Customer had issue with his geofencing on his thermostat. When he is home his phone and thermostat shows him as away. When you go to the app, it shows him as home and away but runs the program as away. Exchanged under warranty. Furnace clean and tune. Cycled system. Checked heat exchanger. Found rust in heat exchanger, no cracks seen at this time. Checked and cleaned burners and flame sensor. Checked and cleaned sparker. Checked for CO in airstream , none found. Normal levels of CO and XS air in exhaust. Blower is very loud on start up. Possible motor or capacitor issue. System is old, but operating normal at this time. Job complete.