High
F7 228 on Worcester Bosch Greenstar i

Your boiler has detected an unexpected signal that suggests it might not be safely detecting when the flame is actually on or off, so it has locked itself out to prevent a potential hazard.

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

Ionisation current detected before burner-start

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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