Performed a heating maintenance on two Lennox heat pumps. Test Furnace Safety Controls. Tighten Electrical Connections. Measure the Voltage and Amperage. Flush the Condensate Drains. Measure Tempurature Difference between Supply and Return Air. Vacuum Furnace Return Grille. 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 this visit. System was fully operational on time of departure.