DuraVent FasNSeal Insulated Wall Thimble with Termination Damper: keeps cold air from blowing back toward the appliance
The DuraVent FasNSeal Insulated Wall Thimble with Termination Damper is an insulated sleeve that carries the vent through an outside wall. It includes the outdoor vent ending and a flap that blocks cold air from blowing back toward the appliance when it is off. The insulation keeps cold air from entering around the vent. It fits walls 4 1/4 to 8 1/2 inches thick. FasNSeal is DuraVent’s stainless steel vent for high efficiency gas boilers, furnaces, and water heaters, built to carry pressurized exhaust and its acidic condensate outside.
Choose a 3, 4, 5, 6, or 8 inch size on this page. FasNSeal serves natural gas or propane appliances that call for a special gas vent. The appliance maker determines whether the vent can exit through a wall or roof and how long the run can be. The maker’s required distances for a wall exit still apply with this thimble. Don’t need the damper? See the DuraVent FasNSeal Insulated Wall Thimble with Adjustable Vent Length, a sleeve without a damper. The DuraVent FasNSeal Insulated Wall Thimble with Termination Damper ships free from My Cozy Outdoors with No Sales Tax (except WY) and the full manufacturer warranty.








Commercial projects may require custom parts and unique system designs. Duravent offers complete project assistance:








































