Table of Contents
Advertisement
Section 1 — Installation
Guardian Air-cooled Generators
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 tamper-proof dual fuel sys-
tems. The unit will run on natural gas or LP gas, but it
has been factory set to run on natural gas. Should the
primary fuel need to be changed to LP gas, the fuel sys-
tem needs to be reconfigured. See Section 1.6.4 (Page
6) for instructions on reconfiguration of the fuel system.
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 (*)
1/2 Load Full Load 1/2 Load
6 kW
74.1
105.3
8 kW
79.7
140.0
10 kW
100.8
177.9
Sound Attn. 84.6
126.6
**LP is in gallons per hour/cubic feet per hour.
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.
6
Generac
®
Power Systems, Inc.
LP Vapor (**)
Full Load
0.86/31.30 1.08/39.30
1.07/38.94 1.56/56.77
1.16/42.21 2.15/78.24
1.06/38.57 1.7/61.86
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
½"
¾"
15'
76
172
30'
52
120
45'
43
99
60'
38
86
75'
77
90'
70
105
65
120
150
180
210
240
270
Consumption in
300
Cubic Feet Per Hour
450
600
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).
2. Remove the blanking plug from the LP port of the
load block (Figure 1.2).
Figure 1.2 – Natural Gas Setup`
Iron Pipe Size (IPS Inches)
1"
1 ¼"
1 ½"
345
750
1,220
241
535
850
199
435
700
173
380
610
155
345
545
141
310
490
131
285
450
120
270
420
109
242
380
100
225
350
92
205
320
190
300
178
285
170
270
140
226
119
192
2"
2,480
1,780
1,475
1,290
1,120
1,000
920
860
780
720
660
620
580
545
450
390
Hide quick links:
Advertisement
Table of Contents
