Hi, i realize that the title is unusual and contrary to other posts you will get very few specs. But please, finish reading and if you have any ideas post. BTW I am the home owner and very satisfied with the installer who is still my servicing my units. About 15 years ago we decided on geothermal and had 4 WaterFurnave units installed. 2 units have their own closed loop and 2 share a larger loop. About 2/3 winters ago - yes, it has been dragging on - i realized there was a problem with the 2-ton split system for the family room which is on the shared loop. If we had a cold night in the 20s or 30s I would come downstairs in the morning and find the auxiliary heat running most of the time. Once the room temperature, 74 degrees, was reached the auxiliary would switch off but the air coming out of the ceiling vent was a rather cool 82 degrees and it didn't take long before the auxiliary heat came on again. By the time the service guy came in mid-morning, the company is about 45 minutes away, the air coming out of the vent was back to the usual mid to high 90s and I was told everything checked out fine. As a precaution the insulation in the return air shaft was redone but that made very little difference. Winters are short in southside Virginia and once we got into the cooling season all was well again. Last fall though the situation deteriorated and now I had 60 degree air coming out of the vent in heating mode. This provided a clear-cut answer, the compressor had failed. Here a word of caution for owners of older WaterFurnace units, WaterFurnace no longer made these compressors and I was forced to go with a complete replacement and opted for a 2-ton WaterFurnace 5 system. I was assured this unit would take care of my problem but I was a bit skeptical. The unit at the coil produced 110 degrees but at the vent I was reading 96 degrees. The cold nights came and yes, still the same problem. Now all the ductwork in the attic was redone and again nothing changed. By now I had a ladder under the ceiling vent on a permanent basis to check the temp. here are some of the results from one morning; outside temp 25 degrees - room temp 73 degrees - H-2, Sp-6 - vent 88.2 outside temp 43 degrees - room temp 74 degrees - H-2, Sp-6, vent 92.3 outside temp 50 degrees - room temp 74 degrees - H-1, Sp-4, vent 104.1 Before taking those temps the unit had been running at least 10 minutes and the second unit being supported by that same loop has no problems. Also, the return in the family room has been relocated from being close to the floor and adjacent to an outside wall to the ceiling toward the middle of the room. We are stumped, there was no problem for over 10 years and nothing has changed in the room. I'm really hoping someone will take the time to read this and come up with an explanation.