Noisy Boiler: Why is My Boiler Making Noises?

Noisy Boiler: Why is My Boiler Making Noises?

Unable to determine the source of the noise your boiler is making? Click here to learn about the most common causes of a noisy boiler.

Boiler noises can be indicative of quite a few issues that ought to be addressed swiftly, including air blockage, inadequate water flow, overheating, and limescale, to name a few.

Identifying the exact problem hindering your boiler’s performance based on the noise that it’s making can be challenging, though, as there’s a host of different noises that a boiler can make, from rattling and banging to vibrating and humming.

If your boiler is making strange noises, you ought to stick around, as we’re about to cover the reasons behind different boiler noises and how you can go about addressing each one.

The Boiler is Making Rattling Noises

Loud rattling noises from a boiler are typically indicative of loose objects vibrating freely or against each other. In this case, loose objects need to be tightened firmly.

Rattling can also be indicative of other problems like air-filled pipework. If that’s the case, you need to bleed your radiators to eliminate the excess air within the system. Fortunately, bleeding radiators is a simple process that doesn’t require professional help.

Please bear in mind that bleeding the radiators will reduce the pressure in your boiler, meaning you’ll need to repressurise it. Click here for more insights on pressurising boilers.

What if you still hear rattling noises after having bled the system and repressurised your boiler? Well, in this case, you might be dealing with one or more loose valves. Try to identify the exact source of the noise and tighten any loose valves near that area.

Lastly, check if you have any poorly clipped pipes, as they may also be behind rattling noises. If so, you may need professional help with reclipping your boiler’s pipework.

The Boiler is Making Humming Noises

If your boiler is emitting humming noises, it’s highly likely that the heating element is slightly loose and needs to be tightened firmly.

If your boiler is rumbling more so than humming, you might be dealing with limescale, rust, or sediment, which, in this case, calls for the use of a magnetic scale reducer or some sort of mineral collector.

Boiler rumbling can also be indicative of overly high pressure. If this is the case, you’ll need to readjust your incoming supply’s pressure.

It’s worth noting that a pump that’s set too high can cause your boiler to hum, trickle, or vibrate. Consider lowering your pump if that’s the case.

Lastly, boiler humming and rumbling can be the result of loose bearings within the fan inside your boiler. If none of these reasons is behind your boiler’s humming noise, you should call a professional.

The Boiler is Making Vibrating Noises

There are quite a few potential reasons why your boiler is vibrating. Firstly, it could be the result of improper pump setting. The pump might be placed too high, or it might be shaking within its case.

Secondly, you might be dealing with a build-up of sludge, which can result in boiler overheating. Regardless of the reason behind your boiler’s vibrations, this is a pretty serious noise that calls for a professional inspection.

The Boiler is Making Boiling Kettle Noises

If your boiler is emitting kettle-like noises, it’s highly likely that your central heating system has some trapped air inside it. In this case, you’ll need to bleed your radiators. Like we mentioned earlier, don’t forget to readjust your boiler’s pressure after bleeding the radiators.

If the noise persists, you might be dealing with an accumulation of corrosion debris or limescale that’s restricting the water flow. When the trapped water heats up and boils, it’ll release steam and expand, resulting in whistling noises.

Unfortunately, there’s no quick fix to this problem. You’ll need to phone a qualified professional to help you with this problem.

The Boiler is Making Banging Noises

Banging/tapping noises are usually a result of boiler kettling, which, as we already established, is a result of a build-up of sludge or minerals in or around the heat exchanger. This is quite common with older heat exchangers made of cast-iron. It’s also common in areas with a supply of hard water.

When a build-up of sludge or minerals takes place, the water flow becomes restricted or even blocked, in more extreme cases. This causes the water to boil and release steam, resulting in banging, kittling, and whistling noises.

If the banging noises you’re hearing from your boiler are notably loud and shocking, you might be dealing with the emergence of large air bubbles that are constantly popping. Don’t be alarmed, though, as kittling won’t make your boiler explode.

We don’t recommend attempting to eliminate these banging and kettling noises all by yourself. You need to hire a professional to do it, as there’s no easy fix that can help you get rid of build-up.

The Boiler is Making Gurgling / Dripping Noises

Gurgling boiler noises can come from two sources: the radiator or the pipework. The reason behind this noise is trapped air mixing with water within the boiler system.

Even though the presence of air within a boiler isn’t normal, it’s not something that you should be worried about. You can easily get rid of the air by bleeding your radiators.

If you choose not to bleed your radiators to get rid of the air inside the system, you should know that trapped air hinders heat radiation, which will result in your boiler consuming more gas and staying on for longer. This, in turn, translates to higher utility bills, especially in the frigid months of winter.

Gurgling or dripping noises can also be the result of a frozen condensate pipe. In this case, you should unfreeze the pipe as soon as possible to prevent your boiler from getting damaged.

The Boiler is Making Drone Noises

A droning boiler, as the name suggests, sounds like a drone or foghorn. If your boiler is making such a sound, there’s likely something wrong with the pump within your boiler.

There are a few reasons why your boiler’s pump isn’t working properly. For instance, the impeller might have caught some air or debris. It can also be just a mechanical failure.

Pump-related problems cannot be fixed without professional help. So, if you start hearing drone noises from your boiler, you need to phone a qualified engineer.

Note that the pump may need to be replaced entirely. And if the internal system has suffered significant damage, the entire boiler may need to be replaced.

Noisy Boiler – Final Thoughts

As you can see, some boiler noises are indicative of problems that can be easily fixed, whereas others are indicative of serious problems that require the assistance of a registered heating engineer.

Note that some boilers are equipped with an error code functionality that can be quite beneficial when it comes to problem diagnosis. If you have such a boiler, we recommend checking the boiler’s manual to learn about the different fault codes and how you can go about addressing each one.