Wiring compatibility for TCONT802AS32DA thermostat with a variable heat pump and auxilliary sensor

[chockham]

Can you confirm if the standard Nest Thermostat is compatible with my Trane thermostat (TCONT802AS32DA). 

TCONT802AS32DA wiringThe heat pump is a variable heat pump and auxiliary temperature sensor.  The explanation of wiring is on page 4 of the manual - see here.

1) The auxiliary sensor connects to S1 & S2. Does the basic Nest Thermostat have that wiring option?

2) Does the Next allow for X2 and W1 which connects to the air handler - wires W1 [white] & W2 [black].

[RomanandsonAC]

S1 & S2 are normally used for a remote sensor. In commercial systems, like for a restaurant, thermostats are located in the kitchen area so remotes are installed in the dinning area to read temperatures there, not in a hot kitchen. So with S1 & S2 that is where the temperature is being read from, not the thermostat location. So with your system it may be reading temps from the return air, however with out knowing the model of air handler I am not sure. As for X, that is going to be your common wire from your system low voltage transformer, and W1 normally is your heating strip. So from your picture it appears you have a heat pump system. The Orange wire is used for energizing and de-energizing your heat pump. If it is a Trane system it will energize to cool, de-energize to heat. The W1 would be your emergency or auxiliary heating. Again form the picture it appears to be a Honeywell made Trane logo 8000 thermostat. the large screen version. W1 would be used for the aux heat.

[Patrick_Caezza]

None of the Nest thermostats is compatible with external sensors.

Your current thermostat is only compatible with the Nest 3rd Gen Learning Thermostat.

Give this wiring a try

Black - X2 to * (set for emergency heat)

White w/black - W1 to W2

White - S1 - not used

Red w/black - S2 - not used

Red - R to Rc (jumper to RC not needed)

Orange - O to OB

Yellow - Y to Y1

Green - G to G

Blue - B to C

Trane uses the X terminals for emergency heat usually and the B terminal for the Common (C) terminal

[MelbaDT]

Hey folks, 

Thanks for taking the time to answer this thread, RomanandsonAC and Patrick_Caezza — your inputs are greatly appreciated. 

chockham, I'm just dropping by to check if everything is good here. Let us know if you have more questions. 

Best, 

Melba

[Ryan_G]

Hey there,

Just wanted to jump in here to check to make sure that you saw our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Have a great day.

Best regards,

Ryan

[Ryan_G]

Hey folks,

It looks like we haven't heard back from anyone so I'm going to go ahead and lock the thread. If you have any further questions or concerns, feel free to create a new thread.

Have a great day.

Best regards,

Ryan