Our geothermal system was installed a few years ago. During the summer it works great for A/C but in the winter as the temperature drops to freezing, our heating can't keep up. We have a Climatemaster Tranquility 27 two stage 5 ton geothermal package with two 400ft wells and a desuperheater tank. I looked at the temperatures in the ground loop at the first bend after the loop pumps using a couple of electronic thermometers logging to a laptop. The return water temp EWT is about 56F when the system is running. However the water entering the pipe is always 1F or so warmer (I checked I had my probes the right way around a number of times and even reversed the probes). Also the pipe to the pre-heat tank is always very, very hot when the heating is running even though the system doesnt seem to produce much air heat. Eventually the house thermostats panic and try and bring on the AUX heat. What should the typical temperature difference be for a ground loop in Maryland? Why is the LWT warmer than the EWT? Could the ground loop be reversed and the unit still heat and cool to a limited extent? Is this a indication of something else wrong? How can I tell?