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Noisy Central Heating Pump [Problems & Fixes]

Having issues with a noisy central heating pump? Luckily, most circulator pump issues have a relatively simple fix.

So whether your pump is banging, ticking or humming, this guide will help to diagnose and fix the problem as soon as possible. We’ll also explain how much a replacement pump may cost you to install, and outline the rare cases when getting a replacement boiler is a good idea.

Noisy central heating pump

If you’d prefer a Gas Safe heating engineer to fix the problem, you can get in touch here.

Or, if you’d rather get a new boiler fitted and have repairs covered on a warranty of up to 10 years, we recommend Heatable. They have backing from Worcester Bosch, so they fit boilers at competitive prices. You can get boiler quotes on your screen in less than 90 seconds using their clickable online form.

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Sounds, Causes, and Fixes for a Noisy Central Heating Pump

Below, we’ve listed the most common causes of a noisy central heating pump. If you don’t believe that your fault is covered here, skip over to boiler problems guide.

#1 – Pump is airlocked

Heat pump noise

You may hear: knocking, banging

Let’s start with the #1 most common reason behind a noisy central heating pump — airlocks.

Air can get into the central heating system, and when it does, it travels through the system and gets trapped in various places, causing noisy boilers, radiators, heating pipes, and, of course, boiler pump noise.

The Fix

Bleeding your central heating pump should get rid of the airlock and the noise. You’ll need a central heating pump bleed screw to do this; luckily, most modern central heating pumps, such as Grundfos, have one.

Start by carefully opening the screw until you hear a hissing noise, and leave it in this position until the hissing stops. At this point, you’ll notice a slight dribble of water, which indicates that the pump has been completely bled of air. Now, you can close the screw.

#2 – Pump shaft isn’t horizontal (incorrect installation)

Central heating humming noise

You may hear: knocking, banging, whining

Now that you’ve bled the air, check if the pump has been installed correctly (this is a surprisingly common central heating pump problem).

If the pump isn’t installed correctly, it will continue to get airlocks even after bleeding. This means you’ll have a noisy central heating pump within a matter of days of removing an airlock.

Also, an incorrectly installed pump will cause excess wear on the shaft’s bearing. This will lead to a whining noise coming from the heating pump.

The Fix

The pump should be horizontal. Typically, you’ll know that it is if the screw for bleeding airlocks is at the side.

And if it’s not, you’ll need to adjust it so that it is — the screw shouldn’t be at the top. Even a few degrees off horizontal could affect the pump’s ability to circulate water (causing a boiler lockout) and lead it to wear out prematurely.

#3 – Seized internal components

You may hear: humming, vibration

If the boiler pump noise you hear includes humming or lots of vibrations from the pump, the pump’s shaft is probably seized.

And since the energy that turns the pump’s shaft must go somewhere, it converts to the noise you’re hearing (and likely leads to the pump overheating).

The Fix

A slight tap on the side of the pump should free internal parts. But this is just a temporary fix — you’ll want to take the pump apart and clean it out.

And while you’re at it, inspect the bearing on the shaft. If the shaft hasn’t been sitting horizontally, the bearing will be worn out and you can expect the pump to seize again.

#4 – Pump is blocked with dirt

You may hear: humming, vibration

If you’ve got a noisy central heating pump, there’s a good chance it’s blocked full of dirt. This is notably true if you don’t have a boiler filter or it’s been fitted incorrectly, on the wrong side (yes, this actually happens). Older central heating systems are also quite vulnerable to this issue, as they’ve been accumulating debris for years.

The Fix

You’ll need to take the pump apart, clean out the debris build-up, and inspect it for wear. If the pump is in otherwise good working order, fit a boiler filter to catch debris in the heating system, so dirt can’t build up there again.

#5 – Incorrect speed settings

You may hear: loud humming

Another cause behind boiler pump noise is a speed setting that’s too high for the heating system. If this is the case, you’re likely wasting precious energy because your heating system is generating a higher flow rate than necessary and thus not operating efficiently.

So, by fixing the issue behind the noisy pump, you’ll also reduce your electricity consumption and prolong your pump’s lifespan.

The Fix

Locate the flow rate setting switch on the pump. If it’s on the highest setting, turn it down one, then check whether your radiators and towel rails are still getting up to temperature. If they are, this setting should be fine.

All the above being said, your pump may have been set this way for a reason, so it’s always good to get the opinion of a Gas Safe heating engineer first.

Central Heating Pump Still Noisy? 

We hope that our troubleshooting guide to noisy central heating pump causes will help you sort out whatever issues you’re having, and your pump will be humming along quietly soon.

But if you’re still hearing unusual boiler pump noise, or suspect other issues with the heating system, you can speak to a Gas Safe heating engineer here.

