DuraFlex Pro - DuraFlex Pro is the ultimate in flexible steel liners for strength and flexibility. It features 20% more stainless steel per foot compared to other liners on the market. Its extreme flexibility facilitates problem free installations where multiple offsets are needed. DuraFlex Pro is available in 3″ through 12″ diameters in lengths, kits and custom lengths. DuraFlex Pro is manufactured utilizing highly corrosion resistant 316 Stainless Steel. Listed to UL 1777 and ULC S635. DuraFlex SW - DuraFlex SW is a smooth inner-wall, flexible stainless steel chimney liner. The smooth inner wall provides for no output reduction allowing for full appliance efficiency. Smooth wall construction eliminates ridges that restrict flue gas flow and collect deposits. The lack of ridges facilitates cleaning and maintenance. DuraFlex SW is ideal for relining masonry chimney for wood and gas burning appliances. Listed to UL 1777. DuraFlex 316 & 304 - DuraFlex 304 and 316 are lighter, more economical liners. Excellent when there are minimal offsets in the chimney. DuraFlex 304SS and 316SS are intended for wood burning, non-condensing gas and oil fired appliances. Where greater corrosion resistance is desired, such as coal-fired appliances, DuraFlex 316 is recommended. DuraFlex 304SS and 316SS are listed to UL 1777 and ULC S635. DuraFlex Aluminum - An economical venting system used for relining masonry chimney for natural gas or liquid propane category I, draft hood equipped appliances, and appliances tested and listed to use Type B Gas Vent for a wide range of applications, including: natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications. Protects the masonry chimney from damaging effects of flue product condensation.What's Included DuraFlex SS Top Plate With Welded Storm Collar DuraFlex SS Removable Vertical Cap DuraFlex SS Connector DuraFlex Pro Length Features Available in 3" to 8" diameters. Flex remains secured to the Storm Collar/Top Plate when removing the cap section for inspections and cleaning. Specifications Item Number 55DFPRO-20VCK Series DuraFlex Pro Product Type Top Plate/Cap Kit Size (Diameter) 5.5" Flex Length 20' Warranty Duravent, Inc. (“Duravent”) provides this limited lifetime warranty for all of its products with the exception of Ventinox® (lifetime), and PolyPro® (ten years). Subject to the limitations set forth below, Duravent warrants that its products will be free from defects in material or manufacturing, if properly installed, maintained and used. DuraVent, Inc. (“DuraVent”) provides this limited lifetime warranty for all of its products with the exception of Ventinox® (lifetime), and PolyPro® (ten years). Subject to the limitations set forth below, DuraVent warrants that its products will be free from defects in material or manufacturing, if properly installed, maintained and used. DuraVent products are fully warranted if installed only by a professional installer. This Warranty is transferable from the original homeowner to the buyer of the home. This warranty does not cover normal wear and tear, smoke damage or damage caused by chimney fires, acts of God, or any product that was: (1) purchased other than from an authorized DuraVent dealer, retailer or distributor; (2) modified or altered; (3) improperly serviced, inspected or cleaned; or (4) subject to negligence or any use not in accordance with the installation instructions included with the product as determined by DuraVent. DuraVent provides the following warranties for its products: One Hundred Percent (100%) MSRP 15 years from the date of purchase, and Fifty Percent (50%) thereafter, except for the following limitations on: all Termination Caps and DuraBlack® are warranted at One Hundred Percent (100%) for five years. All warranty obligations of DuraVent shall be limited to repair or replacement of the defective product pursuant to the terms and conditions applicable to each product line. These remedies shall constitute