Raypak 992B-1262B manual Support of Vent Stack, Vent Terminal Location, Combustion Exhaust

Category II – A heater which operates with a non-pos- itive vent static pressure and with a vent gas temperature that may cause excessive condensate production in the vent.

Category III – A heater which operates with a positive vent pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category IV – A heater which operates with a positive vent pressure and with a vent gas temperature that may cause excessive condensate production in the vent.

See Table K for appliance category requirements.

NOTE: For additional information on appliance categorization, see appropriate ANSI Z21 Standard and the NFGC (U.S.), or B149 (Canada), or applicable provisions of local building codes.

CAUTION: When condensate traps are installed, condensate must be routed to an appropriate container for neutralization before disposal, as required by local codes.

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 heater vent connection. Support must be pro- vided in compliance with applicable codes. The vent should also be installed to maintain proper clearances from combustible materials.

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

NOTE: During winter months check the vent cap and make sure no blockage occurs from build-up of snow or ice.

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.

Combustion	Exhaust	Heater Venting	Certified	Combustion Air
Air Supply	Configuration	Category	Materials		Inlet Material
	Vertical Natural	I	“B” Vent
From Inside Building	Draft Venting
(Non-Direct Venting)	Horizontal Through-	III	Stainless Steel
	the-Wall Venting		(Gas Tight)
	Vertical Natural	I	“B” Vent	Galvanized Steel
From Outside Building	Draft Venting				PVC
(Direct Venting)	Horizontal Through-	III	Stainless Steel		ABS
					CPVC
	the-Wall Venting		(Gas Tight)

Table K: Venting Category Requirements

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