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Why is my boiler making a banging noise?

If your boiler is making loud banging noises, it may be the result of a faulty thermostat or a build-up of debris in the boiler's heat exchanger.

If there is a build-up of debris, you'll need a qualified professional to carry out a flush.

Book a boiler repair

What is kettling?

Kettling is the technical term used to describe a boiler banging noise. This noise is often caused by disruption of water, which makes the water boil, steam and expand - water is usually disrupted by a build-up of limescale or debris within the system.

The build-up of debris leads to less water being able to flow through the system, your boiler is unaware of the situation and still tries to heat up the usual amount of water it normally heats up. As less water can flow to the boiler, the heat inside becomes too much so any water that gets pushed into the boiler will immediately turn to steam - which causes the banging noises and doesn't provide as much hot water on demand.

How to stop the boiler banging noise

Don’t worry, we’re here to help! Below is a list of ways to prevent your boiler banging noises:


Bleed your radiators

First, try to bleed your radiators to remove any trapped air within the system.

This is a very easy process and you don’t have to call out an engineer, but don’t forget to check and adjust your boiler's pressure after resetting the system.


Magnetic filter

If you weren’t offered a magnetic filter when your boiler was installed, you may wish to have a magnetic filter installed after your system has been flushed. A magnetic filter catches debris before it enters your central heating system, helping to prevent your boiler making banging noises.

Chemical Flush

If the noise is caused by a build-up of debris, you will need to have the debris removed within your system. Depending on your central heating system we would advise either a chemical flush or powerflush.

Both flushes enter your heating system and either chemically or physically flush out debris using water and special cleaning chemicals. After your system is flushed out an inhibitor is added, which helps to keep the system clean for future use.

After a powerflush or chemical clean, you should notice your boiler quietening down and increased efficiency for your heating.

Can my boiler be repaired?

All boilers can be repaired as long as there are replacement parts available, but it depends on how much you want to spend on repairing it - as it can get pricey for an older system. When a repair costs more than a new boiler install, it’s often known as BER (or Beyond Economical Repair), so it could be a lot more cost-effective in the long run to just purchase a brand-new energy efficient boiler.

We'd recommend getting a free quote from the engineer who will be repairing your system.  

Boiler making noise?

Let our experts take care of it with an emergency repair

If your banging boiler isnt heating up, you may need to seek help from an engineer.

Our Boiler Plan Gas Safe experts will point out any work that needs to be carried out, they'll also provide a fixed price repair quote.

With our 24 hour emergency repair and 95% first time fix rate, we’ll have your heating up and running again in no time.

Book a Boiler Repair

Do I need a new boiler?

If your boiler is over 10 years old and needs a new expensive part, such as a heating cylinder, then it may be more cost-effective to replace your boiler with an A-rated energy efficient boiler instead of repairing it.

Boiler Plan offers a variety of finance options, including a 24-month interest-free plan, so we try to make a new boiler as affordable as possible. You can get a free personalised quote for your home and heating system by clicking the button below.

Get a fixed price quote today