DuraVent’s sole obligation and sole remedy under this warranty. This warranty provides no cash surrender value. The terms and conditions of this warranty may not be modified, altered or waived by any action, inaction or representation, whether oral or in writing, except upon the express, written authority of an executive officer of DuraVent. Corn, bio-fuels, driftwood or other wood containing salt, preservative-treated lumber, plastic and household trash or garbage, or wood pellets containing such materials must not be burned in the appliance or fireplace. In case of a chimney fire, the chimney must be inspected and approved by a certified Chimney Sweep before reuse. After each annual inspection, maintenance, and cleaning, the certified Chimney Sweep must fill out and date the appropriate section of the warranty card provided with the chimney liner. LIMITATIONS ON INTERNET SALES: Notwithstanding any other terms or conditions of this Limited Lifetime Warranty, DuraVent provides no warranty for the following specific products if such products are not installed by a qualified professional installer: DuraTech®, DuraTech® DTC, DuraTech® Premium, DuraPlus HTC®, DDW®, DuraChimney® II, PelletVent Pro®, DirectVent Pro®, FasNSeal®, FasNSeal® W2, FasNSeal® Flex, and PolyPro®, and DuraVent’s relining products including DuraLiner®, DuraFlex® (SW, Pro, 316, 304), and Ventinox®. For purposes of this warranty, a trained professional installer is defined as one of the following: licensed contractors with prior chimney installation experience, CSIA Certified Chimney Sweeps, NFI Certified Specialists, or WETT Certified Professionals. DuraVent must be notified and given the opportunity to inspect defective product prior to replacement under the terms of this limited lifetime warranty. All warranty claims must be submitted with proof of purchase. Labor and installation costs are not covered under this warranty. To obtain warranty service contact: DuraVent Warranty Service, 877 Cotting Ct., Vacaville CA 95688, or call 800-835-4429. WHERE LAWFUL, DURAVENT DISCLAIMS ALL OTHER WARRANTIES, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL DURAVENT BE LIABLE FOR INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR SPECIAL DAMAGES OR DIRECT OR INDIRECT LOSS OF ANY KIND, INCLUDING BUT NOT LIMITED TO PROPERTY DAMAGE AND PERSONAL INJURY. DURAVENT’S ENTIRE LIABILITY IS LIMITED TO THE PURCHASE PRICE OF THIS PRODUCT. SOME STATES DO NOT ALLOW LIMITATIONS ON IMPLIED WARRANTIES, OR THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO YOU. THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO HAVE OTHER RIGHTS THAT VARY FROM STATE TO STATE. Documents & Files DuraFlex SS (Stainless Steel) Catalog DuraFlex AL (Aluminum) Catalog DuraFlex SS: Brochure DuraFlex SS: Relining Factory-Built Chimney Brochure DuraFlex SS: Factory Built Chimney Relining Installation Instructions DuraFlex SS: Flexible Chimney Liners Installation Instructions DuraFlex AL: Installation Instructions DuraFlex Pro Insert Kit DuraFlex SS: Home Safety- Chimney Relining for Gas Appliances (DuraFlex SS) DuraFlex SS: Relining Best Practices (DuraFlex SS) DuraFlex SS: Relining Factory Built Sales Sheet (DuraFlex SS) DuraFlex Pro: Most Flexible Chimney Liner On The Market Bulletin (2011) DuraFlex SS: TherMix Chimney Liner Insulation Bulletin (2011) DuraFlex SS: Relining a Factory-Built Chimney Can Now Be Done Safely With a Listed System Bulletin (2013) DuraFlex SS: Insert Adapter Bulletin (2013) DuraFlex SS: Oil Sizing Chart Bulletin (2017) DuraFlex SS: 3″ – 8″ Removable Vertical Cap and Top Plate Bulletin (2022) DuraFlex AL: Custom Length Flex Liner Component Discontinuation Bulletin (2022) Videos Frequently Asked Questions What are the DuraVent DuraFlex's Stainless Steel Product Details? Applications DuraFlex Pro ultra flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include: fireplace inserts, furnaces, boilers, and water heaters. DuraFlex SW smooth wall flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include: fireplace inserts, furnaces, boilers, and water heaters. DuraFlex 316 flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliance. Applications include: fireplace inserts, furnaces, boilers, and water heaters. 