How much does it cost to fix Baxi error code E.00 – .04?

Typical repair cost for the Baxi E.00 – .04 fault is £90-160 including labour.

E.00 – .04 High

Baxi E.00 – .04 Fault Code

Q: What does the Baxi E.00 – .04 fault code mean?

Your boiler has detected a problem with the internal sensor that monitors water returning from your radiators, meaning it cannot safely regulate its temperature and has stopped working.

Also written as E0004 — same fault.

The Baxi E.00 – .04 fault code means: your boiler has detected a problem with the internal sensor that monitors water returning from your radiators, meaning it cannot safely regulate its temperature and has stopped working.. It appears on 24 Baxi models in our database.

Technical description: Return temperature sensor open-circuit. Sensor not or badly connected.

What causes the Baxi E.00 – .04 fault?

This fault occurs when the boiler's control system loses communication with the sensor that monitors water coming back from your radiators. The most common reason is that the sensor itself has developed an internal electrical failure or the wiring connecting it to the main control board has come loose or become damaged. Without this data, the boiler cannot accurately balance its heat output, so it shuts down as a safety precaution.

Typical repair cost £90-160 (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.00 – .04 fault code

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

Source

Baxi E.00 – .04 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 27 April 2026