BoilerFaultCodesWorcester Bosch Burner reset light green/red alternate flash (0.5s) Fault Code
Also written as BURNERRESETLIGHTGREENREDALTERNATEFLASH05S — same fault.
The Worcester Bosch Burner reset light green/red alternate flash (0.5s) fault code means: your boiler's safety sensor is detecting a flame when there shouldn't be one, causing it to stop the ignition process for your safety.. It appears on 1 Worcester Bosch model in our database.
Technical description: Extraneous light — false flame signal before ignition; locks out after 25 seconds
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Worcester Bosch models that show the Burner reset light green/red alternate flash (0.5s) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch Burner reset light green/red alternate flash (0.5s) fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026