Do I need a magnetic filter on my boiler?
A magnetic filter is an option.
However, you will find some boiler manufacturers insist on certain terms an conditions for extended warranties to qualify.
Any heating system with radiators will eventually form magnetite sludge and it is advised when fitting a new boiler to invest in a magnetic filter to capture this sludge, stopping your radiators and pipework from blockages.
It will extend the life of your heating system when used in conjunction with a system inhibitor to stop the formation of rust.
An inhibitor chemical is a minimum requiremment for your radiator warranty to be valid.