topic Re: Wiring a Dual System to 2020 Nest in Nest Thermostats

Wiring a Dual System to 2020 Nest

jstamatov — Sat, 14 May 2022 20:24:20 GMT

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.

Re: Wiring a Dual System to 2020 Nest

Patrick_Caezza — Sat, 14 May 2022 23:07:19 GMT

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

Re: Wiring a Dual System to 2020 Nest

Houptee — Sun, 15 May 2022 02:39:45 GMT

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.

Re: Wiring a Dual System to 2020 Nest

Ryan_G — Sat, 21 May 2022 22:12:02 GMT

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

Re: Wiring a Dual System to 2020 Nest

Ryan_G — Tue, 24 May 2022 22:46:32 GMT

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

Re: Wiring a Dual System to 2020 Nest

Ryan_G — Wed, 25 May 2022 22:48:33 GMT

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

Re: Wiring a Dual System to 2020 Nest

jstamatov — Thu, 26 May 2022 11:52:53 GMT

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!

Re: Wiring a Dual System to 2020 Nest

aatienza — Fri, 27 May 2022 05:11:28 GMT

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