SLP98DF UNIT
COOLING COIL |
PROPERLY |
PLENUM
(Field Provided)
SECURE FROM |
|
INSIDE CABINET | Side View |
SEALING STRIP (Field Provided)
CABINET
SIDE PANEL
SIZED FLOOR |
|
OPENING | PLENUM |
FIGURE 10
Return Air Opening −− Downflow Units
Return air may be brought in only through the top opening of a furnace installed in the downflow position. The follow- ing steps should be taken when installing plenum:
1 − Bottom edge of plenum should be flanged with a hemmed edge (See figure 11 or 12).
2 − Sealing strips should be used to ensure an airtight seal between the cabinet and the plenum.
3 − In all cases, plenum should be secured to top of fur- nace using sheet metal screws.
4 − Make certain that an adequate seal is made.
PLENUM
(Field Provided) 
SECURE FROM OUTSIDE CABINET
SEALING STRIP | CABINET | |
SIDE PANEL | ||
(Field Provided) | ||
|
Side View
FIGURE 11
FIGURE 12
Filters
This unit is not equipped with a filter or rack. A field−pro- vided filter is required for the unit to operate properly. Table 3 lists recommended filter size.
A filter must be in place whenever the unit is operating.
TABLE 3
Furnace | Filter Size | |
Cabinet Width | ||
| ||
|
|
B Cabinet (17−1/2")
16 X 25 X 1 (1)
C Cabinet (21−1/2")
Duct System
Use
NOTE − Operation of this furnace in heating mode (indoor blower operating at selected heating speed) with an exter- nal static pressure which exceeds 0.8 inches w.c. may re- sult in erratic limit operation.
Return Air Plenum
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 device (i.e., wood fireplace) is installed. When return air is drawn from a room, a negative pressure is created in the room. If a gas appliance is operating in a room with negative pres- sure, 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 combustion and the formation of carbon monoxide gas. This toxic gas might then be dis- tributed throughout the house by the furnace duct sys- tem.
Use fiberglass sealing strips, caulking, or equivalent seal- ing 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.
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