Failure Of The Power Supply To Indoor Units And The Remote Control Switch - Hitachi UTOPIA RAS-4HVRP2E Service Manual

10 Troubleshooting
Initial troubleshooting

10.1.2.3 Failure of the power supply to 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.
Phenomenon
Power failure or power is not ON
Melted Fuse or
Activation of Breaker
at Power Source
Melted fuse for
Control Circuit
Disconnected Cable of Remote Control Switch
Insufficient Contacting
at Connectors of
Remote Control
Switch
Failure of remote control switch
Failure of each PCB
Incorrect wiring connection
?
N O T E
• (*): Refer to the item "10.4.2 RSW, DSWs and LEDs functions RAS-(4-6)HV(R/N)(C/P)2E"
RAS-(4-6)H(R/N)(C/P)2E" in these chapters.
221 SMGB0136 rev.0 - 07/2021
Cause
Short Circuit Supplied
between Wires
Short Circuit of Wires to
Earth
Failure of Indoor Unit Fan
Motor
Short Circuit Supplied
between Wires
Short Circuit of Wires to
Earth
Failure of Indoor Unit Fan
Motor
Contact failure or incorrect
connection of indoor unit
PCB
Contact failure or incorrect
connection of PCB in
Remote Control Switch
Disconnected wire to each
PCB
Failure of each PCB
Check Item
Measure voltage by volt-
meter
Check for any uncovered
part of wires
Measure insulation
resistance
Measure resistance between
wires and insulation
resistance
Check for any uncovered part
of wires
Measure insulation
resistance
Measure resistance between
wires and insulation
resistance
Connect the cable
Check connectors
Check it by self-checking
mode
Check connectors
Check each PCB in indoor
unit and outdoor unit PCB1
check mode (*)
Take action according to the procedure indicated in
"TEST RUN CHECK"
or "10.4.3 RSW, DSWs and LEDs functions
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
Replace fan motor if faulty
Remove the cause of short-
circuit and replace the fuse
Remove the cause of short-
circuit and replace the fuse
Replace fan motor if faulty
Replace cable or repair it
Correctly connect it
Replace it if remote control
switch is faulty
Correctly connect wires
Replace PCB if faulty
10