"CompleteNewb" wrote in message
. ..
My girlfriend's father helped me install a new water heater, and I watched
closely in the interest of eventually being able to do something my darned
self someday. Well, it turns out my chance came sooner than I thought.
The pipe feeding cold water to the tank has a slow leak at one of the
connectors (copper pipe fitted to another copper pipe). Looking at it
closely, it doesn't have the silveryness of the other connections, so
maybe we forgot to solder it, but it's such a slow leak that this seems
unlikely.

Anyway, the leak is from the BOTTOM of the connection, so if I want to fx
this without cutting pipe and dismantling everything all over again, the
solder would have to suck upwards into the joint. So my questions a

1) with a cutoff valve being right above where this leak is, can I assume
that shutting it off and draining the water heater a little bit will give
me a water-free inside of the pipe at that point so I can successfully
heat up the pipe enough for solder?

2) Assuming "yes" to the above, will solder flow upwards into this joint,
"sucked" up by the heat?

Thanks for any input here, I'm a floundering newbie. I appreciate your
time.
Solder will flow up, but not in this case. The reason you have a leak is
that you didn't clean or flux the joint properly. Now that you have heated
it, it is even more oxidized that it was before. No chance it will take
solder. You have to take it all apart and redo it properly. Sorry, but
that's the way it is.

The same thing happened to my water heater a few years back. It was only a
drop every 5 minutes or so and I chose to ignore it, as they sometimes clog
up by themselves. It never did, but when I put on a pressure reducer, going
from 90psi to 55 psi, the leak stopped.
If your leak is worse than that, you better fix it; I don't think it can
result in failure, but the cost if it does is just too high.

As someone else suggested, you have to be careful using heat near the inlet.
Consider using a union there.