Duravent Type B Adjustable Round Gas Vent Pipe Instruction Manual

Duravent Type B Adjustable Round Gas Vent Pipe

Product Information

The Type B Gas Vent is designed for use with natural gas or liquid propane category I appliances and appliances equipped with a draft hood. It is used to safely vent the combustion byproducts of these appliances. Failure to maintain the required clearances to combustible materials can result in vent-related fires.

General Information:

• Type B Gas Vents are suitable for venting boilers, furnaces, water heaters, unit heaters, room heaters, duct furnaces, and decorative gas appliances.

Planning:

1. Review the appliance manufacturer’s installation instructions for proper positioning, venting requirements, and compatibility with Type B gas vent.
2. Ensure that the vent and fittings are installed according to local codes and accepted venting practices.
3. If multiple appliances are connected to the vent, ensure proper clearance and spacing between them.
4. For vent pipes with a diameter of 14 or larger, the termination point should be at least 2 feet higher than adjacent walls or obstructions within 10 feet.
5. Plan a minimum of one foot vertical connector rise coming out of each appliance.

Product Usage Instructions

1. Before installation, carefully read and understand all instructions provided.
2. Ensure that the appliance is compatible with Type B Gas Vent and follow the appliance manufacturer’s installation instructions for positioning and venting requirements.
3. Select the appropriate Type B Gas Vent components based on the installation requirements.
4. Install the vent and fittings according to local codes and accepted venting practices.
5. Maintain the required clearances (air spaces) to combustible materials as specified in the installation instructions.
6. Ensure that the vent termination point is at least 2 feet higher than adjacent walls or obstructions within the specified distance.
7. Plan a minimum of one foot vertical connector rise coming out of each appliance.
8. Regularly inspect and maintain the Type B Gas Vent system to ensure proper functioning and prevent vent-related fires.

For any comments, ideas, input, or complaints regarding DuraVent products, contact the customer service email at customerservice@duravent.com.
For tech support or product information, call 800-835-4429 or email techsupport@duravent.com.

Round and Oval Type B GasVent Systems for use with natural as or liquid propane category I and draft hood equipped appliances and appliances listed to use Type B Gas Vent.

A MAJOR CAUSE OF VENT RELATED FIRES IS FAILURE
TO MAINTAIN REQUIRED CLEARANCES (AIR SPACES) TO COMBUSTIBLE MATERIALS. IT IS OF THE UTMOST IMPORTANCE THAT TYPE B GAS VENT BE INSTALLED ONLY IN ACCORDANCE WITH THESE INSTRUCTIONS.
NOTE:
READ THROUGH ALL OF THESE INSTRUCTIONS BEFORE BEGINNING YOUR INSTALLATION. FAILURE TO INSTALL
AS DESCRIBED IN THIS INSTRUCTION WILL VOID THE MANUFACTURER’S WARRANTY, AND MAY HAVE AN EFFECT ON YOUR HOMEOWNER’S INSURANCE AND UL LISTING STATUS. KEEP THESE INSTRUCTIONS FOR FUTURE REFERENCE.

IMPORTANT:
Read through all of these instructions before beginning your installation. Failure to install this product as described in these instructions will void the manufacturer’s warranty, may create a fire or other safety hazard, and may affect your homeowner’s insurance and safety listing of your appliance.
Keep these instructions for future reference.

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We welcome any ideas, input or complaints and I’ll make sure that someone responds directly back to you.
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ROUND B VENT

GENERAL INFORMATION
Type B Gas Vents are for venting listed Natural Gas or Liquid Propane Category I appliances only. The appliances listed below typically
(but not always) use Type B vent systems. Boilers
Furnaces
Water Heaters
Unit Heaters
Room Heaters
Duct Furnaces
Floor Furnaces
Decorative Gas Appliances

DuraVent Type B Vent Systems may be used on other gas-burning appliances, provided the manufacturer of the appliance states in their installation instructions that Type B-vent is acceptable. Do not use Type B Vents
for Category II, III, or IV gas appliances. Type B Vent shall not be used to vent flue products from incinerators, combination gas/oil appliances, oil- fired, or wood-burning appliances. If there is a question about the use of Type B Vents, contact the appliance manufacturer or DuraVent’s Engineering Department for further information.

