F05 High

Boiler Fault Code F05

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F05 appears across 4 boiler brands and 7 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 a problem with the sensor that monitors the temperature of the water returning to the unit, causing it to stop working for safety. (As reported on Ideal Logic Max System)

Pick your boiler brand for the F05 fix

ECA F05 3 models Ferroli F05 2 models Ideal F05 1 model Viessmann F05 1 model

Source

Information for the F05 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