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The manometer port permits temporary installation of a
manometer to ensure that the engine receives the correct
fuel pressure to operate efficiently throughout its operating
range.
NOTE: A digital manometer, P/N 19495, is available at your
local Briggs & Stratton service center.
When the initial test runs are completed, the manometer
is removed and the port is plugged. A typical final fuel
connection assembly is shown here, where (A) is the fuel
supply and (B) goes to the home generator.
Fuel Consumption
Estimated fuel supply requirements at half and full load for
natural gas and LP vapor fuels are shown below.
Fuel Pipe Sizing
The tables below provide the maximum capacity of pipe in
cubic feet of gas per hour for gas pressures of 0.5 psi or
less and a pressure drop of 0.3 in. water column. Specific
gravity of gas is shown.
Listed values compensate for a nominal amount of
restriction from bends, fittings, etc. If an unusual number of
fittings, bends, or other restrictions are used, please refer to
federal and local codes.
B
A
Natural Gas LP Vapor
1/2 Load Full Load 1/2 Load Full Load
80 C 137 C 33 C 56 C
80,000 B 137,000 B 82,500 B 140,000 B
C = Cubic feet per hour
B = BTU’s per hour
NPT 10ft 15ft 20ft 30ft 40ft 50ft 60ft 70ft 80ft 90ft 100ft
1/2” 168 146 115 93 79 70 63 59 55 51 48
3/4” 346 293 240 192 163 145 132 120 113 106 99
1” 653 549 446 360 307 274 250 230 211 197 187
Natural Gas Pipe Size - Gas Flow chart, in cubic feet per hour, specific gravity=0.65
NPT 10ft 15ft 20ft 30ft 40ft 50ft 60ft 70ft 80ft 90ft 100ft
1/2” 110 96 76 61 52 46 42 38 36 33 32
3/4” 277 192 158 126 107 95 87 79 74 69 65
1” 428 360 293 236 202 180 164 151 139 129 123
Liquid Propane (LP) Gas Pipe Size - Gas Flow chart, in cubic feet per hour, specific gravity=1.50