Magnetic Filter

A revolutionary invention in the heating industry and in our opinion at Ability the greatest benefit to the performance of radiator heat in recent years. A great heating system cleaner and one of the first was the magnaclean.

What is a magnetic filter?

A magnetic filter is a device that helps collect the sludge that can build up in a central heating system.

heating-repair-magnetic filter
Worcester Filter before and after

Much of the sludge is made up of rust particles that have corroded and come away from inside pipes or radiators. A magnetic filter is made up of a giant magnet that attracts these particles and then filters them out of the system. This helps to prevent blockages and keeps the water flowing through the central heating system.

So if you need a heating system cleaner we can fit you a magnaclean.

Why would my heating system need a magnetic filter?

The iron and steel components in central heating systems are vulnerable to corrosion and rusting. This produces a sludge which can block different parts of the system, principally the boiler heat exchanger, pump or the radiators.

heating-repair-magnetic filter
Magna-clean Technology

Old, cast iron pipes were usually a few centimetres in diameter but more new pipework tends to be narrower, making blockages even more likely. So a silt builds up called Magnetite.

What is Magnetite?

Magnetite is a term used in plumbing to describe the dissolved metal held in the water of a heating or hot water system, often seen in the form of a black sludge in radiator water, particularly in the lower parts of heating systems such as the ground floor or basement.

A similar red sludge known as ‘hematite’ also forms in heating systems but normally remains in the top of the system, typically in the header tank (known as the ‘feed and expansion tank’), discolouring the water in the header tank with a reddish stain and blocking the air vent and cold feed pipes.

Does the Theory Work?

This theory is partially true. But sludge can also result from the corrosion of copper, zinc or aluminium components. This is nonferrous, and will not be caught by a magnet.

Ideally, your central heating system should not contain any sludge anyway, because it should be dosed with the corrosion inhibitor, although older systems won’t. This is easy to do, and so we do, unlike us at Ability,  some heating engineers do not routinely install inhibitor or even check for its presence, preferring to sell magnetic filters to the customer as an extra. We do not feel this is good practice.

This is very worrying for us at Ability, because we have heard that some boiler manufacturers, when called out on warranty claims, are first testing the system water for the inhibitor, and saying that if the inhibitor concentration is not adequate, then this invalidates the warranty. So we make sure that this is done and done correctly.

There are many different manufacturers of the magnetic filter and so we have listed some with links to the websites. We can find for you the right heating system cleaner and fit a magnaclean if necessary.

Magnetic Filter
Blockage caused by magnetite in filter-before and after


Fernox TF1

Worcester Bosch 

For more information please call our office and one of our qualified team will be happy to visit your property and discuss your requirements.