BoilerFaultCodes 1p4 High
Boiler Fault Code 1p4
Also written as 1P4 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 1p4 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 effectively, which is causing it to shut down to prevent overheating. (As reported on Ariston Alteas One)
Pick your boiler brand for the 1p4 fix
Source
Information for the 1p4 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