Cold-weather boiler advice
Could the condensate pipe be frozen?
Start with safe checks.
During freezing weather, the external pipe that carries condensate away from a condensing boiler can freeze. The boiler may then stop and show a fault code—but other faults can look similar.
Check before doing anything
- Read the boiler display and write down the fault code.
- Check the boiler manual or manufacturer’s support information for that code.
- Look for an accessible external plastic pipe connected to the boiler’s condensate drain.
- If you cannot identify the pipe confidently, stop and call for advice.
If the manufacturer confirms a likely freeze
- Switch off as directedFollow the boiler manufacturer’s instructions before trying to thaw the pipe.
- Warm the frozen section gentlyUse a warm-water bottle, heat pack or warm—not boiling—water on an accessible section.
- Work patientlyA long frozen section may take time. Do not strike, force or disconnect the pipe.
- Restart only as instructedUse the reset procedure in the boiler manual. If the fault remains, stop resetting and call an engineer.
If it happens again
Repeated freezing may mean the outside pipework needs assessment or improvement. Do not permanently alter condensate pipework yourself; ask a qualified heating engineer to inspect the route and installation.
