Nest Thermostat cycling through “G” logo

[EH123]

Hi!

My nest thermostat started regularly disconnecting from WiFi a few months and I eventually realized it was because it wasn’t holding a charge/battery was low. Since then, I’ve been charging it manually every few days (plugging into usb charger). 2 days ago it stopped working and I charged it and did a restart, but now when I plug it into the base it just cycles through the start up screen over and over — never going to the thermostat controls. The light flashes yellow then green and then starts blinking green and the G logo appears. It stays on the screen for 15 - 30 seconds and then starts over again from black screen. I also hear a clicking noise when the cycle restarts. 

Any ideas on how to fix? We having only been using it for about an year (bought it 2 years ago). Is this thermostat just a lemon? I have owned 2 other nest learning thermostats for 5+ years with no issues. 

[EH123]

Update: I checked the voltage of the c wire to see if it’s a power issue and it’s reading at 27 volts which is in the proper range. This makes me think this thermostat itself is a dud/lemon since I haven’t experienced this with my two other nest learning thermostats, but let me know if there is something I’m missing or another fix to try. It’s going to be in the 20s this week so we need to get a working thermostat asap. 

[jb76]

Hi - If the Nest is set up to detect and use the C connection of its baseplate, the 27V you detected on that wire should be getting to the Nest and charging its internal battery and providing power for wifi/control etc. Can you confirm what the Equipment setup detected for that Nest when you go through the initial setup e.g:

W - Heat/Furnace
Rh - Furnace/power
G - Unconditioned fan control
Y1 - AC/Compressor control

C - Common wire - Power to Nest thermostat

Can you also confirm what the Nest voltage is under Settings --> Technical Info-->Power?
If you are charging it with a microUSB - it is possible the battery is bad in the thermostat which would require a new unit be installed - but first check to see what the power readings are after a 1 hour charge on the microUSB.

J

[EH123]

Thanks, J!

Attached, you’ll find photos and screenshots of the set up and nest voltage.

One discrepancy in the set up of the wires is there is a white wire instead of a brown wire (shown in the nest set up picture) attached to W2 aux. There is a brown wire not being used that’s coiled inside the wall. I had this nest set up by an hvac professional so I would hope that they chose the white vs. the brown wire for a reason, but let me know if you think that could cause this issue. Note, the unit was functioning fine for several months before experiencing any issues. 

The nest battery voltage reads 3.69 after charging for an hour and being attached to the base plate for about an hour. I’ll redo that process now and see if there are any big variations in the reading. 

thoughts?

 

 

 

[jb76]

Hi - one other thing to check is to bring up the Technical Info -->Power from the Nest itself (not the app.)? If you are getting 27 V over that blue Common line, then you should be seeing the following for the Power readouts on the Nest:
Battery: 3.923 (as long as it gets above 3.85 V - good)
Voc: 39.13 V
Vin: 39.13 V
lin: 200 mA (c)

Also there is an Equipment menu item under the Tech Info menu:
which should match the layout of the wire connections you sent earlier:
Y1-G-Ob-Rc-C-W2aux

If you are seeing a similar 'lin' value - then the Nest battery is faulty which would require getting a new/replacement unit

J

[EH123]

Hi J,

Thanks for all your help!

The display wouldn’t turn on, so I couldn’t check the technical information you laid out via the nest itself. I *think* because I couldn’t get the battery to hold a high enough charge for the display to work or for it to continuously connect to WiFi.

I ended up just buying a new nest last night (sigh) since I needed to be able to heat my kids’ rooms during this cold front. I plugged the new unit directly into the old base and it seems to be working. The wiring set up matches up with the unit readout, but the power reads outs don’t match exactly. Below, is a photo of the power read outs you described. Does that look right? The VOC and VIN readouts are different than what you listed. Is that an issue?

Moonshot - but do you think I can get Google/Nest to cover the cost of the new unit since it seems like it was a battery issue/bad unit? 🫣 

Thanks!

 

 

[jb76]

Hi - yes - those power readings look good - voltage to thermostat is above 3.85 V and 'lin' value of 200 mA (c) is the most critical value showing the battery in the thermostat is getting sufficient power to be charged so you will have full control of the thermostat and HVAC. As for returns/refunds of the old thermostat - please reach out to Google directly - they may be able to help and or contact the retailer you got it from.

Let  me know if you have any other questions.

J

[Markjosephp]

Hello everyone,

I'm dropping by to make sure everything is covered here.

I appreciate your input, @jb76.

@EH123, I'm sorry to hear about the trouble you've been experiencing with your Nest Thermostat. It's frustrating when technical issues disrupt the functionality, especially during a cold front.

Your approach of getting a new thermostat and connecting it to the existing base is a reasonable solution. From the photo you shared, it's important to note that variations in power readouts may not necessarily be a cause for concern. The VOC and VIN readings might differ based on specific conditions, and slight variations are not uncommon. In addition to this, make sure that the thermostat's software version is up-to-date. Also, try disconnecting the thermostat temporarily from the Wi-Fi network for 24 hours and monitoring its behavior to see if it still drains its battery. If it does, let me know.

As for seeking reimbursement from the Nest Thermostat for the new unit, if it's a newly installed unit and still covers the buyer's remorse, you can reach out to our Google Store team for an arrangement. Make sure to provide as much detail as possible. It's a moonshot, as you mentioned, but it's worth exploring.

If anything comes up, let me know so I can check for other available options for you.

Best regards,
Mark