How much does it cost to fix Baxi error code 23?

Typical repair cost for the Baxi 23 fault is £100-250 including labour.

23 High

Baxi 23 Fault Code

Q: What does the Baxi 23 fault code mean?

Your boiler has detected that water is not circulating properly, most likely because the system pressure has dropped too low to operate safely.

The Baxi 23 fault code means: your boiler has detected that water is not circulating properly, most likely because the system pressure has dropped too low to operate safely.. It appears on 4 Baxi models in our database.

Technical description: Fault on Pump or Low System Pressure

Typical repair cost £100-250 (including labour)

DIY fix possible

Check the pressure gauge on the front of the boiler; if it is below 1 bar, your system pressure is too low.Locate the filling loop (a silver braided hose or a small key valve) underneath the boiler.Open the filling valve slowly until the needle on the gauge reaches between 1 and 1.5 bar, then close the valve tightly.

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Baxi models that show the 23 fault code

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

Source

Baxi 23 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