How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Brian HVAC Guy Your Own Question
Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 797
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
67988511
Type Your HVAC Question Here...
Brian HVAC Guy is online now
A new question is answered every 9 seconds

Having trouble converting trane thermostat to nest. Using a

Customer Question

Having trouble converting trane thermostat to nest. Using a heat pump. The x2 wire has no place to go. Has both B and O wire
Submitted: 10 months ago.
Category: HVAC
Expert:  Lee Traxler replied 10 months ago.

Your B wire will no longer be used.

Expert:  Lee Traxler replied 10 months ago.

Was I able to help you on this problem?

Expert:  Lee Traxler replied 10 months ago.

Please let me know if that helped and rate me, thanks

Customer: replied 10 months ago.
This did not help at all.
Expert:  Brian HVAC Guy replied 10 months ago.

Hi I'm Brian and I'm here to help! I'm sorry you haven't received the help you need so far. Would you like to continue with me as your expert? I assure you I am well versed in both Trane heat pumps and Nest thermostats.

Thanks,

Brian

Customer: replied 10 months ago.
Answer the question I asked
Expert:  Brian HVAC Guy replied 10 months ago.

Very good then. The short answer (without knowing your old thermostat model and what wires went to what terminals) is:

B will go to C on the Nest, this is 24 volt ac common and Trane designates this B while all other mfrs. designate it C. Since you had one on the Trane thermostat, you should connect it to the Nest even though it may not be necessary.

X2 would have been for emergency heat on the Trane thermostat and if you had a connection at W on the old Trane thermostat and transferred it to W/Aux/E on the Nest, then you will tape up the end of the X2 wire and tuck it back in the wall. Newer electronic thermostats don't need a separate terminal for W (or Aux) and E where older ones did.

With all that said, the Trane XL16I is a two stage heat pump so you should have connections on: R, Y, Y2, G, W (Aux/E), C and O and that should complete the needed wires for your system with the Nest thermostat. The Nest should configure your system automatically as a two stage heat pump with auxiliary heating.

Let me know if you have further questions on this subject. Otherwise, please remember to rate before leaving (3 stars or higher please!). Bonuses are always appreciated! Thanks for allowing me to help and thanks for using Just Answer!

Thank you,
Brian

Related HVAC Questions