2019 Armstrong Air furnace running in good condition. 16x25x1 air filter in good condition. Clean flame sensor and check ignitor. Visual inspection of burners. 4" galvanized B-vent in good condition and no sign of leaks. 0PPM CO detected during testing. Run test unit in heating mode from thermostat. Delta t of 48F with supply temp of 116F, sp3c Delta t of 30-60F. Blower motor and inducer motor running within spec. System is operating properly, efficiently and ready for Winter.