How to fix a frozen condensate pipe…
Feeling chilly? If your boiler has stopped working when it’s freezing outside, there’s a good chance that your boiler’s condensate pipe has frozen.
This pipe is responsible for taking waste from your boiler out into a drain. If it gets blocked with ice, your boiler will automatically shut down as a safety measure until it’s resolved.
Luckily, this isn’t a big problem, and it might be something you wish to try resolving for yourself. Read our step-by-step guide to get up and running again.
What are condensing boilers?
There’s a common misconception that a ‘condensing boiler’ is a type of boiler, when in fact, it isn’t.
The terms ‘condensing boilers’ and ‘non-condensing boilers’ are confusing, because they actually describe the technology within the boiler itself, rather than what sort of boiler it is.
The regulations changed because condensing boilers are more energy efficient than their non-condensing counterparts, and can typically extract 90-92% of heat from fuel, compared to 50-80% that a non-condensing boiler can.
How do condensing boilers work?
Condensing boilers typically use gas as a fuel to condense water vapour to create heat.
This is different from old non-condensing boilers which worked by creating hot gases which passed through a heat condenser to then heat water. These old non-condensing boilers wasted between 30-50% of heat due to combustion gasses escaping into the flue.
Condensing boilers are much more efficient because they extract the latent or additional heat from the combustion gasses and ‘recycle’ them back into the heating system to heat the water inside the boiler.
What is condensate?
When your boiler is fired up to heat your home or produce hot water, it is burning a fuel (typically gas) and this process produces carbon dioxide and water vapour.
Once enough heat is produced from this vapour, the temperature of the flue gas is reduced from around 130℃ to 50℃. This rapid fall in temperature produces condensate water waste, as much as 2-3 litres per hour.
This condensate is slightly acidic (3-5 pH) and needs to be drained away from your heating system. The boiler condensate pipe allows this water to be drained and disposed of with your household waste water.
What is the condensate pipe?
Your boiler’s condensate pipe is a plastic pipe which is responsible for taking the wastewater from the condensing process away from the heating system and disposing of it into a sewer.
Often this pipe exits behind the boiler, through your external wall, and into a drain.
Condensate pipes that are fitted externally or that run through wall cavities or unheated outbuildings are vulnerable to becoming frozen in extremely low temperatures.
The problem with condensate pipes
During cold snaps, condensate pipes can freeze, causing your boiler to stop working completely.
For this reason, it is desirable for the condensate pipe to discharge less than 3 m away from the boiler; be positioned at a gradient; and be insulated with lagging.
Nonetheless, even with our best efforts, a condensate pipe will still freeze. This is one of the most common problems modern heating systems face in the winter months.
The water inside the pipe freezes and the boiler’s inbuilt sensors will therefore prevent the boiler from lighting. This means that you’ll have no heating or hot water, right when you need it most!
Luckily, this is a very straightforward issue to solve, because once the ice melts, and the water can flow again, your boiler’s sensor will recognise that it can ignite again.
How do you know when your condensate pipe is frozen?
You’ll know that your condensate pipe has frozen if you hear a gurgling sound coming from your boiler or if you have a digital display it may show error code: “EA”.
A quick guide to thawing your condensate pipe
If your condensate pipe has frozen, don’t panic – just follow these simple steps to get back up and running:
1. Find your condensate pipe.
Your condensate pipe should be a white plastic pipe that comes out of the wall directly behind your boiler. Check that it runs from the boiler to an exterior drain.
2. Get the kettle on
Boil your kettle and let the water cool. It’s important that you don’t try to thaw the pipe with boiling water. Instead, let the water cool for approximately 15 minutes. Pour the warm water down the length of the pipe until the ice has thawed.
3. Reset your boiler
Now you need to rest your boiler. Wait a few minutes and check that it is working properly. If you have fully thawed your frozen condensate pipe, everything should be working as normal.
Preventing your condensate pipe from freezing again
Prevention is better than cure, so now that you’ve solved the problem, you’ll want to make sure that it doesn’t happen again.
The Heating People have some tips to help prevent your condensate pipe from freezing:
❖ Install a larger condensate pipe
A larger pipe is less likely to freeze. Usually, manufacturers will recommend pipes in the range of 32-40mm, but it is possible to have The Heating People install a thicker pipe if you are frequently experiencing very cold temperatures, or a recurring problem.
❖ Reduce external piping and check gravity is working in your favour
The less pipe that is external to your home, the less likely it will freeze. So, you may wish to speak to an engineer to see whether it;s possible for you to move your condensate pipe to minimise exposure to the elements. Ensuring that the waste water falls from your pipe as quickly as possible will help to keep the pipe clear so that it’s unlikely to become blocked.
❖ Get a siphon trap
If you’re going to be replacing your boiler soon, choose one that has a siphon trap. This will release the waste-water in one go (rather than in drawn out drips), thereby lowering the risk of freezing.
❖ Insulate the pipe
Insulation isn’t just for your house. Insulating your condensate pipe will help to keep it warmer, reducing the chances of it freezing again.
❖ Get a trace
A trace is an electrical element that can be bonded to the area below your condensate pipe. It is able to warm the pipe when the temperature drops below 5°C. If you install it, you must also add insulation to the pipe.
We hope you’ve found this guide helpful. For more heating advice, check out our other blogs!