Cleaned and serviced one oil Boiler, vacuumed combustion chamber and around boiler, inspected chimney flu which was clean, changed filter, nozzle, and strainer, bled oil filter housing by tank, cleaned burner head which was very dirty, cleaned and inspected burner tube, tested two zones, air vent good, expansion tank good, wiring in aquastat looks good, bled oil line, performed combustion and efficiency test which had to make a slight adjustment to air band system running a little rich, system operational and working. Customer took out maintenance agreement for one oil system.