BoilerFaultCodesBiasi L 01 Fault Code
Also written as L01 — same fault.
The Biasi L 01 fault code means: your boiler has shut down because it is getting too hot while trying to provide hot water.. It appears on 1 Biasi model in our database.
Technical description: Primary circuit temperature limit during D.H.W. operation
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the gaugeEnsure all isolation valves under the boiler are fully openTurn the boiler power off and back on again to reset the system
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Gas Safe Register →Biasi models that show the L 01 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi L 01 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 27 April 2026