Boiler Fault Code 1 05

Also written as 105 — same fault.

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

Fault code 1 05 appears across 1 boiler brand and 14 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to push water around your heating system, likely because the radiators are blocked, a valve is shut, or the pump is having trouble. (As reported on Ariston Clas HE 24)