Condensate water backs up or boiler shuts down in freezing weather

Safety: Condensate is mildly acidic; wear gloves and eye protection when handling.

• 1. Inspect external pipe: Check the external condensate pipe for ice buildup. If frozen, thaw gently with warm (not boiling) water or a warm cloth.
• 2. Improve insulation: Insulate the external condensate pipe and increase its diameter if undersized, following Buderus and local regulations.
• 3. Clean trap: Remove and clean the condensate trap inside the boiler, ensuring no debris is blocking flow.
• 4. Check slope: Ensure the condensate pipe has a continuous fall to the drain with no sags where water can collect and freeze.