Fujitsu AU*A12LALN Service Instruction page 86

Trouble shooting 16
OUTDOOR UNIT Error Method:
CT error
Detective Actuators:
Outdoor Unit Main PCB Circuit
Outdoor Unit Filter PCB Circuit
(Input current sensor unit)
Forecast of Cause :
1. Defective connection of electric components 2. External cause 3. Filter PCB failure 4. Main PCB failure
Check Point 1-1 : Reset Power Supply and operate
Does Error indication show again?
YES
Check Point 2 :
Check connections of Outdoor Unit Electrical Components
Check if
the terminal connection
Check if connector is removed.
Check erroneous connection.
Check if cable is open.
>>Upon correcting the removed connector or mis-wiring,
reset the power.
OK
AU*A12L- 24L
Check Point 3 : Check Filter PCB and Main PCB
Check DC voltage of CN1 (between 2 (Brown) and 3 (Red)) on Filter PCB.
>> After 40seconds upon starting the Compressor,
If it is higher than 0.2V, Main PCB is failure. (Filter PCB is normal) >> Replace Main PCB
>> If it is lower than 0.2V, Filter PCB is failure.
If it does not improve the symptom, change Main PCB.
Check Point 4 : Replace Main PCB
If Check Point 1, 2 do not improve the symptom, change Main PCB.
Indicate or Display:
Outdoor Unit (AU*A12L- 24L) : LED 2sec ON/ 2sec OFF
ERROR CODE : E : 18
Detective details:
When Input Current Sensor has detected 0A, while Inverter Compressor is
operating at higher than 56Hz(for AU*A12L-24L) or 50Hz(for AU*A36L/ 45L),
after 1minute upon starting the Compressor.
(Except during the defrost operation)
is loose.
(AU*A36L/ 45L) : No indication
NO
Check Point 1-2 :
Check external cause at Indoor and Outdoor
(Voltage drop or Noise)
Instant drop : Check if there is a large load electric
Momentary power failure : Check if there is a defective
Noise : Check if there is any equipment causing harmonic
wave near electric line.(Neon bulb or electric
equipment that may cause harmonic wave)
Check the complete insulation of grounding.
>> Replace Filter PCB
07-19
apparatus in the same circuit.
contact or leak current in the
power supply circuit.