Boiler Fault Code 7 1

Also written as 71 — same fault.

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

Fault code 7 1 appears across 3 boiler brands and 3 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 its internal software settings have been accessed or modified via a computer, preventing it from operating normally. (As reported on Atmos Interopen HE22)