316 is designed for use in harsher conditions, for more resistance to corrosion, such as coal. DuraFlex 304 flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include: fireplace inserts, furnaces, boilers, and water heaters. Materials and Construction DuraFlex Pro: Single-wall .005″ 316 stainless steel.DuraFlex SW: Single-wall .005″ overlapped 316 stainless steel (totalling .010″). Overlapped to create smooth inner wall.DuraFlex 316 & 304: Single-wall .005” 316 or 304 stainless steel. Clearances DuraFlex Pro: 0″ clearance for gas, oil, and pellet applications. 1″ clearance to masonry for wood-burning applications. Insulation is required for 0″ clearance to masonry for wood-burning.DuraFlex SW: Clearances 0″ clearance for gas, oil, and pellet applications. ” clearance to masonry for wood-burning applications. Insulation is required for 0” clearance to masonry for wood-burning.DuraFlex 316 & 304: 0″ clearance for gas, oil, and pellet applications. 1″ clearance to masonry for wood-burning applications. Insulation is required for 0″ clearance to masonry for wood-burning. Diameters DuraFlex Pro & SW: 3″ – 12″.DuraFlex 316 & 304: 3″ – 8″. Listings DuraFlex Pro: Listed to UL 1777 and ULC S635 (MH45609).DuraFlex SW: Listed to UL 1777 (MH45609).DuraFlex 316 & 304: Listed to UL 1777 and ULC S635 (MH45609). What are the DuraVent DuraFlex's Aluminum Product Details? Applications DuraFlex AL (DFAL) aluminum flexible relining for masonry chimney. Use with natural gas or liquid propane category I, draft hood equipped appliances, and appliances tested and listed to use Type B Gas Vent. Applications include: natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications Materials and Construction Single-wall .010″ aluminum (2-ply of .005″). Clearances 0″ clearance to masonry. Diameters 3″, 4″, 5″, 5″, 6″, 7″, and 8″ Listings Listed to UL 1777 and ULC S635. What is DuraVent DuraFlex Stainless Steel's Typical Installation? Typical Installation Refer to our Typical Venting Installation drawings to select the appropriate component parts for your installation. The inner pipe diameter 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! Use proper support and bracing. Follow local building codes and have your venting system inspected. More Typical Installations: Installation Key 1     DuraFlex SS Cap2     DuraFlex AL Cap3     DuraFlex Top Plate4     DuraFlex (SW, Pro, 304, 316) Length5     DuraFlex AL Length6     DuraFlex SS Tee7     DuraFlex AL Tee8     DuraFlex Mortar Sleeve9     DuraFlex AL Coupling10     DuraFlex SS Connector11     PelletVent Pro Appliance Adapter12     DuraBlack Trim Collar13     Rigid Type B Gas Vent14     Rigid PelletVent (L Vent)15     ProFoil Insulation, AluFoil Tape & ProMesh16     DVL or DuraBlack Pipe17     Pipe Collar (B-Vent) Planning Your Installation: Verify the venting requirements of the appliance used. Choose the liner system appropriate for the appliance and installation. Refer to the Typical Installations for the type of liner installation similar to your situation. Identify the needed parts for installation. The size of the liner should match the outlet size on the appliance or the size of the vent/manifold that penetrates into the masonry chimney. Determined the length of the liner needed. Make sure of a proper fit for the Top Plate of the reliner to provide a secure, leak-proof installation. If a free-standing appliance is used, select the vent or stovepipe pieces to connect from the appliance to the liner (refer to the appropriate section of catalog). Important! Check to be sure the installation complies with all local and national code requirements, including clearance to combustibles. Contact the local