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BoilerMag System Filters [5 Minute Guide]

Welcome to our 5-minute guide to BoilerMag filters.

If you’re looking to protect your heating system and your boiler, there’s a few things you can do.

One of those things is fitting a filter such as a BoilerMag.

What BoilerMag Filters Do

A BoilerMag and all magnetic boiler filters have one goal; catch heating sludge.

You’ll notice your boiler has a pressure gauge (probably at around 1.3 bar). That pressure comes from water sealed in the heating system.

The problem?

This water contains minerals. Combined with rust that breaks off from the inside of towel rails, radiators and pipework, they slush around to form dirty heating water; that’s heating sludge.

This sludge gets caught in microbore pipework and can even blocks up expensive parts like the pump and heat exchanger.

That’s going to lead to some extremely expensive repairs, and we don’t like those!

BoilerMag filters catch this heating sludge. They’re fitted on the return side of the boiler, so dirt is caught before it has a chance to cause any internal damage to your boiler.

Long-story-short, a BoilerMag is going to:

  • Keep your heating and hot water working
  • Reduce long-term repair bills
  • Prolong the life of your boiler
  • Improve efficiency of radiators

BoilerMag’s 22mm Heating System Filter

BoilerMag have a tonne of different products.

One of BoilerMag’s top sellers is their 22mm system filter, and here’s why…

Chemical Pack

OK, so your first question is probably, do you buy just the filter, or the chemical pack? 

When you fit the BoilerMag, you’ll need to drain your heating system.

While it’s drained, you should use the cleaner that’s included in the chemical pack to hot flush the system.

This gets rid of most debris before fitting the filter. Because once the filter is full, it won’t be catching heating sludge, so the more you flush out prior to installation, the better.

Once the system has been hot flushed, you’ll need to add central heating inhibitor (included in the chemical pack).

This chemical stays in your heating system long term. It breaks down tough debris that might be too large for the BoilerMag to catch.

It’s also going to start to break down existing heating sludge that might have been sitting there for years. For instance, if your radiators are always cold at the bottom, there’s a good chance that’s sludge build up – this chemical will attack it.

And that’s going to improve the efficiency of your boiler and radiators.

Between the two chemicals you’ll have a clean system, and one that’s ready to catch almost any heating sludge that passes through it.

Long story short, you need these chemicals.

You can get them cheap by buying the BoilerMag chemical pack or buy them separately.

Chemical Pack + Scale Reducer

We’ve actually covered scale reducers in more detail later in the article. What we’ll say is that a boiler filter will catch the majority of heating sludge.

A scale reducer focuses on mineral content in water that can settle on expensive boiler components and cause a lot of damage. So, if you have someone to fit it, we’d go for the chemical pack that includes the scale reducer, given it’s not that much more expensive.

Online Reviews

If you jump onto some of the biggest ecommerce stores, you’ll see that the 22mm BoilerMag has not only a vast number of reviews, but positive ones too.

And, it’s certainly got a lot more positive reviews than the cheaper “no-name” brands that are out there.


BoilerMag’s aren’t particularly difficult to fit. If you’ve got basic DIY experience and a tool kit, you can fit one. 

However, they’d only take boiler engineer around 1 hour to fit, so our recommendation to make sure the installation goes smoothly, is to get a professional in to help.

They’ll be able to fit your filter on any angle pipework, even in compact space.


Filters that look exactly like the BoilerMag will typically only extract magnetic particles. That’s mainly because non-magnetic particles can be caught by fitting an additional filter (a scale reducer).

However, if you don’t have a scale reducer fitted, the BoilerMag will be able to catch both non-magnetic and magnetic debris.

Bonus 😊


If you’re looking at cheap “no-name” brands, there’s a good chance their warranty is minimal at best.

BoilerMag offer one of the longest warranties of any boiler filter on the market. Currently, their warranty offering is a massive three years.


So, we keep going on about cheap boiler filters. But, the 22mm BoilerMag isn’t expensive at all.

Generally, they can be found online for around £70 (filter only).

Some of the Fernox and Magnaclean products are closer to £100, and that makes a BoilerMag an absolute steal for a product from a well-known brand.

Pack Contents

So, what are you going to get with your purchase? 

The 22mm BoilerMag comes with literally everything you need to get it fitted.

The pack includes:

  • Filter
  • ISO valves
  • Seals
  • Filter spanner
  • Tool for cleaning
  • Template for pipe cutting
  • Removal tool for magnet
  • Seals

Is BoilerMag The Best Filter Brand?

The answer to this question is somewhat of an opinion. Due to the popularity of boiler filters, there are now a tonne of brands offering them for sale.

What we know about BoilerMag is owned by a company that has over 100 years experience in the industry, selling over 20,000 products on a global basis, annually.

You just don’t stay that big for that long by producing rubbish.

But, if you’d prefer another brand of boiler filter, consider this. Some brands are specialists in heating protection, such as BoilerMag and MaganClean. We like those.

Others are just cheap imported products. We avoid those.

So, if you’re planning on purchasing a boiler filter, just make sure it’s from a brand on the list below.

Top Boiler Filter Brands

  1. BoilerMag
  2. Fernox
  3. Sentinel
  4. MagnaClean
  5. Worcester Bosch
  6. Instinct

What Else Can Be Fitted Alongside A BoilerMag To Protect Your Heating System

As we mentioned earlier, not all filters of this kind catch non-magnetic debris (but the BoilerMag does).

For extra protection, especially if you are in a hard water area, you can fit a scale reducer.

There’s a tonne of brands that produce them including ScaleMaster, BoilerMag, Fernox, Sentinel and more.

These are small filters that focus on catching scale particles in your heating water.

If this scale makes its way onto important boiler components, it can cause all sorts of problems. One of the most common is a cracked (and leaking) heat exchanger. And they cost 100s of pounds to repair.

Here are a few reasons to fit a scale reducer alongside a BoilerMag:

  • Reduce boiler repair costs
  • Improve boiler efficiency
  • Prolong the life of your boiler

Essentially, they compliment what the BoilerMag is doing on your heating system, by trying to improve efficiency and reduce long term boiler costs.

What’s Next?

Thanks for reading our 5-minute review of BoilerMag filters.

Still got questions about boiler protection?

Go ahead and leave a comment below and we’ll get back to you as soon as possible.

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