Nest Learning Thermostat 3rd Generation Power Issues w/ Power Connector

[Hsapp]

We moved into a new house at the end of last summer, and it came with a NLT 3rd gen installed, connected to the house’s heating and cooling system. It originally had a dead battery (I assumed searching for a non-existent wifi). I eventually fully reset it, and connected to our new wifi. After about a month with little use, the battery was discharged again and it wouldn’t connect to wifi. Unclip, charge, reinstall, repeat. This kept happening, and after a little digging, I realized we didn’t have a Common wire. I assumed with such little use, it wasn’t able to top back off and that’s why it kept dying.

Fast forward, I bought and installed the Nest Power Connector at the furnace, following the instructions to a T. Though I wasn’t able to confirm the thermostat saw the power connector, I assumed this was going to solve all my problems. That is, until this recent heat wave when I’ve had to run the AC for a good amount of time. Now, it’s almost as if the more we use the HVAC system, the more the battery wears down. 

Do I have a faulty power connector? Is this thermostat bad? I’m reluctant to buy another one of these if I’m going to run into the same issue, but I worry the battery on this one is just toast. Thoughts?

[Patrick_Caezza]

Post a picture of how you wired the Power Connector and another one of how the thermostat is wired

[Hsapp]

Hello! Yes, sorry for the delay. I’ve been out of town, and haven’t had a chance to snag a photo of the furnace side of things yet, and am having issues figuring out how to upload a photo on here. I may need to get back to my computer, iPadOS might be the constraint here.

But I appreciate the responses, will update in the next day with photo links at the very least!

[EdwardT]

Hi folks,

@Patrick, thanks for the help!

@Hsapp, how's it going with your Nest Thermostat? Still need our help?

Thanks,

Edward

[EdwardT]

Hi Hsapp,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[EdwardT]

Hi Hsapp,

Just checking in to 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 in 24 hours.

Thanks,

Edward

[Hsapp]

Hi Edward, yes, apologies for the delay but I appreciate the response. I do need to snag a photo furnace side, then figure out how to upload it here. But it’s been giving me the same power issues. Will update hopefully later today!

[EdwardT]

Hi Hsapp,

Thanks for the response. We'll be waiting for the photo. Also, could you check the power readings of your Nest thermostat? You can see this information by going to Settings > Technical info > Power.

Thanks,

Edward

[Hsapp]

[Hsapp]

Ok, I drew up a diagram that shows the wiring as the photos are a bit hard to see. It looks like there was a splice in the wires just outside the furnace to extend the wires inside, and I’m pretty sure that’s why the color for Y1 doesn’t match up. When installing, I undid one wire at a time to install the power connector, so I don’t think I would have mixed anything up… but always the possibility it wasn’t wired correctly to start with?

I also just had to charge the thermostat, and took the Power info photo right after reattaching it to the wall. Not sure if that would change those readings. Basically, the Nest dies after prolonged usage when the AC is running. We ran it all yesterday with this heat wave, and I just received the power down notification this morning. Charge, don’t use (and it’s fine), turn on the AC, and it runs for a day before dying. Repeat.

Any and all help is appreciative. I’ll tear into the wire splice shortly if it looks like that may be the cause of the problems. I have access to a multimeter too. 

[EdwardT]

Hi Hsapp,

Thanks for the added information and for the diagram. We'd like to dig deeper into this. Please fill out this form so we could investigate further.
 

Thanks,

Edward

[EdwardT]

Hi Hsapp,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[EdwardT]

Hi Hsapp,

Just checking in to 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 in 24 hours.

Thanks,

Edward