I don't know if you have the same issue but I have a Dyson Velaire and when it does that it's usually because I have let the oil run out and when it's refilled, as the oil comes through, there are air pockets in the line and the oil kind of puffs out and doesn't ignite properly. I think that the sensor detects the oil is coming through but not igniting and shuts down for a period of time. I've never had it not come back on after a 10/12 attempts but if it is still not starting after a few goes, it is possible you have an airlock. Like I say, I'm not a boiler engineer, just talking from my own experience. Hope it helps. :)
Keith, January 2010
