BoilerFaultCodes C3 (ΔP-C) High
Boiler Fault Code C3 (ΔP-C)
Also written as C3PC — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code C3 (ΔP-C) appears across 1 boiler brand and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected an issue with the internal water pressure or circulation flow, meaning it cannot safely heat your home or water. (As reported on Alpha Intec 28GS)
Pick your boiler brand for the C3 (ΔP-C) fix
Source
Information for the C3 (ΔP-C) 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