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LP Gas Line

35K views 22 replies 5 participants last post by  loyal 
#1 ·
My home uses LP gas supplied from a 300 gallon tank
outside the house. The gas line from the tank to the house
is 1/2 inch soft copper tubing buried to a depth of about
6 to 8 inches. I really don't think that is deep enough.
Also, I'm thinking of replacing the old hot water
heater with a tankless LP gas model. I've heard
that the gas lines must be larger for the tankless.
Can I replace the 1/2 inch copper line with a larger diameter
new type flexible gas line that I see in the in Menards
and HD stores? I think that it should be buried deeper too.
 
#12 ·
I noticed that the 1/2 inch copper tubing that is connected at the LP tank
regulator, is a flared fitting. If I connect 3/4 inch copper to the regulator instead of 1/2 inch copper, does it still have to be a flared fitting?
Are flared fittings the best way to go for gas lines?
 
#14 ·
Here in PA, gas line must be 18 inches, as far as your tankless heater, the btu's can run up to around 200,000. Since your heating your house with a 300 gallon tank and you say you're running 1/2 inch copper, I assume you have a 2 stage system(10 psi regulator(usually red) on the tank and a 1/2psi(11-14 inch water collumn, usually brown) regulator at the house. If so, the half inch copper will work but some repiping may need to be done inside. Here in PA, only flared or brazed connections are allowed, no compression or sweat fittings. A homeowner can run their own lines here but the LP gas supplier must be notified to perform a pressure test before filling the tank. Hope this helps
 
#15 ·
Yes thanks for the reply Bill.

You are exactly right. Red regulator on tank. Brown at house.
If I understand you correctly, the 1/2 inch copper outside is OK.
And I just need to increase the diameter of the black pipe inside the house
from the outside brown regulator to the on demand LP water heater.
I plan to get the smaller heater. There is only the wife and I and
we only have one bathroom. The black pipe inside the house now
is 3/4 inch all the way to where the water heater would be mounted.
which is only a few feet inside the basement from the outside brown
regulator.
 
#17 ·
Thanks for reply Bill.

The tank is exactly 25 feet from the house.
But I think I gave you the wrong size for the
soft copper pipe which runs from the tank regulator to the
house regulator. I thought it was 1/2 inch diameter copper.
But I just put an old flaring tool around the pipe.
It's actually only 3/8 inch diameter soft copper.
Sorry about that Bill. Will the smaller size copper be
a problem?
 
#19 ·
Gas Range, four burners @ 8500 each. Oven 15500.
Gas boiler, 133000 input.
Gas water heater, 36000 input.
Gas dryer, 22000 input.

Found all these ratings on the nameplates.

I added them all together and got 240,500 btuh.
340,000
-240,500
________
99,500

Looks like the 3/8 inch copper has to change to 1/2 inch.
Would that do the trick?
 
#20 ·
yeah, you're gonna have to switch to 1/2... that will give you 800,000 btu, more than enough, try to dig it to 18 inches if you can... Ive been out on enough service calls where the line wasn't buried deep enough and someone, usually a landscaper, hit it with a pickaxe, trencher, sod stripper etc, and since the code prohibits burying splices in copper, the whole line needed to be replaced. When you're done, check for leaks with a soap solution, then have you're LP supplier do a pressure test if you want to be certain. Small leaks outside rarely present a problem but anything on the inside you definately want to be tight. A pressure test will show a leak that may be to small to be noticed with soap bubbles.
 
#21 ·
Thank you Bill!

I'll first try to find out if I'm allowed to run the new line myself.
If I can, then I will definitely have the pressure test done.
It's the people like yourself Bill, that keep me think'in there
might be something worth save'in.

Thanks again Bill,

I'll let you know what happens.
 
#23 ·
Hope your still around Bill.
I found out that around here the LP supplier
gets very upset when someone trenches in
their own line.
But it is my responsibility to have the
in- house pipe taken care of.
I'm sure that you already know all this.
My question is: How much pipe needs to be stubbed
outside for the gas company to connect to?
Should there be a union or anything else on the pipe that stubs outside?
Are there any rules as to height above grade or distance from
basement window or any window or door?
Guess that's more than one question. Sorry:)
 
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