the pump may not be working, the more recent non condensing ferroli boilers (domicompact f24, f30 etc) have a twin pass heat exchanger, so the pump is not in use for the hot water to work. if there is power going to the pump then that's most likely where the fault is. if no power then faulty timer or room stat. watch the room stat connection on this boiler as it often falls off if you disturb the casing.
Ian, September 2009