BoilerFaultCodes Autofrostat Function Low
Boiler Fault Code Autofrostat Function
Also written as AUTOFROSTATFUNCTION — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Autofrostat Function appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected that the internal temperature is very low and has automatically activated its built-in frost protection mode to prevent the system from freezing. (As reported on Worcester Bosch 28 RSF)
Pick your boiler brand for the Autofrostat Function fix
Source
Information for the Autofrostat Function 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