Lennox furnace maintenance and inspection. Furnace is operating safely and efficiently and in great condition at this time. ERV repair After discussing ongoing problems with tech support found that jumper on control board needed to be cut in order to have the defrost damper operate correctly. After cutting the jumper the damper no longer blocks fresh air from coming in when the ERV is calling for air exchange. Also verified ERV would shut off when set to only run 10/20 minutes per hour. Attached PureAirX Electronic air cleaner quote