I had some fun last night and again today. We are on the road, camping in Florida. My wife's little dog got up in the middle of the night to get some water. When he got to the living area, he started barking and whining. My wife got up to see what was wrong, and found the floor was flooded with water. I got up and soon figured out that the leak was from the water heater. I used the bypass valves to turn off the water to the water heater. When the sun came up , I discovered that the problem was that the plastic nipple that screwed into the water heater was leaking. it broke off when i tried to remove it. The thread part of the nipple was still in the water heater. A little Internet research found that I'm not the first one to have this problem. I drove into town to buy some metal fittings, an extractor, some PEX tubing, and a PEX compression tool. Of course, the extractor would not remove the broken part of the nipple.
I spent a couple of hours on my back and elbows, using a knife, screwdriver, and hammer to remove the broken piece. I also changed the fitting on the cold side to metal while I was working. It also broke when I tried to remove it. The plastic fittings had been screwed into the water heater as far as they would go. I'm guessing that the factory installer used an impact wrench for this work. The tension created by the lip of the fitting contacting the water tank boss is probably what caused the fitting to fail (thinking that if it was tension from the PEX tubing install, then the barb part of the fitting would have broken). Should I be happy that the original install lasted 3 years, or be upset to find even more shoddy work?