Hitachi RAS-8FSXN - Failure of the Power Supply to the Indoor Units and the Remote Control Switch

• The emergency operation is a temporary mode of operation used when the Inverter
compressor is damaged.
Therefore, replace it with a new one as soon as possible.
• Turn OFF contact 1 of DSW5 on PCB1 of the outdoor unit after replacing the compressor.
If this setting is not carried out, the Inverter compressor will be damaged.
8.1.5 Failure of the power supply to the indoor units and the remote control switch
• The lights and the LCD are not indicated.
• Inoperative.
If the fuses are blown or the circuit breaker is activated, investigate the cause of the excessive current and take the
necessary measures.
Cause Check Item
Action
(Turn OFF Main Switch)
Measure voltage
by volt-meter.
Supply power.
Phenomenon
Short Circuit Supplied
between Wires
Melted Fuse or
Activation of
Breaker at
Power Source
Power Failure or Power is Not ON
Check for any
uncovered part of wires.
Remove the cause
of short-circuit and
replace the fuse.
Short Circuit of
Wires to Earth
Remove the cause
of short-circuit and
replace the fuse.
Failure of Indoor Unit
Fan Motor
Measure resistance
between wires and
insulation resistance.
Replace the AC
chopper for indoor fan,
fan motor and fuse.
Failure of AC Chopper
for Indoor Fan
Replace the AC
chopper for indoor
fan and fuse.
Replace the AC
chopper for indoor fan,
fan motor and fuse.
Replace the AC
chopper for indoor
fan and fuse.
Short Circuit Supplied
between Wires
Melted Fuse
at Control
Circuit
Check for any
uncovered part of wires.
Remove the cause
of short-circuit and
replace the fuse.
Short Circuit of
Control Circuit to Earth
Measure insulation
resistance.
Measure insulation
resistance.
Remove the cause
of short-circuit and
replace the fuse.
Failure of Indoor Unit
Fan Motor
Measure resistance
between wiring and
insulation resistance.
Failure of AC Chopper
for Indoor Fan
Measure voltage
at secondary side.
Replace the transformer.
Failure of Transformer at Indoor Unit Side
Connect the cable.
Replace cable or
repair it.
Disconnected Cable of Remote Control Switch
Insufficient Connection
or Incorrect Connection
of Indoor Unit PCB
Insufficient
Contacting at
Connectors of
Remote Control
Switch
Check connectors. Correctly connect it.
Insufficient Connection
or Incorrect Connection
of PCB in Remote
Control Switch
8 Troubleshooting
158
SMGB0065 rev. 1 - 12/2010