Hitachi FS3 Series, Service Manual

Page: 34 / 240

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26
TROUBLESHOOTING
Alarm Code
04
Abnormal Transmitting between Inverter and Outdoor PCB1,3
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.
Is LED2 (green) on
PCB1 flickering?
No
Disconnect CN14 of
PCB1.
Yes Yes
Check PCB3
Yes
Is LED4 (yellow) on
PCB3 flickering?
Is LED2 (green) on
PCB1 flickering?
Yes
Check PCB3 and
check the wiring
between PCB1 and
PCB3.
No
No
Check PCB3
No
Is LED4 (yellow) on
PCB3 OFF?
Yes
Check the wiring
between PCB1 and
PCB3.
Faulty PCB1.
PCB1: Control PCB in Outdoor Unit
PCB3: Inverter PCB (High Voltage)
Phenomenon Cause Check Item
Action
(Turn OFF main switch)
Between Control PCB and
Inverter PCB
Disconnected
Wires,
Insufficient
Contacting or
Incorrect
Connection
Power Source Wiring for
Outdoor Unit
Check continuity of wires.
Check for looseness of
connection screws. Check
connection No.
Replacing Wires,
Repairing, Tightening
Screws and Incorrect
Wiring.
Disconnected Wires to PCB Check connections. Repair wiring connections.
Faulty PCB
(PCB1 for
Control, PCB3
for Inverter)
Faulty PCB Replace PCB if faulty.
Disconnected Wires
Insufficient Contacting
Check continuity. Check
for looseness of
connection screws.
Replacing Wires,
Repairing, Tightening
Screws
Incorrect Wiring
Incorrect Wiring Check connection Nos. Correct connect Wires.