BoilerFaultCodes P15 Low
Boiler Fault Code P15
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code P15 appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is receiving an incorrect or inconsistent signal from the weather sensor installed outside your home, which may affect how the heating adjusts to the outside temperature. (As reported on Alpha Pro Tec Plus)
Pick your boiler brand for the P15 fix
Source
Information for the P15 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 7 July 2026