High Lockout
Software Error on Glow-worm Micron 40FF

Your boiler's internal computer brain has encountered a glitch or failure and is struggling to run its operating 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

Software Error

What causes this fault?

This fault occurs when the boiler's internal control board suffers a critical hardware failure or data corruption, preventing it from executing its safety checks. The most common reason is age-related degradation of the electrical components on the circuit board, which eventually stops the 'brain' of the boiler from processing instructions correctly.

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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