How to fix noise in central heating pipes

Central heating systems are complicated devices that provide heating and hot water throughout your home. To facilitate this, a network of pipework spans the entire house to allow the transfer of water and heat to the necessary locations on-demand.

As with any part of your home, it’s not only plausible but likely that you’ll hear or experience some performance issues over the years and it is understandably a cause for concern. One of the most nerve-wracking sounds can be the banging, rattling or vibrating of pipes in your home at seemingly random moments. While these noises can be a cause for concern, there are a number of explanations that are minor in nature; we’ll explain the various noises you might hear during operation and how to fix them in this guide.

All the above noises are signs of potential issues with your system and can be an important step in identifying the issues. In the next section, we’ll discuss the most common problems and how to fix them.

Typical noises - tapping, rattling, clicking and gurgling

Limescale build-up is most prevalent in areas of the United Kingdom with hard water, though can still occur even in areas with softer water. It is a chalk-like substance that is made from the deposits left behind from dried water and can often be seen in kettles and other home apparatus that rely on hot water.

Limescale build-up can cause loss of heating performance and, if left completely untreated, could even block your system and cause bigger issues.

Sludge is built-up from small pieces of rust breaking off and collecting in the system, eventually turning to sludge.

It’s possible to fix this by flushing the system with special cleaning agents, whilst longer-term solutions include a magnetic boiler filter, which can catch sludge and keep it from entering the boiler itself.

Typical noises - knocking, banging, creaking or vibrations

Although this isn’t always an issue, it’s important to understand that pipes - especially when made of copper - are subject to expansion as they heat up during use. This can cause small amounts of creaking, vibrating or knocking sounds from your system, especially as the heating system first starts to fire up and heat cold pipes.

If you experience long-term vibrations, knocking or creaking during operation of your central heating system, it’s possible that your pipes may be moving around and touching floorboards or nearby walls in your home. This can happen if the pipe clip holding the pipe in place breaks, leaving the pipe free to move during expansion and use, or can simply be where the pipe is installed in your home.

If the pipe is secure and simply close to a wall, joist or other pipe, consider putting a small amount of cloth, foam or felt between the wall and pipe to remove the vibration. For pipes that have come loose, it can be much more difficult, especially if they’re beneath the floorboards. We recommend hiring a gas-safe registered engineer to assess the situation and resolve the issue in this instance.

Typical noises - whooshing, gurgling, tapping

Air in the system can cause a number of performance-related problems, most notably cold spots across radiators or loss of heating performance in radiators and gurgling or sputtering taps. This same phenomenon can cause the noises you hear in your pipes, as water passes through pockets of air trapped in the system.

Fortunately, this can be fixed relatively easily through the process of flushing your central heating system.

Typical noises - knocking or banging

One of the most common reasons for unwanted noise in your central heating system, ‘water hammering’ occurs when there is a sudden surge of water within pipework, most notably occurring when taps are turned on or off. Specifically, it is the reversal of water flow within the pipe that causes the banging or knocking noises you might have heard.

It isn’t just taps that can cause this - anything in your home that can draw a water source, such as a shower or a toilet, can be the cause of water hammering. Although relatively common, in extreme circumstances it can cause damage to your system and should be checked by a professional boiler engineer if you are hearing noises from pipes consistently when you use taps, showers or toilets in your home.