Performed preventative maintenance for a high efficiency carrier furnace model #59SC2C040S171112, serial #0715A44258. Upon arrival the system was running so I took a combustion analysis test and received the following readings, o2 is 8.8% and the co levels are 8ppm. The supply temp is 133°F and the inducer motor amp draw is .28 and the blower motor amp draw is 5.6. I powered the system down and removed the access panels. Performed humidifier service for a Aprilaire 500m humidifier. Removed and replaced the #10 water panel. Cleaned out the housing and drain. Checked all electrical connections to ensure that they are secure and in good condition. The air filter was replaced in the spring and is still good. Checked the pressure switch for clogs and tested the drain line with several bottles of water to ensure that there are no leaks or clogs. Removed and cleaned carbon off of the flame sensor and cleaned out the burners and burner box. I powered the system back up and called for heat. Tes