What the manual says
Manufacturer manualBoiler ON condition (function control in C.H. or D.H.W. position).
From this model's manual
Verified against the Biasi Riva Compact 24s installation & service manual.
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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