamp: 9 time Flash, Timer lamp: 9 time Flash
Economy lamp: Continuous flash.
3. Coil failure
02-22
4. 4-way valve failure