Emergency
2923 on Worcester Bosch Greenstar 4000

Your boiler has detected an issue with the internal gas supply component and has shut itself down to keep you safe.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Boiler electr. system fault - Unexpected feedback from the modulating/current controlled gas valve.

From this model's manual
Verified against the Worcester Bosch Greenstar 4000 installation & service manual, page 76.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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