1- Check Your Thermostat For Proper Operation.

2- Vacuum Area Around Furnace Or Air Handler.

3- Replace Standard Air Filter

4- Inspect Motors

5- Visually Inspect Furnace Heat Exchanger

6- Inspect All Electrical Wires

7- Clean & Inspect Hoses & Drains

8- Check Refrigerant Levels

9- Measure Sub Cool

10- Measure Superheat

11- Measure Capacitor Value

12- Check & Tighten Any Belts

13- Inspect Metering Device

14- Inspect System Coils

15- Inspect High Limit Operation

16- Inspect Gas Connections In Unit

17- Clean Flame Sensor And Pilot

18- Check Supply & Return Air

19- Lubricate Moving Parts

20- Inspect Flue Vents & Combustion Air