Install Instructions

Gas piping — sizing gas lines
Part number 550-100-131/0715
– 16 –
™
GAS-FIRED WATER BOILER — Boiler Manual
Pipe size
inches
Equivalent length, feet
90° Elbow Tee
¾
2.06 4.12
1
2.62 5.24
1¼
3.45 6.90

4.02 8.04
2
5.17 10.30

6.16 12.30
3
7.67 15.30
4
10.10 20.20
Boiler gas connection is ¾” NPT. Size gas lines
large enough to provide gas to all connected
appliances.
Natural Gas:
0IPESIZINGFORNATURALGAS
1. Size gas piping from meter outlet to entrance of boiler in
accordance with Figure 17 and Figure 18.
2. Use total input of all connected appliances. Divide total input
in Btuh by 1,000 to obtain cubic feet per hour of natural gas.
a. Pipe lengths in Figure 17 are equivalent length of straight
pipe. Convert pipe fittings to equivalent lengths using
data from Figure 18.
b. Figure 17 is only for natural gas with specific gravity
0.60, with a pressure drop through the gas piping as
listed in the table.
c. For additional gas pipe sizing information, refer to ANSI
Z223.1 (or B149.1 or B149.2 for Canadian installations).
.ATURALGASSUPPLYPRESSURE
1. Pressure required at gas valve inlet pressure port:
a. Maximum: 14” (356 mm) w.c. with no flow (lockup).
b. Minimum gas pressure, with gas flowing (verify dur-
ing boiler startup, while boiler is at high fire):
3½” (89 mm) w.c.
2. Install 100% lockup gas pressure regulator in supply line if
inlet pressure can exceed 14” w.c. at any time. Adjust lockup
regulator for 14” w.c. maximum.
Propane Gas:
You must follow the instructions, beginning on
page 12, to operate the boiler on propane. Failure
to comply could result in severe personal injury,
death or substantial property damage.
0IPESIZINGFORPROPANEGAS
1. Contact gas supplier to size pipes, tanks and 100% lockup
gas pressure regulator.
0ROPANESUPPLYPRESSURE
1. Adjust propane supply regulator provided by gas supplier
between the pressures listed below:
2. Pressure required at gas valve inlet pressure port:
a. Maximum: 14” (356 mm) w.c. with no flow (lockup).
b. Minimum gas pressure, with gas flowing (verify dur-
ing boiler startup, while boiler is at high fire):
3½” (89 mm) w.c.
Gas
pipe
total
length,
feet
Capacity
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Gas pressure 14” (356 mm) w.c. or less
Pressure drop 0.3 inches (7.6 mm) w.c.
Ðv v v v v v v v
10 278 520 1050 1600 3050 4800 8500 17500
20 190 350 730 1100 2100 3300 5900 12000
30 152 285 590 890 1650 2700 4700 9700
40 130 245 500 760 1450 2300 4100 8300
50 115 215 440 670 1270 2000 3600 7400
75 105 175 360 545 1020 1650 3000 6200
100 96 150 305 460 870 1400 2500 5100
150 90 120 250 380 710 1130 2000 4100
&IGURE Pipe capacity for 0.60 specific gravity natural
gas; pipe length is in equivalent feet (for non-
corrugated pipe)
&IGURE Equivalent lengths of straight pipe for typical
gas line fittings