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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 861
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I have an ecobee 3 thermostat. I am connecting to an

Customer Question

I have an ecobee 3 thermostat. I am connecting to an American standard 2 stage furnance which has a trane cnt2184 control board. The thermostat has a wire to connect to the "C" terminal. The control board has W, W1, Y, R, G, B but no C. Any ideas?
JA: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?
Customer: 50/50 The thermostat needs a connection to C and the control board does not have it. If it did there would not be an issue. Your call
JA: Do you plan on doing the work yourself?
Customer: Yes I have already installed one today on another American Standard which had a C terminal in the block and had no issues
JA: Anything else we should know to help you best?
Customer: I do not think so
Submitted: 4 months ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 4 months ago.

Hi I'm Brian and I'm here to help!

The B on the Trane control board is 24 volt ac common and will relate to the C terminal on your Ecobee3. Trane is the only manufacturer that doesn't use the more common C designation for the 24 volt common terminal. Wire all others just as they should be, I assume that was a typo and you have W1 and W2 on your control board, these will relate to W and W2 on the Ecobee3. The rest are obvious. On the Ecobee3 you can wire R to Rc or Rh, either one should work and no jumpers are required.

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! And remember, follow up questions about this topic are free even after rating. Just post a new reply on this same question and I'll be notified. Thanks for allowing me to help and thanks for using Just Answer!

Thank you,
Brian