Hitachi RAS-5HVRNM1E Service Manual page 253

8 Troubleshooting
22
Alarm code
• The RUN LED flickers and "ALARM" is displayed on the remote control switch.
• The unit number, the alarm code and the unit code are alternately displayed on the set temperature section.
The unit number and the alarm code are displayed on the display of the outdoor unit PCB.
– This alarm code is displayed when the thermistor is short-circuited (less than 0.2 kΩ) or cut (greater than 500 kΩ)
during the operation. However, this alarm occurs during the test run mode only. In the case that the thermistor is
abnormal during the operation, the operation continues based on the assumption that the outdoor temperature is
35 °C (Cooling) / 6 °C (Heating).
Phenomenon
Faulty thermistor for the outdoor unit
ambient
Faulty PCB1
245
SMGB0060 rev. 1- 12/2010
Abnormal operation of the thermistor for the outdoor temperature (outdoor unit ambient
Cause
Fault
Incorrect connection
thermistor) for ES Series
RAS~(4~10)H(V)RNS(1)E
Check item
Check resistance
Check wiring to PCB
Replace PCB1 and check operation
Action
(Turn OFF Main Switch)
Replace thermistor if faulty
Repair wiring and connections
Replace PCB if faulty
8