How to test for leaks in this situation

[Opifex]

Hello all. As you can see from the picture below, I installed some new Pex plumbing for a double vanity. I only have the hot water line finished at the moment. I can see the water filling the tubing and moving past some of the fittings, so I've confirmed there are no leaks thus far. But the water level won't get high enough to reach the two copper stub-outs, and I assume I'll have the same situation once I have the cold water line finished.

So my question is, how do I test for leaks before putting the drywall back on? For my water shutoff valves, I had planned on using standard brass compression fittings. How does one normally test for leaks in a situation like mine? Do I have to purchase shutoff valves that can be easily taken on and off?

Thanks much for the help!

 

[Reach4]

If the water only goes part way up the pex below the stubouts, then the upper part is filled with compressed air. Air would leak even easier than water. So you have no leaks.

That last connection could be hard, unless you have enough clearance for the hole in the sill plate.

What is below that tee now, a wad of tape or something to prevent the pipe thru the sill plate from falling thru?

 

[Sponsor]

 

[Opifex]

Ahh, I see what you're saying, I think. Are you saying that if there was no compressed air at the stubout, then the water would proceed all the way to the stubout?

Below the tee is the cold water line, capped. I'm heading into the crawlspace now to begin the upgrade. I did the hot water line a few weeks ago....

Wish me luck!

 

[Reach4]

Below the tee is the cold water line, capped. I'm heading into the crawlspace now to begin the upgrade. I did the hot water line a few weeks ago....

I presume there is plenty of slack. I am picturing you pulling the pipe up, cutting the plug off, putting an expansion ring on the pipe, holding the expansion a bit longer than usual, and quickly pushing the pipe toward the crawlspace, and then lifting the ring onto the waiting tee.

A helper below could push upon command to let you not have to have as good of a grip.

A situation like this would be easier with a clamp ring, because you don't have the short time limit between expansion, and insertion.