Power flushing is a deep-clean process for central heating systems that removes the accumulated sludge, magnetite, scale, and corrosion debris that gradually degrades system efficiency. Bristol's housing stock includes a large proportion of pre-1980s properties with older steel panel radiators and galvanised or black steel pipework that corrode internally over time — producing the black magnetite sludge that causes cold spots, noisy boilers, and pump failures. The process involves connecting a high-flow, low-pressure pumping unit to the system, circulating a powerful cleansing chemical through every radiator and pipework run, then flushing with fresh water until the discharge runs clear. Inhibitor is dosed at the end to protect the system going forward. A power flush typically extends boiler life, improves heat output, reduces fuel bills, and often resolves noise and pressure problems without the need for more expensive repairs.
We carry out a full system survey — testing radiator temperatures, checking pressure, and assessing the degree of sludge contamination.
A concentrated cleansing agent is introduced to the system. The power flush unit is connected and we begin circulating the chemical at high flow rate.
We work through each radiator in turn, using the magnetic filter and reverse flow to dislodge and remove stubborn deposits.
The chemical is neutralised and the entire system flushed with fresh water until discharge water runs completely clear.
A full dose of corrosion inhibitor (e.g. Fernox F1 or Sentinel X100) is added. We provide a written report and recommend annual inhibitor checks.
Power flushing from £350 for systems up to 8 radiators. Larger systems from £450. Includes chemical, inhibitor, and a magnetic filter installation if not already fitted. New boiler installation power flush from £280.
Most domestic systems take 6–8 hours. Larger properties or heavily contaminated systems may take a full day. We'll give you a time estimate during the initial assessment.
In the majority of cases, yes. If radiators are cold due to sludge accumulation, a power flush restores full flow and heating. Cold radiators due to air or valve issues are resolved alongside the flush.
Most boiler manufacturers recommend or require a system flush before installation to protect the warranty. We can arrange this as part of a boiler installation package.