16
III. GAS SUPPLY, CONDENSATE DRAIN AND PIPING
A. GAS CONNECTION
IMPORTANT: Connect this unit only to
gas supplied by a commercial utility.
1. Install gas piping in accordance with
local codes and regulations of the
local utility company. In the absence
of local codes, the installation must
conform to the specifications of the
National Fuel Gas Code, ANSI
Z223.1 - latest edition.
2. Connect the gas line to the gas valve
supplied with unit. Routing can be
through the gas pipe opening shown
in Figures 9 or 13A or 13B or
through the base as shown in
Figure 21.
3. Size the gas line to the furnace
adequate enough to prevent undue
pressure drop and never less than
1/2(.
4. Install a drip leg or sediment trap in
the gas supply line as close to the
unit as possible.
5. Install an outside ground joint union
to connect the gas supply to the
control assembly at the burner tray.
6. Gas valves have been factory
installed. Install a manual gas valve
where local codes specify a shut-off
valve outside the unit casing. (See
Figure 17.)
7. Make sure piping is tight. A pipe
compound resistant to the action
of liquefied petroleum gases must
be used at all threaded pipe
connections.
IMPORTANT: Disconnect the furnace
and its individual shutoff valve from the
gas supply piping during any pressure
testing of that system at test pressures
in excess of 1/2 pound per square inch
gauge or isolate the system from the gas
supply piping system by closing its
individual manual shutoff valve during
any pressure testing of this gas supply
system at pressures equal to or less
than 1/2 PSIG.
TO CHECK FOR GAS LEAKS, USE A
SOAP AND WATER SOLUTION OR
OTHER APPROVED METHOD. DO
NOT USE AN OPEN FLAME.
DO NOT USE AN OPEN FLAME TO
CHECK FOR LEAKS. THE USE OF AN
OPEN FLAME CAN RESULT IN FIRE,
EXPLOSION, PROPERTY DAMAGE,
PERSONAL INJURY OR DEATH.
!
WARNING
FIGURE 17. SUGGESTED GAS PIPING
IMPORTANT: Check the rating plate to
make certain the appliance is equipped to
burn the type of gas supplied. Care should
be taken after installation of this
equipment that the gas control valve not
be subjected to high gas supply line
pressure.
In making gas connections, avoid strains
as they may cause noise and damage the
controls. A backup wrench is required to
be used on the valve to avoid damage.
The capacities of gas pipe of different
diameters and lengths in cu. ft. per hr. with
pressure drop of 0.3 in. and specific
gravity of 0.60 (natural gas) are shown in
Table 3.
After determining the pipe length, select
the pipe size which will provide the
minimum cubic feet per hour required for
the gas input rating of the furnace. By
formula:
Gas Input of Furnace
(BTU/HR)
Cu. Ft. Per Hr. Required =
Heating Value of Gas
(BTU/FT
3
)
The gas input of the furnace is marked on
the furnace rating plate. The heating value
of the gas (BTU/FT
3
) may be determined
by consulting the local natural gas utility or
the L.P. gas supplier.
Nominal
Iron Pipe
Size,
Inches
Equivalent Length of Pipe, Feet
10 20 30 40 50 60 70 80
1
/2 132 92 73 63 56 50 46 43
3
/4
278 190 152 130 115 105 96 90
1 520 350 285 245 215 195 180 170
1
1
/4 1,050 730 590 500 440 400 370 350
1
1
/2
1,600 1,100 890 760 670 610 560 530
TABLE 3
GAS PIPE CAPACITY TABLE (CU. FT./HR.)
FROM GAS
METER
*
Factory supplied grommet must be utilized.
MANUAL GAS
SHUT-OFF
VALVE
UNIT GAS SUPPLY
CONNECTION
*
ROOF OR GROUND LEVEL INSTALLATION
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