BoilerFaultCodes OPn High
Boiler Fault Code OPn
Also written as OPN — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code OPn appears across 1 boiler brand and 2 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 a temperature sensor cable has disconnected or become faulty, preventing the system from monitoring water flow correctly. (As reported on Grant Vortex)
Pick your boiler brand for the OPn fix
Source
Information for the OPn 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