Greeted Mildred at the door, who quickly took us downstairs to the basement. We replaced the oil tank filter and pump strainer. Opened up the combustion chamber and removed the gun assembly. Replaced the nozzle with a new 50/60w. Reassembled the unit. Turned the power back on and fired up the furnace. Allowed the unit to cycle and reach temperature. Checked the exhaust for proper ventilation. The unit is running and operating as it should.