How much does it cost to fix Baxi error code E:04.02?

Typical repair cost for the Baxi E:04.02 fault is £120-220 including labour.

E:04.02 High

Baxi E:04.02 Fault Code

Q: What does the Baxi E:04.02 fault code mean?

Your boiler has lost its connection to its internal thermometer, so it can no longer accurately monitor the water temperature and has shut down as a precaution.

Also written as E0402 — same fault.

The Baxi E:04.02 fault code means: your boiler has lost its connection to its internal thermometer, so it can no longer accurately monitor the water temperature and has shut down as a precaution.. It appears on 8 Baxi models in our database.

Technical description: Flow temperature sensor open-circuited

Typical repair cost £120-220 (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 E:04.02 fault code

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

Source

Baxi E:04.02 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