23 High

Biasi 23 Fault Code

The Biasi 23 fault code means: your boiler is unable to control the flow of gas correctly to heat your home, which has caused the system to stop working for safety.. It appears on 4 Biasi models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Gas valve modulator disconnected.
Typical repair cost £120-250 (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 23 fault code

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

Source

Biasi 23 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