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Boiler Noises And What They Mean

Even though it’s essential to your home, it’s likely that you’ve never paid much attention to your boiler. However, if there’s a problem with your boiler, you may start to hear strange noises. Take a look at some common issues that could result in a boiler making noise. We’ll explore what these noises mean, and how to resolve them.

Why is my boiler making a noise?

There are a few different noises you may notice if your boiler is having issues. It’s important to understand what the sounds of a noisy boiler mean, so that you can determine what’s wrong and how to fix the problem.

Simply click on the sound icons below to check whether they sound like the noises your boiler makes and find out how you can solve the underlying problem. Please note we’ve amplified some of the sound recordings for illustrative purposes.


A boiler making banging noises can be the result of a faulty thermostat. This is often caused by a build-up of limescale or a faulty pump, which you should replace. You may also notice banging noises if your boiler is too large for the space that it’s located in.

Kettling or whistling

Boiler kettling usually happens when limescale builds up or corrosion debris gets in the system. It’s more common in hard water areas, where the water flow becomes restricted. If the water heats up too much, it will start boiling and turn to steam. This will then emit a whistling sound, similar to a kettle.

Loud vibrating or humming

Vibrating sounds are a sign of a few different boiler problems. A boiler making loud humming noises could be suffering from a malfunctioning pump or a pump with incorrect settings. If you or an engineer set the pump too high, the heated water will travel too quickly around the pipework, leading to loud vibrations. A build-up of sludge inside the boiler can also cause overheating.


When air gets trapped inside your boiler system and mixes with the water, it can produce gurgling sounds. Before you get an engineer to take a look at a boiler making gurgling noises, there are a few things you can try that might fix the problem.

Try thawing out the condensation pipe, which will drain water from the heating system. It’s easy to do this – simply pour warm water over the pipe.

Bleeding your radiator can also free trapped air in the central heating system that causes the gurgling sound. Head to our guide on ‘How to Bleed Your Radiator’ for the best way to do this.


There are a few reasons behind a boiler making bubbling noises, like incorrect installation or low water pressure. You may be able to repressurise the boiler yourself, depending on what type of boiler you have.

Is a noisy boiler dangerous?

While loud boiler noises can be unpleasant, they usually don’t indicate any immediate danger. However, these issues can reduce the quality of your system and some faults require swifter fixes than others. We recommend getting the problem looked at by an engineer as soon as possible.

Avoid expensive boiler repair costs with Hometree

A noisy boiler often signals that there is a problem with it, and it will likely need to be repaired or replaced. If you are unable to fix your boiler yourself or if it’s not safe to do so, you should seek professional assistance.

At Hometree, we offer fixed price repairs to your boiler. Our experts are here for you 24/7. Get in touch and we’ll arrange a visit from one of our local engineers at a time that suits you best.

We’ll aim to fix the issue on the spot, or if it’s beyond repair and under seven years old, we’ll cover the costs of a replacement. Our comprehensive plans provide full protection for your boiler going forward, so you can live comfortably with the knowledge that you’re covered for the future.

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