Small gas leak or something normal?


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Old 07-04-13, 08:44 AM
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Small gas leak or something normal?

I had found an old thread similar to this but when I tried posting it complained that the thread was over one year old, so I am starting a new post.

I just added a small 3/4" x 20" section of gas pipe to an existing system and after closing all valves and testing with a 5psi guage, found a drop of 2 lines or 2/10s of a pound in a 12 hour span.

I soap sprayed and checked the whole line and all the connections twice and can't find any leaks. Should I spray test again with 15 or 30 pounds pounds of pressure or is this pressure loss normal?

I understand the temperature thing but was wondering if it does drop from the temperature, does it go back up to the 5 pounds? This whole ordeal is driving me crazy.

Thanks for all replies.
 
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Old 07-04-13, 09:09 AM
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When the air heats up the pressure will go up and as it cools it will go down. 2/10's of a pound in how much pipe ? Must be more than 20".
 
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Old 07-04-13, 09:22 AM
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When the air heats up the pressure will go up and as it cools it will go down. 2/10's of a pound in how much pipe ? Must be more than 20".
20" is the piece I added, the whole pipe I tested must be maybe 30' with several connections, maybe more than that.
 
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Old 07-04-13, 10:56 AM
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When you note the system pressure also note the temperature. Then after 12 or 24 hours check the pressure again when the temperature is the same. This will help minimize any pressure fluctuations due to temperature.
 
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Old 07-04-13, 11:15 AM
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When you note the system pressure also note the temperature. Then after 12 or 24 hours check the pressure again when the temperature is the same. This will help minimize any pressure fluctuations due to temperature.

Maybe testing when there is minimal temperature change like at night is best?
 
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Old 07-04-13, 11:39 AM
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Many jurisdictions only want you to hold the pressure for fifteen minutes. When I did the gas piping at my parent's home I used a 5 psi gauge and pumped up to 3 psi in the afternoon. The inspector came by the next day and it had dropped to about 2.5-2.7 psi and (according to my dad) he then pushed the pin on the Schrader valve to release enough pressure to show that the gauge wasn't stuck and that was it.
 
 

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