BoilerFaultCodes C4 273 Low
Boiler Fault Code C4 273
Also written as C4273 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code C4 273 appears across 1 boiler brand and 12 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 a small airflow issue while running its daily safety self-test, often meaning it needs a professional service or a minor part cleaned. (As reported on Worcester Bosch 26 CDi Xtra)
Pick your boiler brand for the C4 273 fix
Source
Information for the C4 273 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