Boiler Fault Code 1 06

Also written as 106 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code 1 06 appears across 2 boiler brands and 16 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 water is returning to the unit hotter than it was sent out, which usually means the water isn't moving through your radiators properly. (As reported on Ariston Genus HE)