Soldering around existing fittings

Hey guys!

Well when it comes to soldering around existing fittings on supply lines I'm a CHICKEN!

I'm working on installing an expansion tank. I have everything set. All that is left is to add the T into the cold water supply going into the water heater. Here's the problem... There is a female adapter that goes into the water heater. Above that by about 3 - 4 inches is a coupler. Above that by about 4 -5 inches is a shutoff valve.

When I heat up the coupler, I'm concerned that I might heat the solder for the other fittings and weaken them. My thought was to wrap the other fittings in wet rags to keep them cool. Once the coupler is removed, what's the best way to clean the copper pipe from the old solder? When I replace a coupler with a T do I need to cut down one of the copper lines to provide enough space for the T? Finally, how much flux do you normally use for 3/4" pipe? I've heard 1/2" for 1/2" pipe and 3/4" for 3/4" pipe.

You guessed it, soldering pipe is not my thing! I have nightmares of failed solder joints.

Thanks, Mike

You won't get those fittings hot enough to affect the solder in them, but if it will give you piece of mind, use the wet rags around them. If somehow a joint does become hot enough to melt the solder, coat it will with flux and reheat it. If there isn't any flex in the line when you add the tee, use the tee as a template to see how much to nip off. To clean a pipe when a fitting is removed, use a rag while the solder is still molten. You may want to do this a couple of times, then emory cloth or sandpaper. The major problem area will be the lower side of the pipe where the melted solder runs off. It's a small problem, but not impossible. As far as how much flux to use, don't be afraid of using too much. I probably use 10xs more than necessary, but it's cheap.

copper

Go at with an attitude that it's easy.
Clean the solder off with a rag so that the fitting will slide on.

Clean excess with a rag too.

Brush or sand the inside of the new fitting and just enough flux to make the copper look greasy.

Get the copper hot enough and then dob the fitting at the back side till the solder flows.

Just keep your solder brush handy and when other solder joints get hot just brush the other solder joints, because they will probably spit a little solder.

If it's a 3/4" fitting take off 3/4" of pipe or a little more if you have slack.

It will be easier than you think.

Thanks guys. I needed the kick in the confidence!

If I read you right you plan on removing the coupler? That is a bad idea. If/when you need to replace the HWH you will need to remove the line to it. That is why the coupler is there. Put the T above the coupler or some place else in the line near the HWH. Also once you cut the line is there room to move the pipe so you can fit the T in place?

TJ - My thought was to replace the coupler with the T. When I need to replace the water heater I could replace the T just as easy as the coupler since the T is going to the expansion tank. That was my thought...

union

A lot of fittings could be called "couplers" but you should have a nipple and an insulated union coming off the heater first. It will make it easier in the future.