How much does it cost to fix Baxi error code E04?

Typical repair cost for the Baxi E04 fault is £150-250 including labour.

E04 High

Baxi E04 Fault Code

Q: What does the Baxi E04 fault code mean?

Your boiler is struggling to detect water moving through the system, which means it cannot safely fire up to give you heating or hot water.

The Baxi E04 fault code means: your boiler is struggling to detect water moving through the system, which means it cannot safely fire up to give you heating or hot water.. It appears on 2 Baxi models in our database.

Technical description: Flow switch failure (Water pressure or pump fault)

Typical repair cost £150-250 (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 E04 fault code

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

130 HE (range) Repair: £150-250
Duo-tec Combi Repair: £150-300

Source

Baxi E04 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