C53 Emergency

Boiler Fault Code C53

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code C53 appears across 3 boiler brands 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 airflow system that brings fresh air in and pushes waste gases out, preventing it from operating safely. (As reported on Keston Combi 2)

Pick your boiler brand for the C53 fix

Baxi C53 1 model Gledhill C53 1 model Keston C53 2 models

Source

Information for the C53 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 7 July 2026