please can any one help me? just been to look at a biasi riva 24s and the client says that when the boiler has not been on for a few hrs it does not come on in ch and dhw, so they have to turn the boiler off at the fuse and turn it back on after 30 seconds then the boiler will work fine for the rest of the day. when i got there it was working fine could ay one help please.