Why is my Heating System Making a Banging Noise?

Posted on February 22, 2017 in  | Tags:

Is your boiler making a great deal of noise? It’s difficult to contend with loud, consistent banging sounds when all you want is for your heating system to just serve its core purpose and warm your home.

While heating systems can naturally make a low level of noise, loud banging sounds are an indicator that there is a problem – and it’s usually a result of one of the following three issues:


-Boiler Kettling

Does the noise coming from your heating system sound like a kettle boiling except on a larger, louder scale? If so, it could be down to an issue fittingly called “kettling”.

This issue is especially prevalent in hard water areas where limescale build-ups occur on the boiler's heat exchanger and constrict the flow of water. When the water flow becomes trapped in the heat exchanger, it gets too hot and eventually expands which leads to the banging noise.

How to fix a banging heating system due to kettling?

This is an issue that only a registered and experienced plumber should tackle as the system will need to be treated with a fit-for-purpose limescale removal solution or thoroughly cleaned depending on the severity of the issue.


-Trapped Air

When air bubbles get trapped in the water in your heating system, the subsequent expanding and collapsing from these air bubbles can cause a loud clicking noise.

How to fix banging heating pipes due to trapped air?

To resolve this issue, you will need to get a radiator key and bleed the radiators.

  • Turn your heating system off then wait approx. 15-20 minutes to allow the air bubbles to move to the top of your radiators.
  • Take the radiator bleed key and release the air from the system.
  • If required, repeat several times over the course of a couple of hours to release all of the trapped air, depending on the severity of the issue.


-Expanded Pipes

As the pipes in your heating system heat up, they expand. This expansion can subsequently cause pipes to move ever so slightly. However, if the pipes are resting on a hard object or surface, even the slightest movement will result in banging noises as they expand.

How to fix banging heating systems due to pipe expansion?

  • If possible, put a foam pad between your pipes and the object/surface to minimise noise.
  • If this does not resolve the issue, it may be the case that the pipes of your heating system are encapsulated in steel or timber joists. This is a more complex issue to resolve and requires the skills of a plumber to expand the joists that the pipes are sitting in and to surround the pipes with expanding foam.


While the above three issues are the main culprits, there are several other factors which may be contributing to a banging noise – incorrect installation or settings, fault thermostats or a broken/worn pump to name a few.

If in doubt, call a registered plumber to resolve your issue. They offer the expertise and knowledge to quickly and effectively solve the issue and this shouldn’t be overlooked!


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