P-Stop Failure - What Happened?

[Baumgrenze]

During the summer of 2010 we did some remodeling. The contractor installed a new vanity in the master bath. I was tired of the stem leaks and incomplete shutoff I've come to associate with classic rubber washer p-stops when they are needed, so I asked for quarter-turn ball valves.

Tonight, at 9:00 PM, on a Friday night I was disappointed to see water flowing out of the vanity and onto the bathroom floor. I shut off both the hot and cold p-stops but the leak did not stop so I shut off the water at the main shutoff, hunted up my tools, and pulled off the p-stop and replaced it with a 1/2" schedule 40 PVC cap I had in my sometimes denigrated pile of used parts too good to junk. By 9:45 we had the water back on and the leak corralled for the time being. My bride of 52 years was more pleased than my 75-year-old body. I thought I was done in the small corner vanity for a while.

I need analytical help to effect a long term solution. Here is what I could see before I shut off the water. I didn't want to fiddle while it leaked. The leak appeared to be a 'knife-edge" shaped sheet of water coming from the valve. I think it is a decent product. The handle reads BrassCraft quarter turn. Could it be that the Teflon tape on the joint failed? The corrosion I can see in the valve appears greener than copper verdigris. I know that brass has been respecified to eliminate lead. Are we seeing galvanic corrosion as a result of connecting 'new brass' fittings to copper plumbing? Is my wisest course of action to buy a new p-stop and install it or should I try fresh Teflon tape and a reinstallation?

It was the cold water line that failed. Should I be anticipating a failure of the hot line?

Thanks,

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[JerryR]

I replaced all 22 old angle stops in my recently acquired home that was built in 1996. I used Dahl 1/4 turn, compression fiitting stops, as recommended on this site. They are Canadian built with American raw material. Very nice product. Seems better built than the BrassCraft that are sold in the big box stores.
http://www.dahlvalve.com/index.php

 

[Sponsor]

 

[Reach4]

I have not seen the term "P-stop" before.

It sounds as if you have a threaded copper nipple, and the stop valve screwed onto that. Right?

The water was coming from the screw thread area where the stop valve screwed onto the copper nipple? If so, I would suspect that the stop valve was not screwed in tightly enough, and your theory about the corrosion followed by the teflon tape seal failing makes sense. I had to look up "copper verdigris". I haven's seen people discussing that

And you fortunately had a PVC threaded cap that screwed onto the copper nipple after you had unscrewed the valve. That permitted you to turn the water back on for the house.

Is my understanding accurate? I am not a pro.

 

[hj]

What is a "P stop". I do not think I have ever heard that term in my 60+ years in the business. If a thread, which I think you are referring to, is leaking, it is because it did not have the proper thread sealant, (I NEVER use ptfe tape on metal threads), or it was not tightened properly.

 

[Baumgrenze]

Everything is buttoned up and functioning properly. In the clear light of day it was obvious that the 1/2" FPT had split from the end to where it met the 3/8" branch. There was another obvious flaw in the internal threads.

I had an early morning meeting today. I stopped at the local Ace hardware and bought the 'made in China' version of the valve sold by Ace. When I read the replies to the thread I decided to return it and to try a warranty return claim on the BrassCraft. The Big Orange Box took the cracked valve in even exchange for a new one. The clerk would have liked to have the contractor's phone number but processed the claim without it. It would not have been cost effective for anyone but a retired bloke like me.

I was gentle with the installation. I used 2 turns of Teflon tape and an 8" Crescent wrench to tighten, one time around with the wrench after hand tight so that the 3/8" fitting was pointing up.

My 1955 copper plumbing has soldered on 1/2" FIP ells at the ends of the runs. They have ears to screw them down to 2x4 blocks. About 40 years ago, a few years after we bought the house, I systematically removed all the galvanized nipples that had been installed between the copper plumbing and any brass fittings and installed brass nipples. At least one hose-cock came away in my hand as I was finishing the replacements. I had to use a scribe to clean the last bit of iron out of the threads in that hose-cock. There was no pipe left.

I checked with my local 'real plumbing supply,' Barron Park Supply, now being run by the second generation, est. 1963.

www.barronparksupply.com/

Paul sells an average of 30 BrassCraft angle stops a month. They are still made in the USA. He's not seen any returns. His comment on dope vs. tape was that out of 12 plumbers 5 would say use tape, 5 would say use dope, and the last 2 would use both. Finish plumbers who work inside use tape because it is cleaner. It is hard not to get it on your hands and tools and thus on the customer's cabinets and plumbing fixtures.

Somebody in the plumbing community on the San Francisco Peninsula taught me the term p-stop as an alternative to angle-stop. I gave up after a few minutes of Google searching to find a source for the term.

I hope I made the right decision to stick with BrassCraft. There are 2 valves in the master bath and 2 under the kitchen sink. These were all installed by the 'lead' employee on our remodel. He did wiring, plumbing, and carpentry all in a day's work while supervising helpers. A sub-contracted plumber used different angle-stops in a new bath. I can't make out who made them. They have full width tee handles that are ribbed on the outward face.

Thanks for the education.

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