Hitachi RAS-(4-12)HNP(1)(E) - Failure of the Power Supply to the Indoor Unit and the Remote Control Switch

8 Troubleshooting
209
SMGB0087 rev.0 - 12/2013
8
8.1.2 Failure of the power supply to the indoor unit and the remote control switch
• The LED and the LCD are not indicated.
• Not operated
If the fuses are blown out or a breaker is activated, investigate the cause of the overcurrent and take the necessary action.
Phenomenon Cause Check item
Action
(Turn OFF the main switch)
Power failure or power is not ON
Measure the voltage by means
of the voltmeter
Supply the power
Blown out fuse or activation
of the breaker at the power
source
Short circuit supplied between
the wires
Check for any uncovered part
of the wires
Remove the cause of the short
circuit and replace the fuse
Short circuit of the wires to
earth
Measure the insulation
resistance
Remove the cause of the short
circuit and replace the fuse
Failure of indoor unit fan motor
Measure resistance between
wires and insulation resistance
Replace the fan motor and fuse
Blown out fuse at the control
circuit
Short circuit supplied between
the wires
Check for any uncovered part
of the wires
Remove the cause of the short
circuit and replace the fuse
Short circuit of the control
circuit to earth
Measure the insulation
resistance
Remove the cause of the short
circuit and replace the fuse
Failure of indoor unit fan motor
Measure the insulation
resistance
Remove the cause of the short
circuit and replace the fuse
Failure of the transformer at the indoor unit side
Measure the voltage at the
secondary side
Replace the transformer
Disconnected cable of the remote control switch Connect the cable
Replace the cable or repair the
cable
Insufcient contacting at the
connectors of the remote
control switch
Insufcient connection or
incorrect connection of the
indoor unit PCB
Check the connectors
Correctly connect the
connector
Insufcient connection or
incorrect connection of the
indoor unit PCB in the remote
control switch
Failure of the remote control switch
Check the remote control
switch by means of the
self-check mode *1)
Replace the remote control
switch if it failed
Failure of PCB
Unconnected wires to PCB Check the connectors Correctly connect the wires
Failure of PCB
Check PCB by means of the
self-check mode *2)
Replace PCB if it failed
Incorrect wiring connection
Take action according to the procedure that is displayed in
“7. Test run”
N O T E
• *1): Refer to section “Self-checking procedure of the remote control switch”.
• *2): Refer to section “Self-checking procedure of PCB by means of the Remote Control Switch”.