Boiler Kettling & How To Fix a Boiler That Sounds like a Kettle

James Elston
Written by James Elston
Updated on 5th December 2023
Posted on 4th December 2023
Boiler Kettling & How To Fix a Boiler That Sounds like a Kettle

My boiler sounds like a kettle, is it safe & how to fix it?

boiler kettling noise

You’ll hope that everything is always working well with all aspects of your home, and when it does, you can sit back and enjoy all the fun of owning a home.

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When things aren’t working so well, it’s another matter, such as if your boiler sounds like a kettle boiling.

In this quick guide we’ll take a look at why your noisy boiler sounds like a kettle, why it is making the strange noise, how you can stop it and why you might not need a new boiler just yet.

Of all our home’s infrastructure, it’s our boiler that we always want to ensure is working correctly and do not want to face a new boiler cost, this, after all, plays such a huge role when it comes to how comfortable our home is.

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How Do I Stop The Boiler Kettling Noise?

You’ll sometimes know pretty quickly if your boiler needs to be repaired or replaced (everyone hates stepping into a cold shower, after all), but sometimes things are a little more complicated.

If your boiler appears to be making a strange noise, also known as a boiler kettling sound, then it’s understandable that you’ll want to get to the bottom of the issue. A replacement boiler might be on the cards, but not always.

It may be that their is a boiler kettling sound on full power or your boiler is banging, and you have very little tolerance left, hence reading this!

If you discover that your boiler is popping or at boiling point, then what you’ve got is a clear case of ‘boiler kettling.’ In this blog, we’re going to take a look at what exactly this phenomenon is and the steps you can take to put it behind you.

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Why does my boiler sound like a kettle? boiler kettling

Your boiler isn’t really supposed to make any noise.

Indeed, your boiler and central heating system are not supposed to get your attention in any way – it’s usually out of sight as well as silent, and should just do its job without any fuss. Or at least that’s the idea.

Sometimes, you will notice that your boiler is making a noise that it shouldn’t be. Even the best combi boilers and best system boilers can ‘kettle’ at some point!

Why does my boiler sound like an aeroplane?

The noise can make a few different noises, but the most distinct one is when it sounds like a boiling kettle. Another noise it can sound like is an aeroplane. If it sounds like an aeroplane, you are likely to have the same problem.

This is where the word ‘kettling’ comes from.

parts to fix kettling

Aside from being annoying to listen to, it can also be a little disconcerting. A boiler making loud noise will always raise eyebrows – is this thing planning to blow?

We’ll talk about whether boiler kettling is dangerous later on, but first, let’s take a look at some of the most common reasons for the boiler kettling noise.

You’ll usually find that your boiler is singing a strange song because of:

  1. Your central heating system leaks.
  2. There’s been a build-up of limescale and limescale deposits.
  3. Your boiler is overheating and be restricting the flow of water, or the thermostat isn’t working correctly.

Did you know a boiler service can make sure your boiler is working properly and is often required to maintain a boilers warranty?

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Boiler Noises Causes and Common Reasons

Boiler leaks causing noise

You’ve Got a Leaky System.

boiler leaking water

More often than not, you’ll find that the noise from your boiler is coming from a boiler leak.

This could be in the boiler itself or somewhere in the pipework that runs throughout your home.

While this might sound like a serious issue, at least you can check to see where the leak is coming from.

Indeed, this should be the first thing that you should do.

You can go throughout your entire system and see if you can find where the leak is coming from.

You should begin with the boiler itself, as well as the space immediately around it. It’s more likely that it’ll be there than anywhere else.

If it’s not there, then begin your investigation of the rest of the home.

You’ll want to look extra close at your radiator pipes, and indeed the radiator too — a radiator that leaks could just as easily be the cause of all the strange noises.

Some spots are more likely to be affected than others — for instance, the joints where pipes meet.

pressure gauge

It’s all good and well finding the leak, but you’ll be curious as to how it happened in the first place.

There are a few ways it can happen.

It’s possible that the person that installed the pipework didn’t do the best job in the world, which would make the pipes vulnerable, to begin with.

High pressure in the boiler system

Or it could be that there’s been too much boiler pressure put onto the pipes.

The most common reason is probably general corrosion, which happens over a long term period.

It might sound scary to discover that you’ve got a leak, especially when your boiler is making a noise so loud that it feels like the boiler could explode pretty soon.

But there’s no reason to panic: even though it might sound pretty darn loud, it’s not going to happen.

Boilers are really safe, and the majority of them are authorised and regulated so that they will automatically shut down the boiler before it gets anywhere close to being dangerous.

If you’ve got a leak, then it’ll need to be taken care of, of course, as this will cause low boiler pressure. In some cases, it’ll be possible to repair the leak, but if it’s too big and can’t be fixed, then you’ll need to replace your boiler.

Limescale build ups

boiler kettling

You’ve got a build-up of limescale.

There’s no reason for the water in your boiler system to be particularly clean.

It can’t be hazardous, of course, but it’s not as if you’re going to drink this water.

Alas, the water’s lack of purity does pose a different threat — it means that a build-up of limescale can happen and be a common cause of boiler problems.

