BoilerFaultCodesBaxi B, C, D, E & F neons flashing Fault Code
Also written as BCDEFNEONSFLASHING — same fault.
The Baxi B, C, D, E & F neons flashing fault code means: your boiler's safety system has detected an issue with the airflow inside the unit, causing it to shut down to prevent unsafe operation.. It appears on 2 Baxi models in our database.
Technical description: Air pressure switch failure; go to section D
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A cover plan would handle faults like B, C, D, E & F neons flashing: no call-out fees, no surprise bills.
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Baxi models that show the B, C, D, E & F neons flashing fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi B, C, D, E & F neons 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