Everbuild P11 Central Heating System Cleanser – 1L

The Everbuild P11 Central Heating System Cleanser is a liquid treatment designed to flush out the built-up sludge, rust particles and limescale that accumulate inside central heating systems over time. If your radiators are cold at the bottom while the top runs warm, or your boiler is working harder than it should, there is a reasonable chance the system needs a clean. This is where the Everbuild P11 heating system cleanser earns its keep.

Central heating sludge is mostly magnetite, the black iron oxide that forms as pipework and radiators corrode from the inside. Left untreated, it settles at the bottom of radiators, blocks circulator pumps and reduces heat output noticeably. It is one of those problems that gets quietly worse until something expensive fails. The P11 cleanser works by breaking down these deposits and holding them in suspension so they can be fully flushed from the system.

How the Everbuild P11 Cleanser Works in Practice

You dose the system through the feed and expansion tank or via a radiator bleed valve using an appropriate adaptor. Once circulated at operating temperature, the cleanser gets to work on deposits throughout the pipework, heat exchanger and radiator panels. The recommended contact time allows it to loosen and suspend the contamination before the full flush-out. It works across all standard central heating systems including sealed and open-vented types.

One litre treats a typical domestic heating system. After flushing, you follow up with a quality inhibitor such as the Everbuild P11 Inhibitor to protect the clean system going forward. Skipping that step would be a bit like washing your car and leaving it outside in a salt spray, so do not skip that step.

Using P11 Before Inhibitor Dosing

The cleanser should always be used before adding inhibitor, not instead of it. A clean system holds inhibitor far more effectively, meaning the protection lasts longer and your corrosion warranty stays valid. Most boiler manufacturers now require evidence of regular system maintenance, and using a recognised cleanser like the Everbuild P11 sits comfortably within those guidelines.