Dumb question(s) time. I have just run new hot and cold water lines for a new vanity. I have stubbed them out fo the eventual installation lf 1/2" compression 1/4 turm shut-off valves. My question is how can I test that branch for leaks when the water won't get there until I cut the sealed ends off and install the valves? The whole purpose is for rough-in and ease of drywall installation correct? can I cut the ends, install the valves, open the lines and test, remove the valnes and re-seal the stubs until the final install? How many times can you re-use the compression fittings in the valves? Are they single use, do they degrade with repeated re-use? Or can you take them on and off as much as you like?

Thanks. Happy Memorial Day and my thanks to all the vets and service folks today.

darrel1953

If the water is on to those lines, then you are already testing them. Is it? When you say stub out do you mean you stubbed out with a bullet or just open pieces of pipe? As to whether you can use the compression stops over again it really depends on the pipe you used. If it is thin wall or m, I wouldn't do it, if it is L then I probably would but I've done it a hundred times before and I have a good feel for it. When I test with it I just go about 1 full turn with the wrenches after I have it hand tight. After the test I usually go a little tighter. You dont want to crush the pipe and you don't want to have it too loose. At 5 bucks a pop you might want to just go with a new pair. To tell you the truth I like the threaded adapters better. You have your flexibility to use threaded caps to do your testing. But I understand if you are weary of soldering so close to the new wall. Hope that helps.
Darrel

nervous

Yes, the water is on and no leaks. I was just unsure if the water would displace the air in a capped off line. The only reason I even ask this is that when making the water hammer extensions I was under the impression that he air that remains in that extension does the job. Therefore the water does not displace that air. Stubbed for me means a cap soldered to the end of the pipe that will eventually receive the vanity shut-offs. Additionally, I had always used threaded connections in the past but have chosen compresion for their ease of shutoff orientation which is unsure for me with threaded connections when fully tightened. The prior threads have given the compression connections the 2 thumbs up so that nuged me to them. Also, I am using the thicker walled copper pipe and always do. Looks like I am in pretty good shape here so far. Thanks for the useful reply.

Herb.