This split unit was started almost a year ago and this is where it is currently performing. Carrier 50YDS049 with FV4006 upflow AHU and 15KW Aux (only 5-kw wired in) 800' of vertical closed loop with 20% methanol. Outdoor temp 35 degrees Indoor temp 72 Water temp in 42 degees Water out 38 degrees Water Pressure 35 PSI In Water Pressure 28 PSI Out I took the above readings in 1st stage. In order to keep unit running I bumped tstat one degree and the air temps were taken in 2nd stage Air Temp out 95 degrees Air Temp in 71 degrees This unit runs 75% of time in 1st stage but will bring in 2nd stage at day break, or if thermostat is raised from set point. I have seen Aux on only once or twice. I hope that I will not have to wire in the other 10KW of strip heat before the end of winter. Most of the house is very comfortable and I really like the varible speed air flow. I took all of the above with the desuperheater wired and running and I know that is not suppose to happen. I am very pleased with this units performance and am a firm believer in the payback capabilities of these systems.