BoilerFaultCodes RY4 High
Boiler Fault Code RY4
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code RY4 appears across 1 boiler brand 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 is failing to start because it cannot confirm that the internal fan is operating correctly, preventing the safe clearing of exhaust gases. (As reported on Ferroli Hawk II)
Pick your boiler brand for the RY4 fix
Source
Information for the RY4 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