While you wait for answers, we may have found some information which could help you.
Click here for Combi Firing Radiators HotReplace a diverter valve?
Parts for ferroli optimax he 31c ?
How can i repair a noCN fault on my boiler?
Ferroli Optimax HE31c a26 problem?
Ferroli DOMIcompact F 30 D?
i have a ferroli combi boiler i have 1/2 the radiators working and 1/2 not ?