F20 High

Boiler Fault Code F20

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F20 appears across 6 boiler brands and 24 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's computer components are having trouble communicating with each other because they are running incompatible software versions. (As reported on Glow-worm Xtramax HE)

Pick your boiler brand for the F20 fix

Ferroli F20 4 models Glow-worm F20 10 models Heatline F20 2 models Ideal F20 1 model Saunier Duval F20 3 models Vaillant F20 4 models

Source

Information for the F20 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 31 August 2026