And if you feel that your boiler may be up for replacement, have a look at our guide to boiler fitting costs here.

Heatable are an online boiler installation company with some of the best new boiler deals on the market, including boilers from Worcester Bosch, Viessmann, Ideal, and others. Thanks to Heatable’s low overhead, the company can pass on their savings to the consumer. You can get your own fixed-price quote from them here.

Worcester Bosch Greenstar 4000

FAQs About Central Heating Pump Noise

Before we wrap up, we will answer some common question and concerns about noisy central heating pumps and other central heating problems.

How do I stop my heat pump from making noise?

First, you’ll have to determine what’s causing the circulator pump to make the unusual noise. A number of boiler problems can result in a noisy circulator pump, with the noises differing depending on the issue.

Depending on the underlying problem, you’ll need to undertake appropriate repairs to get the pump working properly again — this should take care of the noise.

Repairs can be as simple as removing an airlock, or as complex as replacing the circulating pump altogether.

Why is my circulating pump making noise?

There is a number of problems that can cause the circulator pump to make unusual noises. These include:

  • Airlocks in the pump — knocking, metal clanking noise
  • Pump shaft isn’t horizontal — whining, banging, knocking
  • Seized pump components — humming, vibration
  • Debris build-up in the pump — humming, vibration
  • Incorrect pump speed settings — loud humming

How long does a central heating pump last?

The circulator pump can last for a long time — as long as the boiler itself, or more — given that you adequately maintain the central heating system. Central heating pumps are susceptible to all the ailments that can plague boilers, radiators, and copper pipes, such as debris build-up.

That’s why it’s essential to keep the heating system as clean as possible; you can do so by having annual boiler service that includes a hot or power flush, as well as fitting a magnetic and limescale filters. Doing so will prolong the life of the pump and the boiler’s other components.

What does a faulty boiler pump sound like?

Faulty central heating pumps can produce a variety of noises; some of these are absolutely normal, whilst others point to a fault.

If the circulator pump is running without issues, all you should hear is a very slight whirring noise.

However, if the pump is airlocked, clogged with debris, installed incorrectly, or set to an incorrect water flow rate setting, you can expect to hear other, abnormal noises, such as:

  • Banging
  • Loud vibrating
  • Knocking
  • Humming
  • Whining

To get rid of the noise, you’lll have to get a heating engineer to identify and fix the root ploblem.

Will an airlock clear itself?

It is possible for an airlock to clear itself, but you shouldn’t count on this to happen.

If you suspect that your circulator pump has air trapped inside, you should bleed the pump to remove the airlock.

How do you get rid of an airlock in a central heating pump?

If your boiler circulator pump has an airlock, you can bleed the pump to get the trapped air out.

Most boiler pumps are manufactured with a special screw exactly for this purpose. You can turn the screw and keep it open until air stops hissing and you see water leaking out instead; the airlock should be gone at this point.

How much does it cost to replace a boiler circulator pump?

It depends on the pump brand and model, but if you replace your faulty pump with one from Grundfos (industry standard nowadays), you can expect to pay around £250, including installation.

Now, there are cheaper circulators pumps out there, but they’re generally less reliable than Grundfos, and may not be worth the short-term savings.

What causes a boiler pump to fail?

A central heating pump can fail for several reasons. Firstly, it may accumulate central heating sludge — debris comprising bits of rust from the heating system — and stop working properly the more clogged up it gets.

Secondly, the pump may start to malfunction if subjected to undue stress; for example, if it’s not installed correctly.

Finally, the pump may simply fail due to normal wear-and-tear as time goes by. The good news is this: this “natural death” shouldn’t arrive early if the heating system is well maintained. In fact, you can normally expect the pump to last as long as the boiler, if not longer.

What’s Next?

Is there anything we’ve missed in this post?

If you have any questions about your noisy pump that are not covered above, or have an experience you’d like to share, please leave a comment below.



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  1. Ian Wood says:

    When removing bleed screw to check if pump was stuck,after the initial trickle of water there was a jet of water as if under pressure. Does my pump need replacing?

    1. Alex Ion says:

      Just because of that pressure jet of water? No. If you have other problems with it, then yes.

  2. Bill Harshbarger says:

    I have a new Viessmann Vitoladens 300c with Grundflos Alpha2 pump. When the unit gets to its upper limit(3+ cubic meters per hour), it sings throughout the system. The original pump was replaced with a lower capacity, but it to has started to sing (2+). The only setting which does not sing is the lowest of the 10 available. Any thoughts appreciated

    1. Alex Ion says:

      Hi Bill, I think the pump must be checked again by someone who really knows their business. You have some links in the article above to find someone in your area.

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