One system heat tune-up in Duluth. Arrived on site, changed filterand cleared barometric ports. Checked ignition systems, electrical connections, amp draw and capacitance. Found system with a dirty blower assembly, corroded evaporator coil, no water safty, filter is not properly installed, inducer motor drawing higher than normal amp. Plenums and duct work have organic growth, drip-t for gas line is not properly installed, and duct work is all R-6. Due to high cost of repairs I recommend replacing the equipment.