How much does it cost to fix Baxi error code H.03 .00?

Typical repair cost for the Baxi H.03 .00 fault is £300-500 including labour.

H.03 .00 High

Baxi H.03 .00 Fault Code

Q: What does the Baxi H.03 .00 fault code mean?

Your boiler has lost communication with its internal safety components, meaning it cannot safely operate and has disabled itself to prevent potential risks.

Also written as H0300 — same fault.

The Baxi H.03 .00 fault code means: your boiler has lost communication with its internal safety components, meaning it cannot safely operate and has disabled itself to prevent potential risks.. It appears on 8 Baxi models in our database.

Technical description: No identification data for boiler safety device. MAIN PCB ERROR Replace the main PCB

Typical repair cost £300-500 (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 H.03 .00 fault code

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

Source

Baxi H.03 .00 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