Hitachi FSG Series Service Manual page 34

1
TROUBLESHOOTING
26
Alarm Code
04
n "RUN" light flickers and "ALARM" is indicated on the remote control switch.
n The unit No., alarm code and the unit code is alternately indicated on the set temperature section, and the
unit No. and alarm code are indicated on the display of the outdoor unit PCB1.
‘
This alarm is indicated when abnormality is maintained for 30 seconds after normal transmitting between
the outdoor unit PCB1 and inverter PCB3, and also abnormality is maintained for 30 seconds after the
micro-computer is automatically reset. The alarm is indicated when the abnormal transmitting is maintained
for 30 seconds from starting of the outdoor unit.
Yes
Check PCB3
Check PCB3
PCB1: Control PCB in Outdoor Unit
PCB3: Inverter PCB (High Voltage)
Phenomenon
Disconnected
Wires,
Insufficient
Contacting or
Incorrect
Connection
Disconnected Wires to PCB
Faulty PCB
(PCB1 for
Control, PCB3
for Inverter)
Incorrect Wiring
Abnormal Transmitting between Inverter and Outdoor PCB1,3
Is LED2 (green) on
PCB1 flickering?
Yes
Is LED4 (yellow) on
PCB3 flickering?
No
No
Is LED4 (yellow) on
PCB3 OFF?
Yes
Check the wiring
between PCB1 and
PCB3.
Cause
Between Control PCB and
Inverter PCB
Power Source Wiring for
Outdoor Unit
Faulty PCB
Disconnected Wires
Insufficient Contacting
Incorrect Wiring
No
Disconnect CN14 of
PCB1.
Yes
Is LED2 (green) on
PCB1 flickering?
No
Faulty PCB1.
Check Item
Check continuity of wires.
Check for looseness of
connection screws. Check
connection No.
Check connections.
Check continuity. Check
for looseness of
connection screws.
Check connection Nos.
Yes
Check PCB3 and
check the wiring
between PCB1 and
PCB3.
Action
(Turn OFF main switch)
Replacing Wires,
Repairing, Tightening
Screws and Incorrect
Wiring.
Repair wiring connections.
Replace PCB if faulty.
Replacing Wires,
Repairing, Tightening
Screws
Correct connect Wires.