High Lockout
F61 on Glow-worm Flexicom hx

Your boiler's main control board has suffered a communication failure or internal electrical fault, meaning it can no longer send instructions to heat your home.

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 internal computer, the PCB, loses its ability to communicate with the gas valve and other vital components. The most common reason is an electrical short-circuit or a component failure on the board itself, preventing it from safely controlling the ignition sequence. Think of it as the brain of the boiler losing its connection to the rest of the system.

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

F62View →F63View →F64View →

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