F.XX-F.XX Low

Boiler Fault Code F.XX-F.XX

Also written as FXXFXX — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F.XX-F.XX appears across 1 boiler brand and 13 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning This code isn't an active fault but rather a menu view showing the history of past errors your boiler has experienced. (As reported on Vaillant ecoTEC plus)

Pick your boiler brand for the F.XX-F.XX fix

Vaillant F.XX-F.XX 13 models

Source

Information for the F.XX-F.XX 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