Basically after someone shedding a little light on a problem I've got, my hot water works fine everytime, fan runs, ignites, everything is OK but the heating doesn't, I don't have a room stat so using the clock, it doesn't matter either way timed or just on, basically turn demand on fan runs it ignites but only runs for a few seconds then the flame seems to deteriate and the sparker trys igniting then it locks out, flashing red reset button, anyone any ideas??