Communication fault Unknown

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 2 boiler brands and 7 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

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Main Communication fault 1 model Vaillant Communication fault 6 models

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 31 August 2026