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b. High altitude (H) - 2,000 to 4,500 feet
(610 to 1370 m)
FOR PROPANE GAS
a. Factory Released - 0 to 4,500 feet
(610 to 1370 m)
5.
Use only wrought steel piping or when permitted by
local codes, other rigid piping material. Do not use
flexible gas connectors, which restrict gas flow to the
heater.
6.
Table 4 specifies sizing for gas supply piping based
on 1/2 WC (3.45 kPa) pressure drop in the piping.
Larger piping may be necessary if the local gas
supply is at pressures which will not guarantee
adequate pressure at the heater. Table 5 specifies the
maximum and minimum supply pressures necessary
at the heater
when it is operating.
7.
Install a sediment trap (drip leg) ahead of the gas
controls (see Figure 7). Fit the trap with a threaded
cap which can be removed for cleaning.
8.
Install a manual gas shut-off valve for service and
safety. Do not use a restrictive gas cock.
CAUTION
Permanent damage to the gas valve will occur
if the following procedures are not followed.
9.
Disconnect the heater and its individual shutoff valve
from the gas supply system during pressure testing of
the system at pressures higher than 1/2 pounds per
square inch (psi) (3.45 kilopascals [kPa]). If the test
pressure is equal to or less than 1/2 psi (3.45 kPa),
close the manual shutoff valve on the heater during
the piping pressure test.
Table 5. Gas Supply Pressure Requirements
Supply Pressure
Natural Gas
Propane Gas
Water Column
in. (kPa)
in. (kPa)
Minimum
6
(1.5)
11
(2.8)
Maximum
10.5(2.7)
14
(3.5
)
Figure 7. The Proper Design for a Sediment Trap/Drip
Leg.
Table 4. Natural Gas Pipe Size Requirements
Distance from Gas Meter
0-50 feet
50-100 feet
100-200 feet
Heater
(0-15 m)
(15-30 m)
(30-60 m)
Size
in.
in.
in.
250
1
1-1/4
1-1/4
400
1-1/4
1-1/2
1-1/2
Notes:
1. These numbers are for natural gas (0.65 Sp. Gr.) and
are based on 1/2 inch (3.45 kPa) water column pressure
drop. Check supply pressure with a manometer, and
local code requirements for variations.
For liquefied
petroleum gas, reduce pipe diameter one size, but
maintain a 3/4 inch minimum diameter.
2. Check supply pressure and local code requirements
before preceding with work.
10. If the gas supply pressure is less than required, check
for undersized pipe between the meter and the heater,
a restrictive fitting, or an undersized gas meter. Gas
supply pressures to the heater, when it is operating,
are listed in Table 5.
NOTE
: The maximum inlet gas pressure must not
exceed the specified value. The minimum value listed is
for the purpose of proper heater operation. Refer to Table
11. To connect the gas supply line to the heater's gas
valve, you must first install a steel elbow (supplied
with the heater in the installation and instruction
box). Screw the elbow into the inlet side of the gas
valve. The heater is designed so that the gas supply
line may enter through either side of the heater. Hand
tighten the elbow until the desired orientation is
achieved.
CAUTION
Do not over tighten the elbow. Over tightening
will crack the gas valve. Do not use teflon tape
to wrap the elbow threads.
Manual Shutoff
Valve
Gas Supply
Inlet
To
Equipment
Inlet
Union
Cap
T-Fitting
3" Min.
Nipple