Cleaned and serviced oil boiler. Brushed and vacuumed heat exchanger. Cleaned flue pipe. Inspected expansion tank, water feeder, air vents, 2 zone valves, circulater pump, and relief valve. Replaced oil filter, pump strainer, and burner nozzle. Performed smoke test, Adjusted air band till I had zero smoke on my smoke tester. Performed combustion and efficiency test. Tested two heating zones. System operational.