1p3 Medium

Boiler Fault Code 1p3

Also written as 1P3 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 1p3 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 is struggling to circulate water properly, which is causing it to overheat and shut down temporarily for safety. (As reported on Ariston Alteas One)

Pick your boiler brand for the 1p3 fix

Ariston 1p3 1 model

Source

Information for the 1p3 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