Boiler makes loud banging or knocking noises (kettling) during operation.
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: Noisy operation can indicate overheating; do not ignore persistent banging. Allow the boiler to cool before any work.
User checks:
- Ensure all radiator valves are open to allow good circulation.
- Check system pressure is correct (1.0–1.5 bar cold).
Engineer checks:
- Assess the system water quality; if dirty, carry out a chemical flush and fit a magnetic filter on the return to the EHC boiler.
- Descale the primary heat exchanger using an appropriate descaling pump and chemicals, following EHC guidance.
- Verify pump operation and adjust speed settings to ensure adequate flow.
- Check for partially closed isolation valves or blocked strainers.
After cleaning and restoring circulation, noise should reduce significantly. Persistent kettling may require heat exchanger replacement.
Repair Difficulty
Required Part
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