High
Rapid flashes on Worcester Bosch Greenstar 25CDi

Your boiler is sensing a flame even when it should be turned off, causing the system to lock down for safety.

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

Flame detected even though appliance switched off. Check electrode assembly, dry pcb. Flue clear?

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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