30 Medium

Baxi 30 Fault Code

The Baxi 30 fault code means: your boiler is currently struggling to correctly detect or manage the demand for hot water, which may result in your taps running cold or the system failing to ignite when you turn a tap on.. It appears on 8 Baxi models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Domestic Hot Water Mode
Typical repair cost £120-250 (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 30 fault code

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

Source

Baxi 30 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