Hitachi UTOPIA RAS-4HVRP2E - Failure of the Power Supply to Indoor Units and the Remote Control Switch

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