PLANNING

1. Appliances. Carefully review the appliance manufacturer’s installation instructions for positioning the unit, any special venting or connector requirements, and verify that it is a Category I appliance or an appliance that requires the use of Type B gas vent.
2. Placement. The placement of the vent and fittings must be in accordance with Local Codes, as well as accepted venting practices. If more than one appliance is to be connected to one venting system, the common vent must be correctly sized. It is a good idea to make a sketch of the proposed installation, labelling the components you will need. Adjustable Pipe Lengths are available to make up odd lengths. Minimize the number of turns and lateral runs, as the National Fuel Gas Code places limitations on these. A 45° turn is preferable to a 90° turn. The appliance reference material should be consulted at this time, as well as any Local Authority having jurisdiction. In most localities, building permits are required for any new appliances, or modifications to existing venting systems.
3. Figures 1, 2, & 3 show examples of some typical residential installations.
4. Clearance to Combustibles. A 1-inch clearance (air space) to combustible materials must be maintained, when using DuraVent Round B-Vent, regardless of the pipe diameter.
5. Combustion Air. Refer to appliance installation instructions and local building codes to ensure compliance with required volume of combustion air for each appliance installed .
6. Slope. If the venting system contains lateral (horizontal) components, they shall be positioned so they have an upwards slope away from the appliance of not less than 1/4-inch rise per foot of run. (Horizontal vent installed in attics, unconditioned area, or between floors have further restrictions, please consult your local building codes for specific limitations.)
7. Termination Area. Examine the area where the vent system will terminate. The height of the termination above the roof is determined by the roof pitch, and also it’s proximity to adjacent walls or obstructions. Consult Table 2 for proper termination height requirements. Vent pipe with 3”-12” diameter must terminate at least 2 feet higher than an adjacent wall or obstruction, if it is within 8 feet. Vent pipe with 14” or larger diameter must terminate at least 2 feet higher than an adjacent wall or obstruction, if it is within 10 feet.
8. Connector Rise. Plan a minimum of one foot vertical connector rise coming out of each appliance.

STEPS FOR TYPICAL INSTALLATION

1. Location. Building Code requires the appliance(s) to be located as close to the vent as possible. After consulting the local codes, appliance installation instructions and any other applicable reference material determine the optimum location for the appliance(s).

2. Penetration Point. Locate and mark the center of the penetration point through the ceiling or the wall. Refer to Step 3 or 4, as appropriate.
   TABLE 1

   PIPE SIZE| STOCK NUMBER OF CEILING SUPPORT| FRAMED INSIDE DIMENSIONS (X & Y) FIG.4
   3 INCH| 1440| 6″x6″
   4 INCH| 1441| 7″x7″
   5 INCH| 1442| 8″x8″
   6 INCH| 1443| 9″x9″
   7 INCH| 1444| 10″x10″
   8 INCH| 1445| 11″x11″
   10 INCH| 1446| 13″x13″
   12 INCH| 1447| 15″x15″

3. Ceiling Support. For a ceiling supported system, install the Square Firestop/Support as shown in Figures 6, 7, and 8. The Firestop Support must be framed in and the dimensions are shown in Table 1 and shown in Figure 4. Firestop Supports are currently manufactured for pipe sizes of 3” through 12” only. Larger sizes may be locally fabricated from sheet metal, provided that the mandatory 1-inch clearance is maintained, the pipe is adequately supported, and the installation is acceptable to Local Authorities. In multistory buildings, a Firestop/Spacer must be provided at every floor /ceiling level other than the first floor which requires a support.

4. Wall Thimble. For a through-the-wall system, install the Wall Thimble, as shown in Figure 5. The Wall Thimble is designed to accommodate walls up to 6 inches thick. If you have thicker walls, a sleeve extension should be fabricated and attached to the existing sleeve . Do not fill the air space between the B-vent Pipe Section and the Wall Thimble with insulation, although an RTV-type sealant may be applied around the flange and nail heads if desired.

5. Pipe Assembly. Sections of DuraVent round pipe are joined together by lining up the female end of the locking lug with the male end slot, pushing them together, and turning clockwise to twist lock. Refer to Figure 9. Sheet metal screws are not needed for 3” through 8” diameter pipe. However, if desired, use 1/4-inch long sheet metal screws for 3” through 8” diameter pipe. Never penetrate the inner liner with screws. For 10” through 16” diameter pipe, DuraVent recommends using a minimum of (4) 3/8” sheet metal screws per joint, and a minimum of (6) 3/8” sheet metal screws are required per joint for 18” and larger diameters. Each Pipe Section is labelled, and an arrow shows the direction of the exhaust flow.
   For ceiling supported installations, place a Pipe Section, or assembled Pipe Sections, through the hole in the Square Firestop Support, and tighten the Clamp. The Clamp will rest inside the Ceiling Support, and prevent the Pipe Sections from dropping down. The Pipe Section(s) should protrude a minimum of one inch below the ceiling.
   An optional Pipe Collar is available for decorative purposes.

6. Connectors. Only DuraVent connectors should be used between the appliances and the venting system. Some appliances require Type B-Vent as a complete dedicated system from the flue collar of the appliance to the termination of the vent to the outside atmosphere. DuraVent’s DuraConnect, a UL listed flexible connector, can be used if single wall connectors are allowed. If a B-vent connector is required, UL listed double wall flexible DuraConnect II, can be used.

7. Elbows. When Elbows are required, strap the Pipe Sections and/or Elbows in place using Wall Straps. Important: the offset must be supported with Wall Straps to prevent the weight from stressing the elbows, as shown in Figure 10.

