Nest Thermostat Blinking Red

Is your Nest thermostat blinking red? If so, don’t worry – you’re not alone. This common problem with Nest Thermostats is usually an easy fix. 

If you see a flashing red light at the top of your thermostat’s display, it signifies that the battery is critically low but is currently charging. Don’t use the thermostat to manage your heating or cooling until the battery has sufficiently charged. Once the battery has adequate charge, your thermostat should automatically power on.

However, other causes might also contribute to this issue.

To fix this issue, we must thoroughly understand what is causing it and then only we can successfully troubleshoot it. 

This blog post will give you a few tips on how to fix the blinking red light problem on your Nest thermostat. 

Why is my Nest Thermostat Blinking Red?

Nest Thermostat Blinking Red

Generally, a low battery charge or a worn out battery cause the Google Nest thermostat to blink red.

This applies to all versions of Nest Thermostats, including:

  • First-generation Nest Thermostat
  • Second-generation Nest Thermostat
  • Third-generation Nest Thermostat
  • Google Nest Thermostat E
  • Google Nest Learning Thermostat

Most of the time, the Nest battery will charges itself, and the red light will go away.

However, if the red blinking light continues and doesn’t stop, you will have to determine the root problem.

You need to be patient enough to fix this issue if your Thermostat persists with the issue, and allow your Nest thermostat to charge for at least an hour (30 minutes or perhaps longer).

Also Read- How To Fix Blinking Green Light on Nest Thermostat?

How To Fix Nest Thermostat Blinking Red Light?

It’s quite simple to fix a blinking red light on the Google Nest learning thermostat. You can choose to recharge your Thermostat as soon as you see the red light blinking, or you can let it run entirely out of energy, then recharge it to full.

Give your Thermostat enough time to recharge fully. The latest Nest thermostat models can fully charge in 10 minutes to two hours. 

Nest thermostats occasionally struggle to charge; in these cases, you will need to use a USB cord to charge your thermostat.

When your Thermostat is fully charged, it will resume normally, and the red light should stop flashing. (1)

Check Thermostat Wiring or System Issue

thermostat wiring

The next step that you can do is to examine and make sure the wiring of your Nest thermostat is done perfectly.

Turn down your system’s power before inspecting your Thermostat’s wiring to prevent any defective wires from harming you or your Nest thermostat.

The method as to how you should inspect your Nest thermostat’s wiring is listed below:

  • Start by going to your Thermostat’s Settings.
  • Now, we will move to the next step and choose Wiring Info.
  • A diagram of the cables connecting to the Nest thermostat must be shown in the app now.
  • Keep in mind that all wires must be colored. If you notice any grey cable, it means that that wire is not supplying power to the Nest thermostat. Similarly, if all the cables are grey, there is a power problem.

If you are unsure about the electrical components of your Nest thermostat or if you need any assistance with this wiring problem, you may call the electrical specialist.

Install a New C Wire

Nest C wire

If the wiring of your Nest thermostat is done perfectly and you still have the blinking red light problem, then it might be a sign that your Nest needs a new C-wire.

The addition of a new wire will provide more power to operate your Nest thermostat. The process of installing this new wire is long and complicated, so you may need a professional to do it for you.

If you are comfortable enough and want to install the new wire by yourself, follow the steps below:

  1. Start by turning off your breaker box to prevent any accidents while working with electricity.
  2. Now, detach your Nest thermostat from the wall.
  3. Locate the Nest base and unscrew it from the wall.
  4. You will see 4 small wires connected to 2 terminals now; these are responsible for supplying power to your Nest.
  5. One of these wires is the C-wire that we need, and the other 3 are not needed.
  6. Now, twist all 4 of these wires together and screw the base back on.
  7. After you have installed the new C-wire, turn on your breaker box and reattach your Nest thermostat to the wall.
  8. The red light blinking problem should now be solved.

Having a C-wire helps with low-voltage heating devices, so I recommend installing a C-wire to fix any power issues with your Nest thermostat.

The devices with C-wire can occasionally become loose over time, preventing the Thermostat from receiving the required electricity to recharge itself. For that, make sure your c-cable is completely attached to the Thermostat.

Common Wire Colors

Modern thermostats with Wi-Fi and led displays require a constant power source. The common wire, or what is known as the “C wire,” enables the Thermostat to receive 24 VAC electricity continuously.

Generally, electricity comes from the red R cable but doesn’t flow continually. You must use a common wire to finish the circuit to make it constant. A constant flow of 24V energy will ensue after the circuit is complete.

