Best Magnetic Filters for UK Central Heating — 2026 Ranked
A magnetic filter traps the black iron oxide sludge that would otherwise clog your heat exchanger. Fit one and your boiler warranty doubles. Here are the four filters UK Gas Safe engineers actually install.
Step-by-step method
1. Adey MagnaClean Professional 2
The default install for good reason. 22mm/28mm compatible, twin magnets, transparent housing for at-a-glance service checks. £110–£140.
2. Fernox TF1 Omega
Compact, 360° rotation for tight airing cupboards. Slightly better capture than early MagnaClean but pricier at £130.
3. Spirotech MB3
Combined air + dirt separator. Ideal if you also have air-lock issues. £160 but does two jobs.
4. Boilermag XT
Budget UK option at £75. Not as elegant but captures well and services in 2 minutes.
Frequently asked questions
Where should a magnetic filter be fitted?+
On the return pipe to the boiler, ideally within 1m and after a service valve so it can be isolated for cleaning.
How often should I service a magnetic filter?+
First clean at 6 weeks post-install, then annually with the boiler service. Fresh systems shed sludge fast in year 1.