Communication Error (Serial Reverse Transfer Error) - Fujitsu AB A30LBT Series Service Instruction

Trouble shooting 2
OUTDOOR UNIT Error Method:
Communication Error
(Serial Reverse Transfer Error)
Detective Actuators:
Outdoor Unit Main PCB Circuit
Forecast of Cause:
1. Connection failure
Check Point 1-1 : Reset the power and operate
Does Error indication show again?
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.
Check connection between Outdoor Unit Main PCB.
(If there is loose connector or open cable)
OK
Check Point 3 : Check the voltage of power supply
Check the voltage of power supply.
>> Check if AC198 - 264V appears at Outdoor Unit Terminal L - N.
OK
Check Point 4 : Check Serial Signal (Reverse Transfer Signal)
Check Serial Signal (Reverse Transfer Signal)
>> Check if Indicated value swings between AC70V and AC130V
at Outdoor Unit Terminal 1 - 3.
>> Replace Main PCB.
N
WHITE
L
BLACK
RED 3
2
WHITE
1
BLACK
Indicate or Display:
Refer to error code table.
Detective details:
When the indoor unit cannot receive the serial signal from Outdoor unit
more than 10seconds, then permanent stop after 20seconds.
2. External cause 3. Main PCB failure
+
-
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).
AC
AC
02-06