How to Fix a Condensate Pipe

Condensate pipes are a part of every combi boiler. When all is well with them they contribute to a healthily running boiler, transporting heat and hot water to your home. In winter especially, we all rely on our boilers daily. They offer protection from the cold blustery gales outside and keep us toasty at home, whether that’s while we’re relaxing on the sofa or having a family dinner.

The problem occurs if your combi boiler stops working. Suddenly there’s no protection from the elements: your home is no longer warm and cosy and you can’t even warm up with a bath or shower because the hot water doesn’t work either!

If it’s winter and this happens, it’s first worth investigating whether it’s your condensate pipe that needs repairing. This is something you can possibly do yourself - without needing to call out a plumber. In the following post, we explain how to find your pipe, assess if there’s a problem with it and how to fix it. 

How your condensate pipe works

Condensing technology in your combi boiler increases its efficiency. It allows the heat from flu gasses to be brought back into the system to help heat the water in the boiler. In essence, this recycles some of the fuel being used, helping the environment by reducing energy use. 

While this process happens it reduces the temperature of the flue gas which causes condensation. This obviously has to be drained quickly, which is where the condensate pipe comes in. It drains the condensation water from your heating system and sends it to be disposed of with the rest of your home’s waste water. Sometimes the condensate pipe is fitted internally, but for various reasons this is not always possible and it’s often installed as an external pipe. 

Problems with condensate pipes

When your condensate pipe is fitted externally or in an outbuilding without heating, such as a garage, it is at risk of becoming frozen, which stops your combi boiler from working. 

Condensate pipes have to be plastic so they are fairly easy to spot amidst the array of piping in your heating system. Connected to your boiler, the condensate pipe is quite short and positioned at a steep angle. It will be 22-32mm in diameter and probably positioned at a similar height to your window sill. 

How to fix a frozen condensate pipe

If your boiler has been appearing to work well but you have no heat or hot water, the culprit, in winter, is probably your condensate pipe. If the pipe is frozen, the boiler can detect this and will turn off as a safety measure. You will not be able to relight your boiler until the pipe has thawed. 

If the following steps don’t work, it’s important to contact a Gas Safe registered engineer next. Don’t attempt to do anything else to your condensate pipe and never try to cut or disconnect it from your boiler. 

To try to thaw your condensate pipe, use warm to hot water. Don’t use boiling water as this can damage your pipe, and is also a safety risk to you in case you slip and scald yourself. Pour the water across the pipe, concentrating on flat sections or any corners, as these are more at risk of freezing. If you suspect a certain part of the pipe has frozen, pour more water over this area. 

If your pipe is still icy, you could also try using a hot water bottle. Leaving it on the pipe for a longer period can help it thaw inside gradually. If the ice inside the pipe melts and it is no longer frozen, you may hear the sound of trickling water or water exiting the pipe, indicating your efforts are working. 

You can then try to reset your boiler. If this works it means the pipe has been unfrozen and your boiler should come back to life. If you are unsure about any of the above, or if this doesn’t work, always contact a trusted Gas Safe registered heating engineer. 

Need boiler help in Tadcaster, Wetherby or York?

If you need help with any aspect of your boiler, give the expert team at Armstrong Plumbing & Heating a call. We offer our friendly and professional services across Tadcaster, Wetherby, York and the surrounding areas, bringing heat and hot water back to homes as quickly as we can! To contact us you can telephone 07834 168464 or 01904 373075, email or fill out our short contact form outlining your query.