8. Tees and Wyes. Tees and Wyes are used to combine connectors from 2 or more appliances into a common vent as shown in Figures 2 and 3. A Tee should be used in a through-the-wall application, (Figure 11), as they have a removable Tee Cap (available as a separate item) attached to the bottom. This Tee Cap may be removed in order to inspect the system, or to clean out debris or collected condensate from the common vent. Wall Straps should be used to support the vertical pipe as needed to provide a secure installation. Wall Straps every four feet are required.

9. Enclosures. Any portion of the vent which passes through an occupied area must be enclosed, to prevent accidental damage to the system, as well as burns. Figure 1 shows a system which passes through an occupied second floor.DuraVent does not recommend installation of B-Vent Pipe on the outside wall of a building, particularly in cold climates. If it is necessary to do this, enclose the outside portion of the system in a chase, as shown in Figure 11. Consult the Local Authority prior to construction. Note that the enclosure requires an access door for inspection and maintenance purposes.

10. Terminations. Where the Pipe Sections pass through the roof, a hole must be cut to provide a minimum clearance (air space) of 1 inch between the Pipe and construction materials. Straight lengths of pipe are run up above the roof a minimum of 1-foot. (Refer to Table 2) A Roof Flashing is placed down over the pipe, and adjusted so it fits tightly against the roof, with the Pipe Section held in a position maintaining the 1 inch minimum clearance from combustibles. The Flashing is then nailed to the roof. The roofing material (shingles, asphalt paper, etc.) should overlap the top edge (uphill side) of the Flashing.
    A non-hardening sealant should be used around the edges of the flashing base where it meets the roof. Non-hardening sealant is placed around the joint between the Flashing and the vertical Pipe Section and the Storm Collar is then placed over this joint, to make a watertight seal. (Figure 12) Add sufficient Pipe Sections to attain the minimum height specified in Table 2 TABLE 2

    Gas vent systems using vent caps listed by underwriters laboratories may terminate in accordance with this vent termination table
    ROOF PITCH| MINIMUM HEIGHT
     | FEET| METERS
    FLAT TO 7/12| 1| 0.3
    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

. To connect the Termination Cap to the pipe, hold Cap by its collar, slide collar over locking lugs of pipe, and twist-lock clockwise. Termination Caps of diameters greater than 16 inches do not twist-lock, but are affixed with sheet metal screws.

11. Inspection. This completes the installation steps. Conduct a final inspection to ensure that all joints are secure, the system is properly supported, and is mechanically sound. Especially verify that the one-inch clearance to combustibles requirement has been met, and that adequate combustion air will be furnished to the appliance.

BUCKET SUPPORT

1. Description. The Bucket Support (Figure 13) is for properly supporting the B-vent between 16 or 24-inch O.C. joists or rafters, or for providing a transition fitting between DuraConnect or DuraConnect II and the B-vent Pipe Sections. A maximum of 20 feet of Type B Gas Vent may be supported. Note that the Bucket Support must be installed prior to the sheetrock.
2. Assembly. After you have determined where the B-vent should be located, assemble the Bucket Support and Brackets. Nail the assembly to the bottom side of the joist material as shown in Figure 14. After the Support Bucket is in place, scribe and cut out a hole in the sheet rock 1/8” larger than the diameter of the Bucket, and nail into place. Run the Pipe Sections through the hole in the Bucket Support, connect the DuraConnect or DuraConnect II Connector, and attach the Clamp so that it rests inside the Bucket, and will support the Pipe. Adjust the Pipe to the desired height and tighten the Clamp. This will provide a complete engineered support system.

COMBINATION CAP

1. Description. The Combination Cap, provides an easily installed, safe and efficient B-Vent Cap and Flashing, as one lightweight unit. The two basic components and the assembled unit are shown in Figure 15. The Combination Cap is designed to accommodate roof pitches from flat to 6/12, and is available for 3” through 6” diameter B-Vent pipe.
2. Location. Locate the point in the underside of the roof where the system is to penetrate, using a plumb bob or level.
3. Hole. Remove sufficient roofing material to cut a hole in the roof which will allow a minimum of 1 inch air space between the B-Vent and combustible roofing materials.
4. Flashing. Position the Flashing so the hole is directly over the end of the pipe, as shown in Figure 16. Run the top edge of the Flashing under the roof covering, nail as required, and seal with a non-hardening sealant, as shown in Figure 17. Seal all nail heads.
5. Height. Add sufficient Pipe Sections of B-Vent until the system terminates 1-1/2” to 3” above the collar of the Flashing as shown in Figure 16.
6. Top Cone. Slip the Top Cone over the Flashing, so the vertical straps on the Flashing coincide with the slots at the base of the Cone. Slip the straps up through the slots as shown in Figure 18. Adjust the Top Cone to a generally vertical position. Holding the Top Cone in position, bend the straps down as shown.
7. This completes the installation. Conduct a final inspection of the job to ensure proper joints, correct procedures, sealed nail heads, etc.

