Performed preventative maintenance for a high efficiency Lennox furnace model #EL195UH110P48C-01, serial #5910M22351. Upon arrival the system was calling for heat. I took a combustion analysis test and received the following readings, o2 is 8.8% and the co levels are 9ppm. The supply temp is 140°F. The inducer motor amp draw is 1.95 and the blower motor amp draw is 4.6. I powered the system down removed and cleaned carbon off of the flame sensor and cleaned out the burners and burner box. Checked the pressure switch for clogs and cleaned out the trap. Tested the drain line and condensate pump with several bottles of water to ensure that there are no leaks or clogs. The Merv filter was replaced in the spring. Checked all electrical connections to ensure that they are secure and in good condition. I powered the system back up and checked for proper operation. The system started without any issues. The system is operating properly at this time.