Performed preventative maintenance for a Lennox system model #G43UF-60C-110-06, serial #5905K30911. Powered the system down. Removed and cleaned carbon off of the flame sensor, cleaned out the burners and burner box. Replaced the air filter size 16x25x1. Checked a electrical connections to ensure that they are secure and in good condition. Performed humidifier service. Removed the old water panel and cleaned out the housing and drain line. Installed a new #35 water panel and tested the system for leaks. I powered the furnace back up and called for heat. Took a combustion analysis test and got the following readings, o2 is at 13%, co is at 4ppm. The inducer motor and blower motor amp draws are within normal range. The supply temp is at 105°F. Both systems are operating properly at this time.