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An occasional problem where an orange light blinks on the Nest Thermostat or its equivalent in Europe, the Nest Heat Link, is not commonly seen. Therefore, finding a solution for this infrequent issue could be challenging.

Nest Thermostats differ significantly between the US and Europe as the HVAC systems are completely different.

In the US the blinking orange light indicates low battery levels or hardware faults, while in Europe it points to either connectivity issues between the heat link and thermostat or a defective heat link.

In this article, I walk through your options on how to solve this problem.

US Nest Thermostats

In the US, a blinking orange light on a Nest Thermostat signifies either a charging problem (similar to the red blinking light) or a hardware fault within the device, which may or may not produce an error code.

1. Manually Charge the Battery

Manually charging your Nest Thermostat's battery can help prevent odd behavior and fix the blinking orange light.

  1. To do this, first, remove the display by gently pulling it off.
  2. Then, identify the USB cable required for your thermostat model; either a mini or micro USB.
  3. Avoid using underpowered USB connections for charging. Instead, opt for a wall outlet with a compatible USB adapter.
  4. Once charged, the thermostat's screen will light up with a message asking you to connect it back to its base.
  5. After charging for at least an hour or two, reattach the device to the wall, ensuring it clicks into place.
  6. If unsure about your adapter, test it with a different device, or try a new one.

It's important to mention that newer Nest Thermostat models, such as the Nest Thermostat E and later generations of the Nest Learning Thermostat, have an internal rechargeable battery.

These models charge when the furnace is on and through a common wire connection.

However, for older Nest Thermostat models, users will need to replace the two 1.5V AAA alkaline batteries as they deplete.

If manually charging the battery solves the issue temporarily, it's essential to address the underlying power issue for a permanent fix.

This may involve wiring a C-wire to provide constant power or fixing any loose connections with the existing C-wire. Check out my article here, where I dive into this further.

2. Hardware Fault Requiring a Replacement

A blinking orange light, or a combination of orange and green lights, on your Nest Thermostat and Nest Heat Link may indicate a hardware fault that requires a device replacement.

This could be caused by several issues, such as a problem with the display, Wi-Fi chip, or internal battery.

Multiple cases have been reported on the Google Nest community and Reddit, where users experienced this problem and ultimately needed to obtain a replacement from Google.

In some instances, a Nest thermostat can be damaged by factors like a power surge from your system or connecting it to an incompatible system.

Nest Reset

3. Try to Factory Reset to see if it solves the issue

A factory reset can solve issues caused by corrupted software from an update or incorrect settings in your Nest Thermostat.

Before performing a reset, note your thermostat's wiring information, system heating type, and safety temperature.

To reset, navigate to Settings and select Factory Reset.

Confirming this action will cause your thermostat to take a few moments to restart or reset.

If you choose Factory Reset, all personal settings will be erased, meaning you'll need to set up the thermostat and add it to your home in the app again, just like when you first installed it.

UK / European Nest Thermostats

UK and European Nest Thermostats may experience a blinking yellow light (often mistaken for orange) on the Heat Link, indicating a connectivity issue between the devices.

Nest Heat Link

1. Solve the Connectivity Issue

Sometimes the link between your Nest thermostat and Heat Link can drop, causing the blinking orange light on the Heat Link.

These devices connect via the Thread networking protocol so they don’t rely on Wi-Fi. In most cases, the Nest thermostat and Heat Link will automatically reconnect.

However, your Nest Thermostat does need Wi-Fi to connect to the cloud and for you to access it via the app.

A Wi-Fi connectivity issue may be down to an unplugged router, changes to Wi-Fi passwords or security configurations, or a drop in the internet connection.

If the Heat Link is in manual heat mode, simply press the Nest button to switch to manual mode. This allows the thermostat to regain control over the heating system.

Reconnection Failure

If the devices fail to reconnect, try the following: tap “Try Again” on the thermostat, check the message displayed, and search for the error code here for more detailed troubleshooting instructions.

If the issue persists, test the connection between the Heat Link and thermostat by moving the devices closer to each other.

Additionally, ensure that no large objects or electronic devices are interfering with the wireless signals between the devices.

If you identify and resolve the interference-causing device, your Nest Thermostat and Heat Link should reconnect successfully, and the status light will turn solid green, with your thermostat resuming control over your heating and hot water.

2. Any Error Codes Showing?

When encountering a blinking orange light on your Nest Thermostat and Nest Heat Link, it's essential to check for any error codes displayed on the device or within the app.

These error codes provide valuable information to help diagnose the issue.

To understand the meaning of specific codes and their solutions, visit Google Nest's official support page:

By researching the code, you can quickly identify the problem and follow recommended steps to resolve it.

Experiencing a blinking orange or yellow light on your Heat Link accompanied by an H1, H71, or H151 error code signifies a connection issue between your Nest Thermostat and Heat Link.

You'll also notice a yellow status light on your Heat Link, indicating disconnection from the thermostat.

  1. To resolve this, you'll need to restart the Heat Link.
  2. To restart the Heat Link, press and hold its button for approximately 20 seconds, until the light turns off.
  3. After releasing the button, give your Heat Link some time to restart.
  4. A successful re-connection to your thermostat will be indicated by a green status light on the Heat Link.

If the light remains orange/yellow, try to factory reset it.

Performing a factory reset on the Heat Link is a straightforward process but remember that this action will remove the Heat Link from the Nest app, requiring you to set it up again.

  1. First, remove your Heat Link from your account within the app.
  2. Then, hold down the Heat Link's button for about 15 seconds (for Thermostat E) or 20 seconds (for 2nd and 3rd gen Learning Thermostats) until the status light changes color.
  3. Release the button and wait for the factory reset to be completed, which will be indicated by a pulsing blue light.
  4. Once the factory reset is complete, reconnect the Heat Link to the app by scanning the QR code on the device.
  5. If your Nest thermostat asks for a pairing code during the process, you can find a 6-digit code at the bottom of the Heat Link.

After successfully reconnecting the Heat Link to the app and your Nest thermostat, your system should hopefully function normally.

A defective Heat Link can cause the Nest Thermostat and Heat Link's orange light to blink.

If you're experiencing this issue, it's essential to contact support for assistance.

Google is aware of a problem affecting some 3rd Gen Nest Learning Thermostat Heat Links in the UK and European countries.

To remedy this situation, they are reaching out to affected users and offering replacement Heat Links for free, regardless of the thermostat's warranty status.

Residents in the UK have the option of selecting a date for Google’s partner BOXT to supply and install the replacement Heat Link.

For those in other countries, Google will reimburse repair costs when an installer of your choice installs a new device.


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