Raypak 399B-2339B Vent Terminal Location, U.S. Installations, Combustion Air Supply

Use insulated vent pipe spacers where the vent pass- es through combustible roofs and walls.

Vent Terminal Location

1.Condensate can freeze on the vent cap. Frozen condensate on the vent cap can result in a blocked flue condition.

2.Give special attention to the location of the vent termination to avoid possibility of property dam- age or personal injury.

3.Gases may form a white vapor plume in winter. The plume could obstruct a window view if the ter- mination is installed near windows.

4.Prevailing winds, in combination with below-freez- ing temperatures, can cause freezing of condensate and water/ice build-up on buildings, plants or roofs.

5.The bottom of the vent terminal and the air intake shall be located at least 12 in. above grade, includ- ing normal snow line.

6.Un-insulated single-wall metal vent pipe shall not be used outdoors in cold climates for venting gas- fired equipment.

7.Through-the-wall vents for Category II and IV appliances and non-categorized condensing appli- ances shall not terminate over public walkways or 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.

8.Locate and guard vent termination to prevent acci- dental contact by people or pets.

9.DO NOT terminate vent in window well, stairwell, alcove, courtyard or other recessed area.

10.DO NOT terminate above any door, window, or gravity air intake. Condensate can freeze, causing ice formations.

11.Locate or guard vent to prevent condensate from damaging exterior finishes. Use a rust-resistant sheet metal backing plate against brick or mason- ry surfaces.

12.DO NOT extend exposed vent pipe outside of building. Condensate could freeze and block vent pipe.

U.S. Installations

Refer to the latest edition of the National Fuel Gas Code.

Vent termination requirements are as follows:

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.

Combustion

Air Supply

Exhaust

Configuration

Heater Venting

Category

Certified Materials

Combustion Air

Inlet Material

	Vertical Natural	I	“B” Vent
From Inside Building	Draft Venting
	Horizontal Through-	III	Stainless Steel
	the-Wall Venting		(Gas Tight)
	Vertical Natural	I	“B” Vent	Galvanized Steel
From Outside Building	Draft Venting				PVC
	Horizontal Through-	III	Stainless Steel		ABS
					CPVC
	the-Wall Venting		(Gas Tight)

Table K: Venting Category Requirements

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