Hitachi Utopia RPI-2.5HRG Service Manual page 35

TROUBLESHOOTING
Alarm
Code
G "RUN" light flickers and "ALARM" is indicated on the remote control switch.
G The unit No., alarm code and the unit code is alternately indicated on the set temperature section,
and the alarm code is indicated on the display of the outdoor unit PCB.
# This alarm code is indicated when the thermistor is short-circuited (less than 0.24 kΩ) or cut (greater
than 840 kΩ) during the cooling or heating operation. The system is automatically restarted when
the fault is removed.
Is it connected to
THM5 of PCB?
Yes
Is resistance of THM5
between 0.24kΩ and
840kΩ?
Yes
Faulty PCB
Phenomenon
Faulty Thermistor
for Indoor Unit
Heat Exchanger
Gas Pipe Temp.
1-32
Abnormality of Thermistor for Indoor Unit Heat Exchanger
Gas Refrigerant Pipe Temperature (Gas Piping Thermistor)
No
Connect it.
No
Faulty Thermistor
Refer to page 1-30 for
thermistor resistance.
Cause
Fault
Incorrect Connection
Faulty PCB
Thermistor for
Heat Exchanger
Gas Pipe
In Case of 4-Way Cassette Type
Check Item
Check resistance.
Check wiring to PCB.
Replace PCB and
check operation.
Action
(Turn OFF Main Switch)
Replace thermistor
if faulty.
Repair wiring and
connections.
Replace PCB if faulty.