Failure Of Power Supply To Indoor Unit And Remote Control Switch - Hitachi FSG Series Service Manual

1
TROUBLESHOOTING
8
1.1.5

FAILURE OF POWER SUPPLY TO INDOOR UNIT AND REMOTE CONTROL SWITCH

n Lights and LCD are not Indicated.
n Not Operated
If fuses are melted or a breaker is activated, investigate
the cause of over current and take necessary action.
Phenomenon
Power Failure or Power is Not ON
Melted Fuse or
Activation of
Breaker at
Power Source
Short Circuit of Wires to Earth
Melted Fuse at
Control Circuit
Short Circuit of Control Circuit
Failure of Transformer at Indoor Unit Side
Disconnected Cable of Remote Control Switch
Insufficient Connection or Incorrect
Insufficient
Contacting at
Connectors of
Remote Control
Insufficient Connection or Incorrect
Switch
Connection of Indoor Unit PCB in
Failure of Remote Control Switch
Failure of PCB
Incorrect Wiring Connection
*1): Refer to Item 1.3.2.
*2): Refer to Item 1.3.1.
Cause
Short Circuit Supplied
between Wires
Short Circuit Supplied
between Wires
to Earth
Connection of Indoor Unit PCB
Remote Control Switch
Unconnected Wires to PCB
Failure of PCB
Check Item
Measure voltage by
voltmeter
Check for any uncovered
part of wires
Measure insulation
resistance
Check for any uncovered
part of wires
Measure insulation
resistance
Measure voltage at
secondary side
Connect the cable
Check connectors
Check it by self-checking
mode *1).
Check connectors
Check it by self-checking
mode *2)
Take action according to the procedure indicated in
"TEST RUN".
Action
(Turn OFF main switch)
Supply power
Remove the cause of
short circuit and replace
the fuse
Remove the cause of
short-circuit and replace
the fuse
Remove the cause of
short-circuit and replace
the fuse
Remove the cause of
short-circuit and replace
the fuse
Replace the transformer
Replace cable or repair It
Correctly connect It
Replace remote control
switch if failed
Correctly connect wires
Replace PCB if failed