How much does it cost to fix Baxi error code H.01 – .00?

Typical repair cost for the Baxi H.01 – .00 fault is £180-350 including labour.

H.01 – .00 High

Baxi H.01 – .00 Fault Code

Q: What does the Baxi H.01 – .00 fault code mean?

Your boiler has lost its internal connection to the main gas control unit, meaning it cannot safely manage the fuel it needs to fire up.

Also written as H0100 — same fault.

The Baxi H.01 – .00 fault code means: your boiler has lost its internal connection to the main gas control unit, meaning it cannot safely manage the fuel it needs to fire up.. It appears on 24 Baxi models in our database.

Technical description: Loss of communication between gas valve and boiler board. Possible fault in air/gas unit or loose connection to gas valve.

What causes the Baxi H.01 – .00 fault?

This fault occurs when the boiler's internal computer is no longer able to talk to the electronic gas valve, which is the component that controls the fuel supply. The most common reason is a loose or damaged wiring connection between these two parts, or an electronic failure within the valve itself that prevents it from responding to commands.

Typical repair cost £180-350 (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.01 – .00 fault code

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

Source

Baxi H.01 – .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 27 April 2026