ADJUSTABLE ELBOWS

1. Purpose. This section furnishes supplemental information concerning Adjustable Elbows, both 90° and 45°/60°.
2. Connections. In addition to twist locking the elbows, the connection may be further secured by using sheet metal screws at the joint where the male and female parts overlap, provided that the screws DO NOT penetrate the inner liner as shown in Figure 19. One screw per joint is normally sufficient. Use #8 Pan Head sheet metal screws which are no longer than 1/4 inch. Wall Straps must be used to support each elbow (Figure 10). Do not allow the elbows to support the weight of the vent pipe.
3. 90° Elbows. Figure 20. The installer should apply pressure to the section at the points indicated by the arrows. This will prevent the adjacent sections of the elbow from turning, as the next pipe or fitting is twist-locked on. This is important, because once these sections start rotating, the elbow does no longer have a 90° angle.
4. 45° Offsets with 90° Elbows. Figure 21 shows a 90° Adjustable Elbow being utilized to accomplish a 45° offset. This Elbow is completely adjustable from 0° to 90°. Please note that the centers of the upper sections tend to displace by a slight amount, as they are rotated. Again, screws (not longer than 1/4”) may be used to secure the joint. Wall Straps should also be utilized to enhance the stability of the vent system.

MALE AND FEMALE ADAPTERS

1. Description. The male and female adaptors enable an installer to connect DuraVent B-vent components to an existing Type B gas vent system manufactured by the following companies: Air Jet, American Metals Products, ECCO Mfg, Hart & Cooley Mfg, Household Mfg, Metal Fab. Inc, Mitchell Metal Products, White Metal Products.
2. Connecting into Existing Competitors System. To connect into an existing competitors gas venting system from below, or from the appliance side, connect a Female Adaptor as shown in Figure 22, insuring that the inner liner of the adaptor is outside the inner liner of the existing pipe. Push the adaptor as far up as it will go, and tighten the locking bolt until the connection is snug.
3. Extending an Existing Competitors System. To continue an existing competitors  system up towards the termination using DuraVent Type B Gas Vent, connect a Male Adaptor to the last section of the system, as shown in Figure 23, insuring that the inner liner of the Adaptor fits smoothly inside the Pipe or fitting below it. Push the Adaptor down as far as it will go, and tighten the locking bolt until the connection is snug.

RELINING MASONRY CHIMNEYS FOR USE WITH GAS APPLIANCES

1. Description. A masonry chimney should be relined with B-Vent when venting a Category I gas appliance, such as a gas fireplace insert or freestanding gas stove, or to improve the venting and reduce condensation of existing gas appliances which are currently venting into the masonry chimney. These instructions encompass two general configurations: (1) A gas fireplace situated inside an existing masonry fireplace (Figure 24) or (2), a freestanding gas appliance venting into an existing masonry chimney. (Figure 30)

2. Masonry Inspection. Have the masonry chimney inspected by a CSIA Certified Chimney Sweep or other qualified professional to determine it’s structural condition. Clean and repair as necessary.

3. Gas Fireplace. Carefully read the appliance manufacturer’s installation instructions. Use the recommended vent size. Do not reduce the vent size below that of the flue exit on the appliance. Do not common vent gas fireplaces.

   • (a) Measurements. Measure and record the dimension as shown on Figure 25 (Height “A”). You will need an additional 15” of vent above the masonry chimney. It is a good idea to allow for a little extra height in your measurements.
   • (b) Pipe and Fitting Requirements. The bottom 5 foot section of vent will be Flex Pipe (used to get around the smoke shelf, and to connect to the appliance). The remainder will be rigid B-Vent Pipe Sections. For each pipe joint, subtract 1-1/2 inches.
   • (c). Connector. Read the appliance manufacturer’s instructions for connecting the Flex Pipe to the appliance. In most cases, a Draft Hood Connector will be required as shown in Figure 26.
   • If you are not sure, contact the appliance manufacturer for clarification. Place the appliance out in front of the fireplace area, as shown in Figure 27,
   • and install the Draft Hood Connector, or other device in accordance with the appliance instructions. The Flex Pipe Coupling may be able to attach directly to the appliance.
   • (d). Flex Pipe Assembly. Assemble first Rigid Pipe Section to the Flex Pipe, insuring that the “UP” arrows are in fact, pointing up. Push the sections together and twist to lock. Screws are not required, however if you desire to use them, use #8 sheet metal screws 1/4-inch long, being careful to not penetrate the inner liner. Repeat this process for the remainder of the Pipe Sections, and lower the assembly down the chimney. Lower it below it’s normal position as shown in Figure 28.
   • (e). Position and Connect Fireplace. Push the gas fireplace towards the firebox, and connect the Flex Pipe female coupling to the appliance, or to the appropriate connector as specified by the appliance manufacturer. If insufficient space is available between the top of the appliance, and the fireplace opening, an access opening in the opposite side of the masonry chimney may be necessary. Position the gas appliance on it’s final location, again complying with the manufacturer’s instructions in regards to location. Install any shields or covers at this time.
   • (f). Adjust Height. Go to the top of the chimney and pull the vent system up to its desired height. In most cases, this will be 15 inches above the masonry surface. Make a mark on the Pipe Section even with the top of the masonry surface. If the top of the pipe is near a steep roof (more than 7/12 pitch) ,use the height as stated in Table 2.
   • (g). Flashing. Bend and trim the base of the Tall Cone Flashing so it fits onto the top of the masonry chimney. Use masonry anchors and non-hardening sealant to secure the flashing to the masonry (Figure 28).
   • (h). Storm Collar. Slide the Storm Collar over the pipe down to top of the Flashing. Secure the Storm Collar in place with at least (3) 1/4” sheet metal screws (Figure 29). Do not penetrate the inner liner. The Storm Collar and Flashing will support the weight of the vent assembly. Use non-hardening sealant around the top of Storm Collar to make a weatherproof seal.
   • (i). Termination Cap. Install the Termination Cap as shown in Figure 28. This concludes the procedures for installing a gas fireplace in an existing masonry fireplace. Conduct a final inspection of the system, and verify that you have complied with the manufacturer’s installation instructions.

