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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
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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: 8 months ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 8 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.

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