Your boiler has encountered a critical system error and has shut itself down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault causing a boiler shutdown
What causes this fault?
This fault occurs when the boiler's internal computer experiences a major communication failure or a critical hardware error. It typically happens because the main control board can no longer safely monitor the unit's operation, leading to an immediate shutdown to prevent damage. The most common trigger is a sudden electrical surge or a terminal failure of the electronic components inside the boiler.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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