What Are The Most Common Boiler Problems?


There is never a convenient time to experience problems with your boiler. As the cold weather sets in, we becoming increasingly reliant on our heating systems. So when our boilers start making irregular noises or switching off intermittently it can be alarming, especially during the winter months.

Keeping up with an annual service will help you keep on top of your boiler's functionality and potentially prevent major problems from happening. However, small faults are a common occurrence in household boiler systems.

Whilst there could be some simple checks you could do to identify if you have a boiler problem, in most cases we advise getting in touch with a Gas Safe engineer and not trying to fix the problem yourself to avoid any potential danger or escalating the problem.

Intermittent heating and hot water

There are a number of reasons for your boiler not producing hot water or heating. Reasons include valve failure, airlocks, a faulty thermostat or possibly low water levels. By performing a few simple checks such as checking the pilot light to see that it is burning blue or making sure that the thermostat on an electric boiler is set correctly.

Leaking or dripping

If your boiler is leaking or dripping we recommend calling a Gas Safe registered engineer as this could be a sign of corrosion within the boiler or a broken internal component.

A boiler leak could be caused by many different reasons. To determine the problem, the location of the leakage area will need to be identified and repaired by the engineer. In some cases the damage could be so extensive that a replacement boiler may be needed.

'Kettling' (banging or whistling noises)

If you hear unusually loud noises including whistling or banging, your boiler is likely to have a build up of limescale or sludge within the system. When these deposits build up over a period of time it can affect the efficiency of your boiler by blocking the flow of water inside the heat exchanger which then overheats producing noises. This process is called 'kettling' and may become a costly issue by shorten your boiler's lifespan when not treated immediately.

Unreliable pilot light

The pilot light is the characteristic blue flame which should remain lit at all times. If it keeps turning off this means that you boiler is not working properly.

The most common reason for an unreliable pilot light is a faulty thermocouple which inhibits the gas supply reaching the boiler, therefore causing the pilot light to blow out. If you are confident in yourself to relight the pilot light, be sure to check that there are no issues with your gas supply. However, when in doubt, contact an engineer.

This is less common in new boilers.

Frozen condensate pipe

All new boilers are condensing units so anyone can experience a frozen pipes during particularly cold weather often experienced in the UK.

It can be fixed by simply applying warm (not boiling) water to the pipe from the kettle, but if it isn’t fixed by this method, contact an engineer for assistance.

Low boiler pressure

If your boiler pressure is below 1, your central heating system is likely not able to function properly so be sure to check this first.

There can be numerous reasons for your boiler to reduce in pressure including a damaged pressure relief valve or a possible leak inside your central heating system. A simple method you can try is to look for a visible leak in the system. If a leak is found, you'll need to call out a Gas Safe engineer. If you don't find a leak in the system, if you are able, try re-pressurising your boiler.

Boiler switching off

This is a common problem with boilers. If your boiler continues to switch itself off then this could indicate that boiler pressure is too low. Another reason why your boiler is turning off could involve a blockage in the system which restricts water flow, or the pump could be faulty and therefore not circulating the water properly.

Radiators not heating evenly

Radiators will often require bleeding to get the best out of your heating system. The reason for irregular temperatures in your radiator can be due to trapped air which needs to be released through the process of 'bleeding'. This is a simple task and usually doesn't require an engineer. For a step-by-step guide on how to bleed a radiator please click here.