All,
Thank you for all the good ideas. I learned a lot about DOT and pex pipe/fitting specifications with this adventure, so at least that was fun. Long story short, my lines are 1/2 pex, not 5/8 as previously thought. I did not have calipers with me to measure when I found my leak. I was sighting the size off the 3/8 lines that run to the washing machine. Rookie….
After a not so relaxing evening with a fish tape, I am all fixed up with new 1/2 pex supply and return lines. My lines also connect to the registers with heater hose as Ivan’s do. Thanks again!
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