BoilerFaultCodesBiasi lock-out Fault Code
Also written as LOCKOUT — same fault.
The Biasi lock-out fault code means: your boiler has switched itself off because it has detected that it is getting too hot or there is a problem with the exhaust temperature.. It appears on 3 Biasi models in our database.
Technical description: Safety thermostat or flue temperature probe lockout
DIY fix possible
Check that all radiator valves are fully openEnsure the system pressure is between 1 and 1.5 bar on the gaugePress the 'Reset' button on the front control panel and hold for 2-5 seconds
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Biasi models that show the lock-out fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi lock-out 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