How to wire trane heat pump

[Handyman85]

I cannot find where the white B, black X2 and blue wires go.

 

[sporfrog]

These old thermostats can be tricky. Generally O and B control the change-over valve for a heat pump. More common is just one wire/terminal often labeled O/B.  Nest Thermostats don't support separate O and B. However there is a remote chance that B is something like a common or that both are not needed in your case. On the off chance, you happen to have a manual that shows what the terminals mean for your thermostat that would help!  If so send a photo of the page that describes the terminals. Also any additional information about the HVAC system including a photo of the wire terminals inside the unit could help.

[Patrick_Caezza · Accepted solution]

This is a simple Trane wiring. Tran uses the B terminal as Common (C), the X terminal is Emergency heat.

Give this wiring a try.

Red - R to Rc

 Orange - O to OB

Green - G to G

Yellow - Y to Y1

Black - X2 - * (set for emergency heat)(jumper to U not needed)

Blue - W to W2

[Handyman85]

Thank you. What settings should i select on the nest thermostat? I know i have to set it to heat pump, but anything else? Thanks 

[MelbaDT]

Hey folks, 

Thanks again for taking care of this, Patrick_Caezza and sporfrog. 

Handyman85, your Google Home or Nest app should be able to guide you through the whole setup process depending on the answers you provide about your home,what temperatures you like, and your heating and cooling system. If you want more information about the setup process, please check this link: https://bit.ly/3a6peIu

Best, 

Melba

[MelbaDT]

Hey there, 

Checking back in — still need our help?

Best, 

Melba

[MelbaDT]

Hi, 

I haven't heard from you in a while so I'll be locking this thread if there is no update within the day. Should you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.

Best, 

Melba