Oval B Vent, Installation Notes. M&G Duravent 3GV60, 5GVAF, 4GVRRA4, 3GVFS, 4GV60F, 3GVIS, 3GVRS4, 3GVFF, 4GVRS, 4GVX8

OVAL B VENT, TYPE BW

INSTALLATION NOTES

DuraVent Type B Gas Vent shall be used to vent only approved gas appliances with draft hoods and other Category I gas appliances listed for use with Type B Gas Vents:

• Water Heaters

• Space Heaters

• Warm Air Furnaces

• Duct Furnaces

• Room Heaters

• Unit Heaters

• Hot Water Boilers

• Steam Boilers

• Floor Furnaces

• Gas Fireplaces

• Attic Furnaces

Type B gas vents shall not be used for venting incinerators, conversion burners, combination gas/oil appliances, and listed category II, III, and IV gas appliances (NFPA 211).

These vents shall be installed in accordance with their listing as detailed in these instructions, and the requirements of the local authority having jurisdiction.

For more complex installations, or multiple appliance installations, refer to the “Sizing

Handbook”, which can be furnished by

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), 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.

IN CANADA: Only components marked “FOR

EXTERIOR USE ONLY” shall be used above the roofline.

Refer to Table 1 on the next page 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 higher than an adjacent building or wall, if it is within 8 feet of the obstruction.

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STORM

COLLAR

FLASHING

PIPE

HIGH WIND CAP

D URA C AP

ROUND PIPE

SEE TABLE 1

1 INCH MINIMUM

CLEARANCE

FIRESTOP

SPACER

ENCLOSURE

WALL

1 INCH

MINIMUM

CLEARANCE

GAS VENT

SUPPORT

TABLE 1

Roof Pitch

FLAT TO 7/12

Minimum

Height*

1.0

OVER 7/12 TO 8/12 1.5

OVER 8/12 TO 9/12

OVER 9/12 TO 10/12

OVER 10/12 TO 11/12

OVER 11/12 TO 12/12

OVER 12/12 TO 14/12

OVER 14/12 TO 16/12

OVER 16/12 TO 18/12

OVER 18/12 TO 20/12

OVER 20/12 TO 21/12

*THIS REQUIREMENT COVERS MOST INSTALLATION

2.0

6.0

7.0

7.5

8.0

2.5

3.25

4.0

5.0

Gas venting systems using vent caps listed by underwriters’ may terminate in accordance with this vent termination table.

Where the vent passes through the roof, the roof sheathing is cut away to provide a minimum clearance of 1 inch from the vent pipe. Straight lengths of pipe are run up about a foot above the roof. 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-inch minimum clearance from combustibles.

The flashing is then nailed to the roof. A nonhardening 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.

A gas vent support or firestop spacer must be provided where the vent passes through the ceiling. The ceiling opening is framed, using the same sized lumber as the existing joists, to fit around the raised edge of the gas vent support, which is pushed up into the ceiling from below. The hanger straps are nailed to the framing using 1 1/2-inch box nails to hold the gas vent support firmly, and the clamp is then tightened around the vent pipe. Firestop spacers must be utilized in multistory buildings at each level where the vent passes through a floor.

Sections of pipe are connected to each other by pushing them firmly together and twisting.

Screws are not required. If screws are desired, for 3- to 6-inch diameter pipe, use 1/4-inch sheet metal screws. For larger diameters up through 16 inches, use 3/8-inch sheet metal screws. For 18-inch and greater diameters, use 3/8-inch sheet metal screws. Under no circumstances, penetrate the inner liner with screws.

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.

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