ATTIC INSTALLATION
Line contact only permissible | Supply |
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between lines formed by the | Air | Vent (Maintain | |
intersection of furnace top |
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| required | |
and two sides and building |
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| clearances to | |
joists, studs or framing |
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| combustibles) | |
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Filter rack |
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must be a minimum |
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distance | Gas Piping |
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of 18” (45.7 cm) |
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from the |
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furnace |
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30” MIN. Work Area
Return
AirSediment
Trap
FIGURE 10: Typical Attic Installation
This appliance is certified for line contact when the furnace is installed in the horizontal left or right position. The line contact is only permissible between lines that are formed by the intersection of the top and two sides of the furnace and the building joists, studs or framing. This line may be in contact with combustible material. Refer to Figure 10.
When a furnace is installed in an attic or other insulated space, keep all insulating materials at least 12” (30.5 cm) away from furnace and burner combustion air openings.
During installation, doors should remain on the furnace when moving or lifting.
When moving or handling this furnace prior to installation, always leave the doors on the furnace to provide support and to prevent damage or warping of the cabinet. When lifting the furnace, support the ends of the furnace rather than lifting by the cabinet flanges at the return air open- ings (bottom or sides) or supply air opening.
It is acceptable to use the primary heat exchanger tubes as a lifting point provided that the tubes are lifted at the front of the heat exchang- ers where attached to the vestibule panel. Do not use the top return bend of the heat exchangers as lifting points as the tubes may shift out of position or their location brackets/baffles.
SUSPENDED FURNACE / CRAWL SPACE INSTALLATION
The furnace can be hung from floor joists or installed on suitable blocks or pads. Blocks or pad installations shall provide adequate height to ensure that the unit will not be subject to water damage.
Units may also be suspended from rafters or floor joists using rods, pipe angle supports or straps. In all cases, the furnace should be supported with rods, straps, or angle supports at three locations to properly sup- port the furnace. Place one support at the supply end of the furnace, one support located approximately in the center of the furnace near the blower shelf, and the third support should be at the return end of the fur- nace. Maintain a 6” (15.2 cm) minimum clearance between the front of the furnace and the support rods or straps.
All six suspension points must be level to ensure proper and quiet fur- nace operation. When suspending the furnace, use a secure platform constructed of plywood or other building materials secured to the floor or ceiling joists. Refer to Figure 11 for details and additional information.
Support
Rod
Support 
Angle (x3)
Maintain 6” minimum clearance between support rods and front of furnace
FIGURE 11: Typical Suspended Furnace / Crawl Space Installation
DOWNFLOW APPLICATION
To apply the furnace in a downflow position, it will be necessary to rotate the vent blower 90° left or right so that the vent pipe passes through the side of the furnace casing. See Figure 12.
Rotate vent blower 90° either way
LEFT SIDE VENT | RIGHT SIDE VENT |
FIGURE 12: Downflow Venting
8 | Johnson Controls Unitary Products |