No light / Not a fault code Low

Worcester Bosch No light / Not a fault code Fault Code

Also written as NOLIGHTNOTAFAULTCODE — same fault.

The Worcester Bosch No light / Not a fault code fault code means: your boiler has been manually set to run at full power for testing purposes and just needs to be switched back to its normal operating mode.. It appears on 1 Worcester Bosch model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Service mode selected to max, press service button to return to normal.

DIY fix possible

Locate the button with a 'spanner' or 'service' icon on the control panel.Press and hold the service button briefly until the display or light returns to its normal status.The boiler should now respond to your thermostat and hot water taps as usual.

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Worcester Bosch models that show the No light / Not a fault code fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch No light / Not a fault code 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 27 April 2026