Natural Gas Pressure Test - Relief Valve Causing Problems


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Old 11-10-13, 03:11 PM
J
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Natural Gas Pressure Test - Relief Valve Causing Problems

Hi all, I had to add a leg to my natural gas piping for my new gas dryer. Pretty straight forward job since the laundry room is adjacent to where my gas line is for the water heater and furnace. Basically just a tee and short (2 ft) run into the laundry room.

I also added a tee with a plug in the line which will be used for pressure testing, since there wasn't one outside by the meter...I thought that was weird that it didn't exist already.

After I finished up I installed the 15 psi gauge for pressure testing. Surprisingly I could only pump up to about 1.25 psi before I heard air escaping. I discovered the air was flowing out the vent on the pressure regulator that is upstream of the meter. Maybe a pressure relief valve?

I'm not sure how to apply the test pressure now. The system has been holding the 1.25 psi for about an hour with no change...but that pressure isn't technically good enough for a true test.

Any thoughts?
 
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Old 11-11-13, 12:15 AM
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The new piping needs to be tested before connecting to the meter. What you are doing is pressurizing the old and new piping along with the meter and back to the pressure regulator. I hope that you turned off all the manual isolation valves at all the appliances before testing as many of the automatic valves will be damaged if they "see" more than 1/2 psi of pressure on the inlet.
 
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Old 11-11-13, 08:11 AM
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Thanks for the reply. Yes, all the isolation valves were turned off...I've heard about damaging appliances like you say so I knew better.

It seems like everything I've read about pressure testing has the same procedure: turn off main valve at meter and pressurize entire system from wherever a plug exists. There was no mention of any regulators getting in the way; maybe the gas shutoff valve is downstream from the regulators (unlike mine which is upstream). If the shutoff is downstream, then there wouldn't be any problems with pressure testing.

I'm not sure how you would be able to test just the new piping alone. At least in my area, you are only allowed to use unions at the meter and at any appliance location (downstream of isolation valve). Since the new piping has to be assembled in order (rather than installing an entire assembly), you won't be able to disconnect the entire new section at once. Also, wouldn't you want to pressure test the entire system? What about that one joint between the old and new piping that would never be tested (assuming you can isolate the two)?

I think in my case the only remedy would be to install another shutoff valve at the meter, anywhere downstream of the regulator. This would allow me to get the regulator out of the system. That, or remove the meter completely (two union joints) and install a temporary plug on the pipe leading into the house...this will isolate the system in the house.

For now, the gas in on. I went around with soapy water several times on all my new joints and everything looked good. I'm not planning on having this small job inspected, but in the future I may run a longer line into my crawlspace and up into the kitchen for a gas range; in that case I will have it inspected...makes me wonder how I'm suppose to pressure test it for the inspector with my current situation.

Thanks again!
 
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Old 11-11-13, 01:14 PM
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That, or remove the meter completely (two union joints) and install a temporary plug on the pipe leading into the house...this will isolate the system in the house.
This is the correct method. Be sure to wire brush all the old joint compound out of the pipe threads an use new compound, I prefer either Rectorseal #5 or else a Teflon paste listed for use with natural gas. I do NOT use Teflon tape on fuel gas piping.

Yes, this does mean that the joint of the meter union coupling and the beginning of the house piping does not get pressure tested so be sure that you use a bubble solution to test after turning the gas back on.
 
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Old 11-11-13, 05:27 PM
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This is the correct method. Be sure to wire brush all the old joint compound out of the pipe threads an use new compound, I prefer either Rectorseal #5 or else a Teflon paste listed for use with natural gas. I do NOT use Teflon tape on fuel gas piping.
Thanks, good to know. I'll have to go find some hardware to make a plug on the union. I have Rectorseal #5...good stuff. Didn't even think about using teflon tape since I've read about other people not liking it much.

Yes, this does mean that the joint of the meter union coupling and the beginning of the house piping does not get pressure tested so be sure that you use a bubble solution to test after turning the gas back on.
I understand that the union coupling will have to be tested afterwards with the bubble solution, but what do you mean "beginning of the house piping"? Everything downstream of the union coupling is pressure tested, including the piping going into the house, right?

Does it matter (code-wise) where the location of the plug is that you plug in your pressure gauge to pressurize the system? Should it be located outside near the meter or can it be anywhere in the system? Or I guess it can be plugged into some sort of adapter at the meter union coupling...

Thanks again!
 
 

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