How much does it cost to fix Baxi error code 40?

Typical repair cost for the Baxi 40 fault is £90-250 including labour.

40 High

Baxi 40 Fault Code

Q: What does the Baxi 40 fault code mean?

Your boiler is displaying a general flashing error indicator, which means the system has detected a temporary operational fault and locked out for safety.

The Baxi 40 fault code means: your boiler is displaying a general flashing error indicator, which means the system has detected a temporary operational fault and locked out for safety.. It appears on 31 Baxi models in our database.

Technical description: Flashing error

Typical repair cost £90-250 (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 40 fault code

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

Source

Baxi 40 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 31 August 2026