How much does it cost to fix Biasi error code 11 +?

Typical repair cost for the Biasi 11 + fault is £120-300 including labour.

11 + High

Biasi 11 + Fault Code

Q: What does the Biasi 11 + fault code mean?

Your boiler is detecting a flame when it shouldn't be there, which is a safety mechanism that prevents the system from starting up.

Also written as 11 — same fault.

The Biasi 11 + fault code means: your boiler is detecting a flame when it shouldn't be there, which is a safety mechanism that prevents the system from starting up.. It appears on 2 Biasi models in our database.

Technical description: Parasite flame.

Typical repair cost £120-300 (including labour)

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 11 + fault code

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

Antares Combi Repair: £120-300
Antares System Repair: £120-350

Source

Biasi 11 + 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