How to thaw a frozen boiler condensate pipe
When the temperature drops below freezing, the most common reason a condensing boiler stops working is a frozen condensate pipe. It's usually a white or grey plastic pipe running from the boiler through an outside wall and down to a drain.
Signs it's the condensate pipe
- The boiler shows a fault code (often EA, F28, L2 or similar, depending on the make).
- You hear a gurgling noise from the boiler.
- It's been below freezing overnight and the boiler was fine yesterday.
How to thaw it
- Find where the pipe comes out of the wall and look for the coldest point, usually at a bend or the open end.
- Pour warm water (not boiling, which can crack the pipe) slowly along the pipe. A kettle that's boiled and left for 10 minutes is about right.
- You can also hold a hot water bottle or a warm cloth against it.
- Once it's thawed, reset the boiler using the reset button. Check the manual if you're not sure where it is.
Stopping it happening again
An engineer can lag the pipe, increase its size, or re-route it inside where possible. It's a cheap job, and worth doing before the next cold snap.
If the boiler still won't fire after the pipe has thawed, the fault is probably something else. That's the time to get an engineer out.
Need it sorted? No heating or hot water in Newcastle typically costs £80 to £300. A local engineer will give you a price before starting.