OK. . .so after reading your post I headed to the jobsite. It doesn't sound as if you have infloor heating so I have a slightly different dilemna but I think you've answered my question. They have it plumbed opposite to yours. They have the HWG supply feeding into the top of the tank and the boiker return feeding from the cold water in on the amtrol. In other words, the boiler is simply heating storage supply. The domestic is running through the coil. Cold water well line into "boiler supply" and domestic hot out from the "boiler return". Therefore my domestic is capturing heat from the supply water while in the coil. I can tell it works (as you said!) because after 5 minutes in the coil I turn on my temporary domestic hot and get 1 coil worth of hot water. So thanks to your endorsement, I will reverse this (and add a tank for my infloor). I will run the HWG through the coil as you did, but before returning to the heat pump I will send it through a storage tank connected to my infloor feeds. My domestic will go in the proper cold in and hot out on the amtrol and then I should have an isolated supply of domestic water heated by the infloor HWG closed loop. I know . . might sound confusing but I appreciate your post . . . I think it solved all my issues. Thanks!!