P03 Low

Boiler Fault Code P03

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code P03 appears across 2 boiler brands and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is temporarily pausing because the underfloor heating water has become slightly too hot, and it is now waiting for the system to cool down before starting up again. (As reported on Ferroli Leb TS)

Pick your boiler brand for the P03 fix

Alpha P03 2 models Ferroli P03 1 model

Source

Information for the P03 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