Plumbing Question for Plumber -- Plz

Hi,
I recently tackled my own project of replacing a hot water heater with a new one (electric). The heater used 3/4" copper pipe. I had no problems except with a new water gate valve on the inlet side. I replaced the old with an exact new one but now I have a leak that drips one drop of water about every two minutes.
Question:
1.    Should these gate valves be dissembled prior to soldering so the heat won't affect the o-rings inside ? Mine is leaking at the solder connection, not from the top or the valve stem, but I wouldn't want to chance damaging the o-rings.
2.    Should I try heating the fitting up again and apply more solder to stop this very tiny leak or just cut it out and install another new one ?
3.    I used the proper soldering techniques (cleaning, flux, dry pipes, etc.) but any pointers will be appreciated. This fitting was the only problem I had.
Thanks very much in advance.
Joey
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Joey wrote:

Joey-
heat won't affect the o-rings inside ? Mine is leaking at the solder connection, not from the top or the valve stem, but I wouldn't want to chance damaging the o-rings.<<<<<<
Yes, disassemble but gate valves do not generally have O-rings just stem packing.
2. Should I try heating the fitting up again and apply more solder to stop this very tiny leak or just cut it out and install another new one ?
No, at this point you're SOL. MAYBE you can do a reheat & resolder but it's not the right way to fix it. You need to get the water away from the joint, you will not be able to get the joint up to heat with water in it. You need to get back to clean fluxed joint & start over.
3. I used the proper soldering techniques (cleaning, flux, dry pipes, etc.) but any pointers will be appreciated. This fitting was the only problem I had.
Sounds like you have it covered sometimes you just get a bad joint. :(
Too much heat can be a problem just as not enough. I still worry over upside down joints but nearly always work for me. I have an air breathing acetelyne rig that really works for me. I never had prefect luck with the small Bernzomatic type w/ propane esp outside in the wind (inside ok)
When ever I do a water heater change out I use threaded ball valves. I sweat on male threaded adapters. I follow them with the threaded ball valves w/ close nipples & finish the connection to the water heater with the flex copper connector lines.
Using threaded fittings & the flex adapters gives me something to tighten if anything leaks
I put valves on both the hot & cold water lines...........makes water heater changeout next time a REAL short job w/o the water leaking all over the utility closet, garage or basement.
cheers Bob
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Another option may be to just replace the valve with a compression type rather than a solder. They have both valves that have compression fittings, and also fittings that have pipe threads on one end and compression on the other that you can screw into a threaded valve. Good luck Larry
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It sounds like just a bad solider joint, happens. Sweat it apart, heat the pipe wipe of the solider best you can, Put flux on the pipe when it's hot. Clean the inside of the valve, once it slips on the pipe fairly easy reflux and solider. Heat the pipe first then the valve you should be able to see the solider suck into the cup of the valve. The valve is either brass or bronze so let it cool on it's own no wet rag.

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Joey wrote:

This is definitely a hack, but before you go tearing the valve out, if you can spot where the leaking water is exiting, try peening the exposed solder there with something like the end of a screwdriver blade tapped with a hammer, as though you were trying to push the solder into the joint.
It won't take much to seal off a leak that slow, it will probably plug itself with chemical sediment in a few weeks anyway.
If a few seconds of peening doesn't work, it won't leave you any worse off than you are now.
--
Jeffry Wisnia

(W1BSV + Brass Rat \'57 EE)
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On Tue, 28 Feb 2006 22:19:19 -0500, Jeff Wisnia

Yeah, and not only that, but if the leak is that small, a little JB Weld should take care of it. But the water must be drained and that pipe very dry and clean. They sell a 5 minute dry JB Weld. Use that, but leave the water pressure off overnight. BE SURE to shut off the electric to the water heater when you drain it. This is not an ideal solution, but your leak sounds very minor.
Mark
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gate valves tend to be heavier requiring more heat to sweat. the next time MAPP gas might be better
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wrote:

I never use solder in valves. Either they dont get enough heat, or they get too much and the heat ruins them. I always solder on adaptors and use threaded valves.
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wrote:

It's less trouble -- a *lot* less -- to disassemble the valve before soldering, and reassemble after it cools, than to use adapters and threaded valve bodies. And if you use a MAPP torch, you don't need to worry about not having enough heat. They're about double the cost of a propane torch, and worth every penny.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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