Certain limitations exist to the popular Nest thermostat’s claim that it can operate without a C-wire. Your HVAC system powers the Nest without a C-wire provided it is turned on. The Nest still requires electricity even when it is not in use.

The Nest will activate the furnace by pulsing the heating wire, using a little electricity to keep it running.

In a Nest thermostat, the wires are typically arranged as given: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common, although the common wire may be a different color.

Charge Your Nest Thermostat Battery

For the versions of the Nest thermostat that are battery-powered, the blinking light issue, which is a sign of insufficient power, can be resolved by removing the old and inserting new batteries.

Ensure you use only 1.5 V AAA alkaline batteries of the highest caliber from reputable manufacturers. Below steps in case you need to know how to replace batteries:

  1. Remove the base of the thermostat display.
  2. Extract the old batteries out of place and discard them.
  3. Now, place the two fresh AAA alkaline batteries in place of the old ones.
  4. Make sure that the battery ends marked “+” and “-” correspond to the marks in the battery compartment.
  5. Once it snaps into place, slide the thermostat screen back onto the frame.

Permanently Plug Nest Thermostat into an Outlet

Alternative to replacing batteries and installing a C wire, you may resolve power-related difficulties with your Thermostat, such as battery draining too rapidly or Wi-Fi often disconnecting, by permanently plugging your Thermostat into an outlet.

This way, you can stay clear of the tension of battering draining and the red light on the display blinking.

Having a separate power outlet for your thermostat device can help you better control your device usage.

You can always use it when there is electricity at your home, regardless of whether nest’s battery is charged.

Reset Your Thermostat

Resetting the Thermostat is the final option you should go for if none of the solutions I’ve listed above worked for you. The reason why your Nest thermostat may not be able to charge is due to a software problem.

Resetting your Nest Thermostat is the recommended course of action, as it helps in restarting the software.

To quickly reset your Nest thermostat, here are the steps that you should follow:

  1. Visit the Main menu.
  2. Click “Settings“.
  3. Choose the “Reset” option.
  4. Select “Factory Reset” by navigating to the option, which shall restore your thermostat to its default settings. 

Contact Support

contact Nest support

Nest thermostat is a widely used temperature control device offered by Google; hence, it has a fair share of users. Customer support for these devices is also readily available.

You can get in touch with the customer support team through chat, e-mail or direct phone calls. You can choose one of these methods depending on how convenient you are.

Chat support gives instant replies for your minor queries; you can use on-call support if you figure out that the issue with your device is elaborate and you have additional queries, the response for which is not available on the chat support menu. 

Frequently Asked Questions(FAQs)

How long does it take for the Nest thermostat to charge?

Charging the Nest thermostat is a pretty fast process. Your Nest thermostat should typically recharge in around 30 minutes. However, if the battery is completely dead, it may take up to two hours to recharge.

How do I know if the Nest thermostat is charged?

The front light on your Nest thermostat keeps flashing while your device is still charging. Your LED will flash different colors as per the battery level of your device.

When your Thermostat is not charged, it will keep flashing a blinking red. Once the charging is done, it will stop blinking. 

How can I speed up charging for my Nest Thermostat? 

Usually, you charge your Thermostat by plugging it in conventionally, and it is fast enough. In about 2 hours, you can fully charge your Nest Thermostat can be fully charged from a level of zero battery.

Nevertheless, most Google Nest thermostats have a USB port for rapid battery charging. The Google Nest support staff occasionally utilizes the same port for troubleshooting. 

Why does the blinking red light keep coming back on my Nest Thermostat? 

The potential reason is that the charging in your Thermostat is extremely low, and the blinking indicates that your device is being charged.

Before using it to regulate your temperature control, wait till the battery is fully charged. When the battery is fully charged, your Thermostat should activate.

Why is My Nest Thermostat showing No Lights?

Nest Thermostat showing No Lights can happen for multiple reasons. Typically, this occurs as a result of improper wiring. It implies that the wires are wrongly placed into the circuit, which will show in the app.

The system wires are entered and linked properly by checking them. Before inspecting the system cables, switching the system off is important.

Final Thoughts

This article will quickly assist you in determining the primary cause of your Nest thermostat’s flashing red light, and I’m hoping the techniques listed above may be useful when you need them.

As stated, low battery is the main reason your Nest thermostat has a blinking red light on the front. However, there can be other problems too that can be listed as possible culprits.

You need to recharge your Thermostat’s battery or your Thermostat itself to fix the problem. However, if there is a problem with the wiring or the main power issue, rectify it as necessary.

To successfully resolve the Nest blinking red light issue, follow the methods given in this guide.

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