Furnace Vent Piping Tips for HVAC Contractors Posted on: March 9, 2016 by STL HVAC in HVAC Maintenance Tips No Comments 5 Learn the important factors of venting high-efficiency furnaces. This video is for the professional HVAC installer. This and other tips are available at http://NORDYNEU.com 24 hours a day. Share on PinterestThere are no images.