Generac 5500

[ascalco]

I have a Generac generator model 4703-1 installed on my 5th wheel. I used it all night for the first time a few days ago ,we could not find a campground with a vacancy so we stayed in a wal mart  parking lot for the night. It is a propane unit . It would run about 5 hours and then shut down so I thought I had emptied the tank so I switched over to a new tanks and it started right up . It ran about the same amount of time and shut down again ,I assumed I was out of gas so we just got up and got on the road. I stopped to fuel up a couple of hours later and went ahead and started to fill the propane tanks and realized they were half full. Like I said in the beginning I had never used the generator for over night use before so I don't know what's happening . The unit starts and stops fine. Does anyone have any idea why it does not stay running until it runs out of gas ?

 

[Lou Schneider]

A 5500 watt generator is too large to run reliably from a single vertical tank.  It takes heat to vaporize the propane in the tank, if you withdraw too much gas too fast the tank will chill to the point it can't supply the amount of vapor needed to run the generator.  Once the tank warms up it will again supply vapor.

We had the same thing happen with a 10 kW propane generator on a remote mountaintop.  When the utility power died, it would start and run for a while, but extended running would make it die from fuel starvation before the tanks were empty.

Horizontal tanks seem to fare better because they have more surface area for the vapor to boil out of the liquid propane.

One thing you can try is to replumb the tanks so they are in parallel - replace the automatic changeover switch with a tee so both tanks are supplying vapor instead of relying on one at a time.  Talk to a propane jobber about this - they might have another idea or at least will know how to safely parallel the tanks.

 

[ascalco]

  Thanks Lou, that is what I thought might be happening.