Prevention is always better than cure, and this is particularly true when it comes to your boiler. Boiler issues can be complicated and sometimes costly, so always try and stay one step ahead to ensure problems do not appear out of the blue. Servicing your boiler regularly will help keep it in its best possible condition and reduce the likelihood of problems occurring. We have outlined below, some common boiler problems that we are often called out to, to help you identify issues as they occur.

Strange noises

It is normal to hear a small amount of noise produced by your boiler when it is running, but if its continuous or very loud, it could mean there is an underlying problem that might need the attention of a professional. There are many reasons why boilers make odd noises and if you are experiencing the dulcet tones of banging, gurgling and whistling that is getting out of control it’s always good to get it investigated before the issue escalates and you are left without heating or hot water. Common reasons include:

Air trapped in your system – it might be time to dig out that radiator key and bleed your radiators to release the air.

Low water pressure – check your boiler pressure and gauge is working correctly.

A faulty pump – a pump pushes water around your system so if it is not working properly, you’ll soon know about it.  An engineer can check this for you.

A build up of limescale or sludge – If you have a general build-up of limescale or debris in your system, it will likely make a noise as the water gets trapped and overheats.  If this is the case, get it cleaned out before this causes irreversible damage to the boiler or other parts of the system.


A boiler leak is usually repaired quickly and easily.  However, sometimes a boiler leak can be the result of a more serious issues such as significant corrosion to the heat exchanger or other internal components.  Leaks can also damage other components inside the boiler if not addressed quickly.

High or low water pressure

In order to work, your central heating system needs to be sealed and pressurised. If the pressure is too high or too low, your boiler can stop working.

No heating or hot water

There’s nothing worse than not being able to have your daily hot shower or trying to sleep in a freezing cold house, shivering under the duvet.  When your boiler fails to do the very thing, it is designed to do – heat your home and provide hot water, it can be frustrating and stressful. Identifying the cause of the problem can be difficult as there are a number of components inside the boiler and other external components, all of which could cause similar problems. It is always best for a qualified heating engineer to test the installation carefully and confirm that cause of a problem before undertaking any repairs or replacing any components.

No hot water, but heating working fine (or vice versa)

This problem is typically associated with a faulty diverter valve. The diverter valve’s job is to control whether the water produced by the boiler heats the hot water or the heating system. Hot water generally take priority. Diverter valves can become stuck due to debris from the heating system accumulating inside the valve body. This can affect prevent the hot water supply and/or heating in your home from operating satisfactorily. If there is sludgy in the heating, you could find that the system produces hot/tepid water but no heating and vice versa. Luckily, the problem can be fixed by a heating engineer repairing the valve and cleaning the heating system. We also recommend keeping a heating system clean by carrying out a powerflush and installing a suitable magnetic system filter.

Thermostat problems

We deal with many issues relating to a boiler not responding to the thermostat. Sometimes, the boiler is not responding at all, suggesting the controls are broken or it is just very old and needs replacing. Sometimes, the thermostat behaves erratically – it might be turning the heating on and off or losing its accuracy. Once you have ruled out the obvious, such as checking the thermostat is actually turned on, checking that its settings are correct and checking that the batteries don’t need replacing, you could try positioning the device closer to the boiler to rule out interference issues. If the problem persists and you cannot get the thermostat responding efficiently, it may require replacing.

Frozen condensate pipes

High efficiency condensing boilers have a condensate pipe to transport condense (water) which is produced as a product of the combustion process. The pipe allows the water to drain from the boiler. Condense is acidic so should always be drained into an appropriate part of the drainage system or treated so that it can drain into the rainwater system or the ground. The condensate pipe can often extend externally into the drainage system. If the pipework hasn’t been insulated or protected with an electric heating element then during very cold and frosty weather, it could freeze and cause a blockage. This would cause the condensate to travel back up into the boiler, leading to the system cutting out and breaking down. Homeowners can try to fix this problem themselves by insulating the pipes prior to winter or heating the pipe with a warm cloth or hot water bottle to try and defrost it. Sometimes pouring hot water on the pipe is necessary.

Once the pipe has defrosted and is no longer blocked, reset the boiler so that it starts firing up again.

If you feel unsafe or are just not confident tackling any of the boiler issues we have mentioned here, please do give us a call on 020 8131 1866. We would be happy to help. Likewise, just like any other appliance, boilers function well and for longer when serviced annually.  A regular check will help prevent problems before they escalate and you are left without heat and hot water when you need it the most.