023 8022 5566 | info@brennanheating.co.uk


Sludge builds up inside the pipes and heating components, eventually causing the flow of water to be restricted. One of the first symptoms in a combination boiler is the water going hot and cold.

Particles of metal get caught in the water to water plate heat exchanger, which means it overheats very quickly and the boiler shuts off until it has cooled. To remedy this a new water to water plate heat exchanger may be required but unless the heating system has been cleaned, the metal particles will collect again in the new heat exchanger.

Other symptoms include banging noises, cold spots on the radiators and other boiler problems. Sludge gets stuck on all sorts of components.

Sludge in blue pump

Powerflushing is the method used to clean a central heating system and ensure it runs efficiently. Using specialist equipment, a powerful flow of chemically treated water is pumped through the heating system to remove metallic and corroded materials known as ‘sludge’.

The powerflush and chemical treatment will prolong the life of your heating system by preventing the build up of sludge, guarding against corrosion and preventing wear on pumps and valves. It reduces boiler noise, prevents the need for frequent radiator bleeding and above all will make your heating more efficient, saving you money on your fuel bills.

At Brennan and Son we will carry out a powerflush/chemical clean and install a magnetic filter with every new boiler in accordance with BS7593 and boiler manufacturer’s instructions. Upon completion inhibitor is added to prevent further corrosion. At Brennan & Son we always install a magnetic filter to prevent future sludge build up.

Like antifreeze levels in a car, further chemicals should be added when radiators are changed or if the central heating system needs topping up with fresh water on a regular basis.

What happens during a powerflush? The chemical is added to the heating system and run hot, the powerflushing equipment is connected to a radiator and the chemical water is pumped through the whole central heating system and then concentrated on one radiator at a time. This dislodges sludge and is captured with our large magnet. The process takes most of a day on a 3 bedroom house but depends on how dirty your system is. Most domestic systems are suitable for powerflushing with a few exceptions. Speak to us if you have any questions.