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Last updated: 15th April, 2024


What Are Magnetic Boiler Filters?

What Are Magnetic Boiler Filters?

Various things can go wrong with your central heating system, which can result in a cold home and potentially a lot of money being spent.

This is why many people are looking for ways to prolong their boilers and prevent having to fork out for a new boiler by adding filters and other features into the system.

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A magnetic filter is something that can be installed along with a new boiler that can potentially extend the lifespan of the system.

One of the top causes of issues within your boiler or heating system is a build-up of rust, corrosion and sludge.

This is something that happens over time, as the rust and sludge build-up with the use of water through metal pipework and can be an expensive issue to solve.

While it is recommended for boilers to undergo power flushing every 5 or 6 years, installing a new system filter like a magnetic filter can provide long-lasting results.

If you are looking to save money on your energy bills and want to keep your boiler running in tip top condition, then a magnetic filter might be all you need.

What Is A Magnetic Filter Used For?

A magnetic filter is a simple piece of kit, really, as it is a magnetic piece of material that can be fitted into the pipework of your boiler.

The purpose of a magnetic filter is to capture the rust and other debris that can build over time, thus preventing blockages.

When the pipes become blocked, you will notice that your central heating no longer works as it used to, which can cause your energy bills to increase yet your home to be colder.

This is due to blocks, which prevents water from running through the heating systems effectively and keeping the heating system running well.

Installing a product like a magnetic filter into a heating system can prevent these issues, as well as providing many benefits such as;

  • Improved energy efficiency in central heating

  • Can decrease energy bills

  • Extend the life of your boiler

  • Increase the length of the boiler warranty

  • Prevent regular, expensive repairs from being required

Most boiler manufacturers will also offer magnetic filters along with their central heating systems because they can be installed along with new boilers.

As you can see, there are a lot of benefits that you can get when choosing to have these filters installed.

Even if you spend a long time researching the best boiler out there, they will still be subject to rust and corrosion.

Regardless of whether a boiler is considered to be the best boiler of the year or not, with repeated use, dirt will grow in the pipes, which is something a filter can help with.

Does My Heating System Need a Filter?

Not all issues with your central heating system need you to get a new boiler, as sometimes you just need to clear out what you already have.

Filters can help reduce the debris and sludge build-up that occurs in the pipework and heat exchanger of boilers after years of use.

These pipes support a lot of running water, and when combined with metal, this causes rust.

Rust is just one of the causes of blockages in your central heating, which can result in less efficient heating of your home. It might be time to call out a heating engineer if you notice any of the following with your boiler:

  • Lots of noise coming from the boiler/radiators when the central heating is on

  • Issues with the radiators heating up and insufficient heat from many of them

  • Cloudy or dirty water coming from the taps

  • The boiler is constantly shutting down and restarting

These issues are caused when water cannot run freely through the heat exchanger.

Sludge is the industry term for rust, debris and dirt that builds up over time and prevents water from running as easily.

Sludge is a mud-like substance that sticks to the inner workings of your boiler and radiators and causes issues throughout. If this issue is left to fester, your energy bills will increase, yet you will find that your home has trouble heating up.

Power flushing can be a solution to this issue, which is something that needs to be done every five or six years. You can request a free quote for this service from your gas company.

With a magnetic filter installation, you can keep your central heating system running like new for many years to come, as the filter should capture any dirt in the pipes, preventing blockages before they can even begin.

What Actually Causes Corrosion?

One of the best things you can do for your heating system is to be aware of the issues that can occur in the system.

Corrosion is one of the biggest problems for boilers, and this is something that will happen to almost every heating system over the years.

This is caused by air getting into the heating system and causing the metal to rust. The rust will then crumble into particles, and when it is combined with other debris within the pipes, blockages can occur.

Magnetic filters are supposed to capture the sludge and stop it from causing blocks in the pipes, keeping the system clean and allowing water to run through freely.

