Boiler Fault Code 71:1

Also written as 711 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code 71:1 appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to heat your hot water tank because it is reaching its internal safety temperature limit before the tank is actually full. (As reported on Viessmann Vitodens 300-W)