How much does it cost to fix Biasi error code Safety thermostat lockout?

Typical repair cost for the Biasi Safety thermostat lockout fault is £100-280 including labour.

Safety thermostat lockout High

Biasi Safety thermostat lockout Fault Code

Q: What does the Biasi Safety thermostat lockout fault code mean?

Your boiler has shut down because it reached an internal temperature that is too high, often caused by a circulation issue or a lack of water flow.

Also written as SAFETYTHERMOSTATLOCKOUT — same fault.

The Biasi Safety thermostat lockout fault code means: your boiler has shut down because it reached an internal temperature that is too high, often caused by a circulation issue or a lack of water flow.. It appears on 3 Biasi models in our database.

Technical description: Safety thermostat lockout

Typical repair cost £100-280 (including labour)

DIY fix possible

Check if your radiator valves are open to ensure water can flow through the system.Verify that the boiler pressure gauge is between 1.0 and 1.5 bar; top up using the filling loop if it is too low.Press the reset button on the front control panel to see if the fault clears.

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Biasi models that show the Safety thermostat lockout fault code

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

Source

Biasi Safety thermostat lockout 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