Lennox International Inc EL296UHE General Guidelines for Vent Terminations

CAUTION

If this unit is being installed in an application with combustion air coming in from a space serviced by an exhaust fan, power exhaust fan, or other device which may create a negative pressure in the space, take care when sizing the inlet air opening. The in­ let air opening must be sized to accommodate the maximum volume of exhausted air as well as the maximum volume of combustion air required for all gas appliances serviced by this space.

EQUIPMENT IN CONFINED SPACE

(Inlet Air from Ventilated Attic and Outlet Air to Outside)

General Guidelines for Vent Terminations

In Non‐Direct Vent applications, combustion air is taken from indoors or ventilated attic or crawlspace and the flue gases are discharged to the outdoors. The EL296UHE is then classified as a non‐direct vent, Category IV gas fur­ nace.

In Direct Vent applications, combustion air is taken from outdoors and the flue gases are discharged to the out­ doors. The EL296UHE is then classified as a direct vent, Category IV gas furnace.

In both Non‐Direct Vent and Direct Vent applications, the vent termination is limited by local building codes. In the absence of local codes, refer to the current National Fuel

Roof Terminated

Exhaust Pipe

Ventilation Louvers

Inlet Air

(Minimum

12 in.(305mm) Above

attic floor)

*Intake Debris

Screen

(Provided)

Gas Code ANSI Z223-1/NFPA 54 in U.S.A., and current CSA-B149 Natural Gas and Propane Installation Codes in Canada for details.

Position termination according to location given in figure 30 or 31. In addition, position termination so it is free from any obstructions and 12” above the average snow accumula­ tion.

Furnace

* See table 6 for maximum vent lengths

NOTE-The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm2 per 1.17kW) per hour of the total input rating of all equipment in the enclosure.

FIGURE 28

EQUIPMENT IN CONFINED SPACE

(Inlet Air from Ventilated Crawlspace and Outlet Air to Outside)

Roof Terminated

Exhaust Pipe

					Inlet Air
				(Minimum
Ventilation	Furnace	12 in.(305mm)
Louvers			Above crawl
(Crawl space)			space floor)

Coupling or

3 in. to 2 in. *Intake Debris Screen Provided) Transition

(Field Provided)

* See table 6 for maximum vent lengths

NOTE-The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm2 per 1.17kW) per hour of the total input rating of all equipment in the enclosure.

FIGURE 29

At vent termination, care must be taken to maintain protective coatings over building materials (prolonged exposure to exhaust condensate can destroy protective coatings). It is recommended that the exhaust outlet not be located within 6 feet (1.8m) of a condensing unit because the condensate can damage the painted coating.

NOTE - See table 7 for maximum allowed exhaust pipe length without insulation in unconditioned space during winter design temperatures below 32°F (0°C). If required exhaust pipe should be insulated with 1/2” (13mm) Arma­ flex or equivalent. In extreme cold climate areas, 3/4” (19mm) Armaflex or equivalent may be necessary. Insula­ tion on outside runs of exhaust pipe must be painted or wrapped to protect insulation from deterioration. Exhaust pipe insulation may not be necessary in some specific ap­ plications.

IMPORTANT

Do not use screens or perforated metal in exhaust terminations. Doing so will cause freeze-ups and may block the terminations.

IMPORTANT

For Canadian Installations Only:

In accordance to CSA International B149 installation codes, the minimum allowed distance between the combustion air intake inlet and the exhaust outlet of other appliances shall not be less than 12 inches (305mm).

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