Boiler Fault Code 1.4.3

Also written as 143 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code 1.4.3 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected that a critical internal control component has reached the end of its programmed operational life and requires replacement by a professional. (As reported on Baxi 825 Combi)