Your boiler is a workhorse, providing heating and hot water for your home. But if, for some reason, it fails, you risk being left in the cold.
A build-up of ‘sludge in the system can be catastrophic for your boiler and cost you a fortune in boiler repairs. It’s a common fault, but there are things you can do to protect your heating system before it’s too late.
This blog looks at magnetic filters on boilers. We also consider how to fit a central heating filter and its cost.
What is a magnetic filter on a boiler?
A magnetic filter is designed to collect debris from the water in your central heating system so it doesn’t build up and cause a blockage.
Over time, metal flecks – the result of your pipes corroding – collect in the water. When this mixes with other debris, it can form a sludge-like substance capable of causing a blockage.
A magnetic filter fitted to your boiler attracts the metal particles and removes them from the water, allowing the water to flow uninterrupted.
Do I need a magnetic filter on my boiler?
Without a filter removing the debris from the water in your central heating system, there’s an increased chance of sludge building up and causing a blockage. At worst, this could cause your boiler to break completely.
Even before it reaches this stage, too much debris in the water flowing through your pipes can slow down your central heating system making it inefficient and costing you more in energy bills.
Signs that your boiler may need a boiler filter include:
- Excessive noises coming from your system (gurgling and banging)
- Difficulty getting your central heating or hot water up to temperature
- Cold spots on your radiators (particularly at the top)
- Cloudy water from the taps
- Your boiler shuts down regularly, and there are noticeable leaks
The longer you leave the problem, the worse it’s likely to get. If you’re unsure whether you have a problem with sludge, ask a Gas Safe registered engineer to take a look at your boiler.
Magnetic boiler filter installation
Most boilers are fitted with a filter when they are first installed. Though more common on new boilers, it’s possible to retrofit a boiler with a filter in some cases. It all depends on where your boiler is installed and how much space there is behind it.
The filter fits on the return pipe (the bit that brings water back into the boiler). It involves cutting away a portion of the pipe to fit the filter – a job for a Gas Safe registered engineer.
Are magnetic filters mandatory?
In 2022, part L of the Building Regulations (the section dealing with home heating) was updated to include boiler filters.
It’s now a requirement to fit a magnetic filter when a new boiler is installed. That’s good news for anyone about to have a new boiler fitted.
We fit Worcester system filters on every new Worcester Bosch boiler we install. Vaillant, Ideal, and Baxi boilers also come with boiler filters as standard.
The filter fits on the return pipe (the bit that brings water back into the boiler). It involves cutting away a portion of the pipe to fit the filter – this is a job for a Gas Safe registered engineer.
How to clean a boiler filter
Your boiler filter must be cleaned regularly to empty it of the debris it has collected.
A boiler filter clean is usually included as part of your annual boiler service. You don’t need to do anything between services unless you think there may be a problem with the filter and need an expert opinion.
If you are comfortable with basic plumbing tasks and have experience with DIY, you could try cleaning the filter yourself, but we recommend leaving this job for a professional heating engineer.
While cleaning the magnetic filter doesn’t directly involve working with gas components, any tasks involving gas appliances should ideally be handled by a Gas Safe registered engineer to ensure safety.
Additionally, a professional will identify any potential issues with the system that might be missed otherwise.
Are boiler filters worth it?
Fitting a magnetic filter to your boiler reduces the likelihood of a blockage occurring, which can lead to expensive repair bills – and, potentially, the complete failure of your system.
By getting rid of some of the debris flowing through the water in your central heating system, you can ensure your boiler is working at optimum efficiency.
This comes with several benefits.
- Extends the life of your boiler
- Reduces your energy bill and cuts carbon emissions
- Minimises repair bills
What’s more, manufacturers like Worcester Bosch and Vaillant offer an extended warranty on their boilers when they have a boiler filter installed.
Best magnetic filter for central heating
The best boiler filter for your system depends on your specific needs and the characteristics of your heating system.
MagnaClean and Fernox are popular brands of magnetic filters known for their effectiveness and ease of use, while options from big names like Spirotech and Sentinel offer versatile and efficient solutions.
Always consult with a professional if you are unsure about the best choice for your particular setup.
Worcester system filters FAQs
Arton Heating is an approved installer of Worcester Bosch boilers, so we’re ideally placed to answer your questions on this brand of boilers.
In this section, we look at some of your FAQs on Worcester Bosch boiler filters.
Do I need a filter with a Worcester Bosch boiler?
All makes and models of boilers – even new ones – benefit from having a boiler filter fitted. It makes sense to protect your boiler from day one before debris has had time to build up and cause a problem.
As of 2022, every new boiler installation should include a magnetic filter as standard.
How to clean a Bosch filter
It’s harder to remove a magnetic boiler filter and clean it yourself, as you might with the filters on your other home appliances.
We recommend asking a Gas Safe engineer who can clean your Bosch filter as part of your annual service or come out to do the job separately.
How much does a boiler filter cost?
Magnetic boiler filters cost somewhere between £50 and £200. Worcester Bosch sells its own brand of Greenstar system filters for its best-selling Greenstar boiler range.
For a detailed quote on a boiler magnetic filter installation, contact your local plumbing and heating company.
Can I use any filter on my Worcester boiler?
Whether you’re getting a new boiler installed or having a filter fitted to your old one, your heating engineer can advise you on the correct filter for your central heating system.
Worcester Bosch has a line of filters designed to fit its boilers, including those specifically made to serve its Greenstar range (its flagship boiler range).
This blog was updated in August 2024.
