Filter Arrangement - International comfort products N8MSN Installation Instructions Manual

80% single stage, psc motor, category i, gas furnace

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Figure 13 - Furnace, Plenum, and Coil or Coil Casing

Installed on a Combustible Floor

FURNACE

APPROVED

COIL ASSEMBLY

COIL BOX

COMBUSTIBLE

FLOORING

SHEET METAL

PLENUM

FLOOR

OPENING

Bottom Return Air Inlet

These furnaces are shipped with bottom closure panel

installed in bottom return−air opening. Remove and discard

this panel when bottom return air is used. To remove bottom

closure panel, perform the following:

1. Tilt or raise furnace and remove 2 screws holding bot-

tom filler panel. (See Figure 9)

2. Rotate bottom filler panel downward to release holding

tabs.

3. Remove bottom closure panel.

4. Reinstall bottom filler panel and screws.

HORIZONTAL INSTALLATION

WARNING

FIRE, EXPLOSION, AND CARBON MONOXIDE

POISONING HAZARD

Failure to follow this warning could result in personal

injury, death, or property damage.

Do not install the furnace on its back or hang furnace

with control compartment facing downward. Safety

control operation will be adversely affected. Never

connect return−air ducts to the back of the furnace.

The furnace can be installed horizontally in an attic or crawl

space on either the left−hand (LH) or right−hand (RH) side.

The furnace can be hung from floor joists, rafters or trusses or

installed on a non−combustible platform, blocks, bricks or

pad.

Suspended Furnace Support

The furnace may be supported under each end with threaded

rod, angle iron or metal plumber's strap as shown. (See

Figure 15 and Figure 16) Secure angle iron to bottom of

furnace as shown. Heavy−gauge sheet metal straps

(plumber's straps) may be used to suspend the furnace from

each bottom corner. To prevent screws from pulling out, use 2

#8 x 3/4−in. (19 mm) screws into the side and 2 #8 x 3/4−in.

(19 mm) screws in the bottom of the furnace casing for each

strap. (See Figure 15 and Figure 16)

If the screws are attached to ONLY the furnace sides and not

the bottom, the straps must be vertical against the furnace

sides and not pull away from the furnace sides, so that the

strap attachment screws are not in tension (are loaded in

shear) for reliable support.

Platform Furnace Support

Construct working platform at location where all required

furnace clearances are met. (See Figure 2 and Figure 17) For

furnaces with 1−in. (25 mm) clearance requirement on side,

set furnace on non− combustible blocks, bricks or angle iron.

For crawl space installations, if the furnace is not suspended

from the floor joists, the ground underneath furnace must be

level and the furnace set on blocks or bricks.

Roll−Out Protection

Provide a minimum 17−3/4 in. x 22 in. (451 x 559 mm) piece

of sheet metal for flame roll−out protection in front of burner

area for furnaces closer than 12 inches (305 mm) above the

combustible deck or suspended furnaces closer than 12

inches (305 mm) to joists. The sheet metal MUST extend

underneath the furnace casing by 1 in. (25 mm) with the door

removed.

The bottom closure panel on furnaces of widths 17−1/2 in.

(445 mm) and larger may be used for flame roll−out

protection when bottom of furnace is used for return air

A08556

connection. See Figure 17 for proper orientation of roll−out

shield.

Bottom Return Air Inlet

These furnaces are shipped with bottom closure panel

installed in bottom return−air opening. Remove and discard

this panel when bottom return air is used. To remove bottom

closure panel, perform the following:

1. Tilt or raise furnace and remove 2 screws holding bot-

tom filler panel. (See Figure 9)

2. Rotate bottom filler panel downward to release holding

tabs.

3. Remove bottom closure panel.

4. Reinstall bottom filler panel and screws.

Side Return Air Inlet

These furnaces are shipped with bottom closure panel

installed in bottom return−air opening. This panel MUST be in

place when side return air inlet(s) is used without a bottom

return air inlet.

Not all horizontal furnaces are approved for side return air

connections. (See Figure 20)