I have a Nest thermostat, and a geothermal system with a water heated floor, and a forced air handler. The floor heat, and the forced air heat/AC each have their own thermostat. I have already checked, and found the thermostat for the forced air is not compatible with the Nest because of too many wires being used, however I was thinking that maybe I could use it in place of the floor heating thermostat, which only has three wires to the W1, W2, and Rh terminals. When I check that compatibility on the checker site, and it says that my wiring may be compatible with the Nest Learning, or Nest E thermostat but not the Nest. It also say something about possibly needing a C wire. Since both of these thermostats are located right next to each other, I'm wondering if there is wire that the Nest needs that isn't currently attached to the Honeywell thermostat I want to replace, if I can run a C, or whatever other wire I might need from the Braeburn thermostat next to the Honeywell, so the Nest can work. The Honeywell just controls a water pump that circulates water through the floor heat runs.
