What Your Noisy Boiler Is Trying To Telling You

Sep-2020 / 7 min read

Reading Time: 7 minutes

Windows can rattle, and floorboards can creak. The loud, banging noises of the boiler should be right at home with all the other sounds of a well-lived house. It can be the new headliner in the midnight concerts that happen inside your house. 

Whether you mind these sounds or not, homeowners are encouraged to investigate them since these sounds often point out a problem. For example, drips mean there is a leaky tap and creaks mean there is a loose floorboard. While most of these sounds are harmless, the same cannot be said for boiler noise. 

As a heavy-duty machine, wear and tear can lead to more significant heating problems. When your noisy house is trying to tell you something, it is best to pay close attention. 

Do You Have A Noisy Boiler?

The thumps and hisses can come from different parts of the house, from your central heating system’s pumps and radiator to your plumbing’s pipework and taps. It isn’t difficult to check whether the noise is coming from your boiler or not.

When you hear something out of the ordinary, make it a point to find out what is causing the sound. You can work your way down from a list of the usual suspects like your boiler, radiator, pipework, taps, and showerhead, among many others. By following this list, you can quickly identify the issue and address the problem. 

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So Why Is My Boiler Making Noise?

When you have a noisy boiler, there is a high chance something wrong with your unit. Sometimes it can be fixed with proper annual maintenance by a professional heating engineer, and other times it may signal the final days of your boiler. If you want to avoid paying the exorbitant fees for a new boiler installation, pay attention to your boiler’s unusual noises. 

As soon as you hear the whistling, hisses, gurgling, rattling, or a loud bang, contact your local engineer from Plumbingforce. They can take over issues that you cannot do on your own. With their expertise, your boiler can go back to running smoothly and quietly. You manage to achieve two things at once: 

  1. Keep your central heating in good shape.
  2. Get rid of the boiler noises that keep you up at night. 

It is a win-win situation! 

Common Sounds And Their Causes 

A noisy central heating system can usually be chalked up to poor maintenance. When you stick to your annual boiler checkup and follow the basic maintenance steps, you shouldn’t have to deal with a noisy boiler.

There are several types of sounds you might encounter, and there may be a bit of overlap with the causes of these sounds. Here are some of the things you might hear when your boiler is acting out: 


The rattling noise sounds like there is something stuck in your boiler, and it is being tossed around. It is quite loud, and it tends to be very inconsistent. 


There are two leading causes of rattling in your boiler. The first is that there are loose screws and components that shake and “rattle” when the unit is in use. You can look out for loose valves or any unclipped pipes. The second is because of the excess air in the system. When your central heating system isn’t properly balanced, it can mess with the pressure and create the rattling sound. 


When you have to deal with loose screws and components, you can take your screwdriver and wrench and inspect your boiler. As long as it is exposed, you should be able to tighten them with no problem. However, if the sound is coming from the pipes, then step back and call a plumber or heating engineer to take a look.

If the rattling comes from excess air in the system, you can opt to DIY the repair. You can learn how to balance your boiler and radiator here.  


The banging noise has several degrees of intensity. The mild version sounds similar to the rattling though a bit more heavy and infrequent. The strong version has a loud bang, and the sound and volume can make you feel like the walls are coming down. It can be very startling and problematic if you are a light sleeper or if you have a lot of anxiety. 


Older models are more likely to suffer from boiler kettling, causing loud bangs and pops. Boiler kettling happens when there is debris build-up in the heat exchanger. The debris usually comes from the limescale in hard water. When it builds up, it chips the metal bit by bit adding rust and grime. It can create blockages that clog and pop, which ultimately increases the trapped air in the system.  


While kettling isn’t a real explosion, it can be very troublesome. When the debris builds up, it can speed up the wear and tear of your pipework, increase your energy bills, and affect the other elements of your central heating system. 

Take note that only a heating engineer can address boiler kettling properly. They need to drain your system and have your boiler and radiator power flushed. Once the sludge is out of the system, you should have a quiet boiler. To maintain the work they did and prevent the loud banging noise, you can invest in a magnaclean filter and an anti-limescale solution. 

If you have never heard about the filter before, you can read more about the magnaclean filters here. 

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The tapping noise is very similar to the previous two. It sounds like there is a piece of metal constantly hitting the pipes. While it is softer than the banging, it can still be frustrating to hear around the clock. 


