Performed a heating Lennox on two systems, one was a 2014 carrier and the other was a 2020 Lennox system. Cleaned and Adjust Burners. Check Combustion Air for Proper Venting. Examine the Heat Exchanger for Damage / Corrosion. Test Furnace Safety Controls. Inspect Gas Piping. Tighten Electrical Connections. Measure the Voltage and Amperage. Flush the Condensate Drains. Measure Tempurature Difference between Supply and Return Air. Vacuum Furnace Return Grille. Adjust Gas Pressure & Pilot. Clean in-place Blower Compartment. Inspect Blower Wheel for Proper Balance. Check the System's Static Pressures to Ensure Proper Airflow. Inspect Duct Connections for Air Leaks / Sizing / Insulation. Check all System Safety and Limit Switches. Clean Flame Sensor. Inspect Carbon Monoxide Detector. Check Thermostat for Proper Operation / Calibration. Filters where not changed as customer had just changed them recently. Both systems are fully operational at time of departure.