We may have found other answers which could help you.
Click here for Central Heating Combi BoilerHi how to increase the water pressure on ferroli optimax 25C?
Replace a diverter valve?
How can i repair a noCN fault on my boiler?
Parts for ferroli optimax he 31c ?
Ferroli Optimax HE31c a26 problem?
ferroli plus 31c has a code b2 any ideas?