Boiler Making Noise? Diagnose & Fix It With Our Guide

A combi boiler is a necessity in areas where the temperature is shallow. It is one of those appliances that have the least hassle because they are not often turned off. However, the problem begins when the boiler starts misbehaving due to regular wear and tear. The only trick is to catch this issue in the initial stages to be fixed without incurring any significant expenses.

These boilers start making some very peculiar sounds when something is wrong with them. It is quintessential to be acquainted with these sounds to check the root cause of the problem.

If you are also experiencing these random sounds that are always recurring, make sure that you read this article till the end to get equipped with all the right facts.

Common Noises From Boilers

There are a handful of everyday noises that originate due to various reasons. Here is a look at those variants, along with the things that they indicate.

Rattling Noises

Rattling noises are heard when some loose parts are shaking inside and are striking each other. However, this is not the only reason for these sounds. The most prominent reason is air getting filled in the pipeline. This air quantity is more than the standard quality and can be easily controlled by bleeding the radiators.

Bleeding the radiators is a relatively simple process that you can carry out on your own. You have to open the valve so that the air can be steamed out. If the sounds continue, you can look for loose valves that need some fixing.

In most cases, the sounds stop after retightening the loose valves, but it has something to do with the pump if it does not. The pump could have gone faulty, and now you will need a gas safe registered engineer to help you out of this issue.

Loud Humming Noises

This sound is heard due to the presence of the electric water heater. It is a straightforward fix in which you have to tighten the heating element that might have turned loose. Rumbling noises can also be heard owing to the presence of rust and bits of sediment. These substances interact with the heat of the cylinder and start expanding on the spot.

The main water supply can also be the culprit of these humming sounds. If the main water supply is pushing in water with extended pressure, the valves will start whining. You must check this supply switch so that your equipment does not undergo any damage. Faulty tap washers make a similar humming noise, and thus you should observe the source of the sound.

Just like the water supply, if your pump is pumping the water at a rate higher than the standard rate, the fast water movement in the pipeline can also be held responsible for this noise. There are many reasons, and therefore, you can seek the help of a gas safe registered engineer to understand the deal with your boiler making sounds.

Vibrating Noises

If you hear vibrating noises, it can mean that your pump has gone berserk. A faulty pump starts shaking inside the casing to give out vibrations. The fast rate of water flow is also a constituent of the problem.

Another reason that can be identified is the formation of sludge that takes place. This sludge starts multiplying and consequently results in overheating. Overheating is a threat to the entire system, and thus, you should immediately seek technical assistance at such junctures.

Boiling Kettle Noises

The most common reason for these noises is the same extra air that gets trapped inside the system. Your first instinct should be to remove the air by bleeding the radiators. It is imperative to reassemble the whole appliance correctly after bleeding.

If the kettling noises do not stop after this, it can point out an issue in the boiler. The formation of sludge and debris might have reached the boiler, which results in a very truncated efficiency.

You cannot stop the debris from getting formed because it is a natural process. The flow is bound to get restricted with the limescale formation. The small amount of water that flows will get trapped and will overheat. This will cause the boiler to sound like a whistling noise, or make kettling noises. In such cases, you will want an engineer to have a look at it.

Banging Noise

The above-mentioned process of kettling is also responsible for loud banging noises. These banging noises come from the areas hard where hard water is in contact with cast iron heat exchangers. In most cases, the banging sound will be accompanied by the kettling sound.

However, if the sounds escalate to scary extents, this might be the doing of air bubbles. These air bubbles are trapped in the pipeline, and they make thunderous noise. It will not let the whole system fall, but you should get it checked at the earliest.

Dripping Or Gurgling Noises

Dripping and gurgling noise can be heard from the radiators and pipeline when there is excessive air trapped inside the boiler. The boiler should be free from any air since it takes up a lot of heat to warm very little water.

This will cause the whole system to function for more time than the actual need. Your pocket will be strained with these extra hours. You can solve this issue by bleeding your radiators and letting the air off. This will take the extra load from your boilers and will also preserve them from further damage.

A Frozen condensate pipe is also responsible for these sounds. There is an effortless procedure to unfreeze them. Unfreezing them will put the system back on track.