4. Gas Appliance Venting Into the Side Wall of a Masonry Chimney.

   • (a). Locate Appliance. Set the appliance in it’s desired position, and mark the center of the hole where the lateral Pipe Section is to pierce the masonry chimney. Ensure the manufacturer’s requirements have been followed, particularly in regards to distances from combustible surfaces. Refer to Figure 30.

   • (b). Hole in Masonry. Move the appliance aside, and break out the masonry, forming
     a hole large enough for the Pipe Section to get through, and also large enough to reach through and hold the Tee, while connecting the horizontal Pipe Section. An alternate procedure is to make the hole only large enough for the Pipe Section to pass through, and construct an access gate on the other side of the masonry chimney. Do not mortar directly to the pipe, but use a Mortar
     Sleeve instead.

   • (c). Tee. A Tee is installed at the bottom end of the assembled vertical Pipe Sections, as shown in Figure 30. The Tee has a removable Tee Cap at the bottom, for cleaning and condensate removal. If the configuration of the building permits it, a clean-out access gate is recommended.

   • (d). Vertical Pipe Sections. Run the assembled vertical Pipe Sections (with the Tee attached to the bottom), down the chimney, until the horizontal branch of the Tee is opposite the hole in the masonry.

   • (e). Adjust Height. Hold the assembled Pipe Sections in this position, and make a mark even with the top surface of the masonry chimney. The vertical Pipe Sections should protrude 12 inches (in most cases) above this mark. If the top of the pipe will be near a steep roof (more than 7/12 pitch), use the height as stated in Table 2.

   • (f). Flashing. Bend and trim the base of the Tall Cone Flashing so it fits onto the top of the masonry chimney. Use masonry anchors and non-hardening sealant to secure the flashing to the masonry (Figure 28).

   • (g). Storm Collar. Slide the Storm Collar over the pipe down to top of the Flashing. Secure the Storm Collar in place with at least (3)
     1/4” sheet metal screws (Figure 29).

   • Do not penetrate the inner liner. The Storm Collar and Flashing will support the weight of the vent assembly. Use non-hardening sealant around the top of Storm Collar to make a weatherproof seal.

   • (h). Horizontal Pipe Section(s). Run the horizontal Pipe Section(s) through the hole in the masonry, and connect it firmly to the Tee, either by reaching through the hole, and holding the Tee while twisting the Pipe Section, or by holding the Tee through the access door while someone twist-locks the Pipe Section to it. Use an Adjustable Pipe Length as needed to obtain a specific location for the appliance. Make a mark on the horizontal Pipe Section flush with the vertical face of the masonry, for referencing the vertical position. Slip a Pipe Collar over the horizontal Pipe Section and install the remaining fittings as shown in Figure 30. A minimum of 12 inches of connector rise is required.

   • (i). Insulation. Pull the Pipe Collar towards the 90° Elbow. Fill in the gap between the masonry and the horizontal Pipe Section with ceramic fiber insulation, as shown in Figure 31. The filling may be faced off with grout, if desired. Push the Pipe Collar back flush with the masonry. Make any final adjustments on the Adjustable Length Pipe (if used), and tighten the clamping bolts.

