Hitachi FSXN Series Service Manual page 182

8 Troubleshooting
Phenomenon
Power Failure or No Power Supply
Short Circuit between Wires
Melted Fuse for
Power Source
or Activation of
Outdoor Unit
Breaker
Short Circuit between Wires
Short Circuit of Control
Circuit (to Ground)
Melted Fuse for
Control Circuit Faulty Solenoid Coil for
or Activation of Magnetic Switch for Comp.
Outdoor Unit Motor
Breaker
Failure of Outdoor Unit
Fan Motor
Failure of Fan Module
for Outdoor Fan
PCB1 Power Circuit Failure
Between Outdoor Unit
Disconnected
and Indoor Unit
Wires Insufficient
Contacting or
Incorrect
Connection
Disconnected Wires to PCB
Faulty PCB
(Outdoor Unit,
Indoor Unit)
Disconnected Wire
Insufficient Contacting
Incorrect Wiring
Incorrect Setting of Indoor Unit Number
*1)
12VDC between VCC12 and GND2, 5VDC between VCC05 and GND1.
12VDC between VCC12 and GND1, 15VDC between VCC15 and GND1.
24VDC between VCC24 and GND1, 12VDC between VCC12T and GND1.
176
SMGB0065 rev. 1 - 12/2010
Cause
Short Circuited Wire
to Ground
Faulty Comp. Motor
Faulty Outdoor Unit
Fan Motor
Power Source Wiring
for Outdoor Unit
Faulty PCB
Incorrect Wiring
Check Item
(Turn OFF Main Switch)
Measure voltage by
tester.
Check for breakage
of insulation.
Measure insulation Remove short circuit to
resistance. ground and replace fuse.
Measure resistance
between wires and
insulation resistance.
Measure resistance
between wires and
insulation resistance.
Check for breakage
of insulation.
Measure insulation
resistance.
Measure resistance
of coil.
Measure resistance
between wires and
insulation resistance.
Replace the fan module.
Measure PCB1
output voltage. *1)
Check continuity of
wires.
Check for looseness
of connection screws.
Check terminal Nos.
Check connections. Correctly connect wires.
Check continuity
and looseness of
connection screws.
Check terminal Nos. Correctly connect wires.
Check for unit number
setting of RSW on
Indoor PCB
Action
Supply power.
Remove short circuit
and replace fuse.
Replace comp. and
fuse.
Replace outdoor unit
fan motor and fuse.
Remove short circuit
and replace fuse.
Remove short circuit
and replace fuse.
Replace magnetic
switch and fuse.
Replace the fan motor
and fuse.
Replace PCB1.
Replacing wires,
repairing, tightening
screws and correct
wiring.
Replace it if faulty.
Replacing Wires,
Repairing and
Tightening Screws
Set unit number
correctly by RSW on
Indoor PCB.