7.3.1 Emergency

Baxi 7.3.1 Fault Code

Also written as 731 — same fault.

The Baxi 7.3.1 fault code means: your boiler has detected an issue with the way it is managing its gas supply, which prevents it from operating safely.. It appears on 1 Baxi model in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Cherting the gas
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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Baxi models that show the 7.3.1 fault code

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

Source

Baxi 7.3.1 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026