This is perhaps the number one reason why engineers are called out, and this issue is extremely common.

An engineer can install magnetic filters to your boiler, but it is likely that a chemical power flush will be needed before it can be fitted.

How Do Magnetic Filters Work?

Typically, magnetic filters will be fitted along with a new boiler which is why a chemical flush is also required.

A magnetic filter is a small device that is installed close to the boiler, and they are designed to keep the system clean for a long time.

As we have mentioned, there are various forms of debris that can develop in the pipes of your boiler, which can cause issues throughout the central heating system.

The hot water that is being heated up by the boiler filter is always sent back to the boiler through the pipes within the system.

The magnetic filter will be fitted to this pipe, where the water returns back to the boiler from where it can collect rust and other debris that may have been collected from further within the system.

Magnetic filters work as they rely on a large magnet, which attracts any particles that may have been collected, ensuring that only clean water goes back into the boiler.

Collecting these pieces are debris prevents the issue from getting worse and can stop sludge from developing, which is a cause of various problems.

A magnetic filter can keep your boiler clean and working well for a longer period of time, but they do need to be cleaned every year or so.

This is something that can be done by a heating engineer on your annual check-up for your boiler and will usually be done for free.

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What Is The Best Boiler Filter?

To make this a complete guide to boiler filters, we need to recommend some products that are worth your time.

There are various options out there that you will see when shopping for boiler filters, as you can get filters from multiple boiler manufacturers.

Adey Pro2 Magnaclean

One of the top filters out there that you can get from an engineer is the Adey Pro2 Magnaclean.

The Magnaclean is a magnetic filter that is ideal for using on a larger heating system. The Magnaclean is a thin filter that can provide a greater magnetic capture, and it can fit both vertical and horizontal pipework.

Fernox TF1

Another great magnetic filter that we need to share in this guide is the Fernox TF1. This works by collecting both magnetic and non-magnetic contaminants from the water, making it a complete system filter that operates well.

This heating system filter contains both the magnetic and non-magnetic particles well.

The Fernox filter can be fitted onto vertical or horizontal pipework and is designed to be easy to clean, making it highly versatile.

How To Find The Best System Filter?

The best system filter to get is going to be one that collects the most debris and keeps your heating system working well.

Rust, dirt and other debris that forms the sludge, which collects in the pipework, can cause issues throughout your home.

You may find that radiators are taking longer to heat up or that there are cold spots in your home.

One way to see whether sludge is the problem within your central heating system, and not something else, is to bleed the radiators.

A sign of sludge in the boiler is the fact that radiators need to be bled more frequently because they are not heating up properly. When you are bleeding the radiators, consider what the water looks like when it comes out.

If the water is cloudy or dirty coming out of the radiators, it is likely that you have sludge in the boiler. Typically this water will run clear after a few minutes, but if you are dealing with sludge, this will not be the case.

In most cases, removing debris and sludge from your boiler is covered by a warranty which can reduce the costs. Using a magnetic filter can provide long term cleaning of your boiler system, which is why many people are looking to install one.

The best magnetic filter will be one that collects the most debris, which includes both magnetic and non-magnetic particles.

So while its main purpose is to work like a magnet to attract rust, a non-magnetic filter should also work to collect other particles from the running water to keep the system clean.

Depending on the kind of boiler you have at home and the warranty it is under, your choice of magnetic filters may differ.

This is also the case when we consider the various costs that can come with the installation of a magnet filter, but it is worth it in the long run.

As well as installing a magnetic filter, the best brands may offer a scale inhibitor or a limescale reducer. This scale inhibitor is a chemical lining that can fit in with the magnet filter to offer even better cleaning of your boiler.

As the name suggests, the inhibitor will prevent limescale and non-magnetic particles from building up in the pipework and make it easy for water to flow through. It is worth asking your heating engineer whether this is also something they offer and whether you can get it.

