Boiler Fault Code F A

Also written as FA — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code F A appears across 1 boiler brand and 1 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 unusual temperature difference between the water leaving and returning to the unit, suggesting a sensor or circulation internal error. (As reported on Ideal Instinct2 24)