Specifications

Part number 550-100-090/0809
77
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
ADVANCED INSTALLATION
Gas piping — sizing gas lines
Natural Gas:
Pipe sizing for natural gas
Size gas piping from meter outlet to entrance of boiler in accordance 1.
with Figure 95 and Figure 96.
Use total input of all boilers. Divide total input in Btuh by 1,000 to 2.
obtain cubic feet per hour of natural gas.
Pipe lengths in a. Figure 95 are equivalent length of straight pipe. Con-
vert pipe fittings to equivalent lengths using data from Figure 96.
b. Figure 95 is only for natural gas with specific gravity 0.60, with a
pressure drop through the gas piping of 0.30” w.c.
For additional gas pipe sizing information, refer to ANSI Z223.1 c.
(or B149.1 or B149.2 for Canadian installations).
Natural gas supply pressure
Pressure required at gas valve inlet pressure port:1.
Maximum: 13” w.c. with no flow (lockup) or with boiler ona.
Minimum: 4” w.c. (for all except 5” for -299) with gas flowing b.
(verify during boiler startup, while boiler is at high fire)
Install 100% lockup gas pressure regulator in supply line if inlet pres-2.
sure can exceed 13” w.c. at any time. Adjust lockup regulator for 13”
w.c. maximum.
Propane Gas:
You must follow the instructions, beginning on page 7, to
operate the boiler on propane. Failure to comply could result
in severe personal injury, death or substantial property dam-
age.
Pipe sizing for propane gas
Contact gas supplier to size pipes, tanks and 100% lockup gas pressure 1.
regulator.
Propane supply pressure
Adjust propane supply regulator provided by gas supplier for 13” w.c. 1.
maximum pressure.
Pressure required at gas valve inlet pressure port:2.
Maximum: 13” w.c. with no flow (lockup) or with boiler ona.
Minimum: 4” w.c. with gas flowing (verify during boiler startup, •
while boiler is at high fire).
Manifolded gas supply lines
Construct gas header for multiple boilers using 1. Figure 94 and the
sizing tables below. Refer to the National Fuel Gas Code for other
conditions.
Provide manual shutoff gas valve and ground joint union as shown in 2.
Figure 31 and Figure 94 for each boiler. When gas line enters from top
of the boiler, the boiler internal gas piping provides a drip leg.
A ¾” NPT gas piping riser from header to boiler will be large enough 3.
for most jobs. Ensure the piping is large enough so that the minimum
pressure at the boiler will be at least 5 inches water column with all
connected appliances firing.
Common gas line for multiple boilersFigure 94
Pipe capacity for 0.60 specific gravity Figure 95
natural gas
Gas pipe
total length,
feet
Capacity
(cubic feet per hour, 0.60 specific gravity)
1” 1¼” 1½” 2” 2½”
10
520 1050 1600 3050 4800
20
350 730 1100 2100 3300
30
285 590 890 1650 2700
40
245 500 760 1450 2300
50
215 440 670 1270 2000
75
175 360 545 1020 1650
100
150 305 460 870 1400
150
120 250 380 710 1130
Equivalent lengths of straight pipe for Figure 96
typical gas line fittings
Pipe size
inches
Equivalent length, feet
90° Elbow Tee
1
2.62 5.24
1¼
3.45 6.90
1½
4.02 8.04
2
5.17 10.3
2½
6.16 12.3