Boiler Fault Code 1 12

Also written as 112 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code 1 12 appears across 1 boiler brand and 15 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 its connection to one of its internal temperature sensors, meaning it cannot correctly measure the warmth of the water returning to the system and has shut down as a precaution. (As reported on Ariston Clas Net One)