BoilerFaultCodesYour boiler has shut down because it cannot safely expel exhaust fumes, likely due to a blockage in the flue pipe or a buildup of debris.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Flue blockage
What causes this fault?
This fault occurs when the boiler's internal safety sensors detect that the exhaust gases are not being cleared from the system correctly. The most common reasons are a physical obstruction in the flue pipe, such as a bird's nest or debris, or an internal component failure like a worn-out fan that can no longer push the fumes outside.
This issue is more frequent during autumn and winter, as high winds can dislodge debris into the flue or birds may attempt to nest near the warmth of the terminal.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like Slow flash (normally on, flashes off), Lockout reset: Flashing (reset required) (Alt 2) — no call-out fees, no surprises.
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