BoilerFaultCodesBaxi 23 Fault Code
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 7 Baxi models in our database.
Technical description: Fault on Pump or Low System Pressure
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 7 July 2026