Boiler Clicking & Other Noises

Chances are that you never really pay attention to your boiler until something goes wrong. After all, why would you? Assuming you get regular maintenance, it should work near perfectly just about all of the time. But if you hear your boiler clicking or making other noises, it may be cause for concern (or just annoying). Luckily, DreamyHome is here with a solution as to why it’s making the noises it is.

The most common cause of boiler clicking is a buildup of debris in the radiators or pipes.

Let’s talk about boiler noises, shall we? (I know, this is super exciting, just bear with me.)

Boiler Noises & What They Mean

There are a lot of things you may hear coming from your boiler. Whether it’s a droning noise, humming, tapping/clicking, or something else, there’s a lot to look (or listen) for – so pay attention to what it’s trying to tell you.

Read Next: How to fix a noisy Lay-Z Spa pump.

Clicking Noise

This may sound similar to a kettle heating up – you know the sound. It taps and clicks, thrumming with the rage of water that’s being boiled. This is usually caused by a buildup of limescale (mineral deposits from the water), corrosion (also technically mineral deposits), or physical debris.

The buildup of these things will prevent the flow of water, leading to water boiling where it perhaps shouldn’t. This will, eventually, lead to steam, which will cause all of the noises to only get worse. If you notice this sound getting louder as time goes on, it’s likely that the buildup is getting worse.

You may also be hearing the sound of air getting trapped in your central heating system’s water. These will expand and collapse, leading to a popping or clicking noise. This is especially common in areas with hard (mineral-dense) water. This requires a Gas Safe engineer to come to take a look.

READ NEXT: Boiler tripping RCD: Why?

Humming & Rumbling

This is most common in electric water heaters. Generally, a humming noise is caused by a loose heating element which you can tighten yourself in a matter of seconds. Alternatively, there are a few other things to take a look at. Let’s make a list, shall we?

  • Mineral or sediment buildup – This is a common cause for a humming/rumbling noise. This is caused by sediment or mineral buildup heating up and expanding in your pipes, and should be addressed by a professional.
  • High pressure – The incoming main water supply’s pressure is too high. Check this by closing a tap and seeing if the sound persists. If it does, you need to adjust your water pressure. If it doesn’t, you need to replace at least one washer along the tap, as the boiler isn’t the source of your issue.
  • Water is too hot – If the water your pump is supplying is too hot, it can cause all sorts of noises as the pipes around your home heat up quickly. Try turning down the max temperature for your boiler.
  • Boiler fan & bearings – This is one that you want an engineer to take a look at. The fan (or its bearings) that sits inside your boiler could be dying.

Read Next: Everything you need to know about Vaillant boiler temperature settings.


A rattling noise could be most commonly caused by one of two things – air in the pipes, or a loose object(s) somewhere in the device. If it’s air trapped in the pipes, take a look at our previous article that details how to bleed a radiator. This is a super simple task that could very well solve the problem in a matter of minutes.

If, however, you’ve already bled the radiators, you could have a loose valve. You can try to locate exactly where the sound is coming from by checking all of the valves you have access to and tightening them. One final solution to this is to inspect the pipes leading from your boiler and radiator. If one of them has simply loosened from its wall mount, reattach it!

If you’ve tried all of these fixes and are still hearing a rattling sound, call an engineer. They’ll get it sorted in no time.


Whether it’s a malfunctioning pump, improper settings, or a buildup of sediment, your boiler shouldn’t be vibrating. If you hear a clear vibrating sound coming from your boiler, don’t try to troubleshoot – call an engineer right away. Some of these things (specifically the buildup) can cause major damage to your heating system and even be outright dangerous.

Kettle Whistling

Remember how I compared the clicking boiler to a kettle? Yeah – this is similar. The primary difference is that your boiler is making a whistling sound, similar to a boiled kettle. This isn’t good (obviously).

To fix this issue, begin by bleeding your radiators. This should release any air bubbles and solve the issue, but if it doesn’t, it’s likely that you have a limescale buildup somewhere along the line. You’ll need to call a professional to clean out your pipes. If you don’t, water can get trapped in your pipes, ultimately boiling and turning to steam. This can cause an expansion in the pipes which can lead to leaks and other major issues.

Dripping or Gurgling

Again, this is caused most commonly by trapped air in your pipes. Bleed your radiators and you should see the problem resolve itself. If you ignore this issue, nothing dangerous will happen, but your bill will rise. If the radiator is struggling to do its job, it’ll consume more gas or electricity (whichever you use) – and nobody wants that.

You could also have a frozen condensate pipe. To fix this, turn off your water, locate the pipe, and pour boiled water down it incrementally. If there is a blockage due to freezing, this will sort it right out.

Droning & Buzzing

The best way to describe this is that it’ll sound like a plane just took off inside your boiler. This is a bad sound to hear – no questions about it. That sound usually means that your pump is dying or dead. While this could be caused by a pump failure, air or debris caught inside, or something else, it really doesn’t matter. You need to have a professional take a look right away. If you don’t, you run the risk of the problem spreading and causing even more serious issues.

If there is a significant failure that goes ignored, you could not only suffer a catastrophic failure of your boiler, but you could also end up needing to fully replace it – that’s not cheap. Please, be smart and call for help when you notice the telltale signs of trouble brewing.

Final Thoughts

There’s a lot that can go wrong with boilers. They’re complicated machines, and that means that countless things can fail at any time. Luckily, your boiler will tell you when something is wrong – so listen to it. A good first step is always to bleed your radiators and check your boiler’s pressure. After that, more likely than not, you’re going to be stuck needing to call a professional.

And please, don’t feel bad about asking for help. Professionals exist solely to make your life easier and safer. Generally, it’s not worth risking major repairs or replacements because you can’t be bothered to ask someone to help you out.