Male copper adapter to shower valve slight drip?

I have redone this connection 2X but still have the slightest of drips on the hot water side only. So slight that the water drop will stay suspended for hours.

The connection is 1/2 copper to 1/2" x 3/4" male copper adapter into a new Moen shower mixer (hot water side). All soldered joints are stable and dry.

The adapter was sealed with tape, 3 wraps the first time and tightened well.

2nd time, a new adapter was wraped, 5 wraps with tape and seriously torqued into the valve. Still has the slightest of drips.

Should a re-do it again? What should I do different? Will this drip seal up on its own? I have no rear wall access available if future problems develop. The new CBU is installed - no tile yet.

First, make sure the thing isn't split. It could be a bad casting, and there's a small pore that's weaping. If the thing is not defective, then put some pipe dope on the teflon tape, and put it back together. If you bought the adapter from a big box store, it was probably made in China. The quality of their adapters leaves a lot to be desired, and the threads probably look like they were torn rather than cut, so unless you can fill it with the pipe dope, there'll be a little leak. Sometimes, it's worth it to pay a little more and get some decent stuff at a plumbing supply house. Course, it's not as convenient, since they're not open any where near as many hours or days...

The industry specification for tapered pipe threads is two wraps of tape, tighten fitting by hand, and then 1 to 2 turns by wrench. There are tables which show the lenth of engaged threads on a proper joint, but these are not completely reliable since threads rarely actually meet specs.

Bottom line, you used too much tape, and probably overtightened the fitting. At this point, try a new fitting, use one wrap of tape PLUS some pipe joint compound. If that doesn't work, you may have damaged the valve.

Thanks,

I will also check in with Moen prior to breaking it down again. I did the other (2) connections the same way with on issues, but really went over the top with the hot side after the first drip episode and used more tape / torque the second time.

Some of the Chinese fittings are not up to spec, so 5-wraps may not create problems if you got enough threads engaged. But, since it didn't seal, go back to the norm, and add the pipe dope as suggested. Hopefully, you don't have a defective valve or split it in the process.

I don't normaly recomend this but put a very thin coat of pipe dope in the female end B4 assembling. Is the male adp. bottoming out? If yes the jadnashua has it right about it being split. You may want to consider replacing the male adp. B4 doing this again.

I always disassemble the valve, pipe dope the male adapter, and wrap the valve body and as much of the male adapter threads as possible with a wet rag. I found that when heating the fitting to solder the joint the fitting and the valve body expand at different rates, copper to brass, and a weeping leak can result. The wet rag acting as a heatsink will prevent over expansion of both joints.

tighten the adapter

before you get into this too deeply

if you can shut off the water and drain the system down

just try heating the male adapter till the solder

melts, then while its all nice and hot, take a pair of channel lock pliers and simply

snug up that fitting into the joint a turn or two and then re-solder it....

you will probably win......



I have gotten away with murder like this before....