Completed preventative maintenance for gas furnace. System is operating properly at this time. Cleaned the flame sensor. Cleaned out burner tubes and burner box. Checked for restrictions in the flue, inducer, Pressure switches and tubing. No restrictions present. Checked gas piping and gas valve for leaks. No gas leaks at this time. Checked humidifier for leaks and water panel. Replaced the customer supplied #35 water panel. Checked Merv11 air filter. Replaced the Merv 11 16x25x5 Air filter provided by the customer. All electrical components are working properly at this time. CO level is in the safe operation range (18ppm). Thank you for your continued business with us and for your military service!