When you switch on your central heating system, and the hot water starts flowing, it should come on quietly smoothly and efficiently. It's the sign of a well-maintained system, and you should have your boiler checked every 12 months in order to keep things running well.

However, there are times when you might experience a noisy radiator or pipes and hear noises such as knocking, banging, creaking or ticking and they can be a bit annoying, if not disconcerting.

Sometimes, noisy radiators or pipes are not really anything to worry about and are often part and parcel of having a central heating system. However, in some circumstances these noises could be a sign of something more serious and in need of further investigation.

In this post, we'll explore why your radiators might be making a noise and what steps you can take to reduce or resolve the problem.

Why do radiators make noises?

There are numerous reasons why you might hear noises coming from your radiators or pipes. A lot of the noises differ from one another and the type of noise can help to shed light on the source of the issue and whether or not it's actually a problem.

Air trapped in the heating system

When your central heating is used week after week, month after month, a small amount of air can slip into the system. Over time, and when sufficient air gets trapped, this can cause your pipes and radiators to make noise. You'll often hear this when the heating is first switched on and you hear a tapping, clicking or ticking. You might also notice your radiators are cold at the top but warm at the bottom.

This sound can be a tad annoying, but it can also mean that your radiators aren't operating efficiently and heating up to their maximum capabilities. Your boiler and pump are likely to be working harder to try and compensate, leading to higher energy bills and reducing the longevity of some of your heating components

Limescale build-up

The water in 'hard water' areas (such as London and much of the Suuth East of England) contains a lot of minerals, a high proportion of which is calcium.

When hard water dries, it leaves behind a calcium deposit - a white residue which you may be more familiar to you as limescale. If you live in a hard water area, you're most likely to see evidence of limescale in kettles, around plug holes or anywhere where you have a dripping tap. However, while these spots of limescale are very noticeable, you're unlikely to be aware of it happening inside your heating system until it starts to become problematic.

If you've got a build up of limescale then this narrows the pipework and restricts the amount of water that can flow around your system. You can compare this to the narrowing of arteries around a heart. Again, this means that the components in your system are having to work much harder in order to compensate for the restricted hot water flow. Common noises if you're suffering from this problem are tapping and whistling.

Expanding copper pipes

In houses built over the last couple of decades, plastic piping is the most common pipe material, which is much to do with the fact that they are flexible and cheap to manufacture. However, much older houses are likely to contain their original copper pipes in order to transport water around the home.

As hot water flows through the pipes, it causes the copper to heat up and expand in size. If another surface, such as a wall, floorboard, bracket or joist, is in close proximity then the expanding copper pipe may make contact. Common noises caused by pipe expansion are knocks, creaks and groans.

These types of noise are not in and of themselves problematic and are usually a harmless quirk of having copper pipes in your heating system. However, when these noises sound particularly loud, it could be a sign that one of your pipes is not securely fastened. A loose pipe could weaken over time and potentially cause serious damage.

Water hammering

Not quite related to a noisy radiator, but if you're hearing banging noises when you turn on a tap, you could be suffering 'water hammering' in your system.

Water hammering tends to be caused by water flowing one way in your system then having to flow in the opposite direction when a tap is turned on. It's this sudden change in direction of the water flow that causes the banging and usually stops once the tap is turned off.

While not an immediate cause for concern, this can cause a weakening of pipe joints over time if left unchecked.

How to stop the noises in your rads and pipes

The noises outlined above are not often cause for immediate panic. However, you should have your heating system checked on an annual basis and call in a professional if noises sound particularly concerning or problematic.

Central heating systems are always going to make a little bit of noise, but there are some things you can do to reduce any irritating or concerning noises further.

Bleed your radiators

Bleeding the air out of a radiator is one of the simplest DIY jobs you can do and letting out any trapped air should help reduce the clicking and ticking. You should also notice an improvement in heat distribution evenly across your radiators.

The video below shows a professional plumber going through the simple process of bleeding radiators.

 

Power flush your heating system

Calling in a plumber to clean and power flush your heating system will usually help your heating to run more efficiently and will reduce odd noises

In addition to calcium deposits, your radiators and pipework can see a build up of rust, dirt and sludge. Power flushing your rads will remove most of the debris, and will allow your radiators to get hot to their full potential much more quietly.

Secure loose pipework

Employing a professional to check any banging and loose pipes is a really worthwhile job to have done. Floorboards may need removing so this is something best avoided yourself unless you are very experienced.

If groaning or creaking noises have been plaguing your heating system then securing pipes in place will seriously help to reduce this issue. Securely fixed pipes are much less likely to come into contact with another surface so should not only reduce noise but also help future-proof additional weakening of the pipes.

If in doubt, call a professional

If a noise is particularly loud (such as the water hammering mentioned earlier) or there is an issue with your noisy radiators or pipes that you don't feel happy about, then call in a professional to investigate. Water damage can be very expensive to properties so it's simply not worth the risk of leaving a potential issue unchecked.

A professional heating engineer can perform maintenance on your boiler and heating system, resolve any existing issues and may well be able to identify any other issues before they become serious. Get your system maintained every 12 months to reduce annoying noises, to keep your system running smoothly and efficiently and to prolong the life of all your heating components