BoilerFaultCodes P.11 Low
Boiler Fault Code P.11
Also written as P11 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code P.11 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 currently running an internal calibration test to ensure it is burning gas correctly at its mid-range setting. (As reported on Vaillant ecoTEC plus Aquaplus)
Pick your boiler brand for the P.11 fix
Source
Information for the P.11 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