High Lockout
F62 on Glow-worm Flexicom hx

Your boiler's main control board has suffered an internal electronic failure and is unable to manage the heating process 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

Main PCB fault

What causes this fault?

This fault occurs when the boiler’s central brain experiences an internal electrical failure, preventing it from safely controlling the gas flow and ignition. The most common reason is a component failure on the circuit board itself, though sometimes a faulty gas valve can send an incorrect signal that triggers this specific error.

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

F61View →

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