Gas Piping Connections; General; Upflow Installations - Goodman GMS8 Installation & Operating Instructions Manual

This unit is configured for natural gas. The appropriate
manufacturer's propane gas conversion kit, must be applied for
propane gas installations. Refer to the "Propane Gas and/or
High Altitude Installations" section for details.
Contact your distributor for a tabular listing of appropriate
manufacturer's kits for propane gas and/or high altitude
installations. The indicated kits must be used to insure safe and
proper furnace operation. All conversions must be performed by
a qualified installer, or service agency.
G P C
AS IPING ONNECTIONS
G
ENERAL
T
O AVOID POSSIBLE UNSATISFACTORY OPERATION OR EQUIPMENT DAMAGE
DUE TO UNDERFIRING OF EQUIPMENT, USE THE PROPER SIZE OF
NATURAL/PROPANE GAS PIPING NEEDED WHEN RUNNING PIPE FROM THE
METER/TANK TO THE FURNACE.
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.
Natural Gas Capacity of Pipe
In Cubic Feet of Gas Per Hour (CFH)
Length of
Pipe in Feet 1/2"
10 132
20 92
30 73
40 63
50 56
60 50
70 46
80 43
90 40
100 38
(Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; Based on
0.60 Specific Gravity Gas)
CFH = BTUH Furnace Input
Heating Value of Gas (BTU/Cubic Foot)
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 gas valve. In some cases, the
installer may also need to supply a transition piece from 1/2" pipe
to a larger pipe size.
The following stipulations apply when connecting gas piping.
• Use black iron or steel pipe and fittings for the building
piping.
• Use pipe joint compound on male threads only. Pipe joint
compound must be resistant to the action of the fuel used.
• Use ground joint unions.
• Install a drip leg to trap dirt and moisture before it can enter
the gas valve. The drip leg must be a minimum of three
inches long.
• Install a 1/8" NPT pipe plug fitting, accessible for test gage
connection, immediately upstream of the gas supply
connection to the furnace.
• Use two pipe wrenches when making connection to the
CAUTION
Nominal Black Pipe Size
3/4" 1" 1 1/4"
278 520 1050
190 350 730
152 285 590
130 245 500
115 215 440
105 195 400
96 180 370
90 170 350
84 160 320
79 150 305
gas valve to keep it from turning. The orientation of the gas
valve on the manifold must be maintained as shipped from
the factory.
• Install a manual shutoff valve between the gas meter and
unit within six feet of the unit. 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:
–
Rigid metallic pipe and fittings.
–
Semi-rigid metallic tubing and metallic fittings.
Aluminum alloy tubing must not be used in exterior
locations.
–
Use listed gas appliance connectors in accordance
with their instructions. Connectors must be fully in
the same room as the furnace.
–
Protect connectors and semi-rigid tubing against
physical and thermal damage when installed. Ensure
aluminum-alloy tubing and connectors are coated to
protect against external corrosion when in contact with
masonry, plaster, or insulation, or subjected to
repeated wetting by liquids such as water (except rain
water), detergents, or sewage.
Location of Manual Valve
(Installed Ahead of Ground
Joint Pipe Union)
Height Required
1 1/2" By Local Code
1600
Ground Joint Pipe Union
1100
To Be Installed Ahead Of
Gas Valve
980
760
670 Drip Leg
610
560
Reducing Coupling
530
1/2" x 1/8" with 1/8"
490
Pipe Plug To Measure
460
Line Gas Pressure
U I
PFLOW NSTALLATIONS
When the gas piping enters through the right side of the furnace,
the installer must supply the following fittings (starting from the
gas valve):
• 90 degree elbows (2).
• Close nipple.
• Straight pipe to reach the exterior of the furnace .
A ground joint union, drip leg, and manual shutoff valve must also
be supplied by the installer. In some cases, the installer may also
need to supply a transition piece from 1/2" to another pipe size.
When the gas piping enters through the left side of the furnace,
the installer must supply the following fittings (starting from the
gas valve):
• Straight pipe to reach the exterior of the furnace.
• A ground joint union, drip leg, and manual shutoff valve
19
General Furnace Layout
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