Boiler Noises: What’s Normal & When to Get Help!
You’ve probably noticed that boilers make all sorts of noises, from humming and clicking to banging and whistling. While most are completely harmless, others are red flags that signal possible issues, including limescale build-up (known as kettling) and trapped air in the system.
Knowing the difference is the first step to keeping your boiler running smoothly. In this article, we explain what sounds are normal and when to call the professionals.
Why do boilers make noise?
Boilers are hardworking machines with plenty of moving parts, so it’s perfectly normal for them to make a bit of noise throughout the day. As gas and water move through the system, you’ll hear clicks, hums and whooshing coming from the unit and pipework. Some noises are simply inevitable.
Basically, think of your boiler like a car engine. A steady hum is fine, but if a sound is unusually loud or sudden, it could indicate an underlying issue.
With that in mind, the following sections outline the noises you can expect and the ones that may signal a problem.
Common boiler noises
Let’s start with some of the most common boiler noises. If you hear any of these, you don’t need to worry. They are part of a healthy central heating system.
- Humming or low whirring – pump or fan running.
- Clicking or ticking – metal expanding and contracting as it heats and cools.
- Gentle whooshing – burner igniting.
As a rule, if the noises are gentle, regular and don’t change dramatically in volume or tone, you can rest assured they’re nothing to worry about.
Problem boiler noises
Now, onto the red flags. If you hear any of the following noises, we recommend getting a second opinion from a heating specialist.
Banging or knocking
This is often caused by a build-up of limescale or sludge in the heat exchanger. As water struggles to pass through the obstruction, it creates a banging sound. In some cases, the noise may also come from loose pipework elsewhere in the system.
Gurgling
An ominous gurgling sound suggests there’s trapped air or low water pressure in the system. In many cases, bleeding your radiators solves the problem. If this doesn’t help, then it’s time to enlist professional help.
High-pitched whistling
If you’re hearing a high-pitched whistling sound, like a kettle boiling, your boiler is probably overheating or suffering from pressure issues. This is typically caused by limescale build-up, which forces water and gases through increasingly tight spaces.
In this instance, it’s best to switch the boiler off and call a Gas Safe engineer before the problem leads to a full breakdown.
Loud vibrating
There’s a big difference between steady whirring and loud vibrating. The former blends into the background and maintains a consistent tone, whereas the latter is headache-inducing and metallic-sounding.
If your boiler is vibrating, you might notice the entire unit seems to shake. This usually points to a faulty pump or loose pipework, both of which require immediate attention
When should you call a heating engineer
Ultimately, you should call a heating specialist whenever something just doesn’t sound right. As mentioned, most normal sounds blend into the background – you only need to worry if they become louder, more frequent or are accompanied by issues like loss of heating or hot water.
If you need advice, contact the team at Home Heating Experts on 07990755180. Our boiler repair specialists can quickly diagnose the problem and keep your boiler running safely.
