Communication fault High
Boiler Fault Code Communication fault
Also written as COMMUNICATIONFAULT — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Communication fault appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's internal computer is unable to talk to its display panel, meaning the system has stopped working to protect itself. (As reported on Vaillant ecoTEC Pro 30)
Pick your boiler brand for the Communication fault fix
Source
Information for the Communication fault 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