BoilerFaultCodes 65:0 High
Boiler Fault Code 65:0
Also written as 650 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 65:0 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 lost communication with the internal valve that directs heated water to either your radiators or your hot water tank, meaning your system cannot function correctly. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the 65:0 fix
Source
Information for the 65:0 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