Old American Standard Thermostat to New Honeywell Thermostat


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Old 06-27-24, 11:15 AM
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Old American Standard Thermostat to New Honeywell Thermostat

I'm upgrading my thermostat. I will upload a picture of my current thermostat and my new thermostat. I need some help with wiring. From the research I have found that B is Common so it goes to C, R to R, G to G, Y to Y, O to W - O/B, not sure on what to do with my W and X2 Wires. Another thing I've wired it up before and I get cold air blowing outside when in cooling mode so I'm pretty sure its something to do with the reversing valve. I call myself trying both options on setup O or B. But maybe I'm missing something. Any help would be greatly appreciated. Also my unit is fully electric AC Heat Pump with Emergency and Aux Heat. From what I can tell is my W wire is Aux heat and X2 is my emergency heat, but again I could be wrong.


 
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Old 06-30-24, 04:52 PM
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Welcome to the forums.

Sorry for the delay.
After installing new thermostat....
it needs to be programmed for heat pump operation and backup heat.

R = red = R ( leave R to Rc plug in place)
T = tan = tape off - not used with new stat
O = orange = W-O/B
G = green = G
X2 = black = tape off - not needed (electric reheats- same as white wire)
B = blue = C (common)
W = white = W2-Aux/E

Remember.... slow and steady heating with a heat pump system.
You don't want to activate electric heat unless needed.
It's typically more efficient to leave the stat at one temp.


 
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Old 06-30-24, 09:21 PM
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Thanks for the reply, so by using this layout I'll still be able to call for Emergency Heat and it'll work? Someone had told me the X2 was for Emergency Heat so I was just making sure I understood correctly.
 
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Old 07-01-24, 05:01 PM
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There is typically one set of electric reheats that is controlled by both the white and black wire.
Your new stat has a combo connection.... stage 2 heat/E heat. (stage 1 heat is the heat pump only)

Emergency heat is the electric reheats without the condenser running.
 
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Old 07-02-24, 07:05 AM
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ok thanks, I actually had to send the thermostat back because it appears that my W - O/B terminal was bad it was always putting 24 volts out all the time. My cold air was going outside when in cool. With my unit the reversal valve defaults or fails to the cool position when energized it switches to heat, so it stayed energized the whole time which tells me the terminal was bad.
 
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Old 07-02-24, 04:31 PM
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The O/B line outputs 24v when set to cooling mode but not necessarily calling for cool.
When the stat is in OFF or heating mode.... there should not be 24v on the O/B line.

Only Rheem and Ruud units require 24v on the O/B line for heating.
 
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Old 07-03-24, 06:19 AM
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So the revering valve defaults to cooling position when no power is supplied to it from what I understand, so if O/B terminal pushes 24 volts to it at anytime the valve will switch, So shouldn't the O/B terminal only be hot during heating? That seemed to be the problem that I noticed, it was sending volts to it during cooling mode which was causing the cold air to go outside the house out the condenser.
 
 

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