Strange Noises Form the Boiler

If you are hearing strange noises from the boiler, it could be a sign of a serious problem, it may be working right now, but sooner or later it will break down and you will have no hot water or heating.

It’s probably best now, to call in the local Gas Safe Registered boiler engineer before it stops working, but mainly to ensure it’s not posing any serious safety risks to you and your family.

What are these strange noises from the boiler?

Noises from the boiler can be caused by many things, it could be a build up of limescale on the heat exchanger, sludge even a blockage.

When the flow of water within the boiler is restricted, the boiler will start to make a banging noise, this is due to the water heating up, expanding and pressure building, It needs to go somewhere,

It will normally release itself up the expansion pipe, or if the boiler is pressurised, it should release through the safety pressure relief valve.

Kettling Noise

You may have noticed over time a whistling noise coming from the boiler, a little like when you boil a kettle to make your coffee, as it starts to heat up you start to hear a noise, this is called kettling.

Kettling can be caused by air trapped in the system, if this is the case, it’s normally a quick fix to make the boiler quite again.

Kettling is also caused by the limescale on the walls of the heat exchanger. Overtime as the limescale builds up, the kettling noise gets louder, this will eventually cause the boiler to stop working.

Faulty Pump

Another reason you may hear strange noises from the boiler is the pump. The pump works by circulating the water throughout the whole system. Should the pump start to lose its power, you may well hear strange some noises from the boiler.

Internal Fan

The boiler fan is another part that over time tends to start making a strange noise. It starts off with a low screaming sound then gets louder and louder, other times it like a clunking noise. The reason the fan starts to make a noise is due to the bearings, they tend to dry out, eventually, the fan will become seized and need to be replaced.

The Boiler

The boiler is a very important part of your home, it supplies you with hot water, as well as all the heating you need in the colder months, and yet it always seems to get overlooked until something goes wrong.

Should you start to notice strange noises from your boiler, the first thing you should do is switch it off and arrange for it to be checked over straightaway. By keeping the boiler working you could cause more problems.

Preventative Maintenance

Ensure you have some form of maintenance or service carried out on the boiler every year. Setup an annual contract with a local company who will make sure everything is working as it should be and most important of all SAFE.


If you hear strange noises from the boiler switch it off, don’t risk it. Arrange for someone to come along and investigate and fix the problem. Don’t forget though only use a gas safe registered company or person.


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