Hitachi RAS-5HVRNM1E Service Manual page 238

8 Troubleshooting
07
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 indicated as follows:
– When the temperature at the top of the compressor is lower than condensing temperature and indoor expansion
valve opening is lower than 300 pulse for 30 minutes in cooling operation, retry operation will be performed once.
When outdoor expansion valve opening is lower than 70 pulse for 30 minutes in heating operation, retry operation
will be performed once. If these occurs again within 120 minutes after the retry, the alarm code will be indicated.
Is the thermistor on top of
compressor normal?
Is the thermistor installed
correctly on the compressor?
Is it at cooling or heating mode
when the alarm has occurred?
Cooling operation
Check the I.U. expansion valve opening and the
temperature on the top of the compressor by the outdoor
Yes
I.U. expansion
valve opening <300pls
Yes
Is the temperature on the top of compressor
less than estimated condensation temp.?
Yes
Plug the connectors
properly
I.U.: Indoor Unit
O.U.: Outdoor Unit
230
SMGB0060 rev. 1- 12/2010
Decrease of Discharge Gas Superheat for IVX Series
No
Yes
No
Yes
Heating
Cooling
Yes
unit PCB.
No
Are the connectors for the indoor expansion valve connected properly?
– Connector on I.U. PCB for ex. valve
– Junction connector for ex. valve
Is the outdoor fan normal?
Is the refrigerant corectly
Is gas leaking?
Repair leaks of gas.
Correctly charge refrigerant.
Check the O.U. expansion valve opening and the
temperature on the top of the compressor by the outdoor
Is the temperature on the top of compressor less
than estimated condensation temp.?
Yes
No
Yes
No
charged?
Yes
No
Yes
Faulty thermistor
Install it correctly
Heating operation
Yes
unit PCB.
Yes
O.U. expansion
valve opening <70pls
Yes
Yes
Replace fan motor
Charge correct
refrigerant volume.
Check the ex. valve.
Or remove the cause of
discharge air short-circuit
at indoor and outdoor
units.