Fujitsu AUXB04GALH Service Manual page 95

Trouble shooting 10
INDOOR UNIT Error Method:
Communication Error Between
Controller and Indoor unit
Detective Actuators:
Indoor unit Controller PCB circuit
Indoor unit Communication PCB
Forecast of Cause :
1. Outside cause 2.Connection failure
Check Point 1 : Check if any outside cause such as voltage drop or noise
Instant voltage drop ----- Check if there is any electric equipment with a large load within the same circuit.
Momentary power failure ----- Check contact failure or leak current in power supply circuit
>>Check power supply for Outdoor Unit as well.
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). And check the complete insulation of grounding.
>>If the same symptom does not reappear after resetting the power, possibility of noise is high.
Check Point 2 : Check the connection
After turning off the power, check and correct followings.
Is Indoor Communication PCB loose?
Check loose or removed connection of communication line Indoor unit => Outdoor unit.
Refer to the Service Information -Network Abnormal -
When the signal amplifier is connected , Check the error indication of signal amplifier - Refer to the Installation manual-
OK
Check Point 3 : Check Communication PCB
Replace Communication PCB of the Indoor units that have the error.
OK
Check Point 4 : Check Controller PCB
Replace controller PCB of the Indoor units that have the error.
Indicate or Display:
E16. 4
Outdoor Unit : No Display
Indoor Unit : No Display
Error Code : 1 6 (Peripheral Unit )
Detective details:
When the cut-off of network communication is detected (more than 90 seconds
passed since the last receipt of Outdoor unit signal).
3. Communication PCB failure
04-19
4. Controller PCB failure