BoilerFaultCodesBiasi Lock-out signal lamp ON Fault Code
Also written as LOCKOUTSIGNALLAMPON — same fault.
The Biasi Lock-out signal lamp ON fault code means: your boiler is failing to detect that the flame has lit, causing it to shut down for safety reasons to prevent a build-up of unburned gas.. It appears on 2 Biasi models in our database.
Technical description: The burner doesn't light, the ignition sparks continue and the boiler locks. By pressing the reset push-button the boiler starts the ignition cycle. The burner lights, the ignition sparks continue and the boiler locks again.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Biasi models that show the Lock-out signal lamp ON fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi Lock-out signal lamp 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