# VOC fixed at 50

**URL:** <https://community.purpleair.com/t/voc-fixed-at-50/10109>\
**Category:** Sensors\
**Created:** [August 28, 2024, 9:48pm UTC](https://community.purpleair.com/t/voc-fixed-at-50/10109 "2024-08-28T21:48:31Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Bulgin](https://avatars.discourse-cdn.com/v4/letter/b/ba9def/32.png) [@Bulgin](https://community.purpleair.com/u/Bulgin)\
**Post date:** [August 28, 2024, 9:48pm UTC](https://community.purpleair.com/t/voc-fixed-at-50/10109/1 "2024-08-28T21:48:31Z")

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Hi, just received a touch sensor. The AQ/VOC measurement is fixed at 50. I’ve tried a sharpie and no response from the sensor. This is what is see from the BME. Any ideas before I RMA the unit?

BME680: 88.00°F RH: 43.00% Dew: 62.00°F P: 973.17 hPa AQ: 50.00 ADC: 0.41V

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**Author:** ![Bulgin](https://avatars.discourse-cdn.com/v4/letter/b/ba9def/32.png) [@Bulgin](https://community.purpleair.com/u/Bulgin)\
**Post date:** [August 28, 2024, 11:56pm UTC](https://community.purpleair.com/t/voc-fixed-at-50/10109/2 "2024-08-28T23:56:05Z")

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Quick update. After a while the BME68x did start to respond. I wonder if there is an initial stabilization period that I wasn’t letting complete (moving it around).  
 ![image](https://us1.discourse-cdn.com/flex020/uploads/purpleair/original/2X/8/8a4f7071a6eefa0aae6e9d6582de85d71e4a5db6.png)

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**Author:** ![Me912](https://avatars.discourse-cdn.com/v4/letter/m/a87d85/32.png) [@Me912](https://community.purpleair.com/u/Me912)\
**Post date:** [August 30, 2024, 5:00am UTC](https://community.purpleair.com/t/voc-fixed-at-50/10109/3 "2024-08-30T05:00:14Z")

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Hi @Bulgin

The VOC sensor takes about 48 hours to ‘burn in’. This will cause the sensor to read around the 50 mark for a bit. I generally do not rely on any data produced by the BME for at least 48 hours after first plugging in the device.

Hope this helps 🙂

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**Author:** ![OceanAir](https://avatars.discourse-cdn.com/v4/letter/o/db5fbb/32.png) [@OceanAir](https://community.purpleair.com/u/OceanAir)\
**Post date:** [September 13, 2024, 7:48pm UTC](https://community.purpleair.com/t/voc-fixed-at-50/10109/4 "2024-09-13T19:48:00Z")

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Are you sure about that? Is that what PurpleAir says? What about when moving locations (ie unplugging and plugging back in a few minutes later)? I have not seen it plateau at any number when moving it (I don’t recall when it was new if it did).

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**Author:** ![Bulgin](https://avatars.discourse-cdn.com/v4/letter/b/ba9def/32.png) [@Bulgin](https://community.purpleair.com/u/Bulgin)\
**Post date:** [September 13, 2024, 8:26pm UTC](https://community.purpleair.com/t/voc-fixed-at-50/10109/5 "2024-09-13T20:26:46Z")

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From my research the burn in period is only at first device usage out of the factory. This matches my experience.