Red club fall tune furnace up on 80% Comfort Maker split system. Changed filters for customer, and checked system over. Inspected evaporator coil, blower, blower capacitor, heat exchanger and cleaned flame sensor. Checked and cleaned debris buildup from flue. Cycled system on and checked gas pressure, carbon monoxide levels, delta t from return to supply plenum and amp draws in blower and inducer motor. System is running within manufacturer specs. Helped customer set up Nest thermostat application on mobile device and set min/max settings to 68 degrees for low and 76 degrees for high.