It catches magnetic corrosion debris, often called magnetite, from water circulating in the heating circuit.
Magnetic Debris Capture for Boiler Protection
Black magnetic sludge carried by heating water can collect in narrow parts of a system. MacBlair stocks Sankel magnetic filters and filter-plus-inhibitor kits, along with TFC and Altecnic Dirtmag compliance packs. The listed packs include 22mm and 28mm versions, so pipe size is a practical first check.
A magnetic filter captures ferrous debris as water passes through it. It does not replace flushing or chemical treatment: the listed kit with inhibitor combines two different forms of protection. Follow the inhibitor and cleaner instructions and the heat-source maker’s water-quality requirements when servicing an existing circuit.
The filter position, clearances and isolation arrangement should permit routine cleaning. A competent installer can confirm whether the chosen pack fits the return side of the boiler and existing heating pipe fittings. If a filter fills quickly, investigate the condition of the wider system rather than repeatedly emptying it without treatment.
Central Heating Filters FAQ's
Match the filter connection to the pipework and the system design. Do not reduce a larger circuit without an installer checking flow.
No. The filter captures debris already in the water; inhibitor helps limit further corrosion when used as directed.
Follow the filter and boiler makers’ service guidance. It is commonly checked during routine heating maintenance.
It will not remove an existing blockage by itself. A system assessment and cleaning may be needed before a filter is fitted.