jk96, I didn't realize you had a zoned water to water geothermal heat pump. I was thinking you had one thermostat with a water to air geothermal which is why I suggested adding load. If the Unit ran for under 1/5th of the time period monitored, then I would say it is doing a nice job of saving you money, compared to the 24/7 run time Maurice is experiencing. Ouch! I worked in a building in the south that had an oversized AC system, so the "geniuses" I worked for turned on the ceiling tile heaters to provide a load for the AC, while it was 100 degrees outside. The power source on site was 2 860 MW units so electric cost wasn't considered. Personally I would have called McQuay back to fix the problem at the refrigeration units, but I wasn't in charge. Having the capability of adding a 3 degree band or swing, is a great feature to have on a thermostat. My Trane thermostat is the same model I used in the 70s on a split unit heat pump when I lived in the South. It's a 7 day programmable XT500 Taystat, digital yet simple and reliable. The house has to be at set point. If temperature drops 1 degree, the Unit starts up. At one point I considered going back to a mercury switch heat pump thermostat for the adjustable dead band capability. The newer model Trane XT500c (80's technology) used on the Carrier unit, has a programmable dead band feature which must have been programmed into a Programmable Read Only Memory chip since there are no mechanical adjustments in the thermostat . The Trane help center recently asked me why I didn't buy the latest technology for the Carrier unit. I told her then I wouldn't be having all of this fun trying to trouble shoot the unit. I use old thermostats for the same reason I drive vehicles from the 90s, they are relatively cheap, reliable and easy to work on/maintain.