Together, this filter and chemical lining can keep your boiler running at its full capacity. While getting these installed comes with upfront costs, it is worth it in the long run and can even help you save money on your energy bills from here on out as both of these filters will remove dirt and prevent the build-up of rust, which will keep your boiler and radiators running at full power for years to come.

Can I Install A Magnetic Filter Into My Heating System Now?

Typically, a magnetic filter will be installed along with a new boiler installation. This is something that should be done by a gas safe engineer and can be done under warranty, depending on your gas company.

The best way to get this filter installed is during a new boiler installation, but this does not always have to be the case. If you want to be using a magnetic filter to remove dirt but are not yet ready to replace your boiler, it is possible to get one fitted to the boiler you are already using.

Whether you are replacing your boiler or using what you already have, a chemical flush will need to be done before you can have the magnetic filter installed, as this will flush away any of the built-up debris that already exists.

Sometimes, this product will not be suitable to be installed with your old boiler, depending on the location. For this guide, we would recommend talking to your gas safe engineers to see what they think.

You can get advice from your gas company for free, along with free quotes for how much it will cost for the fit and installation of a magnetic filter.

It is always a good idea to speak with a professional before attempting to adjust your central heating system.

Not only will this ensure you are still under warranty, but it is easy to get things wrong when it comes to boilers, and you do not want to end up doing more harm than good when cleaning away the built up dirt.

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Frequently Asked Questions

Are Magnetic Boiler Filters Worth It?

Magnetic boiler filters are generally considered worth the investment. They capture iron oxide debris (sludge) from the heating system, which can reduce the efficiency of your boiler and even lead to damage over time. By trapping this debris, magnetic filters help maintain the efficiency of your heating system, extend the lifespan of the boiler, and reduce maintenance costs.

How Do You Empty the Magnetic Filter on a Boiler?

Emptying a magnetic filter typically involves the following steps:

  • Turn Off the Boiler: Ensure your heating system is off to avoid any hot water flowing through while you're working.
  • Close the Valves: Most magnetic filters have isolation valves on either side of the filter. Close these to isolate the filter from the rest of your heating system.
  • Remove the Filter: Depending on the design, you may need to unscrew the lid or remove the entire unit.
  • Clean the Filter: Remove the magnetic core and wipe off the sludge with a rag. Some filters may require rinsing with water.
  • Reassemble and Reopen Valves: Put everything back together and open the isolation valves. Check for leaks before turning the boiler back on.

How Long Do Magnetic Filters Last?

Magnetic filters themselves can last as long as your boiler when properly maintained. The magnet needs to be cleaned regularly but should not need replacement under normal conditions. The filter’s body and seals might eventually wear out and require replacement, but this is typically after many years of service.

How Often Should a MagnaClean Filter Be Cleaned?

A MagnaClean filter should be cleaned at least once a year, though this might vary depending on the specific conditions of your heating system, such as the age of the system and the amount of debris typically encountered. It's often recommended to clean the filter during your boiler’s annual service.

Can I Clean MagnaClean Myself?

Yes, you can clean a MagnaClean filter yourself. It involves shutting down the system, isolating the filter, removing the magnet, and wiping off the sludge. The process is straightforward and usually doesn't require special tools, making it a suitable task for a DIY-oriented homeowner. However, if you are unsure, it’s wise to consult with a professional.

Is a MagnaCleanse Worth It?

A MagnaCleanse is considered worth it by many, especially for systems that have never been cleaned or are old and have accumulated a significant amount of sludge. It thoroughly cleanses the system by removing more sludge and debris than a standard flush could, helping to restore heating efficiency and protect the boiler and other components from premature wear.

How Long Does a MagnaCleanse Flush Take?

A MagnaCleanse flush typically takes about 2 to 4 hours to complete. This time can vary based on the size of the system and the amount of sludge present. The process involves connecting the MagnaCleanse unit to your heating system and circulating a powerful cleaning solution to dislodge and capture magnetic and non-magnetic debris.

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Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.