Preventative maintenence inspection two Carrier high efficiency furnaces running in great condition. Air filter for both units, while in backwards, are in decent condition. Filters being in backwards will not hinder the system operation, but when new filters are installed, the must be installed with the arrow pointing towards the furnace. Cleaned flame sensors and checked ignitors. Visual inspection of burners. Flush condensation traps and drain lines. Run test each system in heating mode from thermostat. Both systems are operating properly and within specs for temperature rise, gas pressure, blower speed, blower and inducer motor amp draw. Pvc flue vents in good condition and no sign of leaks. 0PPM CO detected during testing. Systems are operating properly, efficiently and ready for Winter.