I am in the process of replacing a 20+ year-old Geothermal Water Source Heat Pump. The local service tech said it wasn't worth fixing. They have been out here 2 times in the last month and a half adding Freon. According to them, the leak is in the air exchanger. Said it would cost over $2000.00 I found a new one online for $2300 with shipping. So to make a long story short, it's sitting here. Changing everything over should be simple enough. There is only one thing I'm not sure about. To which port does the water out of the flow center go? It has an upper and lower water connection. I have enclosed a picture of the water heat exchanger