TROUBLESHOOTING

1. Purpose. This section is intended as a general maintenance and troubleshooting guide, and as such, cannot encompass all configurations or vent designs. For problems encountered which are beyond the scope of this sheet, contact your DuraVent Dealer, Distributor, or DuraVent’s Engineering Department. It is imperative that the one-inch clearance (air space) defined in these instructions be maintained. In most cases, a one-inch minimum clearance must be maintained to combustibles. The only exceptions are 4-inch, 5-inch and 6-inch Oval B-vent which are installed within stud walls. Oval B-vent and BW Vent are the subject of a separate section of these instructions For Oval B-vent,, the clearances are established by the listed Firestop Spacers described in the instructions for Oval B-Vent.
2. Appliance. Read the appliance installation instructions carefully, ensuring that the prescribed clearances are met, and that it is a Category I appliance.
3. Spillage. Spillage from an appliance draft hood may cause condensation on windows, or odors that the occupant may notice. Spillage may be caused by an incorrectly sized vent system, blockage of the vent system, or a downdraft in the vent. Other causes are: excessive lateral runs, too many elbows, improper pitch to lateral runs (a minimum of 1/4 inch per foot of run is correct), fans or ventilation systems in the same general area as the gas appliance, or wind conditions at the vent cap.
4. Blockage. Check the system for blockage by removing the cap, and looking down into the vent with a flashlight. Check for bird nests, debris, rodents, insects, or other obstructions. If nothing is found, inspect the entire system for physical damage.
5. Downdraft. Downdrafts are generally caused by the system’s termination being too close to an adjacent wall, parapet, or other structure. If the cap is within eight feet of such an obstruction, it must also be at least two feet above it. Also ensure that the top is at the height prescribed for your roof pitch in Table 2. Inadequate combustion air is also a major cause of downdraft problems. Appliances like clothes dryers or other exhausting appliances in the same utility room can cause downdraft problems.
6. Condensate/Corrosion. Continuous condensate can cause corrosion (rusting) of vents, tops, appliance draft hoods, and other components of the system, as well as the inside of the appliance. This situation can be extremely dangerous, and corrective action must be taken immediately. Common causes of corrosion are listed below: If in doubt call a professional to inspect the vent.
   • (a) If the vent system is located in an area where spray cans or solvents are used extensively, (laundry areas, or paint shops, for example), the halogenated compounds get into the combustion air. When they are burned, they form compounds that cause corrosion. The corrective action in this case, is to isolate the appliance, and get the air supply from outside, or an uncontaminated area.
   • (b) Condensate may be caused by incorrect sizing of the vent system. Follow the procedures in the various sizing publications to obtain the correct sizes for connectors and vents. Other causes are: excessive lateral runs, too many elbows, cold attics and crawl spaces, and large areas of the exterior portions of the venting system exposed to cold weather. As a general rule, laterals should be held to a minimum, and be no longer than 75% of the vertical height of the system. Condensate may initially appear as beads on the outside of the connector or vent.
7. Construction. Laterals, offsets, and vertical components should be securely supported with wall straps, as previously described. Components of the vent which are in occupied areas should be enclosed to prevent accidental contact and damage to the vent system. Ensure that insulation, building materials, or debris do not extend into the required clearance spaces. In cold climates, the exterior portions of the vent should be enclosed in a chase. Outside portions of the vent system with may be painted with high temperature paint to help prevent rusting and corrosion on the exterior surfaces.

MAINTENANCE

1. An annual inspection is required to maintain warranty of your DuraVent B-Vent system. You will need to inspect the Cap, Vent Pipe, Connector Pipe, and the connection to the appliance.
2. Verify that the sealant around the Flashing and Storm Collar is intact. Reseal as needed. Remove Cap. Hold Cap by the collar only, and unlock by twisting counterclockwise, and then pull up. Grabbing the Cap by the outer edge or top can cause damage to the Cap.
3. Inspect Cap for any physical damage or damage from corrosion. Look for any foreign material inside the cap or vent. (Example: bird’s nest, leaves, etc.)
4. Shine a light down inside of the vent pipe. Look for any evidence of damage, corrosion or excessive condensation. Also, look for any disconnected sections of the vent pipe or connector pipe. Refer to the installation instructions to reconnect pipe sections. If pipe sections are damaged or corroded, replace immediately!
5. Replace Cap by grabbing cap (by collar only), and slide onto pipe section and twist-locking (clockwise).
6. Inspect appliance connector and make sure that the vent is securely connected to the appliance.
7. Damaged or corroded parts should be replaced immediately! Failure to do so can lead to an extremely hazardous situation!
8. Follow your appliance manufacturer’s recommended instructions for inspection your appliance.

OVAL B VENT, TYPE BW

INSTALLATION NOTES
Oval BW Gas Vent is intended for use with listed gas-fired vented recessed heaters having inputs not exceeding 85,000 btus when installed in a single- story building and not exceeding 65,000 btus when installed in multi-story buildings. Oval BW Gas Vents are for venting only approved gas appliances as permitted by the authority having jurisdiction. BW Gas Vents shall not be used for venting incinerators, conversion burners, appliances listed for use with chimneys, combination gas/oil appliances, and listed Category II, III and IV gas appliances (NFPA 211). The approval of a gas vent is based on the use of the parts supplied by the manufacturer, the performance of the assembly may be affected if not used in actual building construction. These vents shall be installed in accordance with their listing as detailed in these instructions, and
the requirements of the local authority having jurisdiction.

