Lennox International Inc Elite Series Gas Furnace, EL296UHE Filters, Duct System

INTAKE PIPE *GAS CONNECTION

EXHAUST PIPE

*Gas connector may be used for Canadian installation if accept­ able by local authority having jurisdiction.

SERVICE PLATFORM	RAISED
	PLATFORM

FIGURE 19

Return Air -- Horizontal Applications

Return air may be brought in only through the end of a fur­ nace installed in the horizontal position. The furnace is equipped with a removable bottom panel to facilitate installation. See figure 15.

Filters

This unit is not equipped with a filter or rack. A field-pro­ vided high velocity rated filter is required for the unit to oper­

ate properly. Table 1 lists recommended filter sizes.

A filter must be in place whenever the unit is operating.

IMPORTANT

If a high­efficiency filter is being installed as part of this system to ensure better indoor air quality, the fil­ ter must be properly sized. High­efficiency filters have a higher static pressure drop than standard­ef­ ficiency glass/foam filters. If the pressure drop is too great, system capacity and performance may be re­ duced. The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer, resulting in an increase in the number of service calls.

Before using any filter with this system, check the specifications provided by the filter manufacturer against the data given in the appropriate Lennox Product Specifications bulletin. Additional informa­ tion is provided in Service and Application Note ACC­00­2 (August 2000).

TABLE 1

Furnace	Filter Size
Cabinet Width	Side Return	Bottom Return
17-1/2”	16 X 25 X 1 (1)	16 X 25 X 1 (1)
21”	16 X 25 X 1 (1)	20 X 25 X 1 (1)
24-1/2”	16 X 25 X 1 (2)	24 X 25 X 1 (1)

Duct System

Use industry‐approved standards to size and install the supply and return air duct system. Refer to ACCA Manual D. This will result in a quiet and low‐static system that has uniform air distribution.

NOTE - This furnace is not certified for operation in heating mode (indoor blower operating at selected heating speed) with an external static pressure which exceeds 0.8 inches w.c. Operation at these conditions may result in improper limit operation.

Supply Air Plenum

If the furnace is installed without a cooling coil, a removable access panel should be installed in the supply air duct. The access panel should be large enough to permit inspection of the heat exchanger. The furnace access panel must al­ ways be in place when the furnace is operating and it must not allow leaks.

Return Air Plenum

NOTE - Return air must not be drawn from a room where this furnace, or any other gas-fueled appliance (i.e., water heater), or carbon monoxide-producing de­ vice (i.e., wood fireplace) is installed.

When return air is drawn from a room, a negative pres­ sure is created in the room. If a gas appliance is operating in a room with negative pressure, the flue products can be pulled back down the vent pipe and into the room. This reverse flow of the flue gas may result in incomplete com­ bustion and the formation of carbon monoxide gas. This raw gas or toxic fumes might then be distributed through­ out the house by the furnace duct system.

Return air can be brought in through the bottom or either side of the furnace (return air brought into either side of fur­ nace allowed only in upflow applications). If a furnace with bottom return air is installed on a platform, make an airtight seal between the bottom of the furnace and the platform to ensure that the unit operates properly and safely. Use fiber­ glass sealing strips, caulking, or equivalent sealing method between the plenum and the furnace cabinet to ensure a tight seal. If a filter is installed, size the return air duct to fit the filter frame.

Pipe & Fittings Specifications

All pipe, fittings, primer and solvent cement must conform with American National Standard Institute and the Ameri­ can Society for Testing and Materials (ANSI/ASTM) stan­ dards. The solvent shall be free flowing and contain no lumps, undissolved particles or any foreign matter that ad­ versely affects the joint strength or chemical resistance of the cement. The cement shall show no gelation, stratifica­ tion, or separation that cannot be removed by stirring. Re­ fer to the table 2 below for approved piping and fitting ma­ terials.

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