Sears 8MPN100F20B1, N8MPN075F16B1 Ductwork and Filter Downflow, Outlet Duct Flange, Must

11. Ductwork and Filter (Downflow)

CARBON MONOXIDE POISONING HAZARD.

Failure to properly seal duct could result in death or personal injury.

Do NOT draw return air from inside a closet or

utility room where furnace is located. Return air duct MUST be sealed to furnace casing.

FIRE HAZARD.

Failure to connect the return air duct to the top of a

downdlow furnace could result in death, bodily injury, and/or property damage.

Side return air duct(s) may cause excessive furnace

and/or air temperatures, which could result in death, bodily injury, and/or property damage.

Return air duct is to be connected to only the top of downflow furnace.

BURN HAZARD.

The vent may be hot. Failure to install vent shield properly could result in personal injury.

Install VENT PIPE SHIELD NAHAOO2VC as described below.

Vent Shield

Vent shield

is required for all downflowinstallations.

The vent

Must

exit

out the

side

of

the

furnace

for all downflow

installations.

This

places

the

hot vent

pipe

(over

300

° F) within

reach of children. Vent

shield

attaches

to side

of furnace

to cover

vent

pipe. See Figure 5

in

"2,

Installation"section.

FIRE HAZARD.

Failure to install furnace on noncombustible

subbase could result in death, personal injury and/or property damage.

Place furnace on noncombustible subbase on

downflow applications, unless installing on

non-combustible flooring.

Outlet Duct Flange

Downflow installations with cased coils require the furnace outlet duct flange to be bent outward and flat to mate the outlet of the fur- nace to the cased coil.

Sub-Bases for Combustible Floors - Furnace Only

Note: When using the subbase for combustible floors, the dis- charge air duct flanges on the furnace MUST be broken down to provide proper fit up to the subbase. Use duct pliers to bend the duct flanges flat onto the furnace casing. DO NOT bend the duct

flanges inward (toward the heat exchangers) as air flow restric- tions may occur.

The Subbase for Combustible Floors MUST be used when a

downflow furnace is set on a combustible floor, even when the fur- nace is installed on a coil box.

Cut the opening in the floor according to the dimensions in Table 5 because the base is equipped with locating tabs that center the base over the opening.

The opening in the base is 11/4" shorter and 11/8" narrower

than the minimum required size of the opening in the floor. This is done to maintain a 1" clearance between the floor and

the plenum.

2.Fabricate the plenum to the dimensions given in Table 5.

Note that the dimensions given are outside dimensions.

3.Set the base over the opening in the floor, centering the open- ing in the base over the opening in the floor. Fasten the base to the floor with screws or nails. See Figure 27 and Figure 28.

Drop the plenum through the opening in the base. The flange of the plenum should rest on top of the combustible floor base.

]

Sub-bases

for Combustible

Floors

Dimensions

Sub-base

for

Sub-base

for Combustible

Opening

In Floor

Opening

In

Typical

Plenum

Combustible

Floors

Floor

Dimensions

Base For Plenum

Dimensions

Part

Number

H"

J*

K**

L

M

N

P

R

Subbase

for

Furnace

Only

NAHHO01 SB

1511/16

283/4

149/16

18

181/4

145/8

15

131/2

15

131/2

NAHHOO2SB

195/16

283/4

183/16

18

181/4

181/4

15

171/8

15

171/8

NAHHOO3SB

2215/16

283/4

2113/16

16

161/4

21 _/8

15

193/4

15

193/4

Subbase

for

Coil

Box

NAHHOO4SB

1511/16

209/16

149/16

16

161/4

145/8

15

131/2

15

131/2

NAHHOOSSB

19s/16

209/16

183/16

16

181/4

181/4

15

171/8

15

171/8

NAHHOO6SB

2215/16

209/16

2113/16

16

161/4

211/8

15

193/4

15

193/4

Outside Dimension

"* Base

Spacer

Side

To Side

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