Downflow Furnaces; Supply Air Connections; Acoustical Treatments; Furnace Installation - Oxbox J951X U Series Installation Instructions Manual

Downflow Furnaces

• To attach the return air duct to the furnace, bend the
flanges on the furnace upward 90° with wide duct pliers.
See for furnace flange locations. NOTE: If
Figure 29
system installation includes AC coil casing, bend the
flanges on the coil casing upward 90° before attaching
the return air duct.
• Secure the return air ductwork to the furnace or coil
casing (if installed) with sheet metal screws. Make sure
the screws penetrate the sheet metal casing and flanges.

Supply Air Connections

• The supply air must be delivered to the heated space by
duct(s) secured to the furnace or coil box casing, running
full size and without interruption.
• To attach the supply air duct to upflow & horizontal
furnaces, bend the flanges on the furnace upward 90°
with wide duct pliers. See
locations. NOTE: If system installation includes AC coil
casing, bend the flanges on the coil casing upward 90°
before attaching the supply air duct.
• Position the supply air ductwork onto the furnace ensuring
even alignment of furnace air opening and supply air
duct. NOTE: The ductwork must have an opening equal
to that of the supply air opening of the furnace. See
and
29 (page 29) Figure 30 (page 29)
opening size.

Acoustical Treatments

Damping ducts, flexible vibration isolators, or pleated media-
style filters on the return air inlet of the furnace may be used
to reduce the transmission of equipment noise eminating
from the furnace. These treatments can produce a quieter
installation, particularly in the heated space. However, they
can increase the pressure drop in the duct system. Care
must be taken to maintain the proper maximum pressure
rise across the furnace, temperature rise and flow rate.
This may mean increasing the duct size and/or reducing the
blower speed. These treatments must be constructed and
installed in accordance with NFPA and SMACNA construction
standards. Consult with local codes for special requirements.
For best sound performance, install all the needed gaskets
and grommets around penetrations into the furnace, such
as for electrical wiring.
14
for furnace flange
Figure 30
Figure
for supply air

FURNACE INSTALLATION

J951X*U series gas furnaces offer a wide range of installation
options, including installation in the upflow or horizontal
positions with either right, left, or upflow return air. J951X*D
series gas furnaces may only be installed as a downflow
application.

General Requirements

• The furnace must be leveled at installation and attached
to a properly installed duct system. See
5) for the required clearances needed to move the
furnace to its installation point (hallways, doorways,
stairs, etc).
• The furnace must be installed so that all electrical
components are protected from water.
• The furnace must be installed upstream from a
refrigeration system. (If applicable)
• The cabinet plug must always be used to close the hole
in the side of the furnace when rotating the inducer.
• The furnace requires special venting materials and
installation procedures. See
, ,
8 page 9 page 10
venting guidelines and specifications.

Upflow Furnaces

WARNING:
The furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood flooring.
J951X*U series gas furnaces are shipped with the bottom
panel installed as shown in
furnace is installed with only side return air, the bottom panel
must not be removed. If the furnace is installed with bottom
return air, the bottom panel must be removed. See Bottom
Panel Removal on
page 19

Horizontal Furnaces

WARNING:
The furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood flooring.
J951X*U series gas furnaces can be installed horizontally
( Figure 11 ) in an attic, basement, crawl space or alcove. It
can also be suspended from a ceiling in a basement or utility
room in either a right to left airflow or left to right airflow as
shown in Figure 12 (page 15)
These furnaces are shipped with the bottom panel installed.
If the furnace is installed horizontally, remove the bottom
panel from the furnace before attaching the duct system.
See Bottom Panel Removal on
If installing the furnace with an evaporator coil (in an attic), it
is required that a drip pan be placed under the furnace. If the
installation is on a combustible platform as shown in
, it is recommended that the drip pan extend at least 12
11
inches past the top and front of the furnace.
NOTE: Although it is not required to use a drip pan for heat
only applications, state and local codes may require it.
Figure 1 (page
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page 6 page 7
, , &
page 11 page 12
. If the
Figure 30 (page 29)
.
.
.
page 19
page
for
Figure