2021 Bryant running in great condition. 20x25x1 air filter in good condition. Air filter is in backwards, but due to already being slightly used, put filter back in the same way. Arrow on air filter must point to the right. Clean flame sensor and check ignitor. Visual inspection of burners. Flush condensation trap and drain lines. Run test unit in heating mode. Delta t of 54F with supply temp of 123F. 2" pvc flue in good condition and no sign of leaks. 0PPM CO detected during testing in basement. Blower motor and inducer motor running within spec. System is operating properly, efficiently and ready for Winter.