Power suddenly not available

[jasoclark]

Out of the blue one day I get a message stating that the power to the upstairs Nest thermostat is not there anymore.  Nothing changed....it just happened.  I don't touch the wiring on these, so it wasn't something that was bumped or moved.  It just stopped receiving power one day.  I had an HVAC person over, but they don't work with Nest so they weren't real sure of what was going on.  I keep getting an e72 error and it won't let me set my temp nor will it hold a charge as I have to pull it off daily to charge it.  I would upload an image of the wiring, but I have no idea how to here.   Y1(blue), G(green), W1(white) and Rh(red)....same as the other unit, yet no power

[bluenow]

OK here, I have extract same issue , and did some of research before come here .

The basic information , 3rd generation Nest Thermostat , wired on Y1(yellow), G(green), W1(white) and Rh(red), totally 4 wires .

One day get message said lost connection , days after find it in low battery and eventually totally down .  Pull it off and charged through micro USB , and put back on , repeat the same to low battery and completely down . 

By doing some researches , I learned that is what happened .  The first problem is from the wifi on the Nest Thermostat , either the hardware or driver , the wifi no function anymore , look into settings/network , it repeating on searching and nothing showed up , and we have another same 3rd generation Nest Thermostat can list nearby wifi networks properly .  After the wifi issue , the Nest Thermostat started to consume more power since it constantly try to find/connect the network , and with 4 wires configuration of Y1(yellow), G(green), W1(white) and Rh(red) , there will be only trickle charging , end up Nest Thermostat drain battery off eventually . 

Solutions .

1. Replace or fix the wifi on the Nest Thermostat . This seems only to be done with Google staff.

2. Add C wire power supply to provide extra 24V on Rc and C . This wouldn't fix the wifi issue , but could keep the battery on Nest Thermostat to drain off , which to keep the basic Thermostat functions.

Questions .

I tried to turn off wifi from Settings/Network , and it seems does not to prevent battery drain off .  I just wondering the Google firmware does not provide the option to shutdown WIFI completely ? Why ?

[jpres]

I too have this issue.  In fact, it is as if you wrote the issue up for me.  I guess I am stuck trying to figure out how to get to googles staff to fix the wifi issue.  What is funny (in a sad way), my wifi is 100% google.  Google fiber with the google router and googles additional access points.  I had hoped google would work with google, especially given the price of this compared to others.  I also expected the display showing power and the charge level of the built in battery to be a bit more user friendly.  For $270 (what I paid at the time), feels like this thing should just play a yourtube video of what is going on directly on the display 🙂

I guess I am off to see how easy or hard it is to get with google and sort out this wfi setting that is apparently killing my battery.

[Mlabrador]

Hi folks,

Thanks for posting and apologies for the late reply. 

A few questions: Are you getting any message codes or reports? Is your Nest Thermostat not able to connect to your WiFi network? Also, could you give these steps a whirl?

1. Go to your Nest Thermostat settings > Technical Info > Power. If the Battery level drops to 3.7V, your device will be disconnected to your WiFi network.
2. If so, try charging it manually using a micro USB charger for an hour.
3. Then, try reconnecting it back to your WiFi network.
4. Settings > Reset > Account connection. This will disconnect your device from the app and on your account.
5. After the reboot. Do step number 3.

Let us know how it goes.

Regards,

Nikki

[Jake]

Hey there,

I wanted to check in and see if you managed to see Nikki's post. Please let me know if you have any questions from here. I would be happy to assist, and make sure you are good to go.

Best regards,
Jake

[Jake]

Hey there,

I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity.

Best regards,
Jake

[Jake]

Hey Lizsantamaria,

I am glad to hear everything is working properly, and you are good to go. I am going to go ahead an lock the thread at this time. If you have any questions from here, please feel free to create a new post.

Best regards,

Jake

[bluenow]

update .

I have partial fixed to the similar problem of mine .

In my case , the WIFI in Thermostat stop functional , consequentially causes more power consumption as it keep re-try to connect WIFI .  In the 4 wires connection to HVAC , the Nest  Thermostat can only 'steal' the power , aka trickle charging , at up to 40mA , which is can't sustain long time if  Nest Thermostat not in extreme low power sleeping mode .  Have C wire connected would help on charging greatly , then the charging current could up to 200mA , this would be OK for most situation , or last year with microUSB fully charged once. 

There are other option to add dedicated power supply of 24V to Rc and C .  This option should fix the power issue completely .  The 24V power adapter will cost $15 or up though .  24 Volt Transformer, C Wire Adapter Thermostats can be find at amazon , like this or similar https://www.amazon.com/dp/B07MT5VWQN/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B07MT5VWQN&pd_rd_w=m2aIe&pf_...

I have to say that this doesn't solve the WIFI problem , but only for the charging issue which could be critical when WIFI stop to work.

I still have no clue why the WIFI in Nest Thermostat stop working after 2 years installation .  It might be hardware failure or firmware driver over automatic update . Either the case, only Google guy can fix it .

