Fujitsu AOU18RLB, Service Instructions Manual

Page: 46 / 71

Trouble shooting 19
OUTDOOR UNIT Error Method:
Detective Actuators: Detective details:
Forecast of Cause :
OK OK
OK OK
4 Way Valve Error
Indoor unit Controller PCB
Heat Ex. temperature thermistor
Room temperature thermistor
4-way valve
Main PCB
When the indoor heat exchanger temperature is compared with
the room temperature, and either following condition is detected
continuously two times, the compressor stops.
1. Connector connection failure 2. Thermistor failure 3. Coil failure 4. 4-way valve failure
5. Main PCB failure 6. 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 miss-wiring, reset the power.
Check Point 3 : Check the solenoid coil and 4-way valve
Remove CN500 from PCB and check the resistance value of coil.
Resistance value is 1.88k 2.29k at 68°F (20°C).
>> If it is Open or abnormal resistance value, replace Solenoid Coil.
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.
[ Solenoid coil ]
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.
[ 4-way valve ]
OK OK
Check Point 5 : Replace Controller PCB
If Check Point 1- 4 do not improve the symptom, replace Controller PCB.
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
Indicate or Display:
Check Point 4 : Check the voltage of 4-way valve
Check the voltage CN500 of Main PCB.
Check if AC187V(AC208V-10%) - 253V(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
02-22
Outdoor Unit : No indication
Indoor Unit : Operation lamp: 9 time Flash, Timer lamp: 9 time Flash
Economy lamp: Continuous flash.
ERROR CODE : [E : 99]