There is only a 4" opening around this valve. Can this repair be done without ripping out the wall and tile around the valve? I am thinking I can't sweat the connection as there is no way to get it fluxed. I hate to call a plumber if they are just going to tear the wall out–I can do that and fix it myself. I am hoping they have some kind of way to fix this through the access hole.

Call an experienced plumber. He'll work through the access and their will be no leaks.

I have fixed this kind of leak by cutting the pipe, tightening the fitting, and then splicing the pipe back together. However, it sounds like you don't have much space to work with. You have to be able to get the pipes apart enough to slip on the splice.

Another suggestion for the future is to verify whether the Delta rough-in valve has an option for a soldered connection. I bought a Delta shower rough-in valve with threaded fittings, and that's what I bought first. However, after looking more carefully at the valve I realized it was designed to have a 1/2" copper pipe slip inside the threaded fitting, which could then be soldered. I was using PEX, so I just soldered PEX adapters into the hot and cold and a fixed copper pipe on top for the shower head. The valve was designed so that you could pull out the guts made of plastic and rubber, and do the soldering with only metal parts to worry about.

Bruce

The best bet is what Bruce in Northern Virginia said:

1. cut the copper pipe using a bare hacksaw blade. Leave at least 2 inches down from the male adapter.

2. tighten the male adapter

3. clean both of the cut pipe ends with emery cloth

4. insert a copper repair coupling - this is different from standard coupling in that it doesn't have a stop in the middle. It allows you to completely slide it over one of the pipe ends. Be sure to clean and flux it first.

5. flux the cut pipe ends and center the repair coupling over the cut.

6. solder

The issue is I simply do not have the room without opening up the wall. This is why I suspect my only option is to call in a plumber (who according to Joseph above) can do this without opening up the wall.

So good luck with that. I've never met a plumber with magical powers.

The next best thing I can think of is to heat the joint while you have an open end wrench on the male adapter to tighten it. Usually though, you risk the solder joint leaking when you try this.

I guess it's better to try it and then open the wall if it doesn't work.

Be sure that you remove the guts from the valve body and also drain the water to something significantly below the joint you are working on. You can't solder a pipe with water in it.

Local plumber at a large company saying he can't do anything without opening up wall (which I can do…) @joseph-corlett, how can a plumber fix that through the 4" access hole?

Is there drywall on the back side of it? Much easier than opening the tile.

This was the rough in during pressure test.

4" hole with Schluter seal. (Large tiles are 12")

Can we see a pic of it with the trim removed as it is now? So we can see exactly how much clearance there is.

Drips about every 5 seconds or so in threads highlighted by arrow. Did NOT leak for at least six weeks. I have a pressure regulator that keep pressure under 60PSI (municipal water supply)

Dumb question, but did you use teflon tape when putting the fitting on?

You are going to have to open this wall. No way to do this otherwise. I'm not seeing teflon tape either - but maybe just can't see it.

Here is what I plan to do: I am going to use a Dremel and remove most of the small tile covering this joint. I will leave enough that the trim plate will still cover the hole. From there, I think I can get a multi-tool in there to cut the 1/2" copper cleanly. Once I am at that point, I can fix the leak. I just hope that gives me enough room to work. I will use a small brazing tip on my big torch to keep the heat only on the joint when sweating it back in. I will not use the 1/2" adapter. I will slip the copper directly into the valve and solder it. I will let you know how this plan works.

Yes, do let us know.

So here are a few obvious tips:

1. Remove the valve body so you don't damage it with the heat from the torch.

2. drain down the water so there isn't water standing in the pipe you are working on.

3. You may have to fashion some cleaning tools and flux brushes to work in the small area.

4. keep a fire extinguisher handy (seriously!) you are working with an open flame inside a wall with wood behind. You might even keep a sledge hammer handy in case you need to open the wall in a hurry.

BTW: What's on the back side of that? I see it's drywall... but if you could open the back side, remove the blocking and remove the mounting screws from the front this would be a piece of cake! It could go back together easy also

Could it be the valve body is cracked?

@Jake… Behind that wall is a 4'x6' mirror glued to the wall over an adjacent bathroom vanity

@Geoffrey… I have seriously considered that. The reason is that this did not even seep a single drop for nearly two months. Suddenly, it is leaking fairly significantly. At this low pressure, these kind of joints (threads) tend to seal from minerals in the water, not start leaking. A cracked valve absolutely makes sense.

I had this happen to me with a compression x FPT union. Under the sink. That union was in there for 3-4 years. The female brass fitting developed a hairline crack.

You are correct - the minerals in the water should seal a thread leak.

OK… I tackled this leak this morning, and appear to have had success. I cut a portion of a tile to gain additional access. I stayed well away from the edge of the trim plate, even staying inside the gasket on the backside of the plate… I cut the copper with a multi-tool and spent considerable time making sure the end was clean and smooth. I had virtually no room to work, but used emery cloth to clean up the end of the pipe and a rolled up piece of sand paper to clean inside the brass housing. (The tiles are 2") I cleaned and fluxed, put 8 layers of aluminum foil behind the joints and soldered them. I let it cool for about 15 minutes and re-assembled the valve. No leaks.

Question: Water has been dripping in this wall for several days. The wall is insulated. How can I get the moisture out of that way to prevent mold?

You've removed the water supply. It will dry before you get mold.

ummm... you didn't do both sides?

If it ain't broke, you don't fix it.

Yes, but in a situation like this, if one side leaks, the probability is high that the other side will leak as well. Actually, from the looks of the last picture, none of those connections used Teflon tape to seal them. So they all should be redone.

if one side leaks, the probability is high that the other side will leak as well

Garbage, misinformation, FUD (fear uncertainty doubt).

I recently ran into a similar problem. The only correct solution that I found in the comments is to call a professional who will do everything himself

As I posted, I fixed it myself and it is still dry nearly two years later.

How long did it take you to fix it?

Maybe 2 hours start to finish. I wanted to be very careful cutting a new tile installation.

I just don’t have time to fix it. When I called the foreman, he said that it was necessary to change the valves ... I had to look for the best industrial valve manufacturer usa. I spent quite a lot of time comparing reviews of different companies (it's a pity that I didn't think of creating a topic on the forum and asking you). Anyway, now I don't have this problem. The only negative is that the accident site dries up for a very long time. Maybe there are some ways to speed it up?

Extra ventilation and/or a Bernz-O-Matic.