Furnace clean and tune. Cycled system. Checked heat exchanger, ok. Checked, removed, and cleaned burners and flame sensor. All ok. Igniter tested normal. Checked and adjusted gas pressures to maximize efficiency. Checked and tested furnace safety systems. Preformed combustion test and found normal levels in exhaust. No CO found in airstream. System operating normal at this time. Customer is having issues with thermostat and the WIFI settings. It disconnects from Honeywell program a few times. Thermostat is operating normal from what I can test. It appears that the issue may be from the app side or Honeywell side of the process. System operating normal at this time. Job complete.