Black pipe leak or ok?


Old 12-07-12, 04:33 PM
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Black pipe leak or ok?


I have a new 60 foot run on 3/4 inch black pipe I installed for a room addition with a second water heater. I have passed inspection with a 15 psi gauge. It definitely has no perceptible drop at 30 minutes, which is of course why it passed. However, I notice that it dropped about 4 psi over a course of 4 weeks. I still have not hooked it up and still have the gauge on. It has a cap at one end and the gauge at the other. I did a soap test and do not see any bubbles. I repressurized it to 15 psi and it looks like it loses about 0.1-0.2 psi per day. If it really is leaking that slowly, I would guess you would not see a bubble on a soap test. I compared it at the same hour and the temp has been pretty constant.

Do I have anything to be worried about?


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Old 12-07-12, 04:44 PM
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What is this black pipe for?
Old 12-07-12, 05:03 PM
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Gas line for a water heater.
Old 12-07-12, 05:16 PM
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If it held at 15 psi and passed inspection your good to go. NG is like not even a 1/2 psi. What may leak over time at 15 psi will not at 1/2 psi. Thats why they say it needs to only hold for a short time for the inspection at the higher psi.....

Thats how I understand it anyway.
Old 12-07-12, 06:27 PM
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I might be able to help. The pressure drop you are seeing might be caused from the temperature droping.
If temperature drops so would pressure in a pipe that is in static pressure. that means there is no flow and the ends are capped.

Also you might be leaking through the gauge or the gauge connection. Soap test your gauge and connection.

This is just a thought on what you maybe seeing.
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