Frozen condensate pipes cause more winter boiler breakdowns than any other single fault. Here's how to prevent it, and thaw one safely.
Every cold snap our phones light up with the same fault: a modern condensing boiler locking out because its condensate pipe has frozen. The boiler is fine, the plastic waste pipe outside has iced up and the boiler shuts down for safety.
Spotting it
A gurgling sound from the boiler followed by a lockout or fault code, in freezing weather, almost always means condensate. Check the white plastic pipe running outside from the boiler.
Thawing it safely
- Use a hot water bottle, a warm cloth or a jug of warm (not boiling) water on the pipe
- Start at the end of the pipe and work back towards the house
- Never use boiling water, it can crack the pipe or refreeze
- Reset the boiler once the ice clears
Preventing it for good
- Have the condensate re-routed internally where possible
- Upsize the external run to 32mm and insulate it
- Keep the heating on a low background temperature during freezing weather rather than turning it off
- Insulate any exposed pipework in lofts and garages
Also worth knowing
Locate your internal stop tap now, before you need it. In a burst-pipe emergency, knowing where it is and that it turns saves thousands of pounds in damage. If yours is seized, we can replace it in under an hour.