Power Troubleshooting

This article will walk you through what to do if your sensor isn’t receiving power. There are many reasons this could happen, but you are most likely to notice because your sensor’s lights turned off or it went gray on the PurpleAir map. Please follow the steps below to troubleshoot.


Checking Your Sensor’s Power Status

All PurpleAir sensor models indicate, in some way, whether they are getting power or not. Confirming whether your sensor is or isn’t getting power is the first step in power troubleshooting. A majority of PurpleAir models use a red LED to indicate that they are getting power. When plugged in, if the LED shines continually, the device is receiving power. If it isn’t shining, then the sensor could be experiencing a power issue. Please navigate to the sensor model you have below to see how to check its power status.

The PurpleAir Classic or Classic SD

The PurpleAir Classic and Classic SD’s red LED is deep inside the device housing. However, this light can be hard to see if there are multiple other light sources nearby. If possible, we recommend looking for it in a dark place. View the image below for reference.

The PurpleAir Flex

The PurpleAir Flex’s red LED can be seen on the edge of the device’s board. This light is typically easily viewable, although you may want to eliminate nearby light sources to confirm its status. The Flex also contains an AQI indicator LED that will shine different colors depending on the air quality. View the image below for reference.

The PurpleAir Zen

The PurpleAir Zen’s red LED can be seen on the edge of the device’s board. This light is typically easily viewable, although you may want to eliminate nearby light sources to confirm its status. The Zen also contains an AQI indicator LED strip that will shine different colors depending on the air quality. View the image below for reference.

Please be aware that the Zen contains a double-tap feature that can turn the AQI LED strip off. If you don’t see those lights, try double-tapping your sensor to on.

The PurpleAir Touch

The PurpleAir Touch does not contain a red indicator LED. Rather, it contains a series of AQI indicator LEDs like those mentioned above. If they are shining, the device is receiving power. See the image below for reference.

Please be aware that the Zen contains a double-tap feature that can turn the AQI LED strip off. If you don’t see those lights, try double-tapping your sensor to on.


LED Behavior

The behavior of the LED(s) you examined will vary depending on the specific issue the sensor is experiencing. The following section goes over the troubleshooting steps for each LED behavior.

Please note that it is possible you might see the red LED, but it is blinking. The blinking light indicates that the sensor isn’t receiving sufficient power. A blinking LED should be treated the same as if the light didn’t turn on at all.

The following steps require you to look at your sensor on the PurpleAir map to see if it is connected. Navigate to the section that best describes your situation below:

LED(s) are off, but the Sensor is Reporting to the Map

PurpleAir sensors need sufficient power to connect to the map. So, if your sensor is still reporting to the map, that means it is receiving power. Note that a gray dot on the map usually means that the sensor is offline.

There are a few reasons why this situation can occur.

  1. LED visibility can be set during registration, and it is possible that your sensor was registered to display no LEDs. To ensure this isn’t the problem, you can re-register your sensor with updated LED settings. If you want your LEDs to be on base settings, set “LED Mode” to “Power, SD Status and Full Color AQI” and “LED Brightness (%)” to “35.” See the image below for reference.

  1. As mentioned above, the PurpleAir Touch and Zen models support a double-tap feature. Please ensure that your device has not been double-tapped to off.

  2. If the above did not solve your issue, it is possible that your device contains a failed component. In this case, please email contact@purpleair.com to inquire about replacement.

LED(s) are on, but the Sensor isn’t Reporting to the Map

If the LED(s) are on, that means that your sensor is receiving sufficient power. If it’s not reporting to the map, the likely reasons are that either the sensor has disconnected from the internet or your map settings are affecting its visibility.

  1. We’ll first want you to double-check your map settings to ensure they are not the culprit. Follow the steps in our Map Troubleshooting guide to do so. If that doesn’t work, move on to the next step.

  2. Look for a nearby WiFi network named PurpleAir-****. The stars will be the last two to four characters in your sensor’s MAC address. If you see that network, connect to it and follow the steps listed in our WiFi and Registration guide to get it reconnected.

  3. If you don’t see the PurpleAir network, follow the steps in our WiFi Troubleshooting guide to reconnect the device.

LED(s) are off, and the Sensor isn’t Reporting to the Map

This is the situation in which the sensor may not be receiving power. Please follow the steps below to troubleshoot your sensor’s power connection. Some of the steps below may not apply to the Touch model because its cable is attached directly to the device. If troubleshooting a Touch, follow the steps below as best as you can.

Some of the steps below involve using a separate micro-USB cable not supplied by PurpleAir.

  1. Plug the sensor into a different outlet than the one it is usually connected to. This is to test whether the outlet is the problem. Alternatively, you can try plugging a different electronic device into the same outlet.

  2. Try powering the sensor on with a separate micro-USB cable from the one you were previously using to see if the power cable is the problem. You can also try flexing the power cable around in different ways to see if you can get the red LED to light up. If you are able to turn the sensor on with this method, you know the cable is the issue.

  3. If you have a Classic, Classic-SD, or older PA-I Indoor device, move to Troubleshooting the Internal Power Adaptor below. If you have a Flex, Zen, or Touch, your device may be experiencing component failure. Please reach out to contact@purpleair.com to inquire about replacement.


Troubleshooting the Internal Power Adaptor

The PurpleAir Classic, Classic-SD, and discontinued PA-I Indoor models contain internal power adaptors that can cause power issues. Please follow the instructions in our Checking the 6-inch Internal Adaptor Cable article to troubleshoot your device further.


Learn More

PurpleAir Map Guide
View Your Sensor on the Map
SD Card Logging and Troubleshooting