Boiler locks out during cold weather, gurgling noises, condensate pipe outside is frozen or blocked.

Safety: Take care with hot water and slippery surfaces when thawing pipes. Isolate power to the boiler before working on condensate components.

User steps (frozen pipe):

• Locate the white plastic condensate pipe exiting the Grant boiler and running outside.
• If frozen, pour warm (not boiling) water along the external section or wrap it with warm towels until thawed.
• Once thawed, reset the boiler and check operation.

Engineer steps (blockage/design):

• Remove and clean the condensate trap inside the boiler, clearing any sludge or debris.
• Check the fall and support of the condensate pipe to ensure continuous gradient with no low spots.
• Insulate or increase the diameter of the external condensate pipe in line with Grant and local regulations to reduce freezing risk.