DuraVent | Pipe 25' Flex Length DuraFlex 316 Stainless Steel Basic Kit

Save $72.15
DuraVentSKU: 3DF316-25K

Sale price$649.35 Regular price$721.50
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Size: 3"

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Elevate your HVAC and Hearth system to unmatched efficiency and durability with the DuraVent 25' Flex Pipe Kit in premium 316 Stainless Steel. In a world where venting excellence matters, DuraVent stands as the undisputed industry leader, offering innovative and safe solutions to meet your venting needs. Our reputation is built on quality, and this kit is no exception.

Crafted with precision, DuraFlex 316 is your assurance of unmatched corrosion resistance, making it ideal for use with coal-fired appliances and any situation where durability is paramount. This kit is perfect for wood burning, non-condensing gas, and oil-fired appliances, ensuring your system operates flawlessly.

Experience the freedom to customize your venting system precisely as you need it. DuraFlex offers the flexibility of custom lengths, with a minimum order of just 10 feet. For those requiring larger diameters, our DuraFlex Pro and DuraFlex SW lines come in 9"-12" sizes when ordered as custom lengths. With DuraVent, you're in control.


  • Durability Unleashed: Crafted from 316 Stainless Steel, this kit ensures your venting system is built to last even in harsh conditions.
  • Customized Lengths: Tailor your venting system to your specific needs, with custom lengths starting at just 10 feet.
  • Versatile Application: Suitable for wood burning, non-condensing gas, oil-fired appliances, and more, ensuring compatibility with various systems.
  • Easy Installation: The kit includes all essential components for a hassle-free setup, saving you time and effort.
  • Safety Assured: DuraFlex is UL 1777 and ULC S635 listed, providing peace of mind for your HVAC and Hearth systems.

Key Features

  1. Varied Kit Lengths: Choose from 15’, 20’, 25’, 30’, and 35’ lengths to suit your installation requirements.
  2. Comprehensive Kit: Includes DuraFlex SS Top Plate with Welded Storm Collar, DuraFlex SS Removable Vertical Cap, DuraFlex SS Connector, and DuraFlex 316 Length.
  3. Top Plate with Storm Collar: Securely seals the top of masonry chimneys and provides flex support with a fast-connect band.
  4. Removable Vertical Cap: Ideal for terminating a relining system and easily attaches to the storm collar with a fast-connect band.
  5. Connector Included: Ensures seamless connection between DuraFlex SS length and your appliance, rigid length, or flex length.
  6. 316 Stainless Steel Length: Designed for use with wood-pellet, non-condensing gas, wood-burning, and oil appliances, offering exceptional durability.


  • Masonry Chimneys: DuraFlex 316 provides flexible relining, making it compatible with gas, wood pellet, oil, or wood appliances.
  • Versatile Usage: Suitable for various applications including fireplace inserts, furnaces, boilers, and water heaters.
  • Extreme Conditions: Specifically designed for harsher environments, such as coal applications, where superior corrosion resistance is essential.


Model Size Flex Length
3DF316-25K 3" I.D 25 ft.
4DF316-25K 4" I.D 25 ft.
5DF316-25K 5" I.D 25 ft.
55DF316-25K 5.5" I.D 25 ft.
6DF316-25K 6" I.D 25 ft.
7DF316-25K 7" I.D 25 ft.
8DF316-25K 8" I.D 25 ft.
Materials 316 Stainless Steel
Construction Single-Wall
Clearance 0” clearance for gas, oil, and pellet applications.
Clearance 1” clearance to masonry for wood-burning
Listings Listed to UL 1777 and ULC S635 (MH45609).
Warranty Limited-lifetime warranty


About the Manufacturer

Consistently the first to market with new innovations in venting systems, DuraVent has captured a leadership position in emerging markets. DuraVent has patents for several products and continues to design safe and technologically advanced venting.The company’s research into solving problems with corrosion, when biofuels such as corn are used, led to the break-through patent for PelletVent Pro.

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It is very important that you inspect the packaging of your items when they arrive and check if you received all boxes listed on the delivery receipt. If you notice any damage or shortage of packages, you must make note of it on the bill of lading, take pictures, and refuse delivery. Your note should say "refused due to damage". You must also take photos of all sides of the box and send them to us within 2 days. If there are no damages visible before opening the box, you must note "subject to further inspection may contain concealed damage". If you notice any damage after receiving the delivery, do not throw the box away, and contact us with the photos. After we receive information from you about the refused delivery or concealed damage, we immediately initiate a claim with the shipping company or with the manufacturer. After the claim is fully processed, we ship all replacements at absolutely no cost to you.

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We offer free order cancellations before the shipping label or Bill of Lading is generated, or prior to the commencement of production for custom orders. Please note that custom-made items are not eligible for refunds once production has begun. To be eligible for a return, the item must be unused and in its original condition, with all packaging intact and in perfect condition. Orders delivered outside of the United States are not eligible for refunds. If your order arrives damaged, please refer to the "Damages" section. Our refund policy extends for 30 days. If 30 days have elapsed since your purchase, regrettably, we cannot process a refund. Prior to returning an item, please contact us to discuss shipping details. All refunds will be credited to the original credit card or PayPal account used for the purchase, within two days of receiving the returned items at our warehouse.

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