BoilerFaultCodesAlpha Neon B flashing Fault Code
Also written as NEONBFLASHING — same fault.
The Alpha Neon B flashing fault code means: your boiler has automatically shut itself down because it detected that it is running too hot, possibly due to trapped air or a blockage in the system.. It appears on 7 Alpha models in our database.
Technical description: Overheat thermostat or thermal fuse has operated
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Alpha models that show the Neon B flashing fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Alpha Neon B flashing fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026