BoilerFaultCodes P20 Medium
Boiler Fault Code P20
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code P20 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 has too much water in the system, which puts extra stress on the internal components and may cause it to shut down for safety. (As reported on Potterton Powermax HE)
Pick your boiler brand for the P20 fix
Source
Information for the P20 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