DuraVent DuraFlex 304 Basic Kit: a liner and fittings for chimneys with few bends
The DuraVent DuraFlex 304 Basic Kit is a flexible liner kit for a chimney with few bends. It includes a 304 stainless steel coil, a top plate with a welded collar to hold the liner, a removable rain cap, and a connector for the bottom joint. DuraFlex Stainless is DuraVent’s flexible stainless steel liner for relining a masonry chimney that vents a wood, pellet, oil, or gas appliance. The 304 liner is the lightest and lowest priced of the three, for exhaust that is not corrosive. Insulation and a spark arrestor are not included.
Choose a length of 15, 20, 25, 30, or 35 feet, then a diameter from 3 to 8 inches, including 5 1/2 inches. For harsher exhaust from coal or high sulfur oil, 316 costs more but resists corrosion better. For several chimney bends, Pro uses 316 steel with deeper ridges and 20 percent more steel per foot to bend tighter. All three share fittings and wraps. Connecting through the chimney wall? The DuraVent DuraFlex 304 Tee Kit replaces the bottom connector with a tee for that turn. The DuraVent DuraFlex 304 Basic Kit ships free from My Cozy Outdoors with No Sales Tax (except WY) and the full manufacturer warranty.
Details
SKU: 3DF304-15K | 4DF304-15K | 5DF304-15K | 55DF304-15K | 6DF304-15K | 7DF304-15K | 8DF304-15K
SKU: 3DF304-20K | 4DF304-20K | 5DF304-20K | 55DF304-20K | 6DF304-20K | 7DF304-20K | 8DF304-20K
SKU: 3DF304-25K | 4DF304-25K | 5DF304-25K | 55DF304-25K | 6DF304-25K | 7DF304-25K | 8DF304-25K
SKU: 3DF304-30K | 4DF304-30K | 5DF304-30K | 55DF304-30K | 6DF304-30K | 7DF304-30K | 8DF304-30K
SKU: 3DF304-35K | 4DF304-35K | 5DF304-35K | 55DF304-35K | 6DF304-35K | 7DF304-35K | 8DF304-35K
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).
FAQ
What is in the DuraFlex 304 Basic Kit?
A DuraFlex SS Top Plate with welded Storm Collar, a Removable Vertical Cap, a DuraFlex SS Connector and one DuraFlex 304 flex length of 15, 20, 25, 30 or 35 feet. Choose the length and then a diameter from 3 to 8 inches on the selectors; the 3-inch 15-foot kit is the listed price and the other combinations show their own.
When is the 304 liner enough?
DuraFlex 304 is DuraVent’s lightest, most economical stainless liner, intended for wood-burning, non-condensing gas and oil appliances in chimneys with minimal offsets. Choose 316 instead where flue gases are more corrosive, such as coal, and DuraFlex Pro where the flue has several bends. All are listed to UL 1777 and ULC S635 as alternatives to clay tile.
What clearance does it need?
Zero clearance to the masonry for gas, oil and pellet appliances with no insulation required. For wood burning, 1 inch of clearance to the masonry, or a 1/2-inch ProFoil or Flexwrap blanket (1 inch of TherMix) around the liner for the zero-clearance listing. DuraVent also notes insulation improves draft and reduces condensation on exterior chimneys.
How is the liner installed at the top and bottom?
The liner is fed down the chimney, the top plate slides over it with 2 to 3 inches showing, is sealed to the crown with RTV silicone and clamped, and the removable cap locks on. At the bottom the connector attaches the liner to the insert or stove connector pipe. Cut to length with a hacksaw if needed and have the masonry inspected before relining.
Which kit do I need for a side-entry stove?
The 304 Tee Kit, which replaces the connector with a tee and clean-out cap for an appliance that enters through the chimney wall; this Basic Kit is for a liner dropping straight to an insert. Both use the same top plate and cap, and both are listed with the rest of the DuraFlex Stainless range.