Service Manual

PRODUCT DESIGN
17
GAS PIPING
CAUTION
TO AVOID POSSIBLE UNSATISFACTORY OPERATION
OR EQUIPMENT DAMAGE DUE TO UNDERFIRING OF
EQUIPMENT, DO NOT UNDERSIZE THE NATURAL
GAS/PROPANE PIPING FROM THE METER/TANK TO
THE FURNACE. 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
between the meter and unit.
7. Tighten all joints securely.
8. Connect the unit to the building piping by one of the
following methods.
a. Rigid metallic pipe and fittings.
b. Semi-rigid metallic tubing and metallic fittings.
Aluminum alloy tubing shall not be used in exterior
locations.
c. Listed gas appliance connectors used in accor-
dance with the terms of their listing that are
completely in the same room as the equipment.
NOTE: In "b" and "c", 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.
DRIP LEG
MANUAL
SHUT-OFF
VALVE
GROUND JOINT UNION
(INSTALLED AHEAD OF GAS VALVE)
GROMMET
NOTE: The unit gas supply entrance is factory sealed with
plugs. Keep plugs in place until gas supply is ready to be
installed. Once ready, replace the plugs with the supplied
grommets and install gas supply line.
CHECKING THE GAS PIPING
CAUTION
TO AVOID THE POSSIBILITY OF PROPERTY DAMAGE,
PERSONAL INJURY OR FIRE, THE FOLLOWING
INSTRUCTIONS MUST BE PERFORMED REGARDING
GAS CONNECTIONS AND PRESSURE TESTING.
The unit and its gas connections must be leak tested before
placing in operation. Because of the danger of explosion or
fire, never use a match or open flame to test for leaks. Never
exceed specified pressure for testing. Higher pressure may
damage the gas valve and cause overfiring which may result
in heat exchanger failure.
This unit must be isolated from the gas supply system by
closing its individual manual shutoff valve during any pressure
testing of the gas supply piping system at test pressures
equal to or less than 1/2 psig (3.48 kPa).