Fujitsu ASYG09KMCB Service Instruction page 33

Troubleshooting 1-2
Serial communication error (Serial forward transfer error)
INDOOR UNIT Error Method:
Detective Actuators:
Indoor unit Controller PCB
Indoor unit Fan motor
Outdoor unit Main PCB
Forecast of cause:
1. Connection failure
2. External cause
3. Controller PCB failure
4. Indoor unit fan motor failure
5. Outdoor unit Main PCB
Check Point 1-1 : Reset the power and operate
Does Error indication show again?
YES YES
Check Point 2 : Check Connection
Check any loose or removed connection line of
Indoor unit and Outdoor unit.
>> If there is an abnormal condition, correct it by
referring to Installation Manual or Data &
Technical Manual.
OK
Check Point 3 : Check the voltage of power supply
Check the voltage of power supply
>> Check if AC207V (AC230V -10%) - 253V (AC230V +10%) appears
at Outdoor Unit Terminal L - N.
OK
Check Point 4 : Check Serial Signal (Reverse Transfer Signal)
Check Serial Signal (Forward Transfer Signal)
>> Check if Indicated value swings between AC30V and AC130V at Outdoor Unit Terminal 2 - 3.
>> If it is abnormal, replace Controller PCB.
>> If it is abnormal, Check Indoor unit fan motor. (PARTS INFORMATION 4)
>> If Indoor unit fan motor is abnormal, replace Indoor unit fan motor and Controller PCB.
>> If it is abnormal, replace Outdoor unit Main PCB.
GREEN
WHITE
N
BLACK
L
RED
3
WHITE
2
BLACK
1
Detective details:
When the outdoor unit cannot receive the serial signal from Indoor unit
more than 10seconds.
NO
Check Point 1-2: Check external cause such as noise
Check the complete insulation of the grounding.
Check if there is any equipment that causes harmonic wave
near the power cable (Neon light bulb or any electronic
equipment which causes harmonic wave).
+
-
02-05