I hopefully have a quick question. I am thinking of getting a Ecobee or Nest smart thermostat, but doing my checks/research before getting one for this house. I rent, so I can only do minimal changes.
The current system is a heating only system, and only has a W, G, and Rh wire connected (with a jumper between Rh and Rc) in the thermostat. The cable used has 3 other unconnected wires, Yellow, Blue, and Brown. Since I don't have a common wire, I was curious to see if any of the other wires happen to be connected. I used a voltimeter to check each one. Using the Rh wire as the pair.
If I connect the G and Rh, i get 27v. If I connected the Yellow, Blue, or Brown unconnected cable, I get 16 volts.
So I am curious, can any of these 3 wires be used as is for a common wire. They have voltage going through them, just not the full 24volts that a normal common wire has.
The furnace, is under the house in a very tight crawl space, and i have a very hard time getting close to it. I did see it was made by Bryant. I can get closer to it, but didn't have a lot of time making my way to it in a half crouch. It looked fairly newish. Definitely in the last 10 years, or at least looks like it. Obviously once I can get to the furnace, I can just see where the cables terminate. I believe its also a Gas furnace.
I just wanted to see if I could skip all that hassle and deduce everything from just the voltimeter readings.
Anyone have any ideas? I did a search, but none of the other questions were quite what I am asking for.