Best Magnetic Boiler Filters UK 2026
A magnetic filter on your central heating return pipe catches iron oxide sludge before it reaches your boiler's heat exchanger. Fitted at £150-£200 by a Gas-Safe engineer (£40 DIY), it extends boiler life by 5+ years and improves efficiency by up to 6%.
Why it matters
Over time, UK central heating systems develop iron oxide sludge — the black gunk that blocks radiators and kills pumps. A magnetic filter captures it continuously. Required by most manufacturers for a boiler warranty to remain valid.
How we chose
- Magnet strength (measured in gauss)
- Flow rate — must not restrict the return
- Compatibility with common UK pipe sizes (22mm)
- Price including the installation valve kit
Our picks
Adey MagnaClean Professional 2
The UK market leader. Slim profile fits in a kitchen cabinet, dual magnets, clear housing to inspect sludge buildup.
Best for: Standard UK combi installs — default pick.
Check latest price on Amazon UKFernox TF1 Omega
Strongest magnet in class (11,500 gauss). Easier to clean than MagnaClean (quarter-turn drain). Premium pricing matches.
Best for: Heat pump and system boiler installs where flow matters.
Check latest price on Amazon UKSpirotech SpiroCombi
Combines magnetic + air separation in one unit. Cheaper than the big two but smaller magnet. Good budget pick.
Best for: Smaller homes on a budget.
Check latest price on Amazon UKOur verdict
MagnaClean Pro 2 — ubiquity makes it easy for any Gas-Safe engineer to service. Fernox TF1 if you want the strongest magnet for a heat pump.