Why is my boiler making a loud noise and how to fix it?

Every boiler makes different kinds of noise. The roaring sound as it fires up to turn on the hot water. The gentle background humming when you’re warm and toasty inside, escaping the autumn chill. But then there are sounds that you might not recognise. And if that’s the case, you want to find out why your boiler is making a loud noise, what that means and how you can ensure it’s safe.

Is it dangerous if my boiler is making a loud noise?

Although it can be worrying when your boiler is making loud noises, it’s not usually a cause for alarm. This is because boilers have safety mechanisms that mean that the boiler will turn itself off before it can become dangerous. Having said this, safety is not always guaranteed, so booking an engineer to inspect your boiler is advisable if you’re unsure.

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Why is my boiler making a loud noise when it’s not in use?

There a few possible causes for loud noises coming from your boiler even when it’s not in use. These include faulty fans, a broken burner, or a worn-out pump. These noises usually occur when important parts of the boiler system are damaged or simply wear out with old age.

Why is my boiler making a loud noise?

The first thing to do before you go into panic mode is to be aware of the common noises your boiler makes. Remember it’s heating up hot water and pumping. It might sound loud at first, especially when the boiler first comes on, but unless it’s a loud bang or a pop, it’s just working its usual magic. You can also try to find out where the noise is coming from – perhaps a radiator or a pipe?

Chances are, these are just regular noises that should give you no worry. But then of course, you get the loud thumps and wallops (or more like whistling and gurgling) which require more attention. So, here’s a rundown of different loud noises and why your boiler could be making them.

Your boiler is making a vibrating noise

This could be an easy fix that you can do yourself. Maybe there are some loose brackets that are holding your boiler in place and tightening them might stop the sound. However, if the sound continues, you don’t want a vibrating boiler on your wall, which could be potentially dangerous. So get an engineer in to take a look, diagnose the fault and put your mind at ease.

Your boiler is making a gurgling sound

Occasionally your boiler will make this type of sound. But when that gurgle becomes louder it could mean there’s more air trapped in the system. If that’s the case, then it’s time to look at your radiators.

Learn about bleeding your radiator

Your boiler is making a banging sound

Nobody wants to hear an appliance go bang, let alone a boiler. There could be an issue with the heat exchanger, some sludge inside the boiler or perhaps the thermostat isn’t working properly. It could also be because of overheating, which causes the pipes to make the sound when you turn on the hot water.

Boiler is making a sound like an aeroplane

If you’ve noticed that your boiler is making the sound of an aeroplane taking off, there are several things that could be causing it. But the most common reason is a faulty pump.

Your boiler is making a whistling or kettling sound

If you’ve ever noticed your boiler making that high-pitched sound of a kettle – then you’ve heard the infamous ‘kettling’ noise. This could be due to a buildup of limescale debris in the heat exchanger.

When it comes to the kettling noise, these are some of the most common culprits.

Limescale buildup 

Just like at the bottom of your kettle, limescale can gather around the heat exchanger on your boiler. With water trying to heat up in a restricted space, the heat exchangers get too hot, the water boils and that’s why you get the kettling sound.

 As limescale naturally occurs, especially in hard water areas, this is something you need to be aware of. A yearly boiler check will help you keep tabs on this and prepare you for any work which might need doing later down the line.

A leak

This may sound like a quick and easy fix, but it usually isn’t. A leak could be caused by a pipe or the boiler itself, which means it will require a lot of investigative work. We would recommend leaving this to the professionals.


Is your boiler making high-pitched noises, frequently breaking down, not turning on when it needs to, or shutting off when you don’t want it to? It could be overheating, which might be a sign that it’s time for a new boiler.

How to stop my boiler making high pitched noises

The first thing is to make sure your boiler is checked once a year by an engineer. An annual service is the best way to keep your boiler in great condition – and much less likely to be making unwanted noises. Learn more about complete boiler and heating cover with us.

Don’t let the sound of your heating get you down. Our expert engineers can identify your boiler noises and know what steps to take. From powerflushes to magnetic filters, adding liquid inhibitors and more – we know how to get your boiler working again, efficiently, safely and quietly! Find out how we can help.