BoilerTroubleshooting2026-02-26
Boiler Whistling Noise (Kettling) Explained
A whistling or kettling boiler usually means scale or sludge on the heat exchanger.
A kettle-like whistle from your boiler points to localized overheating from build-up.
What causes it
Scale or sludge on the heat exchanger creates hot spots where water flashes to steam, producing the whistle and reducing efficiency.
The fix
A power flush plus inhibitor usually cures sludge-related kettling; descaling addresses scale in hard-water areas.
Key takeaways
- Whistling = scale or sludge
- Power flushing often cures it
- Add inhibitor afterward
- Reduces efficiency if ignored
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