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Two Wires, White and Blue

rockdmoon
Community Member

Hello, trying to install a nest thermostat but the only wires I have are white and blue. Is this compatible?

1 Recommended Answer

Correct, blue would go to Rh or R depending on the type of Nest wire plate. 

View Recommended Answer in original post

63 REPLIES 63

Confirmed the wiring looks good

One more thing, could you please post a picture of your Nest wire base so that we can make sure it’s connected properly, it probably is but just want to make sure. 

Skymom
Community Member

Laurent and scuba Shawn we tried to install a c wire, but it was going to involve ripping walls out, so we picked up a Google power connector because we could get that fastest. Now we've installed that and the app is saying it doesn't detect any of the wires. Here is a photo off that helps. I'll be waiting for ideas because I don't think we have heat till this is corrected

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The C wire from the Nest power connector you currently have plugged into A2 needs to be plugged into A1 instead. All the other connections you made are good. Let me know if any further issues.

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 Laurent thanks for responding. This is how we originally had it set up which I believe is what you're saying to do, however that did not work either and the nest home app said that none of the 3 (r,w and c-here marked with a yellow tape) wires were being detected.

I had asked my husband to connect it to the A2 at that point because I thought ScubaShawn had said that C wire connected to A2, but that might have only been for the wall transformer device? I'm not sure why they would be different though.

We appreciate your thoughts and at this point are running out of options other than to go back to the old thermostat.

Make sure you have the latest version of the software installed on your Nest. Also for the rest of your testing, keep the C wire on A1, not A2. Do a power test on your Nest (accessible from the menu). You might find this video useful https://youtu.be/tgAiEBqUXIk

Hello Laurent yes I did the power test on the nest but it just kept saying that none of the wires were being detected no matter what we did. We have temporarily gone back to our old thermostat. We have already seen this video part of the problem is we don't have an HVAC system and part of it is that we're trying everything that everyone recommends, and so far nothing is working. My husband is an experienced mechanic and electrician so it really seems like we should have been able to figure this out with our basic skill set already. Also tried calling Google nest support but they ended up inadvertently hanging up on my husband so he is through with that avenue.

I appreciate your attempts but so far nothing has been working with our heat only boiler system. At this point I'm trying the wall transformer because it's really the last possibility that I haven't tried yet. We are generally handy people and I wish that Google had made these devices more friendly to older systems.

The transformer method should give you heat immediately but it might not look the best. Just connect to C and R and plug it in.

At this point, the wall transformer is our last shot. Arriving tomorrow. We will also be connecting the W wire correct? 

Okay, no worries. Yes wire from boiler goes to W and R. The transformer, striped wire to C and other wire also to R. Your husband might want to use a wire nut into a 3rd wire if both wires don't fit into R. 

In the end, you will have 1 striped wire into C, one boiler wire into W, and 2 wires into R. Once it works, then you can decide on how to hide the transformer wire.

Thank you scuba Shawn. I am keeping this to look at tomorrow when the device comes. However in the meantime we put everything back together with the old thermostat the way it was and now the entire house is heating up it's at 75° even though we have the thermostat set to 65. Clearly something's gotten mixed up in all this confusion but I have no idea what it is and this is going to end up costing us a boiler repair service call if we don't figure out what we did wrong soon.

Skymom
Community Member

So, unbelievably, the antique thermostat we put back on was the culprit. We are reinstalling the nest from scratch, after clearing out everything electronically. It's up and working fine again, the way it originally started. We'll see if with a day or two it starts saying we have to install a c wire and pull app access. By then the transformer should be here and hopefully that will solve everything. Good night 

Great to hear you got it working. To be clear, did you end up using the Nest power connector with the Nest or just reverted to how it was originally with your Nest?

Hi Laurent

Unfortunately the nest power connector would not work-somehow it made it worse and the home app could not detect any wires at all- so wouldn't work. At first when we re-hooked up the nest, it also would not work, so then we reinstalled the original older (we're talking 50 years old) thermostat which unsurprisingly, just happened to be on its last legs. After figuring that out, I decided to wipe the phone app of any memory of that device, and reconnected the nest by itself with no c wire. Because it seemed confused by the memory of the device. That worked for now. Presently it's working just fine, as it originally did. It took a day or two to decide to throw error messages.

Last thing I try is the wall transformer. I think these units are designed for newer systems, and they also keep assuming we have an HVAC system (we don't).

Good night all, this has been an exhausting day.

 

The Nest usually works with most old oil boilers, I have set it up that way in the past and I had no issue. The thermostat should be configured as oil with radiators, you can set this in the google home thermostat settings.

Yes I had set it that way already. There was some other issue.

Also the wiring diagram accessible from the settings in the google home app should look like this pic when you have a C wire and 24v common should not be bold if no C wire.  Only power and heat should be bold, if that’s not the case you need to click “update wiring” and remove whatever connection is not needed. Good night.

172CBA9F-462B-4678-A61C-CC1820245616.png

Thank you Laurent. That's helpful to know and it's pretty cool you can access the proper wiring diagram from the app and see what's actually functioning. 

AF09A37B-572A-4D67-BCB6-E21B252E10FA.png

This what you should see in your Nest config 

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 ScubaShawn, I wasn't able to get the one you recommended for some reason it wasn't available when I went to order but this is basically the same device and specifically says it works with nest thermostats. however when I read the directions that came with it, they mention adding a jumper from RH to RC and I don't understand why that would be important or and whether or not that is different from what you said- which I believe it is different. What you said made sense. Do you understand these directions that came with the unit?

I read it to say IF your current configuration was using a jumper which you are not. Not needed. Good Luck!

Ok we've installed it and everything is fully functional as far as I can see-finally!!! This is the only thing that worked - thanks so much for your suggestion. Finally, I can rest and feel prepared for the cold weather👍🏻 

Kwart
Community Member

I have a white O and Blue B wire but only one receptacle for “OB”. What do I do with both of the wires? Try and put them in OB together? Also, I have three wires (black, brown and orange) that were not hooked up to old thermostat, do I need to connect them?

Kwart
Community Member

image.jpg

 the white labeled OB was just O on my old thermostat and the blue is B.