Ideal boiler shows H9 and may shut down on overheat
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Overheating is potentially dangerous. Turn off the boiler and allow it to cool fully before any further action.
User checks:
- Check pressure: Ensure system pressure is around 1.0–1.2 bar when cold.
- Bleed radiators: Remove air and re-pressurise.
- Reset: Once cool, reset the boiler once and observe operation.
If H9 recurs, a heating engineer must check pump operation, clean or replace the main heat exchanger, and test the overheat thermostat.
Repair Difficulty
Required Part
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