On Sun, 27 Sep 2015 11:20:44 -0400, Ed Pawlowski wrote:

On Sun, 27 Sep 2015 08:53:14 -0400, wrote:

I'll leave the "under/over" question for others. However, I will comment on your reluctance to sweat copper if the "under" option is chosen.

Consider using SharkBite connectors.

http://www.sharkbite.com/
Not for burried connection on hydronics.

I'd use them to connect the copper to pex above ground on both sides.
Use the pex underground as it will flex where needed to make the run.

PEX will also expand in freezing conditions, less chance of a pipe
bursting.

I'd use brass fittings and crimp rings or the expansion method (rent
the crimp / expansion tool)