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Why does my boiler make loud banging noise?


During the winter months, you may notice your boiler making loud banging noises. This common problem is often caused by frozen pipes or a build-up of pressure in the boiler. While a banging noise from your boiler can be annoying, it is essential to understand the underlying causes of the problem. That way, you can take steps to fix it. Boiler Solutions has put together this blog to explain the reasons for why does my boiler make loud banging noise? You will also gain insight into some solutions to such problems if it happens to you.

Always being vigilant about possible boiler-related problems especially is essential. We depend a lot on our boilers to give us hot water and to keep us warm. The least we could do is take care of it and conduct annual boiler services, especially around the time winter is set to begin. If you reside in North London and are searching for a new boiler, we recommend referring to our boiler installation North London service page to access our skilled boiler engineers’ services. 

Boiler Servicing and Maintenance

We believe that your safety and the safety of your home is of utmost importance during a boiler service or any other gas appliance-related work. Our customer-first approach is what has allowed us to build up a stellar reputation over the last decade. The only way to ensure that your boiler or appliance is functioning efficiently and safely is with regular maintenance and professional servicing, which are usually carried out annually. There are a number of reasons to get a yearly service.


Why does my boiler make loud banging noise?

There are a few different reasons as to why does my boiler make loud banging noise? In most cases, this is caused by what’s known as ‘kettling.’ Kettling happens when there’s a build-up of limescale in the boiler. It is something that all boiler types are susceptible to. Other causes of loud banging noises from your boiler can include the following. At the same time, when having to deal with limescale, there are ways to try and reduce this build-up. Our blog on what is limescale reducer for boiler? will provide you with more insight.

Reasons for banging noice in your boiler


    • If you have a boiler in your home, you may have noticed that it sometimes makes a loud banging noise. This is caused by a build-up of sediment in the heat exchanger. As the sediment heats up, it expands and makes the metal expand. This can cause the heat exchanger to rupture and cause the boiler to make a loud noise. If you think your boiler is making this noise, it’s essential to have it inspected by a professional. This is because the heat exchanger is a vital part of the boiler, and if it ruptures, it can cause severe damage to your home. Alternatively, check out our blog on how to drain down a central heating system combi boiler?

    • Another reason for the loud banging noise is most likely due to a problem with the diverter valve. The diverter valve is responsible for redirecting hot water from the boiler to the radiators. When the valve is not working correctly, it can cause the water to build up in the boiler, which leads to a loud banging noise. If you think you may have a problem with your diverter valve, it’s essential to have it checked out by a professional. A qualified technician will be able to diagnose the problem and make the necessary repairs.

    • Loud banging noise is usually caused by loose pipes or fittings, which can become dislodged and bang against the boiler. While this may seem like a minor issue, it can be pretty dangerous, as it can damage the boiler and cause it to malfunction. It’s essential to have it checked out by a professional. They will be able to fix the loose pipes or fittings and prevent the problem from happening again.

    • Water flow rate and water pressure are two essential factors that affect the performance of your boiler. If either of these factors is too low, it can cause your boiler to make a loud banging noise. Low water flow rate and pressure cause loud banging noises in the boiler because when the water flow rate is too low, the water in the boiler can become too hot and start to boil. This can cause the water to expand and create pressure within the boiler, which can eventually lead to the boiler exploding. To prevent this, it is essential to ensure that the water flow rate and pressure are at the correct levels. You can do this by checking the pressure gauge on your boiler and adjusting the water flow rate accordingly. If you still have problems, you may need to call a professional to look at your boiler.

    • When the airlock is in the boiler pump, it can cause a loud banging noise in the boiler. This is because the airlock is not allowing the water to flow correctly through the pump. When the water is not moving properly, it can cause the boiler to overheat and make a loud noise. If you hear this noise, you should check the pump to see if the airlock is in it.

    • Ignition failure happens when the igniter responsible for igniting the gas in the boiler fails to do its job. When this happens, the gas in the boiler builds up and causes the pressure to rise. This pressure forces the gas to escape through the nearest opening, which is usually the burner. The escaping gas causes the loud banging noise that you hear. In terms of gases from the boiler, it is also important to stay informed about the functionality of your boiler flue. For instance, can a boiler flue go through the roof? Check out video blog on this topic.

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How do I stop my boiler from banging?

If your boiler is making loud banging noises, it could be due to a build-up of sediment in the tank. Over time, deposits can accumulate and cause the boiler to overheat and make loud banging noises. You’ll need to flush the boiler to remove the sediment to fix this.

Here’s how to do it:

  • Turn off the power to the boiler.
  • Once the water is drained, close the drain valve and turn the power back on.
  • Allow the boiler to run for a few minutes to flush out the sediment.
  • If the boiler is still making noises, repeat the process.
  • Once the power is off, open the drain valve at the bottom of the boiler and allow the water to drain out.

If you’re still having trouble after flushing the boiler, it’s time to call a professional.