Gas_680 value on Purple Air Zen never changes!

I’ve had my PurpleAir Zen up and running (indoors) for more than a day now and the gas_680 value has never changed. It is constant at 25.00.

From json?live=true:

From the device web page:
BME680: 82.00°F RH: 30.00% Dew: 47.00°F P: 1018.56 hPa AQ: 25.00 ADC: 0.04V

Note: I record all values every 30s and save to a database. I can state definitively that it never changes — even when I open the door. The other values listed above on the BME680 line do indeed change over time.

Also Note: I also have a PurpleAir Flex (outdoors) that also reports gas_680. That value does indeed change (I’m also saving every 30s and graphing this device).

What’s up with this? Do I have a defective BM688 in my new Zen?

@Amanda_Hawkins Would you be able to find out an answer for this question? I have a new Zen that has always read 25.00 for gas_680 (it never changes). Do I need a new unit?

I can confirm the same behaviour on my Zen

It’s disappointing that PurpleAir never replied to this; but the good news:

As of little after 8 am PDT this morning (March 16), gas_680 is now reporting correctly. I presume the device took an update.

Same here. Thanks for the update! (And the update.)

The VOC monitor in PurpleAir sensors is experimental. This is due to our implementation. We are finding ways to include everything required for it on the little space available (2MB) on the sensors.

We are working on changes to the firmware and hope to soon correct this issue.

Hi Ethan,

As I mentioned above, the issue has already been corrected (as of March 16).