cancel
Showing results for 
Search instead for 
Did you mean: 
Replies are disabled for this topic. Start a new one or visit our Help Center.

Nest learning thermostat compatibility photo

Youngho_J
Community Member

There is no C wire on my system and I'm not sure it is compatible.

The thermostat model is TCONT803AS32DA Touch Screen with Dehumidification Control Comfort Controls

IMG_0998.png

1 Recommended Answer

Houptee
Silver Product Expert
Silver Product Expert

B is your common wire, Trane calls it B instead of C.

Using the inner terminals markings on old Tstat  hook up the Nest the same way but with Blue wire to Nest C.

You lose the functionality of the dehumidification as that is a proprietary Trane thermostat for that system but it wont really effect anything it will still work  the AC normally and AC removes humidity that is how it makes you feel comfortable.


Houptee -- NJ Master HVAC Licensed Contractor

View Recommended Answer in original post

12 REPLIES 12

Houptee
Silver Product Expert
Silver Product Expert

B is your common wire, Trane calls it B instead of C.

Using the inner terminals markings on old Tstat  hook up the Nest the same way but with Blue wire to Nest C.

You lose the functionality of the dehumidification as that is a proprietary Trane thermostat for that system but it wont really effect anything it will still work  the AC normally and AC removes humidity that is how it makes you feel comfortable.


Houptee -- NJ Master HVAC Licensed Contractor

Im glad to hear that the system is compatible. Is there any plan for the dehumidifier integration in the future?

Houptee
Silver Product Expert
Silver Product Expert

The tstat you have was made to work with that Trane system so it runs the AC on low speed if it senses humidity is high.

Possibly the * terminal could be programmed by a Nest Pro installer to activate the system but you would need to pay for them to come out and custom modify the Nest. They have a Pro password that gives them more ability to change the programming of the wire terminals.

I would try it without dehumidification and if you are not happy go the Pro route or reinstall the original T stat.


Houptee -- NJ Master HVAC Licensed Contractor

Patrick_Caezza
Platinum Product Expert
Platinum Product Expert

Your current thermostat doesn't appear to be wired to control a dehumidifier.

Try this wiring,

Orange - Y2 to Y2

Black - W2 to W2

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

White - W1 to W1

Yellow - Y to Y1

Green - G to G

Blue - B to C

The * terminal is used to control a Humidifier or a Dehumidifier, and you would configure the * terminal during setup. THe wiring would depend on what type of dehumidifier you have, built-in or stand-alone.


To ensure that I see your reply, please tag me using @Patrick_Caezza

Youngho_J
Community Member

I'll install the nest and see how it performs.  I also noticed that the dehumidifier was turned off anyway.

Thank you very much for the information!

Young

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@Patrick_Caezza and Houptee, thanks for the help!

 

@Youngho_J, I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

 

Thanks,

Edward

Houptee
Silver Product Expert
Silver Product Expert

Some of the Trane high efficiency units have a built in dehumidifier setting that runs the system on ac but with low fan speed. So it doesn't have a wire to activate it. There are several switches on the control board in the unit to configure the system and the proprietary thermostat from trane controls it. If you Google your trane model number you will find more information about it. I saw several discussions on HVAC-talk.com about the trane custom settings on the control board. 


Houptee -- NJ Master HVAC Licensed Contractor

G1toons
Community Member

So when through the setup prompts and it asked if I had a dual fuel, I have my Ac fan thing out side and then my heating is in the Arctic I believe. It prompted me to get it professionally installed, is this necessary?

Thermostat connections 

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@Houptee, thanks for the help!

 

@G1toons, thanks for the update. Dual fuel system is a type of system with a heat pump outside and a separate heater installed inside your home. Could you share how your Nest Thermostat is wired so we can take a closer look?

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hi G1toons,

 

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

 

Thanks,

Edward

Youngho_J
Community Member

I’m happy to report that everything is in working order.   Thank you very much for your help!

EdwardT
Community Specialist
Community Specialist

Hi Youngho_J,

 

Thanks for the update. I'm glad to hear that it's working fine now. I will be locking this thread in 24 hours. Please feel free to create a new thread should you have some more questions or concerns in the near future and we'll be more than glad to help.

 

Thanks,

Edward