How much does it cost to fix Biasi error code Lock state cause?

Typical repair cost for the Biasi Lock state cause fault is £120-280 including labour.

Lock state cause High

Biasi Lock state cause Fault Code

Q: What does the Biasi Lock state cause fault code mean?

Your boiler has switched itself off because it has reached an unsafe temperature, likely due to a blockage or a failure in how the water is moving through the system.

Also written as LOCKSTATECAUSE — same fault.

The Biasi Lock state cause fault code means: your boiler has switched itself off because it has reached an unsafe temperature, likely due to a blockage or a failure in how the water is moving through the system.. It appears on 1 Biasi model in our database.

Technical description: Intervention of the safety thermostat (primary hydraulic circuit)

Typical repair cost £120-280 (including labour)

DIY fix possible

Check that all radiator valves are fully openEnsure the boiler pressure is between 1 and 1.5 bar on the gaugeTry to reset the boiler once it has cooled down for 30 minutes

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Biasi models that show the Lock state cause fault code

Click a model for the full fault code list and model-specific repair notes.

Gaia Repair: £120-280

Source

Biasi Lock state cause 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