Trane XR80 compatible

[briancole1812]

I'm trying to see if my Trane XR80 (model number TUD080C936K0) is compatible with Nest thermostats.  At first glance the wire colors behind the thermostat and on the actual unit don't appear to be color coated in the traditional manor.  Please help.  I've attached photos

[CoolingWizard]

@briancole1812 ,

you did a really good job providing pictures that help make us understand how your system is wired. From the standpoint of your old thermostat you have a conventional air-conditioning system. You can use any of the Nest Thermostats models. So if you are not interested in the advanced features if the Nest Learning Thermostat, the less expensive Nest Thermostat will work for you.  Do you have a dehumidifier attached to your system?

AC Cooling Wizard.  

[briancole1812]

When I tried to install the thermostat, I wired it to reflect how the old thermostat was wired and it didn’t work.   What is the correct way to wire this?

[CoolingWizard · Accepted solution]

The problem is you have three cables at the indoor XR80. Normally, the R terminal of the air handler is connected to the thermostat.  Your is connected to a white wire, going somewhere, coming back on the red wire, and cross connected to the red wire going to the thermostat.  There is another 2-conductor cable going outside. It has a red wire on Y, and a white wire on C. You need to see if you can follow the one with white on Y and red wire cross connected, and see where that cable goes. What ever it goes to, it is withholding the R power.  

AC Cooling Wizard 

[zoeuvre]

Hi briancole1812, 

Thanks for posting here in the Community forum and for showing interest in our Nest Thermostats.I want to check if you managed to see the response above. Please let us know if you still have questions or concerns, as we'll be willing to assist you further. 
 

I appreciate your help, @CoolingWizard. 

Best,

Zoe

[zoeuvre]

Hi there,

I want to check and see if you are still in need of any help. Please let me know, as I would be happy to assist and answer any questions you may have.

Thanks,

Zoe