High Lockout
16 on Glow-worm Ci Range

Your boiler has detected a problem with the internal gas valve and has shut down as a safety precaution, meaning you will have no heating or hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Gas safety value failure

What causes this fault?

This fault occurs when the boiler's main control board detects an electrical failure or a mechanical blockage within the gas valve assembly. The most common reason is that the valve's internal solenoid has burnt out or is no longer communicating correctly with the electronics, preventing gas from safely entering the burner.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
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Related fault codes

F1View →F4View →

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