The answer depends upon how long you would like the generator to run continuously in a power outage. The 14kW Guardian Series consumes 2.30 gal/hr of liquid propane at full load. At that rate, you will have a little over 43 hours of continuous running time before your are out of fuel. You should size your propane fuel supply based upon how long you would want the generator to run in a power outage.
The only running requirements regarding LP fuel are regarding fuel pressure. At the generator inlet, fuel pressure must be 10 - 12" of water column for the generator to operate properly.
For additional fuel consumption information, please see the product spec sheet at http://www.generac.com/SpecSheets/0...
answered 4 years, 2 months ago