High Lockout
F14 on Glow-worm Ci Plus

Your boiler is struggling to control the amount of gas it uses, which prevents it from heating up correctly.

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 valve modulation fault

What causes this fault?

This fault occurs when the boiler's control board sends a command to the gas valve to adjust the flame size, but the valve fails to respond correctly. The most common reason is a mechanical failure within the gas valve itself or a communication breakdown in the wiring between the valve and the main circuit board.

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.

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Related fault codes

F1View →F12View →F13View →

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