building inspector for permit requirements. Design Recommendations The following design recommendations are intended only as a general guideline to assist in the design and selection of liner components for your installation. Always read and follow Duravent Installation instructions (enclosed with the cap or support box) before installing DuraFlex. Installation instructions can be viewed online at www.duravent.com, under catalogs and instructions. Before relining a chimney, it should be cleaned and inspected to verify the integrity of the mortar and masonry. In addition, have a certified chimney professional determine if the masonry was constructed with 0” or 1” clearance to the surrounding combustibles. This is an important fire safety issue that may have an influence on how the liner is installed. Be sure to select the proper liner for the application. DuraFlex SS is used for appliances that use oil, wood, or wood-pellets for fuel; DuraFlex AL is for a non-condensing gas appliance. Refer to the appliance manufacturer for installation requirements affecting venting. Keep the vent path as straight as possible for best performance. Relining Solutions DuraVent is the first manufacturer to have a UL-listed relining system for factory-built chimneys to be used with solid-fuel appliances in the USA. When a homeowner installs a wood-burning insert into an existing UL127-listed fireplace, relining the existing chimney is critical for performance and safety. Check out the installation video and bulletins. What does the UL listing cover? All 127, 103, or 103HT chimneysInsulated chimneys- all sizes with 2” clearanceAir cooled – clearance based on diameterAll Duravent UL1777 systems up to 8”Flex does not need insulation. Air Cooled Chimney Coverage: Up to 8” I.D. chimneys with at least 1 ¼” wall (ex. 8×10½)6×8½ is OK, 8×11 is OKUp to 8” I.D. chimneys require at least 1 ½” clearanceLarger chimneys with at least 1 ½” wall (ex. 10×13)9×12 is OK, 10×14 is OK, 16×19 is OKChimneys larger than 8” require at least 2” clearance Factory-Built Reline Kit includes: Cap Storm Collar Support Bracket Ventilation Disk Centering Bracket DuraLiner 12” Length Flex Connector Flex Length (25’ or 35’) Adjustable Band Flex Adapter What is DuraVent DuraFlex Aluminum's Typical Installation? Typical Installation Refer to our Typical Venting Installation drawings to select the appropriate component parts for your installation. More Typical Installations: Installation Key 1     DuraCap2     Storm Collar3     Roof Flashing4     High-Wind Cap5     Round Pipe6     Elbow7     Tee8     Tee Cap9     Increaser Tee10     Female Flex Adapter11     Male Adapter12     Double-Wall Wye13     Pipe Collar14     Increaser15     Draft Hood Connector16     Square Firestop Support17     Oval Pipe18     Oval to Round Adapter19     Oval Tee20     Oval Tee Cap21     Oval Tee Support22     Oval Firestop Spacer23     DuraConnect II24     DuraFlex AL Length25     DuraFlex Motar Sleeve26     DuraFlex AL Coupling How Size and Height Affect Stove Performance The amount of heat the vent gases loose as they flow determines how much condensation will occur and how strong the draft will be. To control the heat loses, proper selection of venting materials is of vital importance. Double-wall Type B Gas Vent, with an aluminum inner wall and a galvanized steel outer wall, has proven to be the ideal choice in venting materials. Vent Termination Chart Using listed Type B Gas Vent caps may terminate in accordance with this table. Minimum height Roof Pitch 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 Over 14/12 to 16/12 6 1.83 Over 16/12 to 18/12 7 2.13 Over 18/12 to 20/12 7.5 2.29 Over 20/12 to 21/12 8 2.44 Gas Vent Specification Chart Item Clearances Maximum Height Outer Tube Ø Materials Locking Device UL Listing ULC Listing Type B Vent Round 3″-8″ 1 inch to combustibles 100 feet 5/8″ larger than ID Inner – .012″ Aluminum Outer – .018″ Galvanized DuraLock MH6357 CMH1276 