![background image](http://html1.mh-extra.com/html/carrier/kgatw0601hsi/kgatw0601hsi_installation-instructions-manual_2563046008.webp)
13. Go to PROCEDURE 2A for Single Stage Furnaces or PROCEDURE 2B for Two Stage Furnaces.
C.
Horizontal, Back-to-Back Position
When twinning furnaces in the horizontal position, consideration must be made to the type of building construction. Attic floors should be
constructed to support normal live and dead loads of the furnaces and the person(s) servicing them.
Trusses, wood and metal are engineered for specific applications, and may not support the weight of two (2) furnaces suspended from the top
chords or the bottom chords of the trusses. Long horizontals spans may flex or sag, resulting in damage to the building. Contact the truss
manufacturer for additional design and engineering assistance.
Do not suspend furnaces with straps or suspend furnaces from roof decking.
For attic installations on a platform (See Fig. 8a.):
1. Construct a platform from ¾
″
(nominal plywood), extending out 30 inches from the front of each furnace.
2. Maintain all clearances to combustibles per the furnace Installation, Start-up and Operating Instructions.
3. Follow all additional building codes.
4. Long truss spans may require additional support along the bottom chord of the truss. Consult the truss manufacturer’s guidelines for
engineering assistance.
5. Long rafter or attic joist spans may require additional support along the bottom of the rafter or joist. Consult local or regional building codes
for design and loading requirements.
For suspended installations (See Fig. 8b. Not recommended for wood trusses unless approved by the truss manufacturer or other approved
engineering methods):
1. Furnaces may be suspended using two (2) pieces of 1 ½” x 1 ½” x ¼” thick cold rolled angle iron underneath the furnaces and four (4)
3/8
″
diameter threaded rods.
2. Allow for at least nine (9) inches in front of each door for door removal.
3. Each piece of angle iron must be secured to the bottom of each furnace with at least two (2) #8 x ¾
″
sheet metal screws.
4. Maintain all clearances to combustibles per the furnace Installation, Start-up and Operating Instructions.
5. Unistrut or similar material may be used, provided that the furnaces do not sag in the middle or bend or twist at the support ends. The support
material must be secured to the bottom of each furnace in a manner similar to securing angle iron to the furnace.
Fig. 8a—Attic Installtion of Horizontal Back-to-Back Furnaces
A02241
30˝ Work Platform
Dripleg
Dripleg
Extension Harness
Gas Supply Shut-off
Gas Supply Shut-off
Gas Pipe Union
Gas Pipe Union
30˝ Work Platform
Sheet Metal
Same As Installation Instructions
22˝
12˝
4
3
/
4
˝
1˝
17
3
/
4
˝ over all 4
3
/
4
˝ under door
1˝ under furnace
Extend out 12˝ from face
of door
3/8˝ Lock Washer
3/8˝ Flat Washer
3/8˝ Flat Washer
3/8˝ Lock Washer
3/8˝ Hex Nut
3/8˝ Hex Nut
3/8˝ Threaded Rod
1
1
/
2
˝ x 1
1
/
2
˝ x
1
/
4
˝ Angle Iron
—8—