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DirectVent Pro Installation Guide

DirectVent Pro by Simpson Duravent is a unitized, coaxial venting system designed for use with direct vent gas or propane stoves, heaters, and fireplaces. DirectVent Pro features tight inner connections for superb performance, with no gaskets or sealants required (unless specified by the appliance manufacturer). All black pipe lengths, pipe extensions, and elbows feature laser-welded outer wall seams for a sleek finish. Low-profile locks and no hems or beads allow for a beautiful product that looks elegant in any interior.

DirectVent Pro, in combination with the gas appliance, has been tested and listed as a decorative gas appliance system or as a direct vent heater system by a major testing agency, such as UL, CSA, Warnock Hersey, or OMNI.

Refer to the Typical Installation drawings below to select the appropriate component parts for your installation.

  • Engineered Excellence with innovation and style...DirectVent Pro. Simpson Dura-Vent's direct vent is specified exclusively by nearly every major stove and fireplace manufacturer in the U.S. and Canada, with the largest choice of termination caps for direct vent available.
  • All DirectVent Pro components are compatible with DirectVent GS stock, except for the DirectVent Pro Pipe Extensions.
  • Be fire safe! Use proper support and bracing. Follow local building codes and have your venting system inspected.

DirectVent Pro Installation Key

1.  Vertical Termination Cap 9. 90░ Elbow
2. Storm Collar 10. Horizontal Termination Cap (see listed caps for choices)
3. Flashing 11. Snorkel Termination Cap
4. Cathedral Ceiling Support Box 12. Chimney Liner Termination Kit
5. Pipe 13. 3" Flex
6. 45░ Elbow 14. Co-Axial to Co-Linear Connector
7. Class A Chimney Conversion Kit 15. Masonry Chimney Conversion Kit
8. 4" Flex 16. Elbow Strap

 * Click on the link under the installation key (above) to be taken to the appropriate section.

Planning Your Installation

  1. For vertical gas stove installations, measure the height from the stove outlet to the ceiling to determine the length of black pipe required. Select a ceiling support/wall thimble cover or a cathedral ceiling support box.

  2. TTo determine the length of galvanized pipe required, measure the ceiling thickness and the vertical rise in an attic or second story. Firestops are required at each floor level beyond the first floor ceiling support/wall thimble cover or cathedral ceiling support box. If an offset is required to avoid obstructions, use a pair of 45░ elbows. For proper support, use elbow straps with offsets. Use wall straps for long vertical runs. Attic Insulation Shield is required in attic.

  3. Measure the roof pitch. Select the proper flashing and storm collar. Determine the minimum height above the roof.

  4. For horizontal installations, check the appliance manufacturer´┐1/2s instructions for minimum rise and maximum horizontal run. A snorkel termination may be used if height restrictions prevent adequate rise above the appliance. Select the appropriate Horizontal Termination Cap (see appliance manufacturer installation instructions). To protect vinyl siding, select vinyl siding standoff. Check appliance manufacturer´┐1/2s instructions for wall thimble and firestop requirements.


Design Recommendation 

The following design recommendations are intended as only a general guideline to assist in the design and selection of venting components for your installation. Always read and follow Simpson Dura-Vent Installation instructions enclosed with the cap or support box before installing your chimney system. Installation instructions can be viewed on the item page on our website. 

Important: Check the manufacturer's rating plate and instruction manual to confirm that the Simpson Dura-Vent direct vent system is approved for use on the brand name appliance you have selected.

  • The inner and outer pipe diameters should match the outlet size of the appliance.

  • Check the appliance manufacturer's installation instructions to confirm which types of vent configurations are permitted (i.e. horizontal, vertical, chimney reline, etc.). Also, check for any venting restrictions such as maximum horizontal run, minimum and maximum vertical rise, maximum offset, etc.

  • Be fire safe! Maintain at least the minimum clearances (air-space) between the vent pipe and nearby combustibles, as specified in the appliance manufacturer's installation instructions. Use proper support and bracing. Follow local building codes and have your venting system inspected.

Vent Termination Chart

Roof Pitch

Minimum Height

Feet Meters
Flat to 7/12 1 0.30
Over 7/12 to 8/12 1.5 0.46
Over 8/12 to 9/12 2 0.61
Over 9/12 to 10/12 2.5 0.76
Over 10/12 to 11/12 3.25 0.99
Over 11/12 to 12/12 4 1.22
Over 12/12 to 14/12 5 1.52