Specifications

29
Gas Piping Connections
When sizing a trunk line, be sure to include all appliances which
will operate simultaneously when sizing a trunk line. The gas
piping supplying the furnace must be properly sized based on the
gas flow required, specific gravity of the gas, and length of the
run. The gas line installation must comply with local codes, or in
their absence, with the latest edition of the National Fuel Gas
Code, NFPA 54/ANSI Z223.1.
Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; Based
on 0.60 Specific Gravity Gas
To connect the furnace to the building’s gas piping, the installer
must supply a ground joint union, drip leg, manual shutoff valve
and line and fittings to connect to the gas control valve. In some
cases, the installer may also need to supply a transition piece
from ¹⁄₂" (1.3 cm) pipe to a larger pipe size.
See “Gas Piping Connections” illustrations for typical gas line
connections to the furnace.
When connecting gas piping:
■ Use black iron or steel pipe and fittings for building piping.
■ Where possible, use new pipe that is properly chamfered,
reamed and free of burrs and chips.
NOTE: If old pipe is used, be sure it is clean and free of rust,
scale, burrs, chips and old pipe joint compound.
■ Use pipe joint compound (pipe dope) on male threads only.
■ Always use pipe joint compound (pipe dope) that is approved
for all gases.
■ Do not apply compound to the first 2 threads.
■ Use ground joint unions.
■ Install a drip leg to trap dirt and moisture before it can enter
the gas control valve. The drip leg must be a minimum of 3"
(7.6 cm) long.
■ Install a ¹⁄₈" NPT pipe plug fitting, accessible for test gage
connection, immediately upstream of the gas supply
connection to the furnace.
■ Always use a backup wrench when making the connection to
the gas control valve to keep it from turning.
NOTE: The orientation of the gas control valve on the
manifold must be maintained as shipped from the factory.
■ Maximum torque for the gas control valve connection is
375 in/lbs.
NOTE: Do not overtighten the gas control valve.
■ Install a manual shutoff valve between the gas meter and the
furnace within 6 ft (1.8 m) of the furnace.
■ If a union is installed, the union must be downstream of the
manual shutoff valve, between the shutoff valve and the
furnace.
■ Tighten all joints securely.
■ Connect the furnace to the building piping by one of the
following methods:
1. Rigid metallic pipe and fittings.
2. Semirigid metallic tubing and metallic fittings.
NOTE: Aluminum alloy tubing must not be used in exterior
locations. In order to seal the grommet cabinet penetration,
rigid pipe must be used to reach the outside of the cabinet. A
semirigid connector to the gas piping may be used from
there.
■ Use listed gas appliance connectors in accordance with their
instructions.
■ Gas connectors must be fully in the same room as the
furnace.
■ Keep gas connectors and semirigid tubing away from
physical and thermal damage when installed.
■ Ensure aluminum alloy tubing and connectors are coated to
avoid external corrosion when in contact with masonry,
plaster or insulation, or subjected to repeated wetting by
liquids such as water (except rainwater), detergents, or
sewage.
Natural Gas Capacity of Pipe—In cu ft (m
3
) of Gas Per Hour
(CFH)
Length
of
Pipe—
ft (m)
Nominal Black Pipe Size—inches
¹⁄₂ ³⁄₄ 1 1¹⁄₄ 1¹⁄₂
10 (3) 132 (3.7) 278 (7.9) 520 (14.7) 1,050 (29.7) 1,600 (45.3)
20 (6.1) 92 (2.6) 190 (5.4) 350 (9.9) 730 (20.7) 1,100 (31.1)
30 (9.2) 73 (2.1) 152 (4.3) 285 (8.1) 590 (16.7) 980 (27.8)
40 (12.2) 63 (1.8) 130 (3.7) 245 (6.9) 500 (14.2) 760 (21.5)
50 (15.2) 56 (1.6) 115 (3.3) 215 (6.1) 440 (12.5) 670 (19)
60 (18.3) 50 (15.2) 105 (3) 195 (5.5) 400 (11.3) 610 (17.3)
70 (21.3) 46 (1.3) 96 (2.7) 180 (5.1) 370 (10.5) 560 (15.9)
80 (24.4) 43 (1.2) 90 (2.5) 170 (4.8) 350 (9.9) 530 (15)
90 (27.4) 40 (1.1) 84 (2.4) 160 (4.5) 320 (9.1) 490 (13.9)
100 (30.5) 38 (1.1) 79 (2.2) 150 (4.2) 305 (8.6) 460 (13)
CFH =
Btu/h Furnace Input
Heating Value of Gas (Btu/cu. ft
Goodman 52
Possible property damage, personal injury or death may
occur if the correct conversion kits are not installed. The
appropriate kits must be applied to insure safe and proper
furnace operation. All conversions must be performed by
a qualified installer or service agency.
WARNING
Goodman 56
Edges of sheet metal holes may be sharp. Use gloves as
a precaution when removing hole plugs.
WARNING