Help replacing a shut off valve

[TerryinCO]

I tried to replace my basement bathroom shut off valve last night. It's a copper pipe coming out of the wall, not the floor. I got a compression fit shut off valve exactly like the one that I'm replacing. I also used a standard amount of joint compound to help the seal.

I got the new one on, but noticed that there is a small leak. The compression ring seemed to fit nicely when I was installing it. The leak consists of one drip about every 1/2 hour to an hour.

I've read that I can let this go and the drip may eventually stop. So do you think I should monitor it tonight and see what happens or should I just start over from scratch?

If I do start over and replace it again, any suggestions on how to do this easily?

Thanks so much!!!!

[GregO]

If you're using a compression fitting shut-off valve, you don't use sealant tape or dope. With such a slow, small leak, you should be able to fix it by turning the compression nut one more quarter turn. If that doesn't work, you may have to try a new one or even solder on a sweated valve, which is not very hard.

[jimbo]

Actually, I always use a little dope on compression fittings. It serves to lubricate the extreme pressure on the threads and the ring. It also serves an anti-galling function which helps out down the road.

I would not just ignore it and hope it hardens over.

I will try one additional 1/2 turn on a compression fitting to see if it helps.

If the original fitting was overly tightened, you may have a belly in the copper. A new ring just may never work. Also, if the new ring only partially overlaps the position of the old one, it can't bridge the dimple in the copper.

So, try on more turn and then consider sweating in some threaded adapters.