Tapping Noises

Tapping noises are also a byproduct of kettling. The debris remains to cause the boiler to emit these sounds. The whole sludge building process of kettling remains the same, but it might be something else if it continues for a longer time. You should check the system to conduct preliminary analysis.

The sediment-rich water in hard water areas make this issue a widespread phenomenon, and therefore, you can contact professionals who have a set way of resolving this issue.

Drone Noise

The noise that resembles a drone or an aircraft is not exactly what you would expect from a boiler system. However, when your system’s pump is broken and is barely functioning, you can ascertain that an identical noise is coming.

The common cause of a pump failure can range from many small reasons to one destructive blow. It can also be a result of your ignorance of the signs that your boiler has been giving. The expense of replacing a faulty pump is not small, but it is better to incur that cost to prevent the entire assembly from toppling down.

Why Do Boilers Make Such Noises?

Now that you have learned about all the various noises that a boiler can make, it is best to understand all the common causes responsible for them. This will give you better control over analyzing the situation.

Airlock In The Boiler Pump

Banging airlocks in boiler systems is a regular affair. They are very evident, and you will hear the sound in a couple of minutes after you turn the system on.

Releasing The Air

Since the trapped air has nowhere else to flow, the only remaining option is to bleed the radiators. Almost all the modern combi boilers are equipped with the radiator bleeding screw, and it is a straightforward process.

Low Water Flow Rate & Pressure

If problems circulating the water and the pressure are low, you will hear banging and clanging all over the system. This sound is created in the pressure gauge because of the sudden dynamics of the water pressure.

Increasing The Flow Rate

Lost pressure hints towards a leak in the valve of the boiler. You must conduct a primary assessment of the situation to understand what went wrong. Sometimes the problem can be as little as merely adjusting the water pressure from settings.

Limescale Build Up

As mentioned earlier, limescale is a ubiquitous component that gets generated and accumulated in the pipes that are fixed in hard water areas. Limescale restricts the flow of water and causes air bubbles to pop up.

Fixing The Issue

You will have to conduct an overall flush of the system to ensure that the limescale is removed. Limescale can stick around for years and years depending on how well it was catered to when it just started forming. You should ensure timely action so that this limestone does not reach the boiler and wreck the boiler’s entire assembly. You can also opt for boiler installations of a scale reducer to keep all the future limescale formations under check.

Central Heating Sludge Build Up

You cannot evade the formation of sludge in your boiler. Sludge is bound to be formed with all the small dust fragments and other small parts of debris. When this sludge gains momentum and travels across the pipeline, it will make tapping and trickling noise.

Fixing The Sludge

You will have to remove these layers of sludge every once in a while. To start with, you will have to use an inhibitor to start the cleaning procedure. Post that, you will have to go with a powerful flush so that all the hidden fragments of this sludge can be flushed out. You can also incorporate a precautionary measure by adding a boiler filter that can catch the sludge particles.

Ignition Failure

If the water supply pressure is shallow, it will be termed as an ignition failure because the levels are not enough to meet the minimum requirements. The flow of water should be at a constant rate that should not fall below a particular pedestal.

Correcting The Water Supply

There are many ways to correct the water supply. The first one is bleeding the radiators to create more space for water by venting out the trapped air in the system. It is just a problem with the settings that can be adjusted in a few clicks in some sporadic cases.

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Last Updated on May 3, 2021

Frequently Asked Questions

Is a noisy boiler dangerous?

If your boiler is making some random noise, it indicates that something is wrong with it. Almost all the boilers come with a security feature, so these sounds are not completely dangerous. However, they hint towards your boiler needing some attention.

How do I stop my boiler from making noise?

As mentioned above, there are various ways to stop the different kinds of sounds. Bleeding the radiator and fixing the valve are the two main adjustments.

Will my boiler explode?

It is improbable for a boiler to explode, but you can never rule out the possibility. Almost all boilers have an automatic switch which cuts the power off during accidents. If your boiler does not have that switch, you should be extra careful.

David Thompson

Author: David Thompson

Dave has been involved in the UK building sector for over 3 decades and has developed a particular interest in energy efficiency in the home.

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