Perform preventative maintenence inspection on two Carrier high efficiency gas furnaces running in new condition. Both air filters are in clean condition. Clean flame sensors and check ignitors. Visual inspection of burners. Flush condensation traps and drain lines. Basement system humidifier wiring altered for better control with thermostat. Humidifier pad in good condition. Test ran each furnace in heating mode from thermostats. Both systems are operating properly and within specs for temperature rise, blower and inducer motor specifications, and gas pressures. Pvc flue vents are in good condition and no sign of leaks. 0PPM CO detected during testing. All systems are operating properly, efficiently and ready for Winter.