Nest Thermostat - Trane Conversion

[ForumGuy]

Hi All -

I have a system in which the current wiring is as attached, at the thermostat and the unit.

Google support is telling me to hire an HVAC specialist to wire my Nest, as they can't figure out what combination of terminals I should use given a different nomenclature in the Nest product.

Surely, I'm not the only person who has a Trane A/C system who has wanted to change their thermostat. Can anyone help?

I just really need to know which 3 terminals to use. There are only 6 ways to configure 3 wires, so it shouldn't be that difficult to work through trial and error if needed.

Thermostat also has only D,R,B used

[Jhonleanmel]

Hi ForumGuy,

Thanks for the photo.

Please contact a pro installer to discuss your options. This is to make sure that you're safely setting up your thermostat. Based on the photo you sent, this is an advanced setup which does need help from a technician or a Nest Pro.

Best,
Mel

[Markjosephp]

Hello folks,

Thanks for assisting, Mel.

@ForumGuy, I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Best regards,

Mark

[Jake]

Hey there,

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake

[ForumGuy]

You can lock the thread. I decided to return the thermostats. I’m told I need to buy a conversion box which is roughly $300. Since I’d need two of them (I have two systems) I decided not to spend $1000 to replace two thermostats. I’ll deal with it whenever I need to get my whole system replaced.

[Jake]

Hey ForumGuy,

I am sorry to hear your system would need a conversion box, and you are not able to setup the device. Per your request, I am going to go ahead and lock the thread at this time. If you have any questions from here, please feel free to create a new post.

Best regards,

Jake