Central Heating

What is a magnetic boiler filter?

The water in your central heating system flows from your boiler, where it is heated up, around all your radiators and then back to the boiler to be reheated and circulate again.

 

A magnetic boiler filter is a small device that is installed into the pipework close to where the water goes back into your boiler.

 

As the water passes through the filter, a strong magnet attracts any fragments of rust and other magnetic debris (called magnetite or iron oxide 'sludge') and stops it from entering the boiler and causing damage or blockages. You will need to get the filter cleaned at the same time as your annual service to remove all the debris that has accumulated in it.

 

As well as the potential to damage your boiler, sludge in the radiators will cause cold patches at the bottom, so your heating will have to work harder to reach your set temperature, in turn increasing your fuel bill. Read more about why it is important to look after the water in your heating system.

Related FAQs

Why should I get the water in my central heating system cleaned?

It’s important to have the water in your central heating system cleaned regularly to prevent sludge buildup, which can lead to blocked pipes and ultimately, cause breakdowns. Repairs needed as a result of sludge are not covered by Baxi warranties.  

Why should I have a filter fitted?

Boilers tend to break down as a result of sludge building up in the system. A magnetic filter captures these particles and prevents them from entering your boiler system, extending the life of your appliance and reducing the risk of a breakdown.

Why are my radiators cold?

Cold radiators are usually a consequence of air being trapped inside the radiator. Simply bleed the radiator and the problem should be resolved. Sludge buildup can also cause differences in the top and bottom of your radiator and impact its efficiency. 

How do I know if I've got sludge in my central heating system?

If you notice your radiators are hot at the top but cold at the bottom, or need to bleed your radiators more often, then you may have sludge built up in your system. 

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