Noisy Central Heating Pumps: Common Problems and How to Fix The Noise

If you are getting frustrated with your noisy boiler and want to fix the problem, this is the guide for you. Most boiler noise is caused by the central heating pump and in this guide, we will identify the most common issues and show you how to fix them.

When a boiler starts to make strange noises like banging, humming, or ticking, it is usually a sign of a problem with the central heating pump.

It can be one of the most annoying issues that can arise with a boiler and most people will want to try and fix the issue as quickly as possible. The question is, what is causing the problem.

In this guide, we will answer that question and tell you how to fix the problems too. Some fixes are a simple DIY task while others may require a professional. Either way, you can stop your boiler getting on your nerves as quickly as possible.

Noisy Boiler issues: The main culprits

If your boiler is making an annoying noise, there are a number of things that could be causing the problem. Every boiler is different, but in our experience, most noise issues occur as a result of one of the following common problems:

  1. An Air Lock

An air lock is perhaps the single most common cause of a noisy boiler. When air gets into your central heating system, it can cause noise in the boiler itself, the pipes, and the radiators.

This will usually be a knocking or banging noise that is hugely annoying. Fortunately, it is also quite easy to fix.

How to fix it:

Most modern central heating pumps will have a built-in bleed screw. By gently opening this screw, you can release any air that is trapped in the pump.

Just open the screw slowly until you hear a hissing noise. Then wait until the hissing noise stops and a drip of water appears. Close the screw again and clean up the water that came out. This should now solve the problem.

If the noise is coming from your radiators, that might mean they have air in them too. Use a radiator bleed key to open the valve and release this air. Again, this should now fix the issue.

  1. Pump Shaft Incorrectly Installed

If your boiler hasn’t been installed correctly, it is possible that the pump shaft is not quite horizontal. This might sound like a rare issue, but actually, we see it far often than you might think.

If the pump shaft is not horizontal, this will cause noise regardless of whether there is air in the system. It will also cause excess wear on the pump shaft bearing which can, in turn, lead to a whining noise.

How to fix it:

The pump shaft should be exactly horizontal. If it is even a few degrees out, this will affect the performance of the pump, impact on the lifespan of the component, and could cause noise too.

You should be able to adjust the angle of the pump shaft yourself to solve this issue. Usually, it will only need to be nudged a millimetre or two. If you are not confident doing this, a heating engineer will be happy to help, but you will have to pay a sizable call-out for a simple job.

  1. Blocked With Sludge

Central heating systems are full of sludge and over time this gets pushed around the system. If too much of it ends up in your boiler it can clog up components like the central heating pump and cause a noise

A lot of boilers come with filters to stop this problem but often these are optional extras that people choose not to spend money on. It is also possible for filters to be incorrectly fitted which will mean they can’t work properly.

How to fix it:

If you have a sludge blockage in your boiler, you will need to get a heating engineer out. They will be able to take the boiler apart, identify where the blockage is and clean everything out.

If the filter has been incorrectly fitted, this problem can usually be fixed quite easily. If you don’t have a filter at all, it is probably a good idea to ask them to fit one.

  1. Incorrect Flow Setting

While it tends to be the older, more worn central heating pumps that make noise, this isn’t always the case.

An older pump will be losing more energy which can result in a humming noise. But if the flow setting on a newer boiler has been set incorrectly, this too can cause a noise.

Newer pumps will usually come with 3 or more flow settings. It can be tempting to default to the highest flow setting but this isn’t always necessary and can result in a noise.

How to fix it:

You will need to locate the flow setting switch for your boiler. This should be in your boiler manual, but if not the internet will be able to provide an answer.

If this switch is set to the highest setting, turn it down one. Then check your radiators and towel rails to make sure they are all still reaching the desired temperature. If they are, this should mean that the new lower setting is fine.

A lower setting should also cut out any noise from your central heating pump. It will also save you money on your utility bills and could even extend the life of your central heating pump too.

  1. Internal Components Seized

If your boiler is generating a humming noise or lots of vibrations, it is likely that one of its internal components has seized up. The most likely culprit of this is the central heating pump shaft although it could be something else.

If a component has become seized, finding out why and fixing it should solve the problem.

How to fix it:

If the problem is with the central heating pump shaft, you may well find that a gentle tap on the side of the pump will fix the problem.

The chances are that it will reoccur if this does work so it is worth getting the pump taken apart and cleaned by a heating engineer if this is the case.

It is possible that the issue could be caused by either an incorrectly installed pump shaft or a sludge blockage. If so, you will need to refer to our above sections for the appropriate fixes.

Where to look for a new boiler

If noise is an ongoing problem and your boiler is old anyway, you might want to consider investing in a new energy-efficient boiler with a long warranty. In the long run, this could end up costing you less in terms of both money and hassle.

If you do decide to get a new boiler, we strongly recommend you take a look at WARMZILLA.

WARMZILLA is an online boiler installer that offers some of the best prices on all the top boiler manufacturers and has some great exclusive bonus offers available too.

Just visit the WARMZILLA website and fill in their short form. It only takes 30 seconds and there is no personal information required. WARMZILLA will give you a fixed-price quote on all the best boilers for your home.


Noisy boilers are not uncommon and are usually nothing to worry about. Most problems can be easily fixed by you without needing to trouble an expensive heating engineer.

But some problems can be more serious and will require professional help.

In this guide, we have outlined the five most common causes of boiler noise in central heating pumps and advised you on how to fix them.

Have you had issues with boiler noise? How did you fix it? Do you have any tips for our readers that we haven’t mentioned in this guide? Do you have any questions that we haven’t answered?

It is always useful to hear about your experience and advice, so please do share them with us using the comment box below.

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