Boiler frequently locks out during very cold weather but works normally otherwise.

Safety: In freezing conditions, take care on icy surfaces and ladders.

• Check condensate pipe: Inspect the external condensate run for ice. Thaw gently with warm water and insulate the pipe.
• Inspect flue terminal: Ensure snow, ice, or wind baffles are not obstructing the flue outlet or air intake.
• Monitor gas supply: If other gas appliances also struggle, contact your gas supplier about low pressure.
• Wind effects: In very exposed locations, a flue terminal guard or re-routing may be required; consult a Klimosz installer.