I have been running an open-loop geothermal system in southern NH for 9 years. It has an auxiliary drain set to open when the EWT drops to 47. Until recently the aux drain has never opened, but lately it opens a lot. When the system was installed in the Summer of 2012, the EWT was measured at 54 (which seems too high for NH). I'm pumping less heat this year than the past. I verified the EWT is correct using a second probe. Water is pumped to and from an 800' deep well, and the aux drain dumps into the house perimeter drain. It seems like I may have a problem with my well. Any suggestions for how to diagnose?