1P4 Low

Boiler Fault Code 1P4

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 1P4 appears across 2 boiler brands and 4 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 the water pressure is getting low and needs to be topped up to keep running properly. (As reported on Ariston Alteas One)

Pick your boiler brand for the 1P4 fix

Ariston 1P4 3 models Atag 1P4 1 model

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 31 August 2026