Arrived on site for heating maintenance on 2017 Armstrong air furnace. Homeowner stated he was smelling a dusty smell when the unit kicked on. I asked the homeowner if it was more of a dirty sock smell and he confirmed. I started by cracking open the evaporator coil and inspecting. I noticed a very slight amount of debris around the evaporator and I could not notice any smell coming from the evaporator when I put my head in there. Inspected plenums and noticed a large amount of dust buildup. Proceeded with maintenance as scheduled. 1. Visually inspected condenser coil for debris/ dirty. 2. Inspected condenser fan motor. 3. Inspected condenser fan blades. 4. Inspected/ cleaned wiring connections. 5. Tested for gas leaks 6. Tested functionality and cleaned flame sensor 7. Tested functionality and cleaned pressure switches and ports 8. Inspected / replaced return filter. 9. Inspected return plenum for debris/ dirty. 10. Inspected evaporator coil. 11. Tested functionality and visually ins
