Ya need gas to run. Who knew?

[fuelfarmer]

We have a profane (propane) powered generator on the farm. It has a four cylinder Ford that screams 3600 RPM. I had to fire the thing up a few days ago and it was running just fine. About 1 hour later I found it sputtering at about 1/2 speed. If I grabed the mechanical governor that was slammed wide open and held it partly closed the engine would seem to run OK. As soon as I let go the governor would open wide open and the engine would sputter and lose speed.

So I called someone that works on gensets full time and told him to come fix the generator. He started the unit up and the said you might want to check the gas tank. WELL DUH, I should have thought of that. In my defense, I am not that smart, and most of the engines that I run, stop dead when out of fuel. And how could a 500 gallon tank ever be  empty?  To answer my own question, a freak wind storm and 6 days without power last year.

[TimSR2]

Yep. propane powered engines run at reduced power for a long time after the liquid in the tank runs out. I once made it 10 km, just crawling and coasting to make it to a filling station. It was mostly downhill, but still... it's a bit different!

[LowGear]

I call this "If weren't so damn funny I'd cry." situations.  I'm pretty sure we've all swam this stream.

Thanks for the heads up on Propane.  I'd imagine natural gas powered engines enjoy the same slow road to sleep.

I have some friends that have a propane heater and cook stove.  The contractor recommended electricity for water heating as it wasn't to code to put the two in the same room.  How much can a 36 inch partition cost when projected against the costs of electric water heaters?  Now that same person is trying to sell them on a gasoline backup generator rather than plumbing into the propane tank.  Am I having a bad hair day or does this setting rant for at least a bi-fuel generator?  I forgot to mention that those 50 and 100 years storms can fill their crawl space if the sump pumps fail and those same storms often turn the power off for a day or two.

Outside of forgetting to fill the tank on the propane powered units are there any other problems that I'm ignorant about?

Casey

[fuelfarmer]

Propane would be my fuel of choice for long term storage and ease of use. A tank big enough to last a week or more would be the minimum. The only down side I see is it is not easy to grab few jugs and beg ,barrow, or steal fuel if an outage lasts way past normal.

On the other hand, I like diesel gensets because we grow some fuel and it is easy to move fuel.

[mike90045]

.....

Outside of forgetting to fill the tank on the propane powered units are there any other problems that I'm ignorant about?

Casey

Cold.  Bone chilling Cold, cold, cold.  So cold the propane sits as a puddle in the bottom of the tank, and you have no vapor pressure,  around -20F, you still can maybe get 11" of vapor pressure, but below that, the regulators don't have enough pressure o work.

[Henry W]

Hi fuelfarmer,
If your LP system is plumbed to draw LP vapor from the tank than I see the problem. Is your system set up to draw LP liquid from the tank? The reason I am asking this is an engine such as a Ford four cylinder LRG425 will draw large amounts of LP to run properly. In simple terms this is what happens. When drawing vapor from a tank to operate such an engine the LP and tank will start cooling down to the point that the required LP that is required to run the engine properly cannot vaporize out of the tank and the end result is fuel starvation. I seen tanks about half full and customers complaining that they are out of LP.

If this is the case the proper way to correct this problem is have the system set up to draw liquid from the LP tank, install a converter regulator, plumb the engines heating/bypass cooling lines to the converter regulator. This setup will prevent LP cooling/icing and just about all the LP from the tank should be available to operate the engine.

WARNING!!!  Do not attempt to tap into the LP tank by yourself. Please have your LP company handle this. Chances are the LP company will replace the tank with one set up to draw liquid for your generator, and if needed, vapor for household appliances. There are different avenues the LP company can handle this. They might just install a separate tank just for your generator.

Make sure the LP lines and converter regulator are sized and installed properly. You might need this performed by a licensed technician.

Henry

[LowGear]

Hi Mike,

You know when you live in Aloha-land you forget about the realities of the temperate zones.  This installation is on South Puget Sound, Washington, USA where 0 Celsius is pretty cold.  I'm still on the mission to save these friends.

Almost on thread subject:
     If you install a 15 KW system instead of a 7.5 KW system but rarely use more than 5 KW how much more fuel would you expect to use in the course of 24 hours to maintain that 7.5 KW reserve?  I assume propane would be about the same as gasoline or diesel? 

Casey

Casey