Boiler On light on Low

Baxi Boiler On light on Fault Code

Also written as BOILERONLIGHTON — same fault.

The Baxi Boiler On light on fault code means: your boiler is receiving power and has been told to turn on by your thermostat, so it should be operating normally.. It appears on 2 Baxi models 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: Indicates if the boiler is receiving power and the thermostat is calling for heat.

DIY fix possible

Check that your room thermostat is set to a temperature higher than the current room temperatureEnsure your programmer or timer is set to an 'ON' periodCheck that the boiler temperature control knob is not turned to the 'OFF' position

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Baxi models that show the Boiler On light on fault code

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

Source

Baxi Boiler On light on fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026