Upon arrival unit was off. Turned unit on and it was off on reset. Pushed the reset button and the unit started but was rumbling. Checked oil flow and had good clean flow. Checked the ignition transformer and it had a good strong spark. Checked the nozzle and found it had been dripping and was spraying at an incorrect pattern. Found some oil residue in the blast tube and small amount of carbon buildup. Cleaned the blast tube of all oil and carbon buildup. Replaced the old nozzle with a new nozzle. Started the unit up and performed combustion and smoke tests. Unit is working properly.