Hitachi Set Free mini-HNRQ1 Series, Service Manual

Page: 83 / 187

76
Alarm
Code
03
Abnormal Communication between Indoor Unit and Outdoor Unit
●
The alarm code is flashed 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.
Cause Check Item
Action
(Turn OFF Main Switch)
Event
Blown Fuse for
Power Supply
or Activation of
Outdoor Unit
Breaker
Check for breakage
of insulation.
Short Circuit between Wires
Measure insulation
resistance.
Ground Fault
Measure voltage with
tester.
Supply power.
Power Failure of No Power Supply
Measure resistance
between wires and
insulation resistance.
Failure of Comp. Motor
Measure resistance
between wires and
insulation resistance.
Replace outdoor unit
fan motor and fuse.
Replace O.U. PCB
if faulty.
Failure of Outdoor Unit
Fan Motor
Blown Fuse
on O.U. PCB
Check for breakage
of insulation.
Remove cause of
short circuit and
replace fuse.
Short Circuit between Wires
Disconnected
Wires,
Contact Failure
or
Incorrect
Connection
Check continuity of
wires.
Check for looseness
of connection screws.
Check terminal Nos.
Replace or repair
wires, tighten screws
or correct wires.
Communication Cable
Between Outdoor Unit
and Indoor Unit
Power Supply Wiring
for Outdoor Unit
Correctly connect wires.
Replace it if faulty.
Failure of
O.U. and I.U.PCB
Check connection.
Disconnected Wires to
I.U./O.U. PCB
Failure of I.U./O.U.PCB
Replace fuse.
Check O.U. PCB
output.
Remove cause of
short circuit.
Replace fuse and/or
I.U./O.U. PCB if faulty.
Remove cause of
short circuit to ground.
Replace fuse and/or
I.U./O.U. PCB if faulty.
Replace comp. and
fuse. (O.U.) Replace
inverter PCB and/or
PCB if faulty. (O.U.)
Measure O.U. PCB
output.
Replace O.U. PCB. Incorrect Power Supply Circuit of O.U. PCB
Incorrect Power Supply
Circuit of O.U. PCB
TROUBLESHOOTING