Hello, I recently purchased a portable propane powered generator before Hurricane Sandy (I live in NE Maryland) that runs on an LP gas grill tank (Generac LP3250). Just before the storm, I had a plumber install a quick connect line on the side of the house so I could power the generator from my underground 500 gallon tank. It turns out that setup didn't work, the problem we later found is that the generator needed a supply of high pressure LP gas between 30-90 psi. The gas coming out my 500 gal tank flows through a small copper tube, maybe 1/8 diameter or so, at high pressure then into a first stage regulator dropping it to 10psi. It goes underground to the house, than through a second stage regulator before going into the house. We realized our mistake afterwards that the generator was getting low pressure gas from inside the house. I need to come directly off the tank and am trying to figure out the best way to do this. The plumber said he would tee of the high pressure line in the housing well and trench another line underground to the house, then put a quick connect fitting on the outside wall. Seeing as he messed up the first time, I wanted to get an expert opinion to make sure he does this correctly. A couple questions: how deep does the trench / line need to be. I would like to keep it shallow to save labor and will put a warning tape above it when I backfill (I will be the one digging the trench). What type of pipe would you use - I think the plumber said he would use 1/2 copper, which is what the existing line is (the house supply which is a lower pressure). Not sure why the existing pipe before the regulator is so small and if the new pipe should be that size. Any other thoughts would be appreciated.
Underground piping codes vary from state to state. I don't know what yours is. The trench would have to be at least a foot, as far as I know.
I would not recommend using that generator the way you intend for 2 reasons.
1) There are 3 basic pressures when working with propane. Tank pressure (20 psi to 200 psi depending on the temperature), high pressure (10 PSI) and low pressure (1/2 psi).
Your generator runs on tank pressure. The problem with this is it's not meant to be run off anything but a 20 or 30 pound bbq tank attached to the unit. If you run tank pressure from a stationary tank then you run the risk of over pressurizing the generator. You'll likely be violating some gas codes where you can't run tank pressure through gas lines for residential applications.
2) The second problem with what you want to do is that generator will not provide very much power. A 3250 watt generator will run a refrigerator and a few lights. Depending on your heat it may run a blower on a furnace. I wouldn't attempt to run any 240V appliances on it. Rule of thumb is to run it at 80% load (2600w) as anything more could shorten the life of it.
It turns out that setup didn't work, the problem we later found is that the generator needed a supply of high pressure LP gas between 30-90 psi.
Where did you find this out? This unit is designed to run off of 20# or 30# cylinders. The regulator for those tanks is going to supply pressure at 11 w.c. or about 1/2 psi.
I think you have a volume problem. That generator has a big engine and is going to need lots of fuel to supply it. An 1/8 line is not going to do it. The distance and BTU demand of the generator is going to dictate what size you need.
This page has some better info that you may explain it better than myself: Natural Gas Pipe Size Chart and Installation Information.
Does your local propane supplier offer pipe installation services? Might be best to talk to them.
Here is a chart to help you make the determination: IE Information Chart: Gas Piping Sizing for installation of Pressure Washers, Evaporators etc
You will want to use the distance to the furthest appliance to determine which column you work from. You probably need about 20,000 BTU for that generator. What else runs on propane in your home and how many BTUs do those appliances need?
It turns out that setup didn't work, the problem we later found is that the generator needed a supply of high pressure LP gas between 30-90 psi.
That is what Generac has on their website.
That is what Generac has on their website.
Can you point me to where they say that because they say differently here:
Generac Power Systems - LP3250 Portable Propane Generator
You know what. I found this in the QA section. After reading several responses, I question the reliability. Although it could be true.
The one link I posted talks about being able to use the same regulator for both natural gas and propane. This company designs kits to allow the use of propane, natural gas, or gasoline. I would think that the generac comes with the same type of regulator and should be able to handle a lower input psi. Definitely need to learn more about that. No matter what the pressure, I think you will have a problem with 1/8 diameter line supplying it.
The LP3250 unit is designed for use with only a 20 lb. or 30 lb. tank, but can be utilized with a larger tank. To ensure the unit will properly attach to your larger LP tank, we recommend contacting a local plumber, or the propane company that supplied the tank. Generac does not offer a kit or parts to attach to any other tank, but your local plumber will be able to ensure your connections are proper and meet your local code. The regulator inlet pressure from an LP tank should be between 30 and 100 psi. Please note that any damage to the unit due to utilizing a larger tank will not be covered under warranty. 4 months ago
GeneracPowerSystems01
It's in their product Q A section. All kinds of questions about additional fuel connections.
Drooplug, the regulator for grills give a supply pressure of 11wc. If you have a regulator for a turkey fryer it's for 10psi.
Per the generator specs, it is designed to be hooked up directly to a bbq tank. Just as a grill or cooker, the regulator is part of the appliance, in this case the generator.
Tags: underground, propane, line, tank, generator, high pressure, that generator, between 30-90, didn work, didn work problem, didn work problem later
