Ideal boiler shows H1 and may reduce output or cycle frequently
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: Radiators and pipework can become very hot. Allow the system to cool before touching any metal parts.
User checks:
- Reduce flow temperature: On the boiler control panel, lower the central heating flow temperature to around 65–70°C.
- Bleed radiators: If some radiators are cold at the top, bleed them with a radiator key, then re-pressurise the system to 1.0–1.2 bar.
- Check all radiator valves: Ensure TRVs and lockshields are open enough to allow good circulation.
If H1 persists or the boiler frequently overheats, a heating engineer should check the pump performance and plate heat exchanger for blockage.
Repair Difficulty
Required Part
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