Goodman [A/G]PG, Service Instructions Manual

Page: 15 / 52

PRODUCT DESIGN
15
GAS SUPPLY AND PIPING
This Package Gas unit is factory set to operate on
natural gas at the altitudes shown on the rating
plate. If operation on propane is required, obtain and
install the proper conversion kit(s) before operating
this unit. Failure to do so may result in unsatisfactory
operation and/or equipment damage.
The rating plate is stamped with the model number, type of
gas, and gas input rating. Make sure the unit is equipped to
operate on the type of gas available.
Inlet Gas Pressure
Natural Min. 5.0" W.C., Max. 10.0" W.C.
Propane Min. 11.0" W.C., Max. 13.0" W.C.
Inlet Gas Pressure Must Not Exceed the Maximum Value
Shown in the table above.
The minimum supply pressure must not be varied downward
because this could lead to unreliable ignition. In addition, gas
input to the burners must not exceed the rated input shown on
the rating plate. Overfiring of the unit could result in premature
heat exchanger failure.
GAS PIPING
To avoid possible unsatisfactory operation or
equipment damage due to underfiring or equipment,
do not undersize the natural gas/propane piping from
the meter/tank to the unit. When sizing a trunk
line per the tables, include all appliances on that line
that could be operated simultaneously.
The gas pipe supplying the unit must be properly sized based
on the cubic feet per hour of gas flow required, specific gravity
of the gas and length of the run. The gas line installation must
comply with local codes, or in the absence of local codes, with
the latest edition of the National Fuel Gas Code ANSI Z223.1.
NATURAL GAS CAPACITY OF PIPE IN CUBIC FEET OF
GAS PER HOUR (CFH)
LENGTH OF
PIPE IN FEET
NOMINAL BLACK PIPE SIZE
1/2" 3/4" 1" 1 1/4" 1 1/2"
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 980
40 63 130 245 500 760
50 56 115 215 440 670
60 50 105 195 400 610
70 46 96 180 370 560
80 43 90 170 350 530
90 40 84 160 320 490
100 38 79 150 305 460
BTUH FURNACE INPUT
CALORIFIC VALUE OF GAS
CFH =
CONNECTING THE GAS PIPING - NATURAL GAS
1. Use black iron or steel pipe and fittings for the building
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. Use two pipe wrenches when making connection to the
gas valve to keep it from turning.
6. Install a manual shut off valve. This shut off valve should be
conveniently located within six (6) feet of the unit, and be-
tween the meter and unit.
7. Tighten all joints securely.
8. Connect the unit to the building piping by one of the follow-
ing methods.
a. Rigid metallic pipe and fittings.
b. Semi-rigid metallic tubing and metallic fittings. Alu-
minum alloy tubing shall not be used in exterior lo-
cations.
c. Listed gas appliance connectors used in accordance
with the terms of their listing that are completely in
the same room as the equipment.
NOTE: In "b" and "c" above, the connector or tubing must be
installed so as to be protected against physical and thermal
damage. Aluminum-alloy tubing and connectors must be coated
to protect against external corrosion where they are in contact
with masonry, plaster, or insulation or are subject to repeated
wettings by such liquids as water (except rain water),
detergents, or sewage.