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Boiler making noises? - Common Noisy Boiler Causes & Solutions

Do you have a noisy boiler? Are there strange whistling noises or new, sudden banging sounds causing you concern? 

All boilers make some level of noise since they are mechanical pieces of technology that’s working hard to burn fuel and keep your home warm. 

However, if you are experiencing a new unusual noise coming from your boiler, then there may be a problem. 

In this comprehensive guide, we are going to list some of the most common noisy boiler causes and how you can fix them. 


Common Noises from Boilers:

Common Noises From Boiler

  • Kettling (Whistling)
  • Humming
  • Vibrating
  • Banging And Clanging
  • Boiler Clicking
  • Tapping
  • Gurgling 
  • Rumbling 
  • Boiler Rattling 
  • Boiler Banging 
  • Buzzing Noise 

Common Causes of a Noisy Boiler 

If you are hearing a new and unusual noise coming from your boiler, then it’s likely caused by one of the following common problems. 

Some of these can be fixed quite easily and do not require professional help, while others certainly do need the assistance of a registered Gas Safe Engineer


#1 - Dripping Noises: Boiler Leaking

Dripping Noises From Boiler

If you can hear dripping noises, then the likelihood is that your boiler has an internal leak somewhere.

If you have just started to hear the sound, it’s crucial that you get it looked at sooner rather than later as water can cause serious damage to electrical components e.g. it’s a leading cause of faulty PCBs

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A leak can be caused by a variety of issues, such as corrosion to major components such as the heat exchanger, as well as broken or worn out seals. A registered Gas Engineer will be able to quickly diagnose and repair the issue.

Leaking Heat Exchanger Noise

High boiler pressure can also lead to the formation of pinhole leaks, so it’s a good idea to check your boilers pressure is at the correct level too. 


#2 - Boiler Whistling: Limescale Deposits & Build Up

Boiler Whistling Noise

Is your boiler making a whistling noise? This may be the result of limescale build-up on key internal components, such as your heat exchanger, it may also lead to bubbling due to the production of steam. 

Limescale is not usually an issue unless you live in an area with hard water; you can check using this map.

The issue with limescale is that it can quickly become overheated, which can result in the common whistling or kettling noises. 

Not only is the noise an issue, but consistent overheating can also result in the development of cracks and broken seals in the heat exchanger or nearby components, resulting in a leak.

How to Fix Limescale Build-up 

If you live in an area that suffers with hard water and you suspect limescale is causing the kettling or whistling, you should consult the help of a registered Gas Sage Engineer. 

Unfortunately, if the limescale has been present for some time, it may have caused damage to your boilers components, in which case they will need to be repaired or replaced.

Leaving the deposits to linger can result in long term damage and leaks that may result in more expensive repairs. 

Boiler Noises Limescale Reducer

A Gas Engineer will also be able to take the following steps: 

  • Clean your system with a limescale remover, from a brand such as ADEY
  • Carry out a thorough inspection of your boiler (including the heat exchanger) to check for damage
  • Installation of a limescale inhibitor

The ideal situation is to take preventative steps before limescale has the opportunity to build up and become such a severe issue. 

If you live in a location with hard water, then you can request your engineer to add a limescale inhibitor at the time of your annual boiler service. 


#3 - Ignition Failure: Clicking Sounds and Tapping

Ignition Failure

Is your boiler failing to fire up? Are you hearing a sudden clicking noise or a light tapping? This may be an indication that you have a problem with your boilers ignition. 

How to Fix Ignition Failure 

Unfortunately, since this component is under the cover and is a potential gas related one, you will need the assistance of a registered Gas Safe Engineer.  

This fault may either be related to the gas supply itself, the spark ignitors or the ignition leads. 


#4 - Boiler Pressure Too Low

Boiler Pressure Too Low

If your boilers pressure is too low, then you may hear an associated noise, commonly this is a hammering noise, which can be caused by a sudden drop in pressure or fluctuating pressure. 

Boiler Pressure Gauge Usually, if your boilers pressure drops too low, the boiler will lockout and display a low-pressure error code. You can usually identify low pressure by looking at the pressure gauge too.

