BoilerFaultCodes COM1 Medium
Boiler Fault Code COM1
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code COM1 appears across 1 boiler brand 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 lost its connection to the external wall-mounted heating controller, meaning it no longer knows when to turn your heating on or off. (As reported on Vokera Vision System Sgc)
Pick your boiler brand for the COM1 fix
Source
Information for the COM1 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 7 July 2026