BoilerFaultCodesFerroli P11 Fault Code
The Ferroli P11 fault code means: your boiler has detected trapped air bubbles moving through your heating pipes, which is preventing the system from circulating water effectively.. It appears on 1 Ferroli model in our database.
Technical description: Air release in CH return pipe
DIY fix possible
Check your boiler's pressure gauge to ensure it is between 1 and 1.5 barTop up the system pressure using the filling loop if it is below 1 barBleed all radiators in the house starting from the ground floor and moving upwards to release trapped air
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Ferroli models that show the P11 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ferroli P11 fault code information on this page is sourced and cross-checked against the official Ferroli service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026