Nest 4th Gen Thermostat won’t turn on – only orange light

[Kyjoh]

Hi, I’m a Google Nest user in Korea.

I recently purchased the Nest 4th Generation Thermostat, but it won’t power on at all.

Even when I try charging it via USB-C, the device doesn’t turn on—it only shows an orange light.

Is there any way to do a hard reset or force restart?

Or is this a case where I need to get it repaired?

Any help would be appreciated!

[humbertogarcia · Accepted solution]

Hi Kyjoh,

Thank you for posting in the community! I’m glad to assist you, and I appreciate you looking into using the Google Nest Learning Thermostat in Korea. I understand that your Nest Learning Thermostat (4th gen) isn't turning on despite charging with the USB-C cable and only shows an orange light. 

The possible reasons for this situation can include the HVAC not being turned on post-installation, equipment incompatibility with the thermostat, or the thermostat's installation or wire setup being incorrect.

To better investigate the inconvenience and to address your troubleshooting questions, I’d like to gather the following information:

• Did the issue happen after the installation?

• Did you check your HVAC system's compatibility with the Nest Learning Thermostat (4th gen) previous to installation?

• What is the make and model of your heating, ventilation, and air conditioning (HVAC) equipment?

• Would you mind sharing a picture of the wiring installation?

Consider that some systems may not be compatible with the Nest Learning Thermostat (4th gen) due to regional availability. For more information about country availability, please refer to this article: Learn about devices & services available in your region.

Keep me posted and feel free to post any additional concerns or clarifications.

Regards,

Humberto

[humbertogarcia · Accepted solution]

Hi Kyjoh,

Thank you for posting in the community! I’m glad to assist you, and I appreciate you looking into using the Google Nest Learning Thermostat in Korea. I understand that your Nest Learning Thermostat (4th gen) isn't turning on despite charging with the USB-C cable and only shows an orange light. 

The possible reasons for this situation can include the HVAC not being turned on post-installation, equipment incompatibility with the thermostat, or the thermostat's installation or wire setup being incorrect.

To better investigate the inconvenience and to address your troubleshooting questions, I’d like to gather the following information:

• Did the issue happen after the installation?

• Did you check your HVAC system's compatibility with the Nest Learning Thermostat (4th gen) previous to installation?

• What is the make and model of your heating, ventilation, and air conditioning (HVAC) equipment?

• Would you mind sharing a picture of the wiring installation?

Consider that some systems may not be compatible with the Nest Learning Thermostat (4th gen) due to regional availability. For more information about country availability, please refer to this article: Learn about devices & services available in your region.

Keep me posted and feel free to post any additional concerns or clarifications.

Regards,

Humberto

[Kyjoh]

Due to the design of the Google Nest thermostat, many people choose to upgrade to it during interior remodeling.

Since the wiring work was done by a professional, I believe there should be no issues with that.
However, even when I connect a smartphone charger to the USB-C port on the back, the Nest still does not operate.

Could this be a problem with the device itself?

[humbertogarcia]

Hi Kyjoh,

Thank you for your prompt response and for sharing your thoughts with me. In order to further investigate your Nest Learning Thermostat (4th gen) situation, I need your answer to the following questions:

• What is the make and model of your heating, ventilation, and air conditioning (HVAC) equipment?

• Are the power breakers on, and do you receive power to your home?

• Is the thermostat's display seated properly?

• Are all the wires of your thermostat seated firmly in its terminals (with no loose or exposed wires)?

• Does the thermostat charge with a USB cable?

In addition, please attach to your answer a picture showing the thermostat wiring in the plate. I look forward to your post.

Regards,

Humberto

[Kyjoh]

1. The Google Nest thermostat is connected to an actuator called WESCON.

2. All electrical systems are functioning properly.

3. The display is properly mounted.

4. There are no issues with the wiring or the terminals.

5. When the display is connected to the wall base, there is no light or response.

6. When I try charging it via the USB-C port, the light turns on, but there is still no response.

Based on these points, could this be an issue with the device itself?

[humbertogarcia · Accepted solution]

Hi Kyjoh,

Thank you for the opportunity to address your concern about your thermostat. Your answers and the installation pictures help me to work with you toward the correction of the amber light condition.

For most thermostats, an amber light means that the battery is very low. In order to correct this situation, please leave your Nest Learning Thermostat (4th gen) charging via the USB-C port for an hour, then place it back in its base.

Feel free to share the results with me; I'll be happy to evaluate them.

Regards,

Humberto

[Kyjoh]

I’ve tried charging it via the USB-C port for 10 minutes, 1 hour, and even 8 hours, but it still doesn't operate—only the light turns on.

Thanks you for your kindness

[humbertogarcia]

Hi Kyjoh,

Thank you for taking the time to test your Nest Learning Thermostat (4th gen) battery charge.
I need the confirmation of the wires used in your installation being stranded, as it seems from the picture that you gently provided.
Consider that the Nest thermostats (in the USA) use only solid wires, and one sole wire per connection can be plugged into the base.
Additionally, please reply to these questions:

Do electric installations in Korea use stranded or solid wires?
The Nest Learning Thermostat (4th gen) battery hasn't charged since the installation was completed?
How long ago did you buy the thermostat?
I hope this helps us find a solution to the issue, and I look forward to your response.

Regards,

Humberto

[Kyjoh]

I purchased the Nest in March 2025. (The manufacturing date on the device is November 2024.)

The company that installed the Nest has installed it around 100 times, so I don’t believe there’s an issue with the wiring or connections. Also, since the device doesn't respond even when charged via the USB-C port, I suspect the problem lies with the device itself rather than the wall connection.
When I first unboxed the Nest, it did turn on, but after the battery drained, it hasn't powered back on since.

Additionally, since the Nest is not officially sold in South Korea, I purchased it through a proxy shopping service that shipped it from the U.S. to Korea. In this case, would I still be able to receive any support or service (such as warranty or repair)?

Thank you so much for your support.

[humbertogarcia]

Hi Kyjoh,

Thank you for the Nest Learning Thermostat (4th gen) purchase information and for the time you took to investigate with me. If the product initially worked and then didn't respond to the troubleshooting steps, I agree with you about your reservation of a possible battery malfunction.

About your product's reparation and warranty evaluation, there's no option available on my side because the product was bought from a third-party retailer. I suggest you contact them in order to evaluate their warranty policies. For any additional technical advice and support, feel free to count on me. I hope that the retailer's conditions allow them to provide you a satisfactory resolution.

Regards,

Humberto