Filter
Top Products
Installation & Operation Manual
41
Nominal
Iron Pipe
Size
(inches)
Natural Gas Pipe Capacity Chart
Length of Pipe in Straight Feet
Maximum
Capacity of Pipe
in Thousands of
Btu/hr per hour
for gas pressures
of 14 Inches
Water Column
(0.5 PSIG) or less
and a pressure
drop of 0.5 Inch
Water Column
(Based on NAT
GAS, 1025 Btu/hr
per Cubic Foot of
Gas and 0.60
Specific Gravity)
10 20 30 40 50 60 70 80 90 100 125 150 175 200
1/2
175 120 97 82 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
3/4
369 256 205 174 155 141 128 121 113 106 95 86 79 74
1
697 477 384 328 292 267 246 236 210 200 179 164 149 138
1-1/4
1400 974 789 677 595 543 502 472 441 410 369 333 308 287
1-1/2
2150 1500 1210 1020 923 830 769 707 666 636 564 513 472 441
2
4100 2820 2260 1950 1720 1560 1440 1330 1250 1180 1100 974 871 820
2-1/2
6460 4460 3610 3100 2720 2460 2310 2100 2000 1900 1700 1540 1400 1300
3
11200 7900 6400 5400 4870 4410 4000 3800 3540 3330 3000 2720 2500 2340
4
23500 16100 13100 11100 10000 9000 8300 7690 7380 6870 6150 5640 5130 4720
7 Gas connections (continued)
Table 7A Natural Gas Pipe Size Chart
The gas piping must be sized for the proper flow and length of
pipe, to avoid excessive pressure drop. Both the gas meter and
the gas regulator must be properly sized for the total gas load.
If you experience a pressure drop greater than 1 inch w.c.
(249 Pa), the meter, regulator, or gas line is undersized or in
need of service. Perform the steps below when checking inlet
gas supply:
1. Turn the main power switch to the “OFF” position.
2. Shut off gas supply at the manual gas valve in the gas
piping to the appliance.
3. On Models 399 - 500 loosen the set screw one (1) full turn
from inside the pressure tap on top of the gas valve. On
Models 600 - 800 remove the 1/8" (3 mm) pipe plug on the
inlet flange to the valve and install a suitable 1/8" (3 mm)
fitting (field supplied) for the manometer tubing. Place
the tubing of the manometer over the tap once the set
screw is loosened or the 1/8" (3 mm) fitting is installed
(depending on model) as shown in FIG.’s 7-5 thru 7-7 on
page 42.
4. Slowly turn on the gas supply at the field installed
manual gas valve.
5. Turn the power switch to the “ON” position.
6. Adjust the temperature set point on the control panel of
the SMART SYSTEM control module to call for heat.
7. Observe the gas supply pressure as the burner fires at
100% of rated input. Percent of burner input will be
displayed on the control panel.
8. Ensure inlet pressure is within specified range.
Minimum and maximum gas supply pressures are
specified in this section of the manual.
9. If gas supply pressure is within normal range and no
adjustments are needed, proceed on to Step 11.
10. If the gas pressure is out of range, contact the gas utility,
gas supplier, qualified installer or service agency to
determine the necessary steps to provide proper gas
pressure to the control.
11. Turn the power switch to the “OFF” position.
12. Shut off the gas supply at the manual gas valve in the gas
piping to the appliance.
13. Remove the manometer from the pressure tap on top of
the gas valve. On Models 399 - 500 re-tighten the set
screw inside the pressure tap. On Models 600 - 800
remove the 1/8" (3 mm) field supplied fitting and
reinstall the pipe plug removed in Step 3.
Check inlet gas supply
NOTICE
CSA or UL listed flexible gas connections
are acceptable, but you must exercise
caution to ensure that the line has adequate
capacity to allow your boiler to fire at full
rate. Consult with local codes for proper
installation or service procedures.
DO NOT adjust or attempt to measure gas
valve outlet pressure. Attempting to alter
or measure the gas valve outlet pressure
could result in damage to the valve, causing
potential severe personal injury, death, or
substantial property damage.
ƽ WARNING