We have developed a leak at 3/4" copper elbow at a hard to repair location. This is the second failure in this line. It went in new in 2003, but the plumber was sloppy and did not wipe the joints after soldering. I turned the water off on that line and am now contemplating repair options. Getting this elbow replaced will be difficult as it is very close to two other pipe and an abs drain. I'm tempted to do an epoxy bullet around it, but I know that is a bandaid.
The other option I am considering is bypassing this section of pipe with PEX. However, I have never worked with PEX before and have no tools. There would be two joints: one above the elbow and above the built-in cabinet the 3/4" line runs behind, where I can get access. This would be on a straight piece of pipe. The second joint would be in the crawlspace, on either the straight run of the pipe. For the lower joint, I could solder on a male or female 3/4" threaded fitting if that helps.
What are my options with PEX? I have no PEX tools and it doesn't make sense to do this for two fittings. Do the push fit, slip-on fittings (Sharkbiet or BlueFin) really work and hold dependably forever? Should I look for a compression fittings instead?
Also, the pex line would be run vertically up behind the cabinet and then need to do a 90º turn in the crawlspace to meet the supplying hot water line. Does one put an elbow in the pex or let it make a large sweep 90º turn to eliminate the two extra connections at a pex elbow?
I'm a DIYer, not a plummer. When my two tank system lost a tank last in Q1 of last year, I dropped in a tankless electric but found the gal/min output was terrible and didn't want to up my service panel to handle a larger unit knowing I'll eventually be replacing grid with solar. So, I opted to drop in a propane tankless. I limped along until last month on one tank but then, had enough and started my project after a lot of research. I've done a few sweat joints in houses I've owned in the past. But, this time I opted for Expansion Pex (PEX-A). I got the Dwalt tool in a kit because it was the most available at my local hardware store, a roll of PEX-A, and some fittings. I chose this over push to connect because a youtube video I saw where plumbers did a fitting pressure test of Pex-B, Pex-A (expansion pex, propex), sweat copper, and sharkbite Push-to-Connect. Under pressure, the only fitting that failed was the Push-To-Connect. The rest burst the pipe first. NOTE: Sharbite is a confusing term - in that some people mean "push to connect" when they use the term, but that company makes PEX-A products as well.
Pex-A is super easy to use. Place the PEX-A fittings first. Don't use PEX-B ones by mistake. Use A Pex-A expansion ring, insert the expander and operate the number of times required per the tool's chart. (11 times for a 3/4" pipe as my power tool manual gives) iIt takes less than a minute - then insert it into the fitting. PEX-A is flexible and can make an 8" 90 degree turn. If you kink the pipe, heat it with a low temp airgun and it will self-repair. Using the Milwaulkee or Dwalt battery powered expander - fittings can be made in very tight spaces - but elbows can be avoided altogether in most cases. When I redo my copper lines throughout the house, which I will, I'll do a brass PEX-A manifold and homeruns to avoid unecessary joints in the walls, overhead of my home, and leave a little extra coil on each run to allow for the loss of a couple of inches of pipe if I ever need to replace a fixture. Removing PEX-A from a brass fitting has been easy too. Utility knife, flat screwdriver, and a heat gun. Using the 425 degree gun from my solder kit, takes me about 2 minutes to remove a fitting. I prefer brass fittings because if I have to remove tubing they will not be damaged from a little heat.
My PEX-A connections are better than water-tight, they are gas tight. It may not meet local or national propane code, but in my mock-up test, to see if the new heater would meet my demand goal, I used it for propane both between the regulators and for the leg between stage two and the heater. Testing with soap solution gave me not even a bubble less than 10 minutes after I made the connections. When I transfer this system from my project board to my brick wall, I'll be looking for what plastic piping I can use for direct burial and the above ground portions of propane. I'm leaning towards Home-Flex Underground and Home-Flex CSST. But I also find the GasFlex aluminum core'd plastic inside and out interesting in that they claim it will work above or below ground. I would have just gone to Home-Flex for the gas during my test, but the PEX was just so much cheaper for the test.