Round 10″ to 16″ See note 2 1 inch to combustibles 100 feet 1″ larger than ID Inner – .016″ Aluminum Outer – .021″ Galvanized TwistLock Screws MH6357 CMH1276 Round 18″ to 30″ 1 inch to combustibles 100 feet 2″ larger than ID See note 5 Inner – .020″ Aluminum Outer – .021″ Galvanized Screws MH6357 CMH1276 Oval Type B Vent 4″ and 5″ 2″ x 4″ & 2″ x 6″ stud wall and 1 inch to combustibles See Note 3 2 1/2″ x 7 1/4″ 3 1/8″ x 10 7/8″ Inner – .012″ Aluminum Outer – .018″ Galvanized Button Lock MH6357 CMH1276 Oval Type B Vent 6″ 2″ x 6″ stud wall and 1 inch to combustibles See Note 3 3 1/4″ x 12″ Inner – .012″ Aluminum Outer – .018″ Galvanized Button Lock MH6357 CMH1276 Type B Vent 3″ to 6″ Round Liner” 0″/Masonry 50 feet 5/8″ larger than ID Inner – .012″ Aluminum Outer – .018″ Galvanized DuraLock MH14420 MH6357 CMH1407 DuraFlex AL Gas Relining 3″ to 6″ 0″/Masonry 50 feet 1/4″ larger than ID .010″ Aluminum Flex Screws DuraLock MH14420 — DuraConnect 3″ to 6″ 1 inch to combustibles See Note 4 1/4″ larger than ID .010″ Aluminum Flex .018″ Galvalume DuraLock MH14089 — DuraConnect II 3″ to 6″ 1 inch to combustibles See Note 4 1/4″ larger than ID .010″ Aluminum Flex .018″ Galvalume DuraLock MH14089 — Notes: Clearance to combustibles is the air space between vent and combustibles. Maximum height varies with equipment over 50′, for taller applications refer to SDV sizing handbook (L202). 14″-16″ Pipe require screws. When oval is used on wall furnaces, minimum height required from bottom of furnace to cap is 12′, minimum 16″ stud space. Limited by sizing tables. 18″ pipe OD is one inch larger than ID and 20″ – 30″ OD is 2″ greater than ID What are the DuraVent product lines? DuraVent offers the following product lines: DuraTech 5″-8″: All-fuel, double-wall chimney system. UL 103 HT and ULC S604.DuraTech LDC 10″-24″: All-fuel, double-wall chimney system. UL 103.DuraTech Canada is a double-wall, all-fuel chimney system for use with wood stoves, wood fireplaces, and other appliances using wood, oil, gas, or coal.DuraPlus: Triple-wall all-fuel chimney with two layers of insulation.DuraPlus HTC: Double-wall all-fuel chimney built to Canadian standards.DuraChimney II: Double-wall air-cooled chimney for pre-fabricated masonry chimneys.Combustion Air Systems: DuraVent’s exclusive, patent-pending system is designed to bring in outside combustion air directly to your wood or pellet stoves.DuraBlack: Single-wall stovepipe.DVL: Double-wall stovepipe.DuraLiner: Double-wall factory insulated masonry relining system.DuraFlex: Flexible stainless steel liners.DuraFlex Aluminum: Flexible aluminum relining for masonry chimney. UL 1777 and ULC S635.Ventinox: Flexible stainless steel liner.CVS: Provides Ortal Branded Fireplace Systems and as a Direct Vent for Pellet Stoves.PelletVent: Multi-fuel vent.PelletVent Pro: Vents appliances using oil, wood pellets, corn, and other biofuels.DirectVent Pro: Unitized, co-axial venting system for direct vent gas or propane stoves, heaters, and fireplaces.Type B Gas Vent: Vents natural gas, liquid propane category I, and draft-hood equipped appliancesFasNSeal: Single, double-wall, flex, and concentric venting for category II, III, and IV appliances.FasNSeal 80/90: Combined Category I and IV venting for Gas-Burning Appliances.PolyPro: Single-wall, flex, and concentric venting made of polypropylene for category II and IV condensing appliances that operate up to 248 degrees.PolyPro Flex: PolyPro double-wall flex lining system. Environmentally safe venting system for high-efficiency appliances, including water heaters, condensing boilers, and warm air furnaces. ULC S636.DuraSeal: Single-Wall and Double-Wall Special Gas Vent Boiler Adapters.DuraStack: A modular double-wall, positive pressure chimney for use with boiler breeching and stack, engine exhaust, and grease duct (DIS only)DuraStack Pro: Models DIS and DAS. Modular Double-Wall Positive Pressure Chimney for Boiler Breeching, Stack, and Engine Exhaust.