I bought a new ball valve, 3/4" copper pipe, and a couple. I drained the water heater a few gallons, turned off the house gate valve, and cut out the bad gate valve. I had to have the city shut off the water to the house because the house gate valve allowed water to trickle.
I soldered one end of the new ball valve to one end of existing copper pipe. I soldered the other end into new pipe. I got good seals on both ends of the valve. I next soldered one end of the couple to the length of pipe going into the new valve. I didn't get a good seal. I soldered the other end of the couple into the existing pipe. I also didn't get a good seal.
I called the city and they turned the water back on. I noticed a leak at the top of the couple. I shut off the water at the house and decided to try again today. I bought a few elbows and couples from Lowe's and tried soldering a couple onto pipe. I couldn't get the solder to flow.
I suspected my Bernzomatic torch with Mapp gas wasn't hot enough to sweat the fittings. I gave up and called plumbing contractors. A father and son came out - I got the impression they were home waiting for the phone to ring - and I showed them what I was trying to do. I showed them the pipe and fittings I assembled back in 1997 but they told me they had a better way.
My way was a 3/4" slip x 3/4 fip fitting, pipe, elbow, pipe, elbow, pipe, valve, pipe, and couple. The 3/4 fip fitting connected to a 3/4 fip x 3/4 mip steel braided flex line.
Their way was a 3/4 fip x 3/4 mip copper flex line, 3/4 slip x 3/4 mip fitting, pipe, elbow, pipe, valve, pipe, and couple.
The father did tell me that I was paying for professionals. I told them the problems I had trying to sweat the fittings and the son told me Mapp gas doesn't get hot enough and that they use acetylene gas.
The whole job took less than 30 minutes and I gladly paid them $190. I allowed them to use any of my parts and they used my couple and long length of pipe.
I tried to do the job myself and came within one solder joint of doing the job myself but I knew something was wrong with the couple to pipe seals.
When I know its time to call professionals, I call them. When I got the two good seals at the new valve, I thought I was on my way. And back in 1997 I was using propane and got good seals. Did the copper change? The new pipe and fittings don't look like the 1997 pipe and fittings.