Ok, I am going to rework my system so I have closely spaced tee's to eliminate ghost flows, as has been suggested here. My question is should the return be in front or behind the supply? I am coming in off the greenwood and directly connecting into the vertical 1 1/4 in pipe coming out the oil boiler and to the house heat that goes to 3 zones with a circulator on each pushing into the bottom of the oil boiler. Should the return be on the top or bottom of the supply on that vertical pipe? Sorry for the probable dumbness of this post.