Boiler Fault Code 1 P2

Also written as 1P2 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code 1 P2 appears across 1 boiler brand and 14 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to move enough water through your heating system, which usually means there is a blockage, air trapped in the pipes, or a pump struggling to work. (As reported on Ariston Clas One)