Weil-McLain -105 Manual page 22

5
Gas piping
Natural Gas:
Pipe sizing for natural gas
1. Refer to Table 4 for pipe length and diameter. Base on
rated boiler input (divide by 1,000 to obtain cubic
feet per hour).
a. Table 4 is only for natural gas with specific gravity 0.60,
with a pressure drop through the gas piping of 0.30"
w.c.
b. For additional gas pipe sizing information, refer to
ANSI Z223.1 (or B149.1 or B149.2 for Canadian
installations).
Natural gas supply pressure requirements
1. Pressure required at gas valve inlet pressure port:
• Maximum: 13" w.c. with no flow (lockup) or with
boiler on
• Minimum: 5" w.c. 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 pressure can exceed 13" w.c. at any time.
Adjust lockup regulator for 13" w.c. maximum.
Table 4 Pipe capacity for 0.60 specific gravity natural gas
Gas pipe
length
(feet)
10
20
30
40
50
75
100
150
22
-
GAS FIRED WATER BOILER SERIES
(continued)
½"
132
92
73
63
56
45
38
31
2 — Boiler Manual
Propane Gas:
Ultra boilers are shipped ready to fire
natural gas ONLY (exception: Ultra-80-LP
is propane-ready). You must install the
propane orifice if the boiler will be
connected to propane. See page 9. Failure
to comply could result in severe personal
injury, death or substantial property
damage.
Pipe sizing for natural gas
1. Contact gas supplier to size pipes, tanks and 100%
lockup gas pressure regulator.
Propane supply pressure requirements
1. Adjust propane supply regulator provided by gas
supplier for 13" w.c. maximum pressure.
2. Pressure required at gas valve inlet pressure port:
• 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)
Capacity of pipe for pipe size of:
(Capacity in cubic feet gas per hour)
¾" 1"
278 520
190 350
152 285
130 245
115 215
93 175
79 150
64 120
1¼" 1½"
1050 1600
730 1100
590 860
500 760
440 670
360 545
305 460
250 380
Part number 550-100-026/0404