GE 20 kW Home, Installation And Start-Up Manual

22

fuel Pressure

Both LP vapor and natural gas fuel supply pressure at the 
generator’s fuel inlet port should be between the following levels 
at full load with all gas appliances turned on and operating.

 • 

NG is 5-7” W.C.

 • 

LP is 11-14” W.C.

Ensure that all gas line shutoff valves are OPEN and that 
adequate fuel pressure is available whenever automatic 
operation is desired. 

Power Loss

Air density is less at high altitudes, resulting in less available 
engine power. Specifically, engine power will decrease 3.5% 
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 located in 
these conditions must have their transfer switch adjusted 
appropriately for this power decrease. See Automatic 
Transfer Switch manual on how to adjust for the power 
decrease.

fuel Pipe sizing

There are numerous on-line or otherwise-published 
references for fuel pipe sizing. For example, NFPA 54 - 
National Fuel Gas Code, 2006 (Item #: 320-6031-06) is a 
common resource.
The installer should consider the specific gravity of gas 
and compensate for a nominal amount of restriction from 
bends, fittings, etc. If an unusual number of fittings, bends, or 
other restrictions are used, refer to federal and local codes 
for guidance.

fuel factors

An important consideration affecting the entire installation 
is the type of fuel used by your generator. The system was 
factory tested and adjusted using natural gas, but can 
be converted to use LP vapor. For proper engine function, 
factors that are inherent to each of these fuels, your 
location and the duration of possible utility interruptions are 
important considerations in the following fuel guidelines:
 

•  Use clean, dry fuel, free of moisture or any 

particulate material. Using fuels outside the 
following recommended values may cause 
performance problems.

•  In engines set up to run on propane (LP), commercial 

grade HD5 propane with a minimum fuel energy of 
2500 BTUs/ft3 with maximum propylene content of 
5% and butane and heavier gas content of 2.5% and 
minimum propane content of 90% is required.

Natural gas rating will depend on specific fuel but typical 
derates are between 10 to 20% off the LP gas rating.
Natural gas or LP engines are certified to operate on natural 
or liquid propane gas. The emissions control system for this 
engine is EM (Engine Modifications).

WarninG

  Propane and Natural Gas are extremely flammable 

and explosive, which could cause burns, fire or 

explosion resulting in death, serious injury and/or 

property damage.

•  The residential 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.

NOT 

for 

REPRODUCTION