BoilerFaultCodesYour boiler has shut down because a safety circuit has been broken, which is typically caused by the system overheating or an electrical safety switch being triggered.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety interlock
What causes this fault?
This fault occurs when the boiler's internal safety loop is broken, acting as an emergency stop to prevent damage. It is most commonly triggered because the system has reached an unsafe temperature due to a pump failure or a blockage that stops water from flowing correctly through the heat exchanger.
This issue often surfaces during the first cold snap of autumn when a pump that has been idle all summer fails to restart, causing the unit to overheat immediately.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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