BME280 incorrect RH reading. Reconditioning procedure does not work.

[rob]

We are having an issue with an entire lot of BME280 sensors that have been reflowed onto our design. During reflow we followed the exact recommended curve for the BME280.  We have now noticed the RH to be wildly off from actual RH. About 13% to 15% off. