Boiler Maintenance

The Effects of Air and Dirt in Heating Systems

Did you know that 20% of boilers will breakdown in any given year, but more worryingly 87% of boiler breakdowns are as a result of dirty water in your heating system? It is a common problem that most heating systems face, however if left untreated, it can cause a range of problems. Most people believe that their boilers breaking after 5-10 years is the norm, but it is far from it if you keep your system healthy. Understanding and removing sludge from your system can mean it will operate efficiently for years to come. Here we will be taking a closer look at the effects of air and dirt in heating systems to help you understand the how, why and what to do to prevent future issues.

Boiler Breakdown Infographic

How does air and dirt enter a heating system?

It is difficult to avoid the presence of air in your heating system as before the system is filled with water, it is filled with air. As such, it is likely that air bubbles will remain in the bends in the pipelines whilst water is being pushed through. It may also be present as a result of your system needing to be drained down by your heating installer and refilled with new water as part of servicing or repairs.

Equally during maintenance work air can enter your pipework if there is a leak or incorrect pressure.

The majority of the time, the dirt found in your heating system develops as a result of the air. Any air that is left untreated in your system will inevitably lead to the formation of a substance known as Magnetite. Magnetite is a rock mineral and one of the main iron ores that sits in your systems water, particularly in the lower parts of the property such as the ground floor or basement. It is a black sludge like substance that develops from corrosion that occurs between the water and the metal of the pipes. If you have ever bled your radiators, you may have seen some magnetite in the water that is released.

There are however other ways that dirt can enter your system such as when it is first installed or when repairs are being carried out. If pipes are cut, dirt can latch on and be swept through your system once refilled with water.

How does this impact my heating system?

If left untreated, dirt and air can significantly impact the health of your heating system, causing issues with its reliability, efficiency and overall performance. Magnetite and other dirt can begin to slowly clog up parts within your system which after a while will need replacing. Not only will you have to pay out for expensive new parts, you will also have to pay for it to be installed, all whilst being without heating in your home.

After some time, you may begin to notice that your heating system is starting to make gurgling sounds when you have your heating on. Trapped air and dirt will be the cause of this and won’t resolve itself until they have been removed. The only temporary solution for noisy heating systems that are struggling to heat up efficiently is to regularly bleed your radiators to remove trapped air.

Certain rooms in your home may start to become harder to heat up as air and dirt build up in your radiators. Excessive amounts can begin to create cold spots, making your system work much harder. The water flow will begin to slow down, again forcing your heating system to work harder each time you turn it on. Within a few months you will start to notice the reduced efficiency of your system as well as a hike in your energy bills.

Once the dirt has travelled throughout the entire heating system, the combined water and dirt will return to the boiler as sludge. This sludge will quickly clog up costly parts and cause the inevitable breakdown of your boiler.

What can I do?

If you can remove the air from your heating system, you will be able to prevent the majority of dirt from causing any issues. The corrosive process requires the presence of oxygen and without it, magnetite cannot be created.

The best way to ensure that all the air has been removed from your system is to use a deaerator. Usually your installer will recommend a deaerator from a supplier that they know, trust and are often accredited by. The deaerator uses specialist venting technology that will work to continually remove any air from your system. The unit can be easily installed onto your pipework and can remove any air from your hot water as it starts to exit the boiler. Air will no longer be able to circulate meaning bubbles of air and dirt won’t start to form.

If you have concerns about dirt forming in your heating system either as magnetite or from previous repairs, there are dirt separators that can be installed. Again, your installer will be able to recommend a dirt separator they know and trust. Similar to the aerator, a dirt separator can be easily fitted onto your pipework and using a special filter it will capture any dust and dirt circulating through the system before it reaches the boiler.

The filter will use magnet technology as magnetite is the most magnetic of all the naturally occurring minerals on Earth, so can be easily collected. Any dirt picked up by the magnet will be easy to empty from the dirt separator as part of your annual boiler servicing without causing any mess or damage.

With these components, you can rest assured that your heating system will be remain efficient and protected from damaging effects of dirt and air.

Range Heating are experts in boiler installers with a reputation for outstanding customer service. We’ve been doing boiler installations in Manchester and Cheshire since 2008.

If you are concerned about the effects of air and dirt in your heating system and want more information or advice on how to improve your system’s health, then don’t hesitate to contact us today on 07872 105 094 or email us at

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