We may have found other answers which could help you.
Click here for Ferroli Optimax FaultHow turn off heating in Ferolli Optimax 31c?
Replace a diverter valve?
Ferolli Optimax HE 31C expansion vessel change?
F40 fault?
i have a ferroli combi boiler i have 1/2 the radiators working and 1/2 not ?
Parts for ferroli optimax he 31c ?