What is magnetic filter installation?
Magnetic filter installation adds a serviceable filter to the central heating circuit, commonly on the return pipe before water enters the boiler. Its magnet collects circulating iron-oxide particles, often called magnetite. Some designs also trap other debris. The installer chooses a suitable model and checks that it can be isolated and cleaned without dismantling the surrounding pipework.
Signs you may need magnetic filter installation
- A replacement boiler needs a filter and water treatment to match its installation instructions.
- The system is being cleaned and you want to capture debris that continues to circulate.
- An engineer has identified magnetite contamination in the heating water.
- The existing filter leaks, is difficult to service or is unsuitable for the pipe arrangement.
- You want filter maintenance included in the heating service plan.
What the engineer may do
- Inspect pipe sizes, the boiler return route and space for the filter body, valves and future servicing.
- Check the filter specification and installation orientation against the manufacturer's instructions.
- Agree whether system cleaning is needed separately and whether the filter is included in an existing boiler package.
- Protect the floor, isolate the relevant pipework and drain only as much of the circuit as the work requires.
- Cut and alter the heating return pipe, fit suitable joints and isolation valves, and mount the filter securely.
- Refill, vent and test for leaks; check water treatment and add the appropriate inhibitor where agreed.
- Show where the filter is and explain the cleaning interval, then remove offcuts and leave the pipework accessible.
Decisions that change the job
A magnetic filter only catches particles that pass through it. It does not remove sludge already settled in a radiator or repair a damaged pump. Cold radiators need diagnosis before deciding whether cleaning, balancing or another repair is required. A filter that cannot be opened because it is squeezed against a cupboard panel will be awkward to maintain, so service clearance matters as much as fitting space.
What to include in your enquiry
Take a photograph of the visible pipework below or beside the boiler, without removing any covers. Give the boiler model, approximate radiator count and whether a filter or clean is already included in another quote. Mention restricted cupboard access or a history of leaks.
Costs and timing
The site's indicative UK guide for magnetic filter installation is £120–£300, with a typical timescale of 1–2 hours. These figures are a starting point, not a fixed offer or a promise of completion within that time.
Filter design, pipe diameter, available space, required pipe alterations and drain-down access determine the fitting cost. Cleaning a contaminated system is a separate scope and can cost more than the filter itself. Combining fitting with other heating work may reduce a separate visit charge.
Competence, safety and paperwork
Standalone water-side filter fitting does not automatically require Gas Safe registration. If access or associated work involves gas components or the boiler's combustion safety, the correct gas competence is required. Follow the boiler and filter manufacturers' installation and servicing instructions; fitting a filter does not guarantee a warranty or remove the need for maintenance.
Ask whether the price includes the filter, both isolation valves, inhibitor, leak testing and a demonstration. Do not pay twice if the same filter is already listed in your boiler replacement package.
Request and compare written quotes
Use the free enquiry form to describe the magnetic filter installation work. Boiler Quotes can introduce you to up to four independent heating businesses that cover your postcode. Availability and suitability determine how many respond; there may be fewer or none. The engineers assess and price the work themselves.
Businesses joining the network are asked for relevant insurance details and references. Check the attending engineer's credentials, the written scope, exclusions, VAT position and payment terms before choosing. Sending the enquiry is free and you do not have to accept a quote. Paid diagnosis or survey work must be agreed with the business in advance.
Frequently asked questions
Will a magnetic filter fix a cold radiator?
Not on its own if the fault is settled sludge, trapped air, a valve or poor balancing. A filter catches circulating debris; the engineer should diagnose the radiator problem and quote for any separate cleaning or repair.
Where should the filter go?
It is commonly fitted on the heating return before the boiler, subject to the manufacturer's instructions. The installer needs enough space for isolation valves and future cleaning.
How long does fitting a filter take?
The site guide is 1–2 hours for a straightforward installation. Restricted space, pipe alterations or additional cleaning can require more time.