F03 High

Boiler Fault Code F03

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F03 appears across 2 boiler brands and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has stopped working because the fan that removes waste gases is not spinning correctly, causing the system to shut down for safety. (As reported on Ideal Logic Max System)

Pick your boiler brand for the F03 fix

Ideal F03 1 model Viessmann F03 1 model

Source

Information for the F03 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