We've tested the heat exchanger and it passed with flying colors.
Alex was on the roof of the Bevill Building here at UA, which gave us a drop of about 7 m (a little less than the drop we have at Hengill). The hose could only get 0.3 L per second through the exchanger. Our flow at the field site will be higher than that, but the exchanger should be able to handle it. Now we have to take it apart and figure out the cheapest way to get it to Iceland.