Section 1 — Installation
Guardian
With LP gas, use only the vapor withdrawal system. This type of system uses the vapors formed above the liq- uid fuel in the storage tank.
The engine has been fitted with a fuel carburetion sys- tem that meets the specifications of the 1997 California Air Resources Board for
Recommended fuels should have a Btu content of at least 1,000 Btus per cubic foot for natural gas; or at least 2,520 Btus per cubic foot for LP gas. Ask your fuel supplier for the Btu content of your fuel.
Fuel pressure for both natural gas and liquid propane (LP) vapor set ups MUST be 11 inches to 14 inches of water column (0.6 psi) at all load ranges.
◆1.6.2 FUEL CONSUMPTION
See the following chart for fuel supply requirements at half and full load for both natural gas and LP vapor.
*Natural gas is in cubic feet per hour.
Model # | Nat. Gas (*) | LP Vapor (**) | ||
| 1/2 Load | Full Load | 1/2 Load | Full Load |
6 kW | 74.1 | 105.3 | 0.86/31.30 | 1.08/39.30 |
8 kW | 79.7 | 140.0 | 1.07/38.94 | 1.56/56.77 |
10 kW | 100.8 | 177.9 | 1.16/42.21 | 2.15/78.24 |
Sound Attn. | 84.6 | 126.6 | 1.06/38.57 | 1.7/61.86 |
|
|
|
|
|
**LP is in gallons per hour/cubic feet per hour.
◆1.6.3 FUEL PIPE SIZING
See the following chart for proper sizing of fuel supply piping. Insufficient fuel pipe size can cause hard start- ing, poor engine performance and inability to carry load.
NG and LP Vapor Pipe Sizing Chart:
Length of Pipe |
|
|
| Iron Pipe Size (IPS Inches) |
| |||
| ½" |
| ¾" |
| 1" | 1 ¼" | 1 ½" | 2" |
15' | 76 |
| 172 |
| 345 | 750 | 1,220 | 2,480 |
30' | 52 |
| 120 |
| 241 | 535 | 850 | 1,780 |
45' | 43 |
| 99 |
| 199 | 435 | 700 | 1,475 |
60' | 38 |
| 86 |
| 173 | 380 | 610 | 1,290 |
75' |
|
| 77 |
| 155 | 345 | 545 | 1,120 |
90' |
|
| 70 |
| 141 | 310 | 490 | 1,000 |
105 |
|
| 65 |
| 131 | 285 | 450 | 920 |
120 |
|
|
|
| 120 | 270 | 420 | 860 |
150 |
|
|
|
| 109 | 242 | 380 | 780 |
180 |
|
|
|
| 100 | 225 | 350 | 720 |
210 |
|
|
|
| 92 | 205 | 320 | 660 |
240 |
|
|
|
|
| 190 | 300 | 620 |
270 |
|
|
|
|
| 178 | 285 | 580 |
| Consumption in | |||||||
300 |
| 170 | 270 | 545 | ||||
450 | Cubic Feet Per Hour | 140 | 226 | 450 | ||||
600 |
|
|
|
|
| 119 | 192 | 390 |
◆1.6.4 RECONFIGURING THE FUEL SYSTEM
To reconfigure the fuel system from NG to LP, follow these steps:
1.Remove the carburetor fuel hose from the natural gas port of the fuel load block and the brass fit- ting (Figure 1.2).
Gaseous fuels such as natural gas and liquid propane (LP) gas are highly explosive. Even the slightest spark can ignite such fuels and cause an explosion. No leakage of fuel is permitted. Natural gas, which is lighter than air, tends to collect in high areas. LP gas is heavier than air and tends to settle in low areas.
2.Remove the blanking plug from the LP port of the load block (Figure 1.2).
Figure 1.2 – Natural Gas Setup`
6 Generac® Power Systems, Inc.