Checked the first floor furnace, started it and it did not light. Checked the oil flow which was clear and strong. Checked the transformer and nozzle assembly. There was oil dripping into the blast tube. Replaced the nozzle and the burner started properly. Cycled several times. Also checked the nozzle on the water heater. The nozzle assembly was dirty. Cleaned and replaced the nozzle. Started and tested. Customer had some work done in the furnace room and there is a lot of dust which could contribute to plugging a nozzle.