BoilerFaultCodesYour boiler is struggling to push waste gases out through the flue or is unable to clear internal condensation water properly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue gas non-return flap/condensate pump fault
What causes this fault?
This fault occurs when the boiler detects a blockage or failure in the system that removes waste gases and water. It is usually caused by a stuck internal flap that prevents exhaust fumes from escaping safely, or a pump failure that stops waste water from being drained away. When these systems fail, the boiler shuts down as a safety precaution to prevent internal flooding or the buildup of dangerous gases.
This fault can be more frequent during extreme cold spells if the external pipe that carries waste water away freezes and causes a backup into the pump area.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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