Ran a new gas line, installed a gas pressure gauge and pumped it up to 15 psi. Came back 2 hours later and it had the pressure had dropped a 1/2psi. 24 hrs later it was down to 9psi. It holds at 15psi for at least 15 minutes. I sprayed all the joints with leak detector liquid, and no bubbles. Is this drop off normal, or do I have a leak?
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Replies
Are you sure the gauge doesn't leak?
Something is leaking.
15 pounds?
Gas pressure is measured in ounces unless you are installing a high pressure main.
You need 8 oz. of pressure to hold fo 24 hours.
Call you gas company. they will test it for you.
Gas Test
I don't know where you are from but I've rarely seen where the inspector will have you test a gas line in ounces.
Getting the gas company to do your test is another thing that dosen't happen in the area I'm familar with.
Gas lines
I work for a utility company . We provide both gas and electric service in our area. We operate and maintain an extensive sytem of gas mains, substations, storage, pumping and distribution lines for natural gas.
Break the seal on one of our gas meters and do you own work if you want to. Your gas will be shut off imediately upon the detection of you violation. It will not be turned back on untill our inspector varifies that you work passes our test and meets our requirements for a safe installation.
We are a regulated industry and held accountable for public safety as well as service to our customers.
You want to play with things that can go BOOM, go ahead.
Me I call and get it tested by a trained and certified professional.
Gas Test
You didn't tell me where you are located, I'm located in the N.E. in the area I'm familiar with the utility is responsible for the gas up to the valve or connection for the dwelling, from that point on the gas fitter is responsible for running the lines and testing HIS work, he then calls the inspector and has it inspected, the inspector is the one that tells him what pressure he requires for the test, I don't know where the ulility will test the private part of your line.
I have never seen a test thats in the 8 ounce range, they run between 3lb. and 100lbs.
....Break the seal on one of our gas meters and do you own work if you want to. Your gas will be shut off imediately upon the detection of you violation....
We also have a seal on the UTILITY side of the gas line but on the house or dwelling side there isn't one and a licensed gas fitter can work from that side; he can't break the seal on the UTILITY side
BTW I am a licensed professional, 45+ years
The drop to 9# in 24 hrs. is a leak you should be able to detect with a bubble test.
The leak very often is from the test gauge itself, so be sure to soap that as well.
Your inspector may pass the system if it holds 15 # for 15 min. if that's the standard test for your jurisdiction and/or utility supplier, but a tight system will hold 15# for days with a possible slight fluctuation, up or down, depending on temperature changes. By "slight change", I mean 1 or 2 pounds.
So I checked the pressure test valve by removing it and installing it on a nipple with a cap. I pumped it up to 15lbs, and sure enough after about an hour the pressure dropped. I checked the 3 joints with leak detector and no bubbles. The gas pressure valve leaks, albeit, extremely slowly. Several people mentioned this possiblity, I would like to thank those people for saving me a lot of hassle, and time.
Not sure if it just this valve that leaks, or gas pressure valves in general leak just because of the way they are designed. Would like to know the answer to this question. Thanks again to everyone that took the time to respond to this post.
By "pressure valve", I think
By "pressure valve", I think you mean the test gauge. And, although they are notorious for leaking, that's probably because they get re-used over and over, and get banged around in tool boxes. I have seen gas systems, including the test gauge, holding test pressure for 2 weeks or more with no loss.