High Lockout
17 on Glow-worm 30ci Plus

Your boiler has stopped working because the electrical power coming from your mains supply has dropped too low for it to run safely.

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

Power supply <170V

What causes this fault?

This fault occurs when the electrical voltage entering your boiler drops to a level that is too low for the internal components to operate safely. It is usually caused by an external problem with the national grid supply or a faulty Printed Circuit Board that can no longer accurately monitor the incoming power.

This issue can be more frequent during periods of extreme weather or high national energy demand, which can lead to temporary drops in local grid voltage.

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 →F11View →

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