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5715184-BIM-A-0519
SECTION IV: GAS PIPING
GAS SAFETY
IMPORTANT: Plan your gas supply before determining the correct
gas pipe entry. Use 90-degree service elbow(s), or short nipples
and conventional 90-degree elbow(s) to enter through the cabinet
access holes.
FIGURE 11: Gas Valve
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 PSI (14 in. W.C. [3.48 kPa]). Pressures
exceeding 0.5 PSI (14 in. 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.
GAS PIPING INSTALLATION
IMPORTANT: Ensure that the gas connections have a 1/2 in.
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 in. elbows and two
1/2 in. x 1-1/2 in. pipe nipples must be used. The arrangement shown in
Figure 12 aligns entrance hole in furnace casing with supply gas pipe.
Furnace casing does not support installations completed using street-
elbows.
FIGURE 13: Upflow/Downflow Gas Piping
10
FIGURE 12: 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 13.
IMPORTANT: An accessible manual shutoff valve must be installed
upstream of the furnace gas controls and within 6 ft (1.8 m) of the fur-
nace.
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 9 and 13.
Johnson Controls Ducted Systems
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