Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rblaisdell-at-juno-dot-com> I think I have poor coupling. I have 1/4 inch copper tubing primary. 3/4" inside to inside spacing so 1" center to center. and 2" between innermost turn and primary. What do some of yall run? Thanks Ry