High Lockout
F13 on Glow-worm 30ci Plus

Your boiler's main internal computer has developed a technical hardware fault and is unable to control the system.

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

Main PCB fault

What causes this fault?

This fault occurs when the boiler's main control board suffers an internal electrical failure or memory error, preventing it from sending instructions to the rest of the unit. The most common reasons are natural wear and tear of sensitive electronic components, or damage caused by an unexpected electrical surge in the home's power supply.

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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