f21 error message on ferroli optimax he 31c boiler?

Ferroli DOMIcompact F 30 D?

F40 fault?

I have a Ferroli FF 77 the pilot light has gone out will not stay on ?

Ferroli domicondens he26 C fires up but doesn't appear to rectify ?

i have a ferroli combi boiler i have 1/2 the radiators working and 1/2 not ?

ferroli plus 31c has a code b2 any ideas?

Replace a diverter valve?

How can i repair a noCN fault on my boiler?

Ferroli Optimax HE31c a26 problem?

Hi how to increase the water pressure on ferroli optimax 25C?

Connections on Ferroli F24 Gas Valve?

Parts for ferroli optimax he 31c ?