Performed preventative maintenance on a LENNOX AC unit. Model number: 13ACD-036-230-16. Serial number: 1912E59419. Upon arrival the unit was on at the thermostat. Homeowner adjusted the thermostat down so the AC would keep running. Went upstairs to the unit and watched it run. Turned the unit off by the switch. Removed the evaporator coil panel and checked the coils for any dust build up. Poured water into the condensate trap and watched the water drain properly. Poured water into the condensate drain line and watched it drain properly. Removed the panel to the furnace. Checked the blower motor and fan for any dust build up. Checked all electrical connections to make sure they were properly secure. Changed the 16x25x1 filter supplied by the homeowner. Took an amp draw of he blower motor. It is running within the manufacture’s specs. Placed the panels back in the unit and went outside to the condenser and watched the unit run. Checked the coils for any dirt build up. Removed the panel.