BoilerFaultCodes 81:0 Low
Boiler Fault Code 81:0
Also written as 810 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 81:0 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 has been manually switched between heating and hot water modes, and it is simply notifying you that a changeover has occurred. (As reported on Viessmann Vitodens 300-W)
Pick your boiler brand for the 81:0 fix
Source
Information for the 81:0 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026