Goodman GMSS9 Series Service Instructions Manual page 26

INSTALLATION CONSIDERATIONS
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)
BTUH Furnace Input
CFH =
Heating Value of Gas (BTU/Cubic Foot)
To connect the furnace to the building's gas piping, the in-
staller 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 pip-
ing. Refer to the following figures for typical gas line con-
nections to the furnace.
1. Use black iron or steel pipe and fittings for the build-
ing piping.
2. Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
3. Use ground joint unions.
4. 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.
5. Install a 1/8" NPT pipe plug fitting, accessible for test
gage connection, immediately upstream of the gas
supply connection to the furnace.
6. Use two pipe wrenches when making connection to
the gas valve to keep it from turning. The orientation
of the gas valve on the manifold must be maintained
as shipped from the factory.
7. Install a manual shutoff valve between the gas meter
and unit within six feet of the unit. If a union is in-
stalled, the union must be downstream of the manual
shutoff valve, between the shutoff valve and the fur-
nace.
8. Tighten all joints securely.
GAS PIPING CHECKS
Before placing unit in operation, leak test the unit and gas
connections.
26
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
T
O AVOID THE POSSIBLITY OF EXPLOSION OR FIRE, NEVER USE A MATCH
OR OPEN FLAME TO TEST FOR LEAKS.
Check for leaks using an approved chloride-free soap and
1 1/2" water solution, an electronic combustible gas detector, or
1600
other approved testing methods.
1100
NOTE: Never exceed specified pressures for testing. Higher
980
pressure may damage the gas valve and cause subsequent
760
overfiring, resulting in heat exchanger failure. Disconnect
670
this unit and shutoff valve from the gas supply piping sys-
610
tem before pressure testing the supply piping system with
560
pressures in excess of 1/2 psig (3.48 kPa). Isolate this unit
530
from the gas supply piping system by closing its external
490
manual gas shutoff valve before pressure testing supply pip-
460
ing system with test pressures equal to or less than 1/2
psig (3.48 kPa).
PROPANE GAS TANKS AND PIPING
P
ROPANE GAS IS HEAVIER THAN AIR AND ANY LEAKING GAS CAN SETTLE IN
ANY LOW AREAS OR CONFINED SPACES.
PERSONAL INJURY, OR DEATH DUE TO FIRE OR EXPLOSION CAUSED BY A
PROPANE GAS LEAK, INSTALL A GAS DETECTION WARNING DEVICE.
A gas detecting warning system is the only reliable way to
detect a propane gas leak. Iron oxide (rust) can reduce the
level of odorant in propane gas. Do not rely on your sense of
smell. Contact a local propane gas supplier about installing
a gas detecting warning system. If the presence of gas is
suspected, follow the instructions on this page.
All propane gas equipment must conform to the safety stan-
dards of the National Board of Fire Underwriters, NBFU
Manual 58.
For satisfactory operation, propane gas pressure must be
10 inch WC at the furnace manifold with all gas appliances
in operation. Maintaining proper gas pressure depends on
three main factors:
1. Vaporization rate, depending on temperature of the liq-
uid, and "wetted surface" area of the container or con-
tainers.
2. Proper pressure regulation. (Two-stage regulation is rec-
ommended for both cost and efficiency).
3. Pressure drop in lines between regulators, and between
second stage regulator and the appliance. Pipe size will
depend on length of pipe run and total load of all appli-
ances.
Complete information regarding tank sizing for vaporization,
recommended regulator settings, and pipe sizing is avail-
able from most regulator manufacturers and propane gas
suppliers.
Use pipe dope approved for use with L.P. gas.
Refer to the following illustration for typical propane gas in-
stallations and piping.
WARNING
WARNING
T
O PREVENT PROPERTY DAMAGE,