Is your boiler making noise? Most often, boilers indicate their failure by producing an unnatural sound. Boilers are an essential part of our daily life, and it is usually an unpleasant experience when they break down.

By analysing the noises boilers make, you can determine which part has failed or what is wrong with the boiler.  This article will cover eight reasons your boiler makes noises and how to fix them.

8 Reasons Your Boiler is Making Noises and How to Fix Them

Having a keen ear and listening for exactly what kind of sound your boiler is making is essential. By identifying whether that sound is a thud or something like gurgling, you can pinpoint the exact problem.

Here are eight different common noises boilers make and how to fix them:

Gurgling Sound

If your boiler makes a gurgling noise, like bubbles passing through, it could signify a few things.

Most commonly, air can become trapped in the pipes or the radiator, and your boiler can gurgle with each use. Mineral build-up can trap the air inside. 

Different hardness levels to water cause it to leave deposits, and the hardness depends on the location.

There isn’t much to do for the hardness of the water except for putting it through a filter which can be expensive.

How to Fix the Gurgling Noise

You need to bleed the radiators. You must turn off your boiler, identify the small bleeding valves, and open them.

As soon as you open them, you will hear a hissing sound: the air escaping. When water comes out of the valves, you can close them and reverse all the steps.

If the problem persists, you need to powerwash the internals of the boiler to get rid of sedimentation.

A Strong Banging Noise

Banging noises are indicative of a severe issue. When you hear loud knocks, the heat exchanger is rapidly changing size.

Excessive water pressure can cause the sound, which in turn can be a signal of limescale buildup.

  1. How to fix: Lowering Water Pressure

One way to fix the expansion of the heat exchanger is to lower the water pressure inside the boiler. You need to reduce it until the sound diminishes.

The heat exchanger won’t expand with low water pressure and will be okay to use.

Sometimes a low boiler pressure makes the whole system perform better.

  1. How to fix: Removing Limescale

Since Limestone doesn’t have the thermal capabilities of water and steel found in the boiler, overheating can occur.

To remove sediments, you need to open up the boiler and remove them using a pressure washer or dipping the limescale buildup into a slightly acidic mixture.

Whistling Noise

Hearing a high-pitched annoying noise from the boiler could mean an issue with the water flow or its pressure.

Two things can be faulty with your boiler: the pressure relief valve or a malfunctioning pump.

How to fix: Replacing the Parts

Start by checking the pressure relief valve and see if there are any leaks. If you discover that the valve is not working or is broken, you can look up your boiler serial code and buy a new one.

To inspect the water pump, you might need the help of a professional. The boiler pump needs to be correctly circulating water through the whole system. 

Checking these parts is critical to maintaining an operational boiler. You might need to replace the parts if you have an old boiler.

Humming or Vibrating Sound

Humming noises stem from vibrating parts inside the equipment. It might indicate that something inside is loose and knocking fast.

Loose installation or worn-out parts could cause this problem.

How to fix: Inspecting the Internals

You need to open up your boiler and see inside to find out what is wrong. Look for loose screws and worn-out bolts that might need replacing.

Usually, these bolts can come loose after years of usage, and your job is to replace them.

If someone installed the boiler improperly, you can add anti-vibration pads on the contact points to minimise the vibrating boiler noise.

Continuous Clicking Noise

A clicking noise can mean two things, either a faulty thermostat which might turn on and off repeatedly, causing clicking or a malfunctioning control system.

These two systems might cause the boiler to misinterpret the temperature and cause it to change states from active to turned off constantly.

How to fix: Verifying the Status of The Systems

Usually, the manufacturers provide a guide on how to calibrate your thermostat. You can search the Internet for a solution if you don’t have the manual.

You must ensure that the thermostat is not in contact with units that could affect his heat reading.

If the control system is faulty, you might need to contact an electrician or replace it wholly.

Bubbling sound

Engineers use an expansion tank to protect the lines from pressure because there needs to be a failsafe for the pipes connected to the boiler.

This expansion tank can become faulty and make bubbling boiler sounds, reducing efficiency.

How to fix: Replacing the Internal Bladder

You must turn off your boiler and open it to replace the bladder. Look for cracks or deformations on the expansion tank.

Contact a professional or look online to see which tank your boiler needs.

After ordering the tank, you need to install it correctly, and your boiler is ready.

Hissing Noises

When your boiler makes a loud hissing sound, you mustn’t ignore it. A hissing sound indicates a leak, meaning your boiler loses pressure and heating incorrectly.

Before moving on to the next spot, check to hear if the sound is coming from the boiler or the pipes, as it is common for pipes to leak.

How to fix: Find the Leak

Start by looking over all of the surfaces of the pipes and boiler. Look for puddles or water spots that might occur.

If you find no holes, you will need to open the machine.

Look for cracks and holes where water could be going through. Whether you find a leak or not, it is wise to call a plumber to find and fix the hole.

Rumbling sound

A loud and deep rumbling sound could indicate sediments forming at the bottom of the tank.

These rocks can cause changes in heating and probably damage the internal parts.

  1. How to fix: Cleaning the Insides

This problem can be avoided by often cleaning the tank’s internals. Begin the process by draining any residue or sludge that you might find.

You can use a power washer to remove any sediments thoroughly. This cleaning will improve your heating, making your boiler system more efficient.

  1. How to fix: Regular Cleaning

You need to utilise regular cleaning to fix any further boiler issues and prevent boiler noises.

By preventing mineral deposits from forming, you can ensure that the rumbling sound and any other strange noises don’t appear.


Like every other essential utility in our homes, a boiler requires maintenance. Luckily, they emit certain types of sounds before boilers break down completely.

You need to listen for the sounds your noisy boiler is making and utilise a fix based on that. Whistling noises might indicate a water flow issue, hissing noises indicate leaks, etc.

Regularly maintaining your boiler by cleaning and inspecting it is a great way to have it functioning for many years without buying a new boiler.