Type Of Fuel To Use; Fuel Conversion; Fuel Pressure; Power Loss - Briggs & Stratton FORTRESS Manual Del Usuario

Type of fuel to use:

An important consideration affecting the entire
installation is the type of fuel to be supplied. The system
was tested and adjusted at the factory using either
natural gas or liquid propane (LP vapor). For proper
engine function, follow these guidelines:
• Use clean, dry fuel, free of moisture or any
particulate material.
• For engines running on propane (LP), use
commercial grade HD5 propane with a minimum
fuel energy of 2500 BTU/ft³ with maximum
propylene content of 5% and butane and heavier
gas content of 2.5% and minimum propane
content of 90%.
• For engine running on natural gas, power output
ratings will depend on the specific fuel but typical
derates are between 10 to 20% off the LP rating.
Using fuels outside the recommended values may
cause performance problems.
WARNING
Propane and Natural Gas are extremely
flammable and explosive, which could cause burns, fire or
explosion resulting in death or serious injury.
• The generator is equipped with an automatic safety
gas "fuel shut-off" valve.
• DO NOT operate the equipment if the "fuel shut-off"
valve is missing or inoperative.

Fuel Conversion

The engine was set at the factory to run on natural gas (NG).
To convert the engine to run on liquid propane (LP Vapor), or
to change back to NG later, follow these steps:
1. Remove the control panel door.
2. Locate fuel selector switch on side of circuit breaker
enclosure.
3. Move the switch (A, below) to LP or NG
4. Reinstall the control panel door.

Fuel Pressure

Both LP vapor and natural gas fuel supply pressure at
the generator fuel inlet port should be 7 - 11 inch WC
(17 - 28 cm WC) at full load and with all gas appliances
turned on and operating. Maximimum pressure drop
from static (engine not running) to full load is 0.5 inch
WC (1.3 mbar). Maximum pressure with engine OFF at
no load is 13.85 inch WC (34.5 mbar).

Power Loss

Air density is less at high altitudes, resulting in less
available engine power. Specifically, engine power will
decrease 3% for each 1,000 feet (300 m) above sea
level and 1% for each 10°F (5.6°C) above 77°F (25°C).
Generators using power management technology must
have the transfer switch programmed appropriately for
this power decrease.
Normal Atmospheric State
Boiling Point (in °F):
Initial
End
Heating Value:
BTU per gallon (Net LHV *)
BTU per gallon (gross **)
Cubic feet (gas)
Density ***
Weight †
Research Octane Number
Motor Octane Number
*
** Gross heat value does not consider heat lost in the
*** Density is given in "Cubic Feet of Gas per Gallon of
†
A

Physical Properties

LHV (Low Heat Value) is the more realistic rating.
form of water during combustion.
Liquid".
Weight is given in "Pounds per Gallon of Liquid".
LP Vapor Natural
Gas
Gas Gas
-44 -259
-44 -259
83,340 63,310
91,547
2,500 1,000
36.39 57.75
4.24 2.65
110+ 110+
97
15