Lennox International Inc EL180UHE Filters, Duct System, Supply Air Plenum

CAUTION

If this unit is being installed in 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.

Horizontal Application

Unit Installed on Platform

Line contact is permissible but not preferred

See the unit nameplate for clearances.

GAS	VENT
ENTRY
	PIPE

SERVICE PLATFORM

FIGURE 13

WARNING

Improper installation of the furnace can result in per­ sonal injury or death. Combustion and flue products must never be allowed to enter the return air system or the living space. Use screws and joint tape to seal the return air system to the furnace.

In platform installations with bottom return air, the furnace should be sealed airtight to the return air ple­ num. A door must never be used as a portion of the return air duct system. The base must provide a stable support and an airtight seal to the furnace. Al­ low absolutely no sagging, cracks, gaps, etc.

The return and supply air duct systems must never be connected to or from other heating devices such as a fireplace or stove, etc. Fire, explosion, carbon monoxide poisoning, personal injury and/or proper­ ty damage could result.

WARNING

The blower access panel must be securely in place when the blower and burners are operating. Gas fumes, which could contain carbon monoxide, can be drawn into living space resulting in personal inju­ ry or death.

Filters

This unit is not equipped with a filter or rack. A field-pro­ vided high-velocity filter is required for the unit to operate properly. Table 1 lists recommended filter sizes.

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).

A filter must be in place any time the unit is operating.

TABLE 1

Furnace	Filter Size
Cabinet Width	Side Return	Bottom Return
A - 14-1/2”	16 X 25 X 1 (1)	14 X 25 X 1 (1)
B - 17-1/2”	16 X 25 X 1 (1)	16 X 25 X 1 (1)
C - 21”	16 X 25 X 1 (1)	20 X 25 X 1 (1)
D - 24-1/2”	16 X 25 X 1 (2)	24 X 25 X 1 (1)

Duct System

Use industry‐approved standards (such as those pub­ lished by Air Conditioning Contractors of America or Ameri­ can Society of Heating, Refrigerating and Air Conditioning Engineers) to size and install the supply and return air duct system. This will result in a quiet and low‐static system that has uniform air distribution.

NOTE - Do not operate the furnace in the heating mode with an external static pressure that exceeds 0.5 inches w.c. Higher external static pressures may cause erratic lim­ it operation.

Supply Air Plenum

If the furnace is installed without a cooling coil, a removable access panel must be installed in the supply air duct. The access panel should be large enough to permit inspection (either by smoke or reflected light) of the heat exchanger for leaks after the furnace is installed. The furnace access panel must always be in place when the furnace is operat­ ing and it must not allow leaks into the supply air duct sys­ tem.

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