BoilerTroubleshooting2026-02-26
Sludge in Your Heating System: Signs
Magnetite sludge causes cold radiators, noise and boiler wear — a power flush clears it.
Sludge is the hidden enemy of heating systems, behind many radiator and boiler complaints.
Signs of sludge
Cold radiator bottoms, kettling noise, slow warm-up, dirty black system water, and frequent breakdowns all point to sludge.
The fix
A power flush removes the sludge; adding inhibitor and a magnetic filter prevents it returning and protects the boiler.
Key takeaways
- Cold bottoms and noise signal sludge
- Dirty black water confirms it
- A power flush clears it
- Inhibitor + filter prevent return
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