J801X Installation Manual

10
manually operated damper is installed, it must be designed
so that operation of the furnace is prevented when the
damper is in the cooling position and operation of the
cooling system is prevented when the damper is in the
heating position.
• Seal all connections and joints with industrial grade sealing
tape or liquid sealant. Requirements for sealing ductwork
vary from region to region. Consult with local codes for
requirements specific to your area.
Return Air Connections
• In applications where the supply ducts carry heated air to
areas outside the space where the furnace is installed,
the return air must be delivered to the furnace by duct(s)
secured to the furnace casing, running full size and without
interruption. Do not use the back of the furnace for
return air.
• Position the furnace with the return air ductwork ensuring
even alignment of furnace (or coil casing) air opening and
return air duct. NOTE: The ductwork must have an opening
equal to that of the return air opening of the furnace (or coil
casing). See Figure 18, (page 23) for return air opening
size.
Upflow & Horizontal Furnaces
• The return air ductwork may be connected to the left side,
right side, or bottom of the furnace. NOTE: If using only
the left or right side of the furnace for return air, the bottom
panel (Figure 18) must not be removed from the bottom
of the furnace.
WARNING:
The bottom panel of the furnace must be in place
when the furnace is installed with side return air
ducts. Removal of all or part of the base could
cause circulation of combustible products into
the living space and create potentially hazardous
conditions, including carbon monoxide poisoning
that could result in personal injury or death.
• Side Return Installations: To attach the return air duct
to the left or right side of the furnace, punch out the 4
knockouts from the side of the furnace (Figure 18). Using
sharp metal cutters, cut an opening between all 4 knockouts
to expose the blower assembly. Position the return air duct
over the opening and secure to the side with sheet metal
screws.
• Bottom Return Installations: If using the bottom of the
furnace for return air, the bottom panel (Figure 18) must
be removed from the bottom of the furnace. See page
13 for removal instructions. Position the furnace over
the return air duct and secure together with sheet metal
screws. Make sure the screws penetrate the duct and
furnace casing.
Downflow Furnaces
• To attach the return air duct to the downflow furnace, bend
the flanges on the furnace upward 90° with wide duct pliers.
See Figure 18, (page 23) for furnace flange locations.
NOTE: If 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 Figure 18, (page 23) for furnace flange
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 Figure 18 for
supply air 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, be sure to install all the needed gaskets
and grommets around penetrations into the furnace, such
as for electrical wiring.