28 Medium

Baxi 28 Fault Code

The Baxi 28 fault code means: your boiler is struggling to accurately measure the temperature of the water coming out of your taps, which may cause your hot water to fluctuate or stop working entirely.. It appears on 6 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: Fault on Hot Water Sensor
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 28 fault code

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

Source

Baxi 28 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