Determination of Appliance Category for Venting Purposes and Venting Arrangements
WARNING: Contact the manufacturer of the vent material if there is any question about the appliance categorization and suitability of a vent material for application on a Category III or IV vent system. Using improper venting materials can result in personal injury, death or property damage.
Support of Vent Stack
The weight of the vent stack or chimney must not rest on the boiler vent connection. Support must be provid- ed in compliance with applicable codes. The vent should also be supported to maintain proper clear- ances from combustible materials.
Use insulated vent pipe spacers where the vent pass- es through combustible roofs and walls.
Vent Terminal Location
NOTE: During winter months check the vent cap and make sure no blockage occurs from build up of snow. Condensate can freeze on the vent cap. Frozen condensate on the vent cap can result in a blocked flue condition.
Give special attention to the location of the vent termi- nation to avoid possibility of property damage or personal injury.
a)Gases may form a white vapor plume in winter. The plume could obstruct a window view if the ter- mination is installed in close proximity to windows.
b)Prevailing winds could cause freezing of conden- sate and water/ice buildup on building, plants or roof.
c)The bottom of the vent terminal and the air intake shall be located at least 12 inches above grade, including normal snow line.
d)
e)
over an area where condensate or vapor could create a nuisance or hazard or could be detrimen- tal to the operation of regulators, relief valves, or other equipment. Where local experience indi- cates that condensate is a problem with Category I and III appliances, this provision shall also apply.
f)Locate and guard vent termination to prevent acci- dental contact by people and pets.
g)DO NOT terminate vent in window well, stairwell, alcove, courtyard or other recessed area, unless previously approved by local authority.
h)DO NOT terminate above any door, window, or gravity air intake. Condensate can freeze causing ice formations.
i)Locate or guard vent to prevent condensate from damaging exterior finishes. Use a 2' x 2' rust resistant sheet metal backing plate against brick or masonry surfaces.
j)DO NOT extend exposed vent pipe outside of building. Condensate could freeze and block vent pipe.
k)Multiple direct vent caps, when installed in the same horizontal plane, should have a three (3) foot clearance from the side of one vent cap to the side of the adjacent vent cap(s).
U.S. Installations
Refer to latest edition of the National Fuel Gas Code.
Vent termination requirements are as follows:
a)Vent must terminate at least four (4) feet below, four (4) feet horizontally, or one (1) foot above any door, window or gravity air inlet to the building.
b)The vent must not be less than seven (7) feet above grade when located adjacent to public walk- ways.
c)Terminate vent at least three (3) feet above any forced air inlet located within ten (10) feet.
d)Vent must terminate at least four (4) feet horizon- tally, and in no case above or below unless four (4) feet horizontal distance is maintained, from elec- tric meters, gas meters, regulators, and relief equipment.
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