Performed preventative maintenance for a high efficiency Lennox furnace. Model #EL296UH090XV48C-07, serial #5918A21529. Powered down the system and removed the access panels. Removed and cleaned carbon off of the flame sensor, cleaned out the burners and burner box. Replaced the 201 air filter. The homeowner has her own 201 air filters. Checked all electrical connections to ensure that they are secure and in good condition. Performed humidifier service. Removed and replaced the #35 panel. Cleaned out the housing and tested the drain line for leaks and clogs. Set the humidistat for 35% humidity and tested the system. Called for heat and the system started right up. Took a combustion analysis test and received the following readings, 02 is at 10%, co is at 18ppm. The inducer motor amp draw is at .32 and the blower motor amp draw is at 6.1. Both systems are operating properly at this time.