Four-inch and five-inch Type BW Gas Venting systems are designed to be placed within 2”x4” (50mm x 100mm) stud walls, while six-inch BW Gas Vent may only be placed in a 2”x6” (50mm x 150mm) stud space, and requires a one-inch clearance to combustibles.

Except for installation in single and two-family dwellings, gas vents which extend through any story above that on which the connected appliance is located, are to be provided with enclosures having a fire resistance equal to or greater than that of the floor or roof assemblies through which they pass.

For more complex installations, or multiple appliance installations, refer to the “Sizing Handbook”, which can be furnished by a DuraVent dealers, or can be obtained by calling 800-835-4429.
Consult the appliance manufacturer’s installation instructions to obtain the combustion and ventilation air requirements for the appliance. Additional information is provided in the National Fuel Gas Code (NFPA 54 and CSA-B149), as well as the “Sizing Handbook” furnished by DuraVent.

Use only listed DuraVent vent products. Do not mix and match with other manufacturer’s vents or improvised solutions. Do not install damaged vents. Whenever possible, the vent should be continued straight out through
the roof. If it is necessary to make offsets in the attic space, use 45° elbows, rather than horizontal run. Use Wall Straps or metal tape to support offsets.

Refer to Table 1 to determine the height above the roof the vent cap must terminate. A listed DuraVent top must be used to terminate the vent. It is locked to the top section of pipe, and gives protection against the entrance of rain, snow, debris, and birds.
The vent cap should terminate 2 feet (.61 m) higher than an adjacent building or wall, if it is within 8 feet of the obstruction.

Where the vent passes through the roof, the roof sheathing is cut away to provide a minimum clearance of 1” (25mm) from the vent pipe. Straight lengths of pipe are assembled to the height above the roof penetration specified in Table 1. A roof flashing is placed down over the pipe, and adjusted so the flashing fits tightly against the roof, with the vent pipe held in a position maintaining the 1” (25mm) minimum clearance from combustibles.

TABLE 1

Roof Pitch| **Minimum Height**
FLAT TO 7/12| 1.0
OVER 7/12 TO 8/12| 1.5
OVER 8/12 TO 9/12| 2.0
OVER 9/12 TO 10/12| 2.5
OVER 10/12 TO 11/12| 3.25
OVER 11/12 TO 12/12| 4.0
OVER 12/12 TO 14/12| 5.0
OVER 14/12 TO 16/12| 6.0
OVER 16/12 TO 18/12| 7.0
OVER 18/12 TO 20/12| 7.5
OVER 20/12 TO 21/12| 8.0
THIS REQUIREMENT COVERS MOST INSTALLATION

Gas venting systems using vent caps listed by underwriters’ may terminate in accordance with this vent termination table.
The flashing is then nailed to the roof. A non-hardening sealant may be used around the edges of the flashing base where it meets the roof. Non-hardening sealant is placed around the joint between the flashing and the vertical vent pipe, and the storm collar is then placed over this joint to make a watertight seal. The storm collar serves as a counter-flashing to give additional protection.
Firestop Spacers must be utilized in multi-story buildings at each level where the vent passes through the floor.
Sections of pipe are connected to each other by pushing them firmly together until they lock. Screws are not required. Refer to Fig 33. As can be seen from several illustrations in these instructions, once the oval pipe leaves the enclosed stud space, it may be converted to B-Vent round pipe, by means of a round-to-oval adaptor. Once this has occurred, the instructions for round B-Vent are applicable, and should be referred to when completing the installations.
Any portions of the vent assembly that extend through accessible or occupied spaces must be enclosed with an enclosure that is at least 1-inch away from vent pipe.
Do not install damaged vents. Whenever possible, the vent should be continued straight out through the roof. If it is necessary to make offsets in the attic space, use 45-degree elbows, rather than horizontal runs. For more complex installations, or multiple appliance installations, refer to the Sizing Handbook. Dura-Vent Type B and BW Gas Vent shall be used to vent only gas appliances with draft hoods and other Category I gas appliances listed for Type B or BW Gas Vents.
IN CANADA: Only components marked “FOR EXTERIOR USE ONLY” shall be installed above the roofline. These vents shall be installed in accordance with their listing
as detailed in these instructions, and the requirements of the local authority having jurisdiction.

Correct sizing procedures must be employed in order to have a properly functioning vent system. These procedures, and the necessary calculations are contained in NFPA 54 an CSA-B149 or the Gas Vent Sizing Handbook.
An insulated chase enclosure is highly recommended in instances where a significant portion of the vent system is exposed to the outside elements, particularly in areas with sustained low ambient temperatures. This will reduce condensate, and promote draft.
FOUR, FIVE, AND SIX-INCH OVAL BW GAS VENT

4-INCH OVAL GAS VENT FOR
INSTALLATION IN 2” X 4” STUD WALLS CATEGORY I APPLIANCES ONLY
A typical four-inch oval BW Vent Installation is shown in Figure 32, venting a listed recessed wall furnace. An oval gas vent may be installed within a standard 2×4 stud wall if the following conditions are met:

• If arrows are on parts, should always point up;
• Stud bay must be 16-inch on-center stud bay;
• 2×4 studs must be a minimum of 3.5 inches deep;
• There must be nothing else in the stud bay other than the vent sections. This includes any kind of insulation.

