Upon arrival unit was on and running. Customer stated they have had to push the reset button and when they push it it comes on but eventually goes out again. Checked oil flow and had good and clean flow. Checked the ignition transformer and it had a good and strong spark. Checked the nozzle and found it was dripping and had some carbon on it. Replaced the nozzle and cleaned up the nozzle assembly. Also removed the burner motor and cleaned the burner wheel. There was a good amount of dryer lint on the wheel. Started the unit and performed combustion and smoke tests. Unit is working properly Recommend checking the dryer vent connections for any possible holes. Also recommend having a maintenance done on the oil boiler.