How To Solve Noisy Boiler Problems

A noisy boiler can be a genuine concern for homeowners. Of course, the first thoughts that come to mind are no hot water, cold showers and expensive repair bills! However, before presuming the worst, there are some scenarios where boiler noise is entirely normal. For example, the sound of the pilot light as it ignites.

This article summarises the most common reasons your boiler makes unusual noises and how to identify that cause.

You can use this list to jump to the sound you’re hearing:

• Banging
• Tapping
• Humming
• Droning
• Gurgling
• Clicking

Banging Noises and Boiler Kettling

If your boiler is producing banging sounds, it may be due to kettling. Kettling occurs when limescale builds up in your central heating system, restricting water flow and causing the water inside the boiler to boil and steam. This boiling process produces kettling sounds, which manifest as banging noises.

To prevent further damage to your boiler and heating system, it is essential to call a Gas Safe registered engineer promptly to address the issue. Limescale buildup can cause significant damage to your boiler and, if left unattended, may lead to costly repairs or even a complete replacement.

Tapping Noises from the Central Heating Pipes

Tapping sounds coming from your radiators or pipework may also be caused by kettling, resulting from sludge or limescale buildup within your central heating system. The accumulation of these materials can cause the tapping noises you hear, as well as affect the overall efficiency and performance of your heating system.

A common fix for sludge buildup in your central heating system is a power flush. This process involves flushing your central system with high-pressure water and cleaning agents, clearing it of any debris and restoring its efficiency. In addition to a power flush, regular boiler maintenance performed by a qualified professional can help prevent future buildup, saving you on unexpected repair bills.

Humming Noises and Boiler Thermostat

A gentle humming noise is normal for many boilers, often caused by pipes vibrating during operation. However, if the humming is new or louder than usual, it could indicate loose components, worn fan bearings, or high boiler pressure.

Loose components can create a gentle hum, which is particularly common if your boiler has been recently serviced or repaired. Worn fan bearings inside your boiler could cause a persistent loud hum. If you suspect this is the case, it is essential to consult a heating engineer to diagnose and address the issue.

High boiler pressure can also cause your boiler to hum loudly. If your boiler is making a loud humming noise, turn it off and call an engineer immediately. High pressure can wear your boiler and cause it to break down – which will cost you more than a quick pressure check.

Droning Noises and Circulating Pump

A droning noise may signify a failing circulating pump caused by air and debris buildup or mechanical failure. The circulating pump moves hot water from the boiler to the radiators and back again, ensuring consistent heat distribution throughout your home. A failing pump can lead to uneven heating and even damage other components of your central heating system.

Calling a heating engineer out quickly is essential if you suspect a failing pump. When one part of your boiler deteriorates, it can cause further issues across your central heating system, leading to costly repairs or replacements.

Gurgling Noises and Heat Exchanger

Gurgling noises can be due to trapped air or blockages in your central heating system or combi boiler. The good news is that this can be pretty simple to fix.

The first step is to bleed your radiators, which involves releasing any trapped air to restore even heating throughout your home. To do this, use a radiator key or a flat-head screwdriver to open the bleed valve on each radiator. Hold a cloth or container under the valve to catch any water, and allow the air to escape until a steady stream of water comes out. Then, close the valve.

After bleeding your radiators, check your boiler’s water pressure gauge to ensure it hasn’t dropped. If the pressure is too low, you may need to repressurise your boiler by following the manufacturer’s instructions. If you still hear a gurgling or dripping sound after bleeding the radiators and checking the pressure, you may have a frozen pipe or another issue that requires professional attention.

Clicking Noises and Heat Exchanger

Occasional clicking is normal when your boiler fires up, as this sound is typically produced by the igniter. However, excessive clicking could indicate a failing ignition, a problem with the heat exchanger, or a worn-out motor bearing. In these cases, it is crucial to seek the help of a Gas Safe registered engineer to diagnose and repair the issue before it causes more severe damage to your boiler or heating system.

Regular Boiler Maintenance for Prevention

Scheduling regular boiler maintenance can help identify and fix issues before they become serious problems. Annual boiler inspections, performed by a qualified professional, are more cost-effective than replacing a damaged boiler, which can cost between £1000-£2500. During an inspection, the engineer will check for any signs of wear or damage, clean components, and ensure the system is working efficiently.

In addition to regular maintenance, consider installing a magnetic filter to help prevent sludge and debris buildup in your central heating system. This device captures and removes debris, such as rust and limescale, from the water circulating through your heating system, helping to maintain its efficiency and prolong its lifespan.

It’s also essential to ensure your boiler is serviced according to the manufacturer’s guidelines, as failing to do so may void the warranty. Furthermore, a well-maintained boiler is more energy-efficient, which can save you money on your energy bills in the long run.

About the author

Trades Team are experts in Heating, Plumbing and Gas Services. We have 15 years of experience providing expert Boiler Repair and Boiler Servicing to homes and businesses across the Southeast. Learn more about Trades Team.