BoilerFaultCodesBaxi C neon flashing Fault Code
Also written as CNEONFLASHING — same fault.
The Baxi C neon flashing fault code means: your boiler has detected that water isn't moving through the internal pipes effectively, which prevents it from heating up safely.. It appears on 2 Baxi models in our database.
Technical description: Primary water flow switch not operated; go to section C
DIY fix possible
Check that the boiler pressure is between 1.0 and 1.5 bar on the gaugeOpen any radiator valves that are turned off to ensure water can flowEnsure the main stop tap and any isolation valves under the boiler are fully open
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Baxi models that show the C neon flashing fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi C neon flashing 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