Performed Fall PM on the RTU Checked in with the Customers. Replaced the (1) 20x25x1 standard filter . Walked Maricel through the T-Stat operation & settings. Up at the unit removed and cleaned Burners . Cleaned off the spark igniter and flame sensor electrode Checked the bulk head / heat exchanger for any type of fracture or visible holes . Cleaned out control cabinet the reassembled burners and manifold . Tested all safety and controls . Pulled amp draws on all mechanical components. Checked and regulated gas pressures 3.33 in w.c. The unit is operating at factory recommended specifications . Job Complete