Boiler Fault Code 8/0/3

Also written as 803 — same fault.

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

Fault code 8/0/3 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 lost its internal clock settings, likely due to a recent power cut, and needs to be reset to allow it to operate correctly. (As reported on Worcester Bosch GB162)