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Wiring a Dual System to 2020 Nest

jstamatov
Community Member

Greeting!

I have a separate heating and cooling systems - the cooling system has the RC power wire and and the heating has its own R wire. The 2020 nest only has the a slot for one R wire.  My heating works if I put the red wire to the R terminal.  Similarly, my cooling works if I insert the Rc wire into the R terminal.  But with only one R terminal on the Nest,  I can only run one system at a time.  So to wire both, where should  I put the heating and cooling power wires?  Can I splice them and insert them both into the R terminal?  Thanks for any suggestions.

7 REPLIES 7

Patrick_Caezza
Gold Product Expert
Gold Product Expert

Separate heating and separate cooling systems are only compatible with the Nest Learning Thermostat, 3rd Gen

Houptee
Community Member

You  only use the Air conditioning R and you can wire a 24v ac relay for the heating system that energizes from the W to C Common to the coil of relay, then the normally open contacts you connect red and white from heating system so when Nest energizes the relay the wires from heater R and W connect via relay to turn on the heat.  If you Google it you will find many videos and articles about adding the relay and the part number that would work.  Or any Air Conditioning contactor solenoid will work. 

Ryan_G
Community Specialist
Community Specialist

Hi jstamatov,

 

Thanks for being here in the community.


I'd like to jump in here and check if you've seen Patrick_Caezza and Houptee's responses. I hope the information shared in this thread helps you.

 

Thanks for your help, Houptee and Patrick_Caezza.

 

Best regards,

Ryan

Ryan_G
Community Specialist
Community Specialist

Hey jstamatov,

 

I just wanted to follow up and see if you're still in need of help. Please let us know as we would be happy to answer any questions you may have. 

 

Best regards,

Ryan


 

Ryan_G
Community Specialist
Community Specialist

Hey jstamatov,

 

Thanks for being here in the Google Nest Community. 

 

I'd like to bump in here and make sure that you’ve seen our response.

Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

 

Have a great day.

 

Best regards,

Ryan


 

jstamatov
Community Member

Thanks Ryan, appreciate the follow up.  Looks like I need a bigger/better nest thermostat, as the one i have is not compatible with dual systems.    Thanks!

aatienza
Community Specialist
Community Specialist

Hey jstamatov,

 

Glad to know that it's already working! Appreciate the help, Ryan. Since this has been resolved, I'll mark this thread as complete and will lock the thread in 24 hours.

 

Feel free to start a new thread if you need assistance with your thermostat.


Thanks,

Archie