Hitachi Utopia RPI-2.5HRG Service Manual page 39

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 0.2 kΩ) or cut (greater
than 500 kΩ) during running. However, this alarm occurs during test running mode only. In the
case that the thermistor is abnormal during running, operation continues based on the assumption
that the outdoor temperature, is 35°C (Cooling) / 6°C (Heating).
Is it connected to
THM7 (TA) of PCB1?
Is resistance of THM7
between 0.2kΩ and
500kΩ?
Faulty PCB1
Phenomenon
Faulty Thermistor
for Outdoor Unit
Ambient
1-36
Abnormality of Thermistor for Outdoor Air Temperature
No
Connect it.
Yes
No
Faulty Thermistor
Refer to page 1-30.
Yes
Cause
Fault
Incorrect Connection
Faulty PCB1
(Outdoor Unit Ambient Thermistor)
Outdoor Unit Ambient
Thermistor
Check Item
Check resistance.
Check wiring to PCB1.
Replace PCB1 and
check operation.
Action
(Turn OFF Main Switch)
Replace thermistor
if faulty.
Repair wiring and
connections.
Replace PCB1 if faulty.