Preventative maintenence inspection on Carrier high efficiency furnace running in great condition. 20x25x4 air filter in good condition. Clean flame sensor and check ignitor. Visual inspection of burners. Flush condensation trap and drain lines. Run test unit in heating mode. Temperature rise is within specs. Blower and inducer motors tested good. Pvc flue vents in good condition and no sign of leaks. 0PPM CO detected during testing. Test ran operation of geothermal heating aswell. Temperature rise is within specs. Did not check refrigerant as there is no issues suspected. No fault codes stored in system. All systems are operating properly, efficiently and ready for Winter.