1. Vent must terminate at least 4 ft below, 4 ft hori- zontally from or 1 ft above any door, window or gravity air inlet to the building.
2. The vent must not be less than 7 ft above grade when located adjacent to public walkways.
3. Terminate vent at least 3 ft above any forced air inlet located within 10 ft.
4. Vent must terminate at least 4 ft horizontally, and in no case above or below unless 4 ft horizontal distance is maintained, from electric meters, gas meters, regulators, and relief equipment.
5. Terminate vent at least 6 ft away from adjacent walls.
6. DO NOT terminate vent closer than 5 ft below roof overhang.
7. The vent terminal requires a 12 in. vent terminal clearance from the wall.
8. Terminate vent at least 1 ft above grade, including normal snow line.
9. Multiple direct vent installations require a 4 ft clearance between the ends of vent caps located on the same horizontal plane.
WARNING: The Commonwealth of Massachusetts requires that sidewall vented heaters, installed in every dwelling, building or structure used in whole or in part for residential purposes, be installed using special provisions as outlined on page 53 of this manual.
Canadian Installations
Refer to latest edition of the B149 Installation code. A vent shall not terminate:
1.Directly above a paved sidewalk or driveway which is located between two
2.Less than 7 ft (2.13 m) above a paved sidewalk or paved driveway located on public property.
3.Within 6 ft (1.8 m) of a mechanical air supply inlet to any building.
4.Above a meter/regulator assembly within 3 ft (915
mm)horizontally of the vertical
5.Within 6 ft (1.8 m) of any gas service regulator vent outlet.
6.Less than 1 ft (305 mm) above grade level.
7.Within the 3 ft (915 mm) of a window or door which can be opened in any building, any
8.Underneath a verandah, porch or deck, unless the verandah, porch or deck is fully open on a mini- mum of two sides beneath the floor, and the distance between the top of the vent termination and the underside of the verandah, porch or deck is greater than 1 ft (305 mm).
Venting Installation Tips
Support piping:
•horizontal
•vertical
•under or near elbows
WARNING: Examine the venting system at least once a year. Check all joints and vent pipe connections for tightness, corrosion or deterioration.
Venting Configurations
For heaters connected to gas vents or chimneys, vent installations shall be in accordance with the NFGC (U.S.), or B149 (Canada), or applicable provisions of local building codes.
Natural Draft Vertical Venting (Category I)
Installation
Natural draft venting uses the natural buoyancy of the heated flue products to create a thermal driving head that expels the exhaust gases from the flue. The nega- tive draft must be within the range of
The maximum and minimum venting length for Cate- gory I appliances shall be determined per the NFGC (U.S.) or B149 (Canada).
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