Magnaclean filters are added to central heating systems to remove sludge and dirt. They are recommended and sometimes required by boiler manufacturers to receive extended warranties. Magnetic boiler filters are prone to leaking especially after servicing. This guide will help you if your magnaclean filter is leaking.
Why fit a magnaclean?

Each year when the boiler is serviced the magnetic boiler filter should be opened and cleaned.
Even when done properly the seal on the lid of the magna clean can still leak.
How do I know my magnaclean is leaking?

When your magnetic boiler filter is leaking it would normally show itself by a puddle under the filter, the pressure dropping or crusty marks on the filter itself.
My magnaclean is leaking where can I get the parts?
The leak is usually from the big seal inside the lid. This is available as a kit by clicking here from amazon or from other plumbing suppliers. The different models of Magnaclean have slightly different sizes.

If you aren’t confident or competent get a professional to replace the seal. Or get the service engineer back to fix the leak.
Hot to change the seal
Turn off the two valves on the pipework. When they are open they are in line with the pipe. When they are closed they are across the pipe.

With a tray or towel under the magna clean open the vent on top with a radiator bleed key. If the valves are correctly turned off some water will come out but will stop. When it stops you are sure the valves are working.
Using the big spanner provided turn the lid anticlockwise while holding the body of the filter. When the filter starts to move unscrew it by hand and look inside the lid. There is a thick rubber seal inside the lid. Take this out and replace it with the new seal use some of the silicone grease on the seal that comes with the kit.

When the seal is replaced reassemble the filter. Once the lid is hand tight using the spanner turn the lid but only by a quarter of a turn.
Close the air bleed on top then reopen the valves. Dry off any spilt water. Open the air bleed to remove any air.
Check the Magnaclean after the seal replacement to make sure it is not leaking.