DuraVent - 6" Factory Built DuraFlex 316 Stainless Steel Reline Kit

Save $171.63
DuraVentSKU: 6DF316-25KFB

Regular price$1,544.64 Sale price$1,716.27

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Size (Ft.): 25'
⛟ Estimated Delivery Date: Between and to all states excl. Alaska & Hawaii.

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Elevate your chimney's performance and safety with the DuraVent 6" Factory Built DuraFlex 316 Stainless Steel Reline Kit. As the frontrunner in the venting industry, DuraVent has consistently delivered innovative, reliable, and professional-grade products to the HVAC and Hearth markets. This kit exemplifies our commitment to excellence.

DuraFlex Pro, the core of this kit, boasts 20% more stainless steel per foot than its competitors, ensuring unmatched strength and flexibility. With its extreme pliability, this liner simplifies installations, even when dealing with tricky offsets. DuraFlex Pro, constructed from highly corrosion-resistant 316 Stainless Steel, is UL 1777 and ULC S635 certified, a testament to its quality and safety.

But the advantages don't stop there. DuraFlex SW, a smooth inner-wall stainless steel chimney liner included in the kit, guarantees optimal appliance efficiency. Its sleek, ridge-free design eliminates obstructions, allowing seamless flue gas flow and minimizing deposits. This not only enhances performance but also simplifies maintenance, making it perfect for relining masonry chimneys for wood and gas-burning appliances, all while being UL 1777 listed.


  • Enhanced Safety: This kit is essential for ensuring the safe operation of wood-burning inserts in existing UL-127-listed fireplaces. It's a critical step toward maintaining safety and performance.
  • Versatile Applications: Whether you have a wood pellet, oil, or wood appliance, this kit is compatible. It's perfect for fireplace inserts, furnaces, boilers, and water heaters.
  • Customizable: Tailor the kit to your needs with custom lengths (minimum 10' length) available for both DuraFlex Pro and DuraFlex SW. Ventinox components are also compatible for all 9"-12" flex systems.
  • Efficient Design: The smooth inner wall of DuraFlex SW ensures optimal appliance efficiency by eliminating ridges that restrict flue gas flow.
  • Low Maintenance: Say goodbye to deposits and obstructions. DuraFlex SW's design makes cleaning and maintenance a breeze.
  • UL Certified: With UL 1777 and ULC S635 certifications, you can trust the safety and quality of this kit.
  • Lifetime Warranty: Enjoy peace of mind with our limited-lifetime warranty, showcasing our commitment to your satisfaction.


  • Use as a relining system for factory-built chimneys to be used with solid-fuel appliances in the USA.
  • Relining is critical for performance and safety when a wood-burning insert is installed into an existing UL-127-listed fireplace.
  • Kit includes Cap, Storm Collar, Support Bracket, Ventilation Disk, Centering Bracket, DuraLiner 12" Length, Flex Connector, Flex Length (25' or 35'), Adjustable Band, and Flex Adapter.


DuraFlex 316 flexible relining for a masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include fireplace inserts, furnaces, boilers, and water heaters.


Model Size Flex Length
6DF316-25KFB 6" I.D 25 ft.
6DF316-35KFB 6" I.D 35 ft.
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.

Order Confirmation:

Upon placing your order, you will promptly receive an email confirmation. Subsequently, we will conduct a thorough inventory check to ensure all items are in stock and available for immediate shipment. If your order aligns with the advertised delivery timeframe, we will promptly process it for shipment to our warehouse. In cases where the expected delivery time extends beyond the advertised timeframe, we will reach out to you via email and/or phone for confirmation.

Order Shipment:

Within one business day of your item being shipped, you will receive an email confirmation containing a tracking number. If you do not receive tracking information within six business days of placing your order, please don't hesitate to get in touch with us for assistance.

Estimated Time of Arrival:

Our typical delivery timeframe ranges from 2 to 10 business days. Custom-made products generally require 3 to 5 weeks for delivery. If the expected delivery date for your order would fall outside of the advertised 2-10 business day time frame, our customer service team will contact you to ensure your agreement with the revised timeline.

Covered Areas:

Please note that all estimated delivery dates and shipping costs advertised on our website apply exclusively to the Contiguous United States. For inquiries regarding shipping to Hawaii or Alaska, kindly reach out to our customer service team. While we do not offer direct shipping to Canada, we are more than willing to ship your order to the freight carrier of your choice.


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.

Cancellations & Refunds:

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.

Please contact sales@belleflame.com for any questions regarding shipping time.

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