High Lockout
5.2 on Worcester Bosch Greenstar 25HE

Your boiler has detected a problem with its electronic ignition system, meaning it cannot process the command to start the flame 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

GFA status / error

What causes this fault?

This fault occurs when the boiler's internal computer is unable to communicate with or control the ignition system that lights the gas. It is typically caused by a electronic component failure on the main circuit board or a loose wiring connection between the controller and the ignition hardware. This prevents the boiler from safely starting the combustion process, causing it to shut down for safety.

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

C6View →E9View →EAView →

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