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SIDE RETURN
Locate the "L" shaped corner locator's. These indicate the size of the
cutout to be made in the furnace side panel. Refer to Figures 8 and 9.
FIGURE 9: Side Return Cutout Markings
Install the side filter rack following the instructions provided with that
accessory. If a filter(s) is provided at another location in the return air
system, the ductwork may be directly attached to the furnace side
panel.
IMPORTANT: Some accessories such as electronic air cleaners and
pleated media may require a larger side opening. Follow the instruc-
tions supplied with that accessory for side opening requirements. Do
not cut the opening larger than the dimensions for the "Optional
Return Air Cutout" shown in Figures 8 and 9.
HORIZONTAL FILTERS
Any branch duct (rectangular or round duct) attached to the plenum
must attach to the vertical plenum before the filter. The use of straps
and/or supports is required to support the weight of the external filter
box.
DOWNFLOW FILTERS
Downflow furnaces typically are installed with the filters located above
the furnace, extending into the return air plenum or duct. Any branch
duct (rectangular or round duct) attached to the plenum must attach to
the vertical plenum above the filter height.
Filter(s) may be located in the duct system external to the furnace using
an external duct filter box attached to the furnace plenum or at the end
of the duct in a return filter grille(s). The use of straps and/or supports is
required to support the weight of the external filter box.
SECTION IV: GAS PIPING
GAS SAFETY
DANGER
!
An overpressure protection device, such as a pressure regulator,
must be installed in the gas piping system upstream of the furnace
and must act to limit the downstream pressure to the gas valve so it
does not exceed 0.5 psig [14" w.c. (3.48 kPa)]. Pressures exceeding
0.5 psig [14" w.c. (3.48 kPa)] at the gas valve will cause damage to
the gas valve, resulting in a fire or explosion or cause damage to the
furnace or some of its components that will result in property damage
and loss of life.
IMPORTANT: Plan the gas supply routing before determining the
correct gas pipe entry. Use 90-degree conventional elbow(s) and
short pipe nipples to enter through the cabinet access holes.
FIGURE 10: Gas Valve
Johnson Controls Ducted Systems
GAS PIPING INSTALLATION
IMPORTANT: Ensure that the gas connections have a 1/2" National
Pipe Thread (NPT).
Properly sized wrought iron, approved flexible or steel pipe must be
used when making gas connections to the unit. Some utility companies
or local codes require pipe sizes larger than the minimum sizes listed in
these instructions and in the codes. The furnace rating plate and the
instructions in this section specify the type of gas approved for this fur-
nace.
For left side supply gas pipe arrangement, two 1/2" elbows and two 1/2"
x 1-1/2" pipe nipples must be used. The arrangement shown in Figure
11 aligns entrance hole in furnace casing with supply gas pipe. Furnace
casing does not support installations completed using street-elbows.
FIGURE 11: Left Side Supply Gas Pipe Arrangement
If local codes allow the use of a flexible gas appliance connection,
always use a new listed connector. Do not use a connector that has
previously serviced another gas appliance. Use only approved gases.
Use a drip leg and ground union as required. Refer to Figure 12.
IMPORTANT: An accessible manual shutoff valve must be installed
upstream of the furnace gas controls and within 6 feet (1.8 m) of the
furnace.
The furnace must be isolated from the gas supply piping system by
closing its individual external manual shutoff valve during any pressure
testing of the gas supply piping system at pressures equal to or less
than 0.5 psig (3.5 kPa).
CAUTION
!
The gas valve body is a very thin casting that cannot take any exter-
nal pressure. Never apply a pipe wrench to the body of the gas valve
when installing piping. A wrench must be placed on the octagon hub
located on the gas inlet side of the valve. Placing a wrench to the
body of the gas valve will damage the valve causing improper opera-
tion and/or the valve to leak.
Gas piping may be connected from either side of the furnace using any
of the gas pipe entry knockouts on both sides of the furnace. Refer to
Figures 8 and 12.
GAS ORIFICE CONVERSION FOR PROPANE (LP)
This furnace is constructed at the factory for natural gas-fired operation,
but may be converted to operate on propane (LP) gas by using a
factory-supplied LP conversion kit. Follow the instructions supplied with
the LP kit.
5750149-UIM-D-1219
9
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