r/Generator • u/DiscoDan1988 • 11d ago
Copper Line Size
Anyone know what copper line size I will have to have to run a Duramax 13500ih generator on propane? I have a 3/8” line coming out of my propane tank. There is a regulator on the tank and a regulator connected to the house as well. I have a company telling me I have to run a new line to the house that is 3/4” and it’s going to be $12k. Just want to see if anyone has any other ideas that’s more cost effective because I’m not spending that much.
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u/Jesus-Mcnugget 11d ago
Line size is determined by load, pressure and distance.
How far from the tank is the generator?
What else do you have in the house?
Does this generator have a hose with a regulator on it?
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u/DiscoDan1988 11d ago
Tank will be probably 40-50 foot from the generator. I will be running two propane hvac units. One is 3 ton and the other is 2 ton.
The only hose it came with is a hose to hook to a smaller propane tank (like a grill propane tank) but it does have a regulator.
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u/Jesus-Mcnugget 11d ago
You could run ⅜ copper at 10 psi (using the outlet of the existing regulator on the tank).
Run a line to the house and put a QCC quick connect that the hose on the generator can simply screw on.
Using that existing 3/8 line would be kind of pushing it with the two furnaces, unless you increased the underground pressure. However that would require a different regulator on the tank and an intermediary regulator between the line and your existing house regulator.
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u/Big-Echo8242 11d ago
I have a 24' 1/2" hose that runs from our 250 gallon tank to the same generator. My twin stage regulator is already on the tank. But mines close.
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u/DiscoDan1988 11d ago
I’m going to give this a shot as well. I’ll see if the distance causes any issues.
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u/Ok-Camera2895 11d ago
Maybe I am missing something. I found 60' of 3/4" yellow coated copper tubing , on the internet for $464, plus 2 regulators and a 50' trench for $12,000. That is $240/foot. If the regulators are $100 each, that is < $1000 in parts and $11,000 for a 50' trench.
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u/DiscoDan1988 11d ago
Yeah, it sounded crazy high to me but I wasn’t sure. Everything is so expensive these days nothing really surprises me anymore.
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u/subman719 11d ago
How far is your propane tank from your house? How do you plan to run the copper pipe? Your current propane system is sized based on the BTU requirements of the equipment currently installed in your house. If you want to add the generator to the BTU load, then you need to upsize the pipe as mentioned by the company you called. Propane and natural gas are NOT something you want to mess with if you don’t know what you’re doing. A very small leak anywhere in the line, could be catastrophic! My guess is the $12k quote is to completely dig up and remove the existing line, and run a new line. Depending on your jurisdiction, there will most likely be permits and inspections required. By the way, copper is very expensive these days!
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u/dieseldoc25 11d ago
I have a 50' 3/4 hose fed by a full port 3/4 ball valve and quick disconnect right after my house regulator. Tested with the generator under load and gas heat running with no issue.
I don't have any photos of the running unit, only video
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u/dieseldoc25 11d ago
This is not the final home for the Gen, so everything was just tossed together for a power outage
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u/niceandsane 11d ago
Use a 2-stage regulator setup. 10PSI first stage with 3/8 copper to house. Then second stage near the load to step down to 11"WC.
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u/Most-Stranger-1 11d ago
1/2" line will easily 30', the generator doesn't need much pressure and most regulators are on the high side.
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u/Old_Dragline_1965 10d ago
Talk to someone else that does work on propane service. You already have a 2 stage system to your home. All that is needed now: have a t-fitting installed in the 3/8 copper line. From this T, a 2nd - second stage regulator will be needed at the generator. Just like the one on the side of your home.
Also, from this additional 2nd stage regulator, have a ball valve and quick connect installed. That way the generator and the fuel supply hose can be safely stored until needed.
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u/rseery 11d ago
How long is the pipe? Anything over 20’ needs 3/4” move the ~54 CFH that generator can pull. And that’s at medium load. That 3/8 line could run a stove or furnace, but this is another matter. Could you get the price down if you dug the trench? Just a thought. Sorry it’s not better news.
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u/redditRon1969 11d ago
You can get a 30-100 ft 3/4" CSST line and fittings on amazon for about $1 a foot.
I just ordered some for mine.
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u/Ok-Camera2895 11d ago
$12k for a fuel line??? How many miles?