Fujitsu ASU18RMLQ Service Instruction page 44

Trouble shooting 11
INDOOR UNIT Error Method:
Outdoor Communication Signal Error
(Forward Transfer Signal Error)
Detective Actuators:
Indoor Unit Control PCB (AS,AR),
Main PCB, Power PCB (AU) Circuit
Forecast of Cause:
1. Connection failure 2. External cause 3. Controll PCB (AS,AR), Main PCB, Power PCB (AU) failure
Check Point 1-1 : Reset the power
Does Error indication reappear?
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.
Check connection between Indoor Unit Control PCB
and Filter PCB.(AR)
(If there is loose connector or open cable)
Check connection between Indoor Unit Main PCB
and Power PCB.(AU)
(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 AC208 - 230V appears at Outdoor Unit Terminal L - N.
OK
Check Point 4 : Check Serial Signal (Forward Transfer Signal)
Check Serial Signal (Forward Transfer Signal)
>> Check if Indicated value swings between AC70V and AC130V at Outdoor Unit Terminal N - 3.
>> If it is abnormal, Controller PCB is failure. >> Replace Control PCB (AS,AR),
N
WHITE
BLACK L
RED 3
Indicate or Display:
Indicate or Display:
Refer to error code table.
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).
Main PCB , Power PCB (AU)
+
-
02-18