I have a forced air heating/cooling system. Heat pump with propane backup. Trying to figure out if the Nest is compatible with my system. I have not found a wiring diagram for the Nest. My current system has
E @ T stat to W2 on furnace
Aux @ T stat to Y on furnace (same terminal as the wire coming from the T Stat Y terminal)
G @ Tstat to G on furnace
O/B @ T stat to O on furnace
C @ T stat to C on furnace
Y @ T stat to Y on furnace (same terminal as the wire coming from the T Stat Aux terminal)
R @ T stat to Ron furnace.
I have a gas furnace with a heat pump. I wired the Nest per Nest instructions and went thru the Pro set up. I am a master electrician with over 30 years experience. I set up the W2/Aux as gas furnace and * as emergency heat. When I do the test, the heat pump test works, the emergency heat works but the Aux heat does not. With the Nest in test mode it indicates power should be output on the W2/Aux wire. I do not have any voltage on this wire during the test mode. I have not been able to find any help for this situation on the Nest web site.
I'm so sorry for the delay in our response, but I wanted to hop in here to make sure we addressed your concern. I can definitely understand the confusion when it comes to thermostat issues as it can be very odd to figure out sometimes, but I'm happy to look into this for you.
First off, I would suggest using the Compatibility Checker to see if your system is compatible. Then, if it is, I would suggest contacting a pro to come out to help you with this since I know that the Nest thermostat is not compatible with stranded wires, every wire has to be connected to the Nest Thermostat system.
Please let me know if you have any further questions or concerns as I'm happy to help.