Why is My Boiler Making a Noise?

Person adjusting boiler settings

A boiler is something we usually all take for granted, but when things start to go wrong with it, we quickly realise just how integral it is to the everyday running of a household. With hot water access and central heating system all regulated from a property’s boiler, it’s important that any issues with it are fixed as soon as possible. If your boiler has started making a noise that isn’t normal or usual for it and you’re frantically searching for answers, look no further. This article may be able to help!

Diagnose the source of the noise

Boilers aren’t usually entirely silent, and older boilers tend to be noisier than newer models, so don’t panic if you can hear it occasionally. If a boiler makes noise when heating is on, this is simply caused by its powering of heating and cooling, so can be considered normal unless it’s unusually loud or sounds different.

If you’re still wondering, “why is my boiler making a noise?” and need to diagnose the problem, start first with the kind of noise you can hear:

Boiler making a banging noise

A boiler making banging noises isn’t just annoying – it can be a bit startling! Banging noises from a boiler are often caused by kettling; that is, a build-up of mineral deposits, residue and sludge in the heat exchanger. This is very common in older boilers and can happen quickly in areas with hard water. The banging can be caused by air bubbles popping, and this loud banging noise can be quite concerning. In the case of your boiler making banging noises, it’s best to seek the advice of a professional who will be able to help give further guidance on removing the sludge or replacing the boiler.

Boiler making a gurgling noise

Gurgling or ‘dripping’ type sounds coming from a boiler are usually caused by trapped air in the system. There shouldn’t be any air at all in your boiler, but it can be pushed through by the water travelling through the central heating system. In the case of gurgling, simply bleed your radiators. This allows the trapped air to be released through the system. Make sure you’ve got plenty of cloths though – in cases where there’s enough noise to make you notice, it’s quite common to find some spillage from the bleed valves on each radiator… or even a kind of ‘burping’ sound when you relieve them!

Boiler making a vibrating noise

A boiler making vibrating noises could have one of two issues. The first is another case of trapped air; for which a quick bleed of your radiators should fix. The second is a loose fixture or fitting that’s causing disproportionate noise as it rattles out of place. Do a quick once-over of your boiler and radiators and ensure all valves and screws are tightly in place. If this doesn’t fix the boiler making vibrating noises, call a heating engineer and have them check for anything loose internally.

Boiler making a humming noise

If your boiler is making a humming noise, there’s lots to troubleshoot. First, check all fixtures and fittings to ensure they’re tightly secured. Secondly, check the boiler’s pressure. If this is running too high, the valves and fittings within the boiler can begin to strain and ‘whine’. If the pressure is fine, the humming could be caused by sediment build-up in the tank or cylinder, tap washers needing an upgrade, or the pump being set too high and pushing water around the central heating system too fast. A professional heating engineer will be able to advise you on exactly what the issue is and how best to proceed.

How to stop your boiler from making a noise

There’s lots that a homeowner can do in their quest of how to reduce boiler noise, and routine maintenance such as checking in on the pressure and bleeding radiators can help keep things quiet. However, if your boiler is consistently making an unduly loud or disruptive noise, or starts making noise that isn’t typical for your set-up, it’s always best to seek the advice of a professional.

Unfortunately, there is no one way of how to stop a boiler making noise, but more importantly: there’s no safe way to carry out maintenance on it unless you’re a registered gas engineer. If you’re drawing a blank and can’t either locate the source of the noise or the cause of it, call a qualified heating engineer and get an expert opinion.

If you need further expert advice on central heating systems or radiators, or would like to learn more on how to bleed or balance radiators, get in touch with the Great Rads team!


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