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Noisy Central Heating Pump and How To Fix It


Everyone enjoys the convenience of a quiet central heating system. Therefore, finding your central heating pump whining, banging, ticking, or humming, for that matter, is quite a frustration.  A noisy central system can also be an indication of some internal problem that needs immediate attention.

If the problem is not resolved in time, it may escalate and inflict some severe damage to your central heating pump, and you’ll find yourself paying several pounds in repair costs.

In this guide, we will outline some of the common central heating pump problems that can make it produce those frustrating noises. Even better, we will throw in the fixes that’ll help you eliminate those annoying noises from your central heating system asap.

However, it is crucial to note resolving some of these issues may be beyond your capabilities, and you are better off engaging the services of a certified boiler engineer.

That said, let’s take a deep dive and look at some of the reasons why your central heating pump is producing those annoying noises that have been getting on your nerves of late.

Causes of a noisy central heating pump and their fixes

Presence of an airlock in the system

One of the leading causes of noisy central heating pumps is the presence of airlocks in the pump. When air enters the central heating system, it is trapped in various parts of the system, including the boiler, the radiators, the heating pipes, and of course, the pump. When air builds up in the pump, it will cause a blockage, resulting in humming or whining noises coming out of the pump.

Airlocks are also responsible for noisy boilers, radiators, and heating pipes.

How to fix this

The fix for a noisy central heating pump caused by an airlock is quite simple. All you have to do is bleed the pump, and voila! The problem is gone.

And as luck would have it, most modern central heating pumps have an in-built bleed screw specifically for this reason. To resolve an airlock issue in the central heating pump, gently open the screw until you hear a hissing sound. The hissing sound is an indication of air exiting the central heating pump.

When the pump is completely bled of air, the hissing sound will stop, and a drip of water will emerge from it. Once you’ve confirmed that the bleeding is complete, retighten the screw, and you are good to go.

Incorrect installation of the pump shaft

One of the reasons why it is recommended that you have a Gas Safe registered engineer install your boiler to ensure the pump shaft is precisely fitted in a horizontal position. However, if you opt to bypass this recommendation and install the boiler yourself or engage John down the street for the task, chances are, your pump shaft is off the mark.

And if the pump shaft is not precisely horizontal, the pump will let you know of it by producing some annoying noises regardless of whether there is air in the system or not. The central heating pump will continue to make unwanted noises even after you bleed it.

Moreover, if the pump shaft is incorrectly installed, the pump shaft bearings will be subjected to excessive wear and tear, which will, in turn, lead to a whining noise.

How to fix this

To solve the issue of an incorrectly installed pump shaft, you need to slightly adjust the angle of the shaft by nudging it a millimetre or two. If you are not confident of doing this yourself, you can call a registered Gas Safe engineer to diagnose and correctly install the pump. However, you will have to pay a sizeable fee for a simple job that you could complete on your own.

Seized internal components

If your central heating pump is giving off humming sounds and lots of vibrations, chances are, it has one or more seized internal components. Seizure of internal pump components usually results from poor installation of the pump shaft or build-up of dirt and debris in the pump.

In most cases, the seized internal component is often the central heating shaft. However, it could be anything else and having a certified engineer look at the pump will help identify and resolve the issue.

How to fix this

If the seized internal component is the central heating pump shaft, a gentle tap on the side of the pump will be sufficient to release it and get the pump going smoothly again. However, take care not to hit the pump too hard as it might develop some internal issues.

Although the simple tap may work, it’s almost given that the issue will reoccur again since the problem has not been entirely fixed.  Therefore, it is recommended that you get a registered engineer to take apart the system and give it a thorough cleaning.

The engineer will also inspect the central heating pump shaft bearings and replace them if they are worn out due to incorrect installation of the pump shaft.

Sludge blockage

As time passes, rust and other debris start to accumulate in your central heating system, forming sludge. The sludge is pushed around the system as the water circulates the central heating system. This sludge will collect in some parts of the central heating system, such as the pump and cause blockages.

The presence of a blockage in the central heating pump will cause the pump to be noisy. To tell whether the noise coming out of your central heating pump has something to do with a sludge blockage, check the speed at which the radiators heat up. If the rate is too slow or the radiators fail to come on despite the boiler running, sludge blockage is the culprit.

How to fix this

The only way to fix the noisy central heating pump, in this case, is to give the system a thorough cleaning to remove the sludge. Sadly, this is something you cannot do on your own, and you will have to engage the services of a registered boiler engineer who will either power flush or chemical flush your central heating system.

You can also ask the engineer to fit a magnetic filter on your central heating system if you have the budget. The magnetic filter will collect the various types of debris in your central heating system and prevent the issue of a noisy pump due to sludge blockage from happening again.

Too high flow speeds

If your central heating pump is a modern one, you’ll notice that it has three speed settings to adjust the flow rate of water coming out of the system. Of the three settings, the lowest will set the flow rate at the bare minimum, while the highest will set the flow rate at the maximum.

It might be tempting to set the flow rate at the highest setting, but it is unnecessary and can even result in noise coming out of the pump. Alternatively, try finding a setting that suits your central heating system, and in most cases, this is the regular flow rate which is the middle setting.

How to fix this

To solve incorrect flow settings on your central heating pump, you first need to locate the flow settings switch of your boiler. If you are having difficulties noticing its location, consult your owner’s manual or the internet.

Once located, switch the pump flow speeds from the highest to the middle one. The lower setting should be sufficient enough to cut out noises from your central heating pump. Lowering the flow speeds will also lower your utility bills and can even extend the life of your central heating pump.

Fan hitting other parts

Every central heating pump has a fan installed to keep it from overheating. If the fan is faulty or has a loose blade, you may hear some clanking noises as the fan hits other metallic components of the pump.

How to fix this

Fixing the issue of a faulty fan or loose fan blades requires the attention of a registered gas engineer who will examine the pump and determine whether it can be fixed or only a replacement works.


Although noisy central heating pumps are pretty frustrating, they shouldn’t be cause for panic since you can solve most of the underlying issues on your own. However, some problems are more severe and will require you to engage the services of a Gas Safe registered engineer. If that is the case, we’ll be happy to connect you with a qualified and registered engineer within the shortest time possible.

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