BoilerFaultCodesYour boiler's internal computer has encountered a logic error and has stopped working to protect itself.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Software Sequence Error
What causes this fault?
This fault occurs when the boiler's control board loses track of its safety sequence or fails to process data correctly. It is usually caused by a physical failure within the printed circuit board's micro-processor or a communication break in the internal wiring. Because the boiler can no longer verify that it is operating safely, it chooses to shut down entirely.
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 Alternating Slow Flashing (2Hz) — no call-out fees, no surprises.
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