BoilerFaultCodes 1 P4 High
Boiler Fault Code 1 P4
Also written as 1P4 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 1 P4 appears across 1 boiler brand and 6 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 move water around your heating system effectively, which is causing it to stop for protection. (As reported on Ariston E-Combi One 30)
Pick your boiler brand for the 1 P4 fix
Source
Information for the 1 P4 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