Hi Boss GS & Gasman have answered the best on the bit of info you have posted, but what they didn't add is if you cut the leak out how do you get the fitting on to a pipe that refuses to move enough to slip it ito place, you can purchase a special repair coupling,or just round file the centre stop ring out of the compression joint, remove any paint clean a good area of copper pipe???? with fine emry/sandpaper mark equal sides of cut, slip on fitting pull back to previous marks made and tighten up. HTH (hope this helps) Tez PS dont forget to drain down first.