I was thinking of paths of least resistance when laying out the the secondary loop system returns coming back into the primary boiler loop.
I looked at http://www.phpinc.us/index.php?actio..._id=1183487865
and bothe the Caleffi Hydrolink and Caleffi Idronics .
The key is having the secondary loop flow having the least effect on primary loop flow. So my layout idea on photobucket would definitely be the wrong way to go, as it would not hydraulically separate the primary and secondary flow of hot water.