Performed preventative maintenance for a carrier furnace model #58SB0A110E211120, serial #0520A29481. Powered the system down and removed the access panels. Removed and cleaned carbon off of the flame sensor, cleaned out the burners and burner box. Replaced the air filter size 16x25x4 homeowner supplied. Checked all electrical connections to ensure that they are secure and in good condition. Tested the drain line and condensate pump with several bottles of water to ensure that there are no leaks or clogs. Checked the pressure switches to ensure that they are operating properly. I powered the system up and called for heat. Took a combustion analysis test and received the following readings, o2 is at 8.9% and the co levels are 35ppm. The inducer amp draw is at .67 and the blower motor amp draw is at 7.3. The system is operating properly at this time. No Charge MA.