DuraVent CVS Wall Thimble with Reduced Air Infiltration: an insulated sleeve for a pellet vent’s wall opening
The DuraVent CVS Wall Thimble with Reduced Air Infiltration is a sleeve for the opening where your vent passes through an outside wall. An included insulation ring fills the space around the pipe to help keep outside air from leaking into the house. The sleeve fits between standard wall studs and leaves 1 inch between the pipe and the framing. That is the clearance a pellet vent needs from wood and other materials that can burn. CVS is DuraVent’s concentric vent: the exhaust runs up a 3 inch inner pipe while combustion air comes in through the 5 inch outer pipe around it.
For a pellet stove or insert, DuraVent requires a wall thimble at this crossing. This version provides the needed gap from the framing, while the plain thimble is designated for gas appliances only. The sleeve does not replace the supports along the wall. A horizontal CVS run needs a wall strap every 8 feet, with straps also supporting any bends that shift the pipe’s path. Venting a gas appliance instead? See the DuraVent CVS Wall Thimble for gas. The DuraVent CVS Wall Thimble with Reduced Air Infiltration ships free from My Cozy Outdoors with No Sales Tax (except WY) and the full manufacturer warranty.
Details
SKU: 35CVS-WTP
Applications
Concentric Venting System (CVS) (direct vent or two-pipe system) for use with condensing natural gas or propane Categories II, III and IV appliances or Canada’s Type BH Gas Vent Systems, (having a maximum rated operating temperature of 500°F). For use with Stoves and inserts of Type L gas, pellet, oil, corn and biofuel (Rated to a continuous use flue temperature up to 570°F). CVS can be used on a wide range of appliances, including: gas boilers, warm air furnaces, water heaters, unit heaters, tankless water heaters, pellet stoves, direct vent gas or propane stoves, heaters, and fireplaces.
Materials and Construction
Unitized concentric construction. Inner: Laser-welded UL approved 444 super-ferritic stainless steel .012″ Outer: Laser-welded, paintable, zincalume .018″ Silicone O-ring seals on inner liner and outer wall. Precision twist-lock connection on outer wall.
Clearances
CVS is listed to 0” clearance as a double-wall vent system for Category II, III, and IV appliances, for flue temperature of up to 400°F for horizontal enclosures, and up to 480°F for vertical enclosures. CVS must maintain 1” clearance to combustibles when used with pellet fuel. When CVS is used as a concentric/direct vent system on gas, the clearance to combustibles is specified by the appliance manufacturer.
Diameters
3″ inner and 5″ outer.
Listings
CVS vent pipe is listed to UL 1738 (MH25700) as a double-wall vent system for Category II, III and IV appliances. It is pressure rated to 10 WC for the inner pipe. This product is also intended to be used as a direct vent system for Listed to UL 1738 (DGSH.MH25700) and ULC S636 (DGSH7.MH25700). Pressure rated to 10” W.C. Listed to UL 641 (DFTX.MH8381), ULC S609 (DFTX7.MH8381), and ULC/ORD 441 (DFVAC.MH21150). Listed in combination with gas appliances, has been tested and listed as a decorative gas appliance system or as a direct vent heater system. Check with your appliance manufacturer for approval.