BoilerFaultCodesBiasi ON Fault Code
The Biasi ON fault code means: your boiler is operating normally and is currently responding to a request for heating or hot water.. It appears on 1 Biasi model in our database.
Technical description: Boiler ON condition (function control in C.H. or D.H.W. position).
DIY fix possible
Check your thermostat or programmer to see if they are calling for heatRun a hot tap to see if the boiler responds normallyNo action is required as this is a status indicator, not a fault code
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Biasi models that show the ON fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi ON fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026