How to fix low boiler pressure  

If your boiler has low pressure, it’s possible that you have a leak somewhere in your heating system. This is usually around the bends of pipework, where you may find broken joints and seals. 

Sometimes the leaks can be more significant and be the result of corrosion to major components. These need to be repaired, or you will continue to experience drops in pressure and the associated hammering noises. 

Top Up Boiler Pressure Fix Noise

If you locate what appears to be a leak, you should not attempt to open the boiler yourself and instead consult a Gas Safe Engineer. 

If there is no obvious leak, you can always try topping up your boiler pressure yourself; this is a relatively easy thing to do. You can find the instructions for your precise boiler in the manual. 


#5 - Boiler Gurgling Noises: Air Trapped in Your Heating System

Boiler Gurgling Noise

Are you hearing gurgling noises when your boiler is running? This may be caused by trapped air in your radiators, which can result in them not heating up evenly. 

Are you finding that some radiators are not getting as hot as they used to? Radiators that are cold at the bottom or that have cold patches and unevenly distributed heat are typically the results of too much air in the radiators.

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How to fix trapped air in your system 

You can easily bleed your radiators yourself, but it’s a pretty messy job, so make sure to lay down rags as the radiator water can be quite dirty.

Bleed Radiator Key To Stop NoiseSimply purchase a radiator key from your local hardware store, and slowly turn the valve counterclockwise until water starts dripping out. This will also release any trapped air. 

Repeat the process on all of the radiators within your home and it should hopefully resolve the noisy boiler issues. 

If you don’t fancy doing the job yourself, a registered Gas Safe Engineer will be more than happy to if for you. It’s a good job to have it done annually, at the same time you get your boiler serviced. 


#6 - Boiler Vibrating Noises

Boiler Vibrating Noises

If your boiler is making vibrations and whooshing noises, this may be caused by a few different issues. Thankfully, these are usually pretty easy to fix, but if left, they can cause significant damage, so it’s always better to deal with the problem head on. 

How to fix a vibrating boiler 

One of the most common culprits of boiler vibrations is something being trapped in the flue. Therefore, check the pipe on the exterior of your property and if you notice anything trapped remove it. 

A simple test is to take your hand and hold it over the vent; you should be able to detect a certain level of airflow, indicating there is no blockage lodged further into the pipe. 


#7 - Boiler Humming Noises

Boiler Humming Noise

Are you hearing a humming noise coming from your boiler? 

All boilers have some level of noise as part of their normal operation, so it’s important to be aware of this. However, if it’s a new noise, then it’s more likely to be the sign of a problem. 

There are a few potential causes for a humming boiler, these include the following: 

How to fix a humming boiler 

First things first, turn your boiler off and then check for any loose screws or panels on the exterior of the boiler.

Tighten them as necessary. However, if that doesn’t rectify the issue, there may be loose internal components inside the boiler, in which case you will need to consult the help of an engineer. 

You may also want to check that your boilers pressure isn’t too high. You can do this by checking the pressure gauge, typically, the needle being beyond (above) the normal green region indicates that the pressure is too high. When this happens, the system releases excess pressure via the pressure release valve causing a humming noise.

Correct Boiler Pressure

If your boiler’s pressure is frequently getting too high, you may want to seek the assistance of an engineer, as it may be a sign there’s a problem with a component. 

Another common culprit of a humming boiler is a circulating pump operating too fast. Its function is to pump cold water back to the boiler, if set too fast, it can cause vibrations and humming. The fix? Simply set the circulator pump to a lower speed.


Noisy Boiler - What should you do if you can’t find the cause?

Cant Fix Noisy Boiler

If after carrying out the above checks, you can’t find any obvious cause for your boilers new, unusual noises, you may want to check our guide on the most common boiler problems

It could be related to one of these issues, some of which can be resolved without professional assistance.

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If you are still struggling to find the cause of the noise, then you should seek the help of a qualified Gas Safe Engineer, who will be able to diagnose and repair the boiler.  


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