Gas Piping - Sizing Gas Lines - Weil-McLain Ultra 3 series User Manual

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gas fired water boiler
Gas piping — sizing gas lines
Natural Gas:
Pipe sizing for natural gas
1. Size gas piping from meter outlet to entrance of boiler in accordance
with Figure 95 and Figure 96.
2. Use total input of all boilers. Divide total input in Btuh by 1,000 to
obtain cubic feet per hour of natural gas.
a. Pipe lengths in 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.
c. For additional gas pipe sizing information, refer to ANSI Z223.1
(or B149.1 or B149.2 for Canadian installations).
Natural gas supply pressure
1. Pressure required at gas valve inlet pressure port:
a. Maximum: 13" w.c. with no flow (lockup) or with boiler on
b. Minimum: 4" w.c. (for all except 5" for -299) with gas flowing
(verify during boiler startup, while boiler is at high fire)
2. Install 100% lockup gas pressure regulator in supply line if inlet pres-
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
1. Contact gas supplier to size pipes, tanks and 100% lockup gas pressure
regulator.
Propane supply pressure
1. Adjust propane supply regulator provided by gas supplier for 13" w.c.
maximum pressure.
2. Pressure required at gas valve inlet pressure port:
a. Maximum: 13" w.c. with no flow (lockup) or with boiler on
• Minimum: 4" w.c. with gas flowing (verify during boiler startup,
while boiler is at high fire).
Manifolded gas supply lines
1. Construct gas header for multiple boilers using
sizing tables below. Refer to the National Fuel Gas Code for other
conditions.
2. Provide manual shutoff gas valve and ground joint union as shown in
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.
3. A ¾" NPT gas piping riser from header to boiler will be large enough
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.
Part number 550-100-090/0809
— Boiler Manual
Figure 94
Figure 95
total length,
Figure 96
Figure 94 and the
Common gas line for multiple boilers
Pipe capacity for 0 60 specific gravity
natural gas
Capacity
Gas pipe
(cubic feet per hour, 0 60 specific gravity)
feet
1" 1¼"
10
520 1050
20 350 730
30 285 590
40
245 500
50 215 440
75
175 360
100 150 305
150 120 250
Equivalent lengths of straight pipe for
typical gas line fittings
Equivalent length, feet
Pipe size
inches
90° Elbow
1
2 62
1¼ 3 45
1½
4 02
2 5 17
2½
6 16
1½" 2" 2½"
1600 3050 4800
1100 2100 3300
890 1650 2700
760 1450 2300
670 1270 2000
545 1020 1650
460 870 1400
380 710 1130
Tee
5 24
6 90
8 04
10 3
12 3
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