Preventative maintenence inspection on two Trane furnace units. Attic system air filter replaced today. Basement system filter in good condition. Replaced humidifier pad. Cleaned flame sensors and checked ignitors. Visual inspection of burners. Basement system flushed drain trap. Both exhaust systems in good condition with no sign of leaks. 0PPM CO detected during testing. Test ran both in heating modes from thermostats. Both systems are operating properly and within all operating parameters. Temperature rise is within specs, blower and inducer motors tested good. Both systems are operating properly, efficiently and ready for Winter.