Last updated on December 2nd, 2023
Having a frozen condensate pipe will cause your Worcester boiler to stop working, which means no heating or hot water when you need it most, in freezing winter weather.
I have been fixing boilers full-time for over a decade and when the weather is freezing, the majority of calls I get for a boiler not working are for frozen condensate pipes.
Here I’ll show you what to do when your Worcester boiler condensate pipe freezes and how to stop it from happening again.
Frozen Condensate Pipe Symptoms
A condensate pipe carries the wastewater created in a condensing boiler from reusing the heat vapour to make it more energy efficient.
The only symptoms of a frozen condensate pipe are that the boiler stops working and you might also hear gurgling noises when the boiler fires up before it goes to lockout.
Some Worcester boilers have fault codes when they go to lock out.
If your Worcester boiler is not working and it’s freezing cold outside (below 0℃), there is a good chance your boiler’s condensate pipe has frozen and you need to defrost it.
How to Defrost a Worcester Condensate Pipe
To fix a frozen Worcester boiler condensate pipe, you must defrost the ice that has formed inside by thawing it out and resetting the boiler.
Once it has defrosted the pipe will be clear and your heating system will start heating your home again.
The best way to do this is to pour hot water on it.
How to thaw a frozen condensate pipe:
- Fill a kettle with water and boil it
- Let it cool down a bit as you don’t want it too hot
- Pour it over the plastic pipe outside
- Repeat until it seems defrosted
- Reset the boiler
- Check if the boiler fires up when you put the heating on
- Repeat the process until the boiler fires up and the heating comes on
You can also cut a section of the pipe out with a hacksaw if pouring hot water on won’t fix it, and push the ice out to clear it.
How to Stop Condensate Pipe Freezing
The best way to stop a condensate pipe from freezing is to have it discharge internally inside the property, or if it has to go outside, make sure it’s a 32mm waste pipe and it stays as vertical as possible.
Most frozen condensate pipes happen on undersized external pipes (22mm) going horizontally.
It’s best to fix either of these problems before trying to protect the pipe but sometimes that’s not an option.
Condensate Pipe Frost Protection
You should take condensate pipe frost protection seriously, especially if it has frozen before, but if the weather is cold enough virtually nothing will stop it from freezing.
There are a few ways to help stop your boiler condensate pipe from freezing and minimise the chance of it happening, but nothing is guaranteed.
To maximize your chances of a condensate pipe not freezing, you can:
- Fit a drain cover
- Insulate any pipe that’s outside
- Fit a trace heating kit
Fitting a drain cover is the simplest action you can take to help protect against the wind chill freezing your condensate pipe.
These are cheap to buy and easy to fit and can make a real difference to condensate and waste pipes freezing.
Insulate External Pipe
Insulate every piece of condensate pipe outside the house with external pipe insulation. This will help greatly in those freezing temperatures.
It’s typically undersized (22mm) horizontal pipes that freeze, but you can insulate any external condensate pipe, especially if it has frozen before.
My recommended condensate pipe insulation on Amazon:
Trace Heating Cable
Fitting a trace heating cable is a great way to stop your boiler condensate pipe from freezing. It uses a self-regulating cable to heat the pipe when it drops below a specific temperature.
You simply run the trace heating cable along any pipe you want to protect and wrap some cable ties around it, insulate the pipe, and then plug it into a power supply.
This will keep the pipe warm and is the best way to stop a condensate pipe from freezing in the winter.
Worcester Bosch boilers also do a frost protection product called a CondenseSure.
I have never fitted or used one but as far as I know, they clip on the flow pipe of your Worcester boiler and hold a certain amount of condensate water in there like a condensate trap.
The heat from the flow pipe will heat the condensate wastewater before it heads down the condensate pipe, preventing it from freezing.
Worcester Boiler Condensate Pipe Blocked
if your boiler condensate pipe is blocked without it being frozen, this will need to be cleared to fix it.
Condensate pipes can get blocked by the gunk in the waste pipe that the pipe connects to, typically on a kitchen sink.
There are many Worcester boiler problems that can be fixed quite easily, including condensate pipe problems.
Thawing out a Worcester boiler frozen condensate pipe is something every homeowner should know how to do to get your heating system going again.
This is definitely not something to call a plumber for as it will cost you, but also if your condensate pipe has frozen then it’s likely lots of people’s pipes have frozen and boiler repairers will be super busy!
Make sure to keep pouring that hot water over the pipe and resetting the boiler as sometimes the ice is solid and takes a while to defrost. It is possible to use a hot water bottle also but this will take a lot longer.
Feel free to ask me any questions in the comment section below and I’ll try my best to help.
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What is the fault code for a frozen condensate pipe on a Worcester boiler?
There are three fault codes a Worcester boiler might show when it locks out due to a frozen condensate pipe. They are EA 227, EA 229 or D5.