Boiler shows condensate fault, often during cold weather; the boiler will not fire.

Safety: Condensate is mildly acidic. Wear gloves and eye protection when handling. Isolate power before removing the trap.

• Check external pipe: Inspect the external condensate pipe for ice. If frozen, pour warm (not boiling) water over the pipe to thaw. Insulate the pipe to prevent recurrence.
• Empty and clean trap: Remove the condensate trap beneath the boiler, empty it into a suitable container, and rinse out any debris. Refit securely, ensuring seals are in place.
• Check pipe fall: Ensure the condensate pipe slopes continuously downward with no sags that can trap water.
• Reset boiler: After clearing the blockage, reset the boiler and confirm normal operation.