BoilerMaintenance2025-12-20
Radiators Cold at the Bottom? Sludge and Power Flushing
Cold spots at the bottom of radiators point to sludge — power flushing restores even heat.
Radiators cold at the bottom but warm at the top are a classic sign of magnetite sludge settling in the system.
Why it happens
Over years, rust and debris form sludge that sinks to the bottom of radiators and collects in pipework, blocking flow and creating cold spots while reducing boiler efficiency.
The fix
A power flush clears the sludge, and adding inhibitor plus a magnetic filter prevents it from returning, restoring even heat and protecting the boiler.
Key takeaways
- Cold bottoms = sludge; cold tops = trapped air
- Power flushing restores circulation
- Add inhibitor and a magnetic filter afterward
- Flushing protects the boiler heat exchanger
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