[vergeon]

I have the same problem. Literally happened on Monday. Downstairs Nest Thermostat just stop receiving power out of the blue. I was clueless. I checked all the wiring and everything was good, glad I found this post . So it's a wifi issue? My upstairs thermostat is working fine (so far). Does this mean it may suffer the same fate? Any word from Google of a wifi issue with the Nest? How can this just happen out of the blue..

[Krazyskibum]

Same exact issue. Outnof the blue stopped working. Only had it for two months! It was hooke sup to my google home, even called the google nest team for help with set up. Had some jumpers on previous thermostat and i didnt know how to wire it. Wired it, worked fine for two months then disaster. Thought just the batteries were dead but now after replacing them it cant detect my wires anymore. Called nest help again for support and this time their solution was I NEED a c wire. Will be returning. My system heat/cool heat pump, low volt, red green yellow white wires. 

[vergeon]

I finally figured out my issue. The door on our furnace wasnt closed properly. Come to find out, there is a little switch behind the door tha is compressed when you place the door back into position properly. Question is, I never touched the door in the first place. So how did it get loose enough to not be pressing down on the switch? I dont know. But point is, my thermostat now works. So check your door on your furnace and make sure it is properly seated in place. Something so simple caused me a headache for over a week. Give it a try......

[Rkaleto]

Im having the same issue out of the blue after my nest working properly for 5+ Years 🥴. Not the door on the furnace either. 

[vergeon]

You sure? I assume that you made sure it was absolutely shut tight and correctly, pushing in the switch..

[Lizsantamaria]

Thank you!!! I had the same problem with the thermostat not working. I had my furnace serviced for the winter and they must not have closed the door properly. They came back and looked at the door, Literally just pressed on it and the furnace kicked on and the thermostat started working again

[Krazyskibum]

Update had a c wire installed and it worked. When switched over to ac realized the air was t cold. I have a heat pump central ac unit. Got a home warranty they came and had to replace the fan coil. Thermostat working fine since march when the ac was finally fixed. Then 3 days ago guess what yall……. Low power again not holding charge and cant control ac/heat. Its been working since march! Called an hvac guy and his diagnostics found my system requires 240v which is coming from the breaker but not getting to the unit. Sooooooo  now i need an electrician. idk i may be going back to a dumb thermostat. 

[Rkaleto]

This exact thing has happened to me twice in the last three days. I have had my nest hooked up for probably 5 years with no issues, and now all of a sudden this. Going to check the furnace door now. 

[DRooster]

Wi-Fi issue makes more sense than door switch in most cases

[Nessa1]

Had this happen last night. Turns out my furnace door was ever so slightly open causing a loss in connection. That simple! Some one else had said this and I thought it too simple and didn’t even check. The furnace was over a year old and I’ve never opened anything. Turns out that when it was put on by installer, the knob was never fully tightened so I guess vibration caused it to eventually move. I would say always check since it’s so simple.

[LittleMsRN]

We found our thermostat not holding a charge this morning. These were the things we tried: 1. Took it off the wall and charged it manually. It worked for a minute and died. 2. Reset the breaker for the whole house with no luck. 3. Changed it out to the old Honeywell which indicated power but would not run the heater. 4. Called the HVAC company for an emergency visit since its the weekend and my house temperature is dropping into the 50s with the potential to get to the 20s if it meets outdoor temps. 5. HVAC says fuse in the heater control panel was blown. He replaces fuse but heater still won't start the pilot. He manually jumps the circuit which lights the pilot. So he knows the circuit is complete. He realizes that the condensor is running non stop and in our case its wired not only to our AC but the heater as well to prevent flooding. He notes that the toggle switch, which is similar to the toilet filling, was not closing which was sending an auto shut off to the unit which ultimately led to the power loss to the nest which drained the battery! Hope this can save someone the headache in the future!!@

[Rhett77]

Same issue for me. Two years working without a problem. Then the Wifi wasn't connecting for a few weeks but I didn't pay much attention since everything else was working. Then the other day it was out of power. I added a C wire and it says it isn't getting power from it. Both the C and R wires are getting 24-28v. Don't know what to do next but put the old thermostat back on. 

[dburke]

This has happened to me as well. Did you find a solve or were you able to get support from Nest / Google?

[rich_cariddi]

The product is great. For 1 - 2 years. then had to swap, all but one, out for standard. Had electricians just flat out say, "They suck".  Anyway, after spending 1000 dollars on this crap (Many zones in the house) I'm back to the 'dumb' thermostats. And they work fine.

[TonyM1]

This just happened to me. 

I have three best thermostats, each floor is it’s own zone. 

after four years yesterday the upstairs nest says it’s not receiving power. 

I pulled it off and switched it with the downstairs one and again it’s saying no power it’s  not the unit itself. 

but I haven’t touched the wiring and I don’t have ac or a furnace. I have baseboard hot water heating with a propane boiler, so there’s no furnace door to shut. 

the boiler was just serviced a few months ago and according to the display it’s working fine. 

no idea what to do other than switch to a different thermostat. 

I had this install by someone four years ago but he’s since relocated and I have no clue about how heating or wiring works. But it shouldn’t have just stopped. Everything else is working fine and nothing has changed