BoilerFaultCodes LD4 High
Boiler Fault Code LD4
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code LD4 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's internal computer brain is reporting a critical communication or hardware failure, meaning the system cannot safely operate. (As reported on Biasi Riva Advance M96.24SM)
Pick your boiler brand for the LD4 fix
Source
Information for the LD4 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