Is my system compatible? Compatibility checker says yes, but self-install says no.

[Ctbevan12]

 

Before purchasing I ran the compatibility checker and it said yes to the learning thermostat. However on install it says no. I’ve searched other forms and no one seems to have the same set up that I do. 

Original wires RH, RC, Y1, W1, G

I have a gas boiler heat and standard HVAC AC (non heat pump). 

see pic of current. 

[Dave991]

Not sure why it won’t work. Double check the Rh and Rc wires are attached correctly. They cannot be crossed. Search YouTube for One Hour Smart Home videos. I believe he has a video that covers your setup. They are very good videos. 

[Dave991]

Reviewing your photo you might need a C wire if the R wires aren’t providing enough voltage through the Nest. 

[Ctbevan12]

Thanks, Dave. I haven’t processed much in the install as when the setup questions ask which wires I have it says not compatible and I can’t keep moving along. Also when I select “C” wire in addition to what I have it says not compatible. 

It is worth the effort to plug in and see if it would work? Or perhaps I find the combination of wires that would work and I could rewire on my terminals at boiler/AC? I would think with 5 wires this would work… 

[Dave991]

Before you do that I would verify the wires/colors match each connection on both ends. Double check the equipment setting on the Nest is correct. I don’t see why it won’t work.

[Patrick_Caezza]

It is extremely important that you do not mix up the Rc and Rh wires.

When you have separate systems, two cables usually go to the thermostat—one from the AC and the other from the heat source. The cable for the heat source is often just 2-wires (red & black).

Your setup is common and is referred to as a dual transformer system which only the Nest Learning Thermostat works with.

What is the error message that you are recieving?

[Jake]

Hey Ctbevan12,

Thanks for the help Dave991, and Patrick_Caezza.

I am glad to hear everything is installed, and you are good to go. I am going to go ahead and leave the thread open for 24 hours in case you have any questions from here. Let me know, as I would be happy to review.

Best regards,

Jake

[Ctbevan12]

Thanks all. Turns out this appears to be an issue with the google app. It still thought I was trying to install the Nest Thermostat (not learning) from when I tried that last month. I even deleted and reinstalled the google home app and still didn’t update the install for the learning. I ended up installing with the Nest App and it worked. Thanks! 

[Dave991]

Excellent