Follow the following steps to install the furnace venting system.

1. Attach a base plate to the wall furnace. Firestop spacers shall be installed as shown on all floors, other than the first floor. Use ceiling plate spacers at this level as shown in Figures 32 and 34.
2. Saw out portion of header between studs and install one firestop spacer or ceiling plate spacer in place.
3. Nail the second firestop spacer in position, after oval pipe is in place. Position the oval pipe, and nail the second firestop/ceiling plate spacer as shown in Figures 34 and 35.
4. All floors above tthe first level require firestop spacers and are installed in the same manner as shown in Figure 35.
5. Maximum BTU input:
   • Single story – 85,000 BTU
   • Multistory – 65,000 BTU

To assemble, align the two pieces, and push together until they click (lock). See Figures 33 and 38.

Where the pipe passes through the roof, maintain a 1-inch (26mm) minimum clearance to all combustible materials.
Install oval flashing, storm collar, and an oval vent cap. Gas vent shall terminate in accordance with Table 1, unless it is closer than 8 feet (2.33m) to an adjacent building or wall, in which case it must terminate 2 feet (.6m) higher than the obstruction.

To vent an appliance other than a recessed wall heater, a system such as described in Figure 37 must be installed.

1. Attach a tee support to a 2” x 4” framed support, as shown in Figure 37. Firestop spacers shall be installed on all floors. Ceiling plate spacers are not required.
2. Saw out portion of header between studs and install one firestop spacer.
3. Position a piece of oval pipe next to the first firestop spacer, and nail the second firestop spacer in place, as shown in Figure 35.
4. Additional floors above are installed in the same manner.

5-INCH OVAL GAS VENT FOR INSTALLATION IN 2” X 4” STUD WALLS CATEGORY I APPLIANCES ONLY
A typical five-inch oval BW Vent Installation is shown in Figure 39 and 40. An oval gas vent may be installed within a standard 2×4 stud wall if the following conditions are met:

• If arrows are on parts, should always point up;
• Stud bay must be 16-inch on-center stud bay;
• 2×4 studs must be a minimum of 3.5 inches deep;
• There must be nothing else in the stud bay other than the vent sections. This includes any kind of insulation.

1. Attach a tee support to a 2” x 4” framed support, as shown in Figure 39. Firestop spacers shall be installed on all floors. Ceiling plate spacers are not required.
2. Saw out portion of header between studs and install one firestop spacer.
3. Position a piece of oval pipe next to the first firestop spacer, and nail the second firestop spacer in place, as shown in Figure 35.
4. Additional floors above are installed in the same manner

Note: Offset must be supported (Figure 40).

Use only vents labeled “For Exterior Use Only”, above roofline. (Canada Only)

6-INCH OVAL GAS VENT FOR INSTALLATION IN 2” X 6” STUD WALLS CATEGORY I APPLIANCES ONLY
A typical six-inch oval BW Vent Installation is shown in Figure 41. An oval gas vent may be installed within a standard 2×6 stud wall if the following conditions are met:

• If arrows are on parts, should always point up;
• Stud bay must be 16-inch on-center stud bay;
• 2×6 studs must be a minimum of 5.5 inches deep;
• There must be nothing else in the stud bay other than the vent sections. This includes any kind of insulation.

Ensure at least 1 inch clearance to all combustibles, including the area the pipe passes through the roof.
Install oval flashing, storm collar, and oval vent cap.
Gas vent shall extend at least 2 feet above the roof, and at least 2 feet higher than any portion of the building within 2 feet.
Attach base plate to 2” x 6” support. Firestop spacers shall be installed as shown on all floors.

1. Saw out portion of header between studs and install one firestop spacer.
2. Nail the second firestop spacer in position, after oval pipe is in place.
3. Additional floors above are installed in the same manner.
4. Requires 1” clearance to combustibles.

Six inch BV pipe sections are joined together by pushing them together until they click as shown in Figure 33.
Use only vents labeled “For Exterior Use Only”, above roofline. (Canada Only)

DURAVENT LIMITED LIFETIME 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 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. Installation instructions are available online at www.duravent.com under Support/Literature and through our Customer Service Department 800-835-4429 or customerservice@duravent.com. This limited lifetime warranty applies only to parts manufactured 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®, DuraPlus HTC®, 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.

For the most up-to-date installation instructions, see www.duravent.com
REV 3.22.2012
Manufactured in Vacaville CA and Albany NY

Customer Service Support: 800-835-4429 • 707-446-4740 FAX • www.duravent.com
All rights reserved. Made in the USA. ©2017, 2022
L204_820003156_Install Instructions_Type_B_Gas_Vent_11-22-22_V5

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