Home / Boiler problems / Frozen condensate pipe
Frozen condensate pipe?
The most common winter breakdown, and often fixed in minutes.
Signs it is frozen
- It is below freezing outside, often after a few cold nights
- The boiler shows a fault or ignition lockout code
- You may hear gurgling from the boiler
How to thaw it
- Find the condensate pipe. It is a thin plastic pipe, usually white or grey, running from the boiler to a drain outside.
- Find the frozen part. It is usually at the open end, or at a bend or dip.
- Pour warm water (not boiling) slowly along the pipe. A watering can or hot water bottle works well.
- Keep going until the ice clears, then reset the boiler.
Do not use boiling water. It can crack the plastic pipe. Do not climb to reach a high pipe. If it is out of reach, call us.
Stopping it freezing again
Long external runs, thin pipes and pipes that end above the drain freeze most. The fix is usually rerouting it inside, upsizing it to 32mm or insulating it. We can do this on a repair visit.
Questions
Why does my boiler have a condensate pipe?
Modern condensing boilers make acidic water as they recover heat from the flue gases. The condensate pipe carries it to a drain.
Will a frozen condensate pipe damage the boiler?
No. The boiler shuts down safely. Once the pipe is thawed and the boiler reset, it should work normally.