I recently purchased a Nest thermostat and Google Power Connector. I have watched the installation video and read the instructions. Each say that I need to update the Nest, in order for it to be compatible with the power connector. Adding the device to the Home app and connecting to WiFi are impossible when I’m repeatedly told there is no power to the Nest. Well, if the power has to be 24v, like a common wire provides, then of course there is no power. How is it that I’m expected to upgrade my Nest using AAA batteries if that’s not how it functions? I am completely perplexed and cannot find a single piece of documentation anywhere that addresses this.
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Most nest thermostats have a little power in them from manufacturing that should allow a connection. What generation of Nest Learning thermostat did you purchase ? If you have a Nest E or a 3rd generation p, you do not need software updates to work with the Nest Power Connector.
Ken, The Cooling Wizard
I have the plain, old fashioned, Nest. If I were a smarter human, I would have purchased the Nest Learning so not to worry about the common wire at all. Unfortunately I’m not that person, especially since these two zones only run heat.
I have a Nest and the new Google Connector adapter. In fact I purchased two. Both thermostats do this. I have swapped in fresh batteries, even though the Nest app says the factory supplied batteries were “good”. There is plenty of battery power.
My only thought is during this entire Nest love affair, I added the lock to my door as well and I’m curious if the Nest range extender, which came with the lock, is causing issues, but I highly doubt it.
The Nest extender that came with the Yale Lock is unique to the door lock.
The Nest Thermostat might need software upgrade so it knows how to use the power extender. Software version 1.1 and above have the support needed.
What the power extender does is use the Y wire to bring COMMON to the Nest Thermostat. This is only needed if there is not an unused wire in your thermostat cable that can be purposed and used as the COMMON wire.
Now, your Nest Thermostat needs to be fully set up and registered in the Nest App. The HVAC system must be in the OFF mode. Then check the software level in Settings. If below version 1.1, it must be updated.
Questions: Is the Nest Power Extender already installed?
Is there no unused wire in thermostat cable behind the Nest Thermostat? Sometimes HVAC Techs will wrap unused wire conductors around the cable insulation.
Ken, The AC Cooling Wizard
Oh look, that green wire that was buried in the wall and wrapped in electrical tape is the common wire isn’t it? Good grief. My entire home needs a week pause before doing any projects, because there’s a mystery behind every corner, in every crevice or hidden by the ghosts of contractors past.
And now the Nest won’t recognize the wire. I’m using a Taco switching relay. The wires are attached properly to it, including the C-wire. The Nest sees the W and R wires, which it didn’t before. Now I’m perplexed.
The thing to remember is that it does not matter what color the wire actually is, just as long as what’s connected to the common in the heating system, is the same one that is connected to the C terminal in the thermostat. HVAC companies have used common colors wire conductors to help however not all people follow this. Basically if it’s a true thermostat wire it will have red, yellow, green, white, blue, Orange, and black typically. Not all conductor wires are needed in some cases. When done to standards, Red to R, Green to G, Yellow to Y, White to W, Orange to O, and Blue to C, and Black to Aux.
At this point we need to verify the Step-Down transformer in the HVAC equipment. We need to find the thermostat wire and see which color conductor is connected or available to connect to the COMMON side of the transformer. Having said this, make no changes without turning the power off first. Can you get to the HVAC equipment?
Ken, The AC Cooling Wizard
What type of system do you have? Forced air furnace, Gas boiler, Oil Boiler, Electrical elements?
How many wires are connected to the original thermostat?
The setup is going to be different for each.
You said you have a "Taco Switching Relay," which tells me you have a boiler system with individual relays for each zone.
Am I correct?
If yes, you will probably need a couple of additional parts to make it work. The Thermostat terminals on the Taco controllers are typically looking for a switch closer (like a light switch), so you'll need to add a relay and an external 24Vac transformer.
Purchasing the Nest Learning Thermostat wouldn't have helped you in the long run.
As we got our resolution here, I'm going to mark this one as resolved in the next 24 hours. Thanks to all who helped and contributed. If anyone has any other needs, please feel free to let me know before the lock.