Is my new Learning NEST Thermostat compatible with my existing HVAC?

[JeetV]

HVAC info - 

Thanks for any help. 

[Patrick_Caezza]

Yes, your current thermostat is compatible.

Try this wiring

Green - G to G

Yellow - Y to Y1

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

White - W to W1

I always suggest that you installed a C wire if you don't have one, you can do it if there is a spare wire or you can use the Nest Power Connector. This will keep you from having problems down the road

[JeetV]

Thanks Patrick..will try and let you know how it worked out..

[MelbaDT]

Hey folks, 

Thanks again for your detailed answer, Patrick_Caezza. 

JeetV, I'm jumping in here to check if you've got the chance to try Patrick's suggestion already. If yes, how was it?

Best, 

Melba

[MelbaDT]

Hey JeetV, 

Checking back in — how's your thermostat now?

Best, 

Melba

[JeetV]

Sorry Melba..for the delayed response..

I will be hooking it up Saturday afternoon..

I will surely come back here and post my experience..Thanks

[MelbaDT]

Hey there, 

Not a problem at all. Keep us posted once you've installed everything ― we'll just be here. 

Best, 

Melba

[JeetV]

Finally hooked it up yesterday..

My c wiring is incomplete..although c (blue) wire was unused at the thermostat end , it wasnt connected at the HVAC end..and also there was a red and white wires connected to c wire connector..so i wasnt sure how to connect that..

Got the nest thermostat connected without the c wire..

When I conncted R ro Rc , the thermostat was not powering up..but when I connected R to Rh, it powered up and it is working..

I tested both cooling and the heating system..it seems to work, atleast so far..

Although, Nest says there is no need to connect the c wire to the thermostat, the advice I am getting is, it is better to get it connected..i certainly dont understand this..but i did learn that the c wire supplies the 24volt to the thermostat..if that is so, why is running now? Obviously i am just getting to learn about it. I will appreciate if someone can explain this.

Thanks...Jeet 

[MelbaDT]

Hey there, 

Sorry for the delay. 

Our Nest thermostats are designed to use very little power, and in many cases they can use your system’s heating and cooling wires to get enough power.  However, there will be instances that you may need to connect a common wire (C wire) to make your system compatible. 

I suggest that you check on this link to know more information about C wires: https://bit.ly/3nIztHl

Best, 

Melba

[MelbaDT]

Hey there, 

It's me again — I just want to ensure that I've answered all your questions. Let me know if you have more in mind. 

Best, 

Melba

[JeetV]

Hey Melba,

Yes you have answered all the questions. I did get the c wire connected. and all is well.

Thanks for reaching out.

Best, Jeet

[MelbaDT]

Hey there, 

That's awesome and thanks for letting us know. Since everything is good now on your end, I'll go ahead and lock this thread. If you have any new issues, updates or just a discussion topic in the future, feel free to start a new one in the community.
 

Cheers, 

Melba