Again the cause is due to boiler kettling. The build-up of debris in the heat exchanger affects the flow of the system. The sound typically comes up when the circulating pump is on, so expect it when you are washing the dishes, taking a shower, or flushing the toilet. 


There is no DIY fix for this. It would be best if you had your central heating professionally cleaned to address these problems. To ensure that tapping sound does not recur, remember to invest in proper boiler maintenance.

Humming/ Vibrating/ Droning 

Not all boiler noises are disruptive or distracting. The humming noise, for example, is like a muffled fan. Unlike the others listed here, it is a lot softer and easier to get used to every day. 


If you have an electric or combi boiler, this sound is quite common, even if the model is new. It just comes with the mechanism in the boiler. However, if your boiler was originally soundless, there are several possibilities as to whether it is humming/ vibrating. 

The first is a loose component with your water heater or with your boiler fan. The second is with the build-up like sludge and limescale inside your boiler. And the third can be because of high boiler pressure. When the pressure is high, your boiler valves may hum a bit. The vibrations can also come from the travelling hot water or air being circulated through the pipes.


The solution for a humming boiler is split between DIY tasks and your boiler engineer. When the problem is the boiler pressure, you can adjust that on your own. If you have never done it before, you can consult our guide for pressuring your boiler

You can also take your trusty screwdriver and wrench and tighten the loose component when it is visible. However, if the issue is on the inside, you need to get a Gas Safe heating engineer to take care of it. The same goes for cleaning a debris-filled central-heating system. 


The hissing of your boiler is very similar to having a kettle on top of your stove. It is a high whistling noise that can sound very eerie at the dead of night. 


The hissing noise can be linked to the boiler kettling or the trapped air in the system. 


Since the hissing sound is often associated with air and gases, you need to contact a Gas Safe engineer. If it is a kettling problem, they are more than qualified to power flush your system to eliminate the debris. However, in the off-chance that the hissing is not coming from your boiler but a faulty flue or gas appliance, they can easily remedy that. 

When the hissing is from trapped air, you can bleed your radiator and adjust the boiler pressure yourself with the manufacturer’s manual and the pressure gauge. 

When you live in an area with hard water, you need to learn to do this regularly. For preventive measures, you can invest in filters and an anti-limescale solution to take care of the sediments. It should keep your boiler’s heat exchanger clear of any rust and grime.

Gurgling/ Dripping

The gurgling noise of the boiler sounds similar to the ones in your water pipes or taps, so it wouldn’t be strange to assume that you have a plumbing problem over a heating one. However, if you hear something bubbling or dripping near your boiler, it probably is. 


The common cause of the gurgling sound is trapped air or by a frozen condensate pipe. 


When there is trapped air in your boiler, you can fix it by bleeding your radiators. If you finish bleeding them, but you still hear the dripping sound, and it is within the late autumn to early spring, it must be a frozen pipe. 

When winter comes around, homeowners are advised to lag their pipes to ensure that this does not happen. When you have a frozen pipe, it can negatively affect both your plumbing and heating system. When it is frozen, you can slowly thaw the condensate pipe with a bit of patience and hot water. 

The sounds listed here are the most common ones, but there are many other unusual noises your furnace can make. When left unchecked, it can ultimately lead to poor water pressure, uneven heat distribution, dirty pipes can affect the performance of your heating system. As your system becomes more and more inefficient, you may end up with a faulty boiler and thermostat. In the worst-case scenario, you may need to invest in a new boiler instead of repairing your current one, and that can set you back £500-£1,500. 

Dealing With Your Noisy Boiler

UK residents should never wait for things to be so bad that you need your boiler to hiss and pop before you properly maintain it. Since they are an essential part of your daily life and expensive to replace, you are encouraged to care for them properly. 

When you find out your boiler is making noise, try the DIY methods listed above. When they fail, work with a heating engineer to get your boiler to work smoothly and quietly. To ensure that you get the right fix the first time around, record the sounds on your phone. As descriptive as the words “hissing” and “banging” are, it is best to have the same frame of reference.

You can book Plumbingforce’s local engineers online or call us at 0330 162 5329, so we can have a look. We offer same day service for boiler maintenance, repairs, and installations. With Plumbingforce, you can go back to enjoying a quiet and peaceful heating system in no time!

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