Condensate pipe repeatedly freezing in cold weather, boiler stops working

Safety: Do not use boiling water on plastic pipes. Take care on icy ground.

• Locate frozen section: Find the external condensate pipe (usually white or grey plastic) and identify any bulges or ice.
• Thaw gently: Pour warm (not boiling) water over the frozen section or use a warm cloth to thaw the ice.
• Reset boiler: Once thawed and condensate can flow, reset the boiler following the manual.
• Engineer tasks:
  • Increase pipe size to at least 32mm externally.
  • Improve pipe insulation and reduce external run length.
  • Adjust pipe fall to ensure good drainage.

Improving condensate pipe installation will reduce recurrence in future cold spells.