Noisy Central Heating Pump [Problems & Fixes]

Having problems with a noisy central heating pump? No problem. In our 5-minute guide, we’ll cover all the possibilities.

Whether your pump is banging, ticking or humming, this guide will help to diagnose and fix the problem, as soon as possible.

Noisy central heating pump

If you’d prefer a boiler 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.

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 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 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 central heating pump bleed screw is at the side.

And if it’s not, you’ll need to adjust it so that it is — the bleed 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.

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 it, and inspect it for wear. Next, fit a boiler filter to catch debris in the heating system, so dirt can’t accumulate there again.


#5 – Incorrect speed setting

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 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 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 an engineer’s opinion first.


Heat Pump Noise, What’s Next?

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

But, if you’re still hearing unusual boiler pump noise, you can speak to a repair engineer here.

And if you feel that your boiler may be up for replacement, you can get a quote from Heatable in only 90 seconds using this form.

Or, if you have any questions about your noisy pump that are not covered above, leave a comment below.

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  1. 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?

  2. 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. 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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