A6 Medium
Boiler Fault Code A6
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code A6 appears across 2 boiler brands 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 communication with the safety sensor that prevents your underfloor heating system from getting too hot. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the A6 fix
Source
Information for the A6 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