Hitachi UTOPIA RAS-4HVRP2E - Page 267

10 Troubleshooting
Troubleshooting procedure
SMGB0136 rev.0 - 07/2021
265
10
Alarm code
03
Abnormal Communication between Indoor Units and Outdoor Units
• Thealarmcodeisashedonthe7-segmentdisplayoftheoutdoorunit.
• The alarm code is displayed on the wired controller of the indoor unit.
When fuses are blown, or the circuit breakers are activated, check the cause of overcurrent and take necessary action.
This alarm code is displayed when an abnormal condition continues for three minutes after normal communication
between indoor units and outdoor units, and also the abnormal condition continues for 30 seconds even after the micro-
computer is automatically reset. If communication failure occurs from the beginning, the alarm code is displayed after
30 seconds from start up.
Phenomenon
Cause
Check Item
Action (Turn OFF
Main Switch)
Power Failure or No Power Supply
Blown Fuse for Power
Supply or Activation of
Outdoor Unit Breaker
Short Circuit between Wires
Ground Fault
Failure of Comp. Motor
Failure of Outdoor Unit Fan Motor
Blown Fuse on
Outdoor Unit PCB
Short Circuit between Wires
Incorrect Power Supply Circuit of
Outdoor Unit PCB
Incorrect Power Supply Circuit of Outdoor Unit PCB
Disconnected Wires,
Contact Failure or
Incorrect Connection
Failure of Outdoor Unit
and Indoor Unit PCB
Communication Cable Between Outdoor
Unit and Indoor Unit
Power Supply Wiring for Outdoor Unit
Disconnected Wires to Outdoor Unit and
Indoor Unit PCB
Failure of Outdoor Unit and Indoor Unit
PCB
Measure voltage with tester
Check for breakage of insulation
Measure insulation resistance
Measure resistance between
wires and insulation resistance
Measure resistance between
wires and insulation resistance
Check for breakage of insulation
Check Outdoor Unit PCB output
Measure Outdoor Unit PCB
output
Check continuity of wires.
Check for looseness of
connection screws.
Check terminal numbers.
Check connection
Supply power
Remove cause of short circuit
Replace fuse and/or Outdoor
Unit and Indoor Unit PCB if
faulty
Remove cause of short circuit
to ground
Replace fuse and/or Outdoor
Unit and Indoor Unit PCB if
faulty
Replace comp. and fuse of
Outdoor Unit
Replace inverter PCB and/or
Outdoor Unit PCB if faulty
Replace Outdoor Unit fan motor
and fuse
Replace Outdoor Unit PCB if
faulty
Remove cause of short circuit
and replace fuse
Replace fuse
Replace Outdoor Unit PCB
Replace or repair wires, tighten
screws or correct wires
Correctly connect wires
Replace if it faulty