H2
Hitachi
Low Temperature / Overcooling Alarm
Freezer shows H2 and may run continuously with very low internal temperature
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Stuck relay on main control PCB, Shorted temperature sensor, Incorrect thermostat setting, Faulty control PCB logic
How to Fix / Troubleshooting
Safety first: Unplug the freezer before accessing control components.
- Check set temperature: Verify that the temperature setting is not at the coldest extreme. Adjust to a normal setting (around -18°C) and monitor.
- Inspect thermistor: Refer to the freezer thermistor fault section (F1) and test the sensor for correct resistance. Replace if shorted.
- Power reset: Disconnect power for 10 minutes to reset the control. If H2 returns and the compressor runs constantly, suspect a stuck relay.
- Inspect main control PCB: Remove the control board cover and look for welded relay contacts or burn marks.
- Replace main control PCB: If the relay is stuck or the board is damaged, install a new Hitachi main control PCB.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Main Control PCB
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements