LD3 ON High

Boiler Fault Code LD3 ON

Also written as LD3ON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code LD3 ON 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 has stopped working because it failed to light or detected a safety issue, causing it to shut down for protection. (As reported on Biasi Riva Compact 24S)

Pick your boiler brand for the LD3 ON fix

Biasi LD3 ON 1 model

Source

Information for the LD3 ON 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