How much does it cost to fix Baxi error code 31?

Typical repair cost for the Baxi 31 fault is £120-250 including labour.

31 Medium

Baxi 31 Fault Code

Q: What does the Baxi 31 fault code mean?

Your boiler is struggling to correctly detect or manage the request for hot water, which usually means it cannot provide a consistent temperature at your taps.

The Baxi 31 fault code means: your boiler is struggling to correctly detect or manage the request for hot water, which usually means it cannot provide a consistent temperature at your taps.. It appears on 6 Baxi models in our database.

Technical description: Domestic Hot Water Mode

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 31 fault code

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

Source

Baxi 31 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