Over time, all the limescale can become like sludge.

Since it has nowhere to go, it’s effectively trapped and then restricts how much water can flow.

This can cause some surface-level issues in your piping, but things become a little bit serious around the boiler’s heat exchanger.

If the sludge rests there, then there’s a chance that the heat exchanger can overheat and begin to stream.

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Why does this cause the kettling noise?

This would produce the ‘kettling’ aspect — after all, it’s steam that makes the noise in a real kettle.

You’ll also find that it causes other problems, such as only heating the upper part of your radiator, and not the bottom. Indeed, this is a good way to test if that is the issue.


There’s not all that much that you can do about preventing calcium. It does, after all, occur naturally in the water.

How much water minerals pass through your boiler system will depend on where you live.

There are different amounts in different parts of the country.

If you live in a hard water area, then your water will have more minerals, and this will mean that it’s more likely that you’ll have a build-up of limescale in your boiler.

If you’re wondering whether that will be the issue, you can check with your local area.

It’s not as if you can do anything about the water if they do tell you you have hard water, though — you’ll just have to accept it but investing in a limescale reducer can definitely help.

Other reasons your boiler will be making a noise like an aeroplane or kettle

Your heater is overheating/you have a faulty thermostat.

Things will become pretty noisy if your boiler is overheating and can lead to no hot water coming from your boiler.

The most common cause of this is a thermostat that isn’t working as it should.

There are other symptoms of overheating beyond strange noises, too.

For example, if you find that your boiler is cutting out, then you’ve probably got a case of uneven heating such as the radiator getting hot at the top but cold at the bottom.

There are a few steps you can take to correct this issue.

boiler kettling

To begin with, have a look at your thermostat settings.

You can adjust or reset them altogether if you think you know how to use a central heating thermostat.

If this works then hey presto, you might just have gotten rid of the boiler kettling noise.

In every other case, you’ll need to work with an expert.

It depends how old your boiler is though.

If you’ve had it for some time, then it’s likely that the faulty thermostat or boiler controls has more problems — it’s a common problem that happens after a while.

In those instances, you’ll need to replace the thermostat or controller.

While it’s nearly always possible to do this, it’s not always the most cost-effective method.

Indeed, if your boiler is 10 – 15 years old, it usually makes more sense to get a new boiler installed.

If your home is too hot or cold even when you alter the thermostat, then your home will not be at your ideal room temperature.

If this is the case, your heating is not working as you wish and it needs sorting.

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How can you stop boiler kettling? boiler kettling

There are only a couple of ways that you can get rid of boiler noises all on your own.

You might be able to fix a broken thermostat, and you can always bleed the radiator to help the flow rate – See how to bleed a radiator here

Both of these things might solve the issue, but if they don’t, then you’ll need to work with an expert.

They’ll have the knowledge and expertise needed to locate the cause of the problem and fix it.

It could be as simple as deposits on the heat exchanger or the gas burner pressure, for example, something that you can’t fix yourself.

Fixing Leaks

There are plenty of components to a leak that the professional will consider.

It could be a small, simple leak, or it could be a more severe problem.

It’ll be easier to fix if the leak comes from an external part that is easily accessible and if it’s coming from something straightforward, such as a seal that is now faulty.

It’s a different matter if the leak is internal.

This can happen when there’s a corroded part of the boiler. These problems are harder to diagnose and fix and thus take a little more time.

It’s also more likely that a replacement boiler will be recommended rather than a repair job.

Fixing limescale build-up 

If there’s a limescale problem, then the issue will be handled with either a chemical clean solution or a power-flush.

These are both ways to blast away the limescale but they can be risky; read more about what a power flush does here.

Stop overheating boiler 

Take a look at your manual to see if there’s a way to fix an inaccurate thermostat yourself.

Your boiler may not be providing hot water, or it may not be at the ideal temperature. If that doesn’t work, then you’ll need to hire a professional to fix the problem for you.

Still unsure? If your boiler is kettling and you need assistance from a professional, you may be best calling a Gas Safe boiler engineer to come and take a look.

Boiler Kettling Repair Cost 

Boiler kettling repair is relatively inexpensive and should cost between £75 – £300 dependent on the company used for the call out.

These costs to repair your kettling banging nose vary by location and company used as well as the time of day.

It would be a good idea to sign up for a home boiler cover plan such as the ones offered by us at Boiler Central to help cover boiler repair costs.

You can get boiler cover from £7.99 per month for basic cover through to their top-of-the-range plan that costs £26.99 per month.

They usually have a special offer on where you can pay £99 upfront today, and then sign up to their £26.99 plan. Click here to view and sign up.

So, if you can stomach the repair cost for your boiler kettling noise, then go ahead and get it repaired.

If you think you need a new boiler as you have struggled with your heating and hot water for a few years, then contact Boiler Central to get a fixed price on your next boiler installation.

You can even spread the cost of your new boiler with finance.

Most boiler companies registered in England are regulated by the Financial Conduct Authority or FCA so you can get boiler finance.

If you are having problems with your boiler or feel you are ready for a replacement or new boiler, click here

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Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 4th December 2023

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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