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failure of sweated copper joints next to new joint

fFngorn__7's picture

I replaced some valves(gate to ball-port)on a loop that attaches to water softener.The loop allows the owner to run water thru the softener or bypass,by opening or closing the correct valves.I had to dry fit the new loop,and then flux it,and sweat it.I worked my way up(the loop was in a vertical position).When I got to the  top joint(3/4 pipe to coupling)-as I was heating the joint I noticed small sparklike points of solder being spat out of a horizontal pipe(coming out of a tee)near the bottom as the heat rose up thru the pipes.Sure enough as I suspected,there was a small pinhole leak in the old joint.How does one solder new work very close to old without compromising the old work.Can I just reheat the old joints in the tee,and the capillary action will refill it?

It's a good idea to wrap (post #206480, reply #1 of 1)

It's a good idea to wrap nearby joints with a wet rag when soldering close to such joints.  As to simply reheating the failed joint -- sometimes that works and sometimes not.

Note that a part of your problem may have been failing to vent the pipe you were working on.

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