Performed preventative maintenance on a Lennox AC a system. Model number: 14HPX-030-230-21. Serial number: 1917B3135. Upon arrival the unit was on at the thermostat. Adjusted the thermostat so the AC would keep running. Went upstairs to the unit and watched it run. Turned the unit off by the switch. Opened the panels to the evaporator coil. Inspected the coil for any dust build up. Poured water into the condensate trap and watched it drain properly. Poured water into the condensate pump and watched it pump out properly. Checked all electrical connections to make sure they were properly secure. Checked the blower motor and fan for any dust build up. Landlord had wrong size filter. It should be a 16x25x4. Landlord will come back soon to replace the filter. Took an amp draw of the blower motor. Running within the manufacture’s specs. Placed the panels back in the unit and watched it run. Went outside to the condenser and watched it run. Checked the coils for any dirt build up. Removed the