Preventative maintenence inspection on three furnaces. All air filters are in clean condition. Cleaned flame sensors and checked ignitors. Visual inspection of burners. Flush condensation trap and drain lines on high efficiency furnace. Test rancall units in heating mode. All systems are operating properly within temperature rise specifications. All blower motors and inducer motors are operating properly. Vent pipes are all in good condition and no sign of leaks. 0PPM CO detected during testing. Systems are operating properly, efficiently and ready for Winter.