Your boiler has detected an internal electrical safety failure and has shut down to prevent damage or unsafe operation.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety relay open when should be closed
What causes this fault?
This fault occurs when the boiler's internal computer detects that a critical safety switch on the circuit board has failed to move into the correct position. The system shuts down immediately because it can no longer verify that the gas and ignition components are being controlled safely. The most common reason is that the electrical contacts on the main control board have worn out or become stuck over time.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like A08 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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