My boiler is making banging noises

Is your boiler making odd noises? Have you noticed that it’s gurgling, banging or whistling? Or maybe it sounds like a kettle boiling, except much louder? 

Most of the time, if we service them regularly, our boilers don’t give us much trouble: they work quietly, day after day, to keep us warm and cosy. Sometimes, though, things can go wrong, and often the first sign of a problem is an unexpected noise.

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These noises can be worrying, especially if they’re loud, but usually, they’re not dangerous. Most boilers have safety controls that turn the unit off if a serious issue occurs. However, they could be a symptom of a problem with your central heating system, perhaps caused by air or a build-up of material. Over time, this could lead to a boiler breakdown and expensive repairs. 

Today we take a look at the most common causes of those noises, and how you can go about getting your boiler back to normal in no time.

The most likely cause of a noisy boiler is kettling, which produces a sound like a boiling kettle, except much louder. It occurs when sludge and limescale builds up inside, and is especially common in hard water areas. When the debris collects at the bottom of the boiler, it restricts the water flow and it becomes trapped in the heat exchanger: it starts to steam, boil and expand, which causes the kettle sound. This issue doesn’t just cause a noise - it often makes your central heating less efficient, leaving you with less heat and higher bills. You might also notice that the hot water isn’t flowing to your taps the way it used to. Over time, kettling can cause your boiler to wear out faster, so calling for an expert inspection can save you money in the long run. 

Arrange for one of our RGII professional Service Engineers to service the boiler and identify the issue. Making an appointment is easy: contact us on 01 611 01 45

It can give you a bit of a surprise, especially during the night, but a banging boiler might have a simple cause. 

First of all, you should make sure the noise is definitely coming from your boiler - quite often it’s actually a loosely-secured pipe that’s at fault. If you can’t see any obvious problems, but the noise is still coming from the pipes, you may need to arrange for a plumber to inspect them. We have a network of qualified, vetted plumbers on LocalHeroes.ie who will be able to help.

If the boiler itself is banging, it might be a faulty thermostat. Our experts recommend checking that your thermostat is working correctly, and that it’s set to the right water pressure (this will be in the manufacturer’s manual). If the pressure is too high, it can cause damage to your system over the long term, so if you’re unsure, it’s best to contact us to arrange for a qualified Service Engineer to take a look.

Conversely, if the water pressure is too low, it might cause a gurgling sound to come from your boiler. Sometimes, if there’s a particularly cold snap, your condensation pipe might freeze, which can create gurgling as the water can’t properly circulate through the system. If you can access the pipe, you might be able to solve this problem with a hot water bottle. It’s a good idea to get the pipe insulated, so the problem doesn’t happen every time temperatures dip below freezing.

Other causes of this noise include trapped air, which means you’re hearing a mixture of water and air flowing through the system. Quite often, you’ll hear it in the radiators too, so bleeding them to release the air is a good first step. If that doesn’t work, you’ll probably have to call for professional assistance.

If you’re in any way unsure or concerned about your boiler, it’s best to make a flexible appointment with us as soon as possible. One of our qualified Service Engineers will visit your property, carry out tests and checks on your boiler, and diagnose the fault. Our team of boiler experts are fully insured and RGII certified so that you can rest assured your boiler is in safe hands.

Like all modern appliances, boilers can sometimes go wrong for no reason, which can be frustrating, and expensive. For extra peace of mind, Bord Gáis Energy offers professional servicing with extra boiler protection options. This means you can get help within 24 hours, and cover towards the repair costs, making those unexpected surprises easier on your pocket. With our Complete Boiler Care or 365 Boiler Care packages, you can rest easy, knowing that we'll make sure your home stays warm - and you stay protected - all year round.

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