J how do you remove the air out of the coil? You each time have an upper part in each turn?
What was the reason you installed it this way and not in a flat position?
In residential systems like this the circulation pump pack comes with purge ports. These ports isolate the heat pump and provide means to connect the ground loop to a purge cart. Essentially it is a open water vessel that pumps water into the loop and the return line dumps back into the open tank, therefore you get a solid water column in your ground loop.
The pump in the purge cart moves the water at high velocity and gets all the air out.