BoilerFaultCodes CP020 Medium
Boiler Fault Code CP020
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code CP020 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 is experiencing a communication error between its internal heating zones, which may cause your heating to turn on or off unexpectedly. (As reported on Baxi 400 Combi 2)
Pick your boiler brand for the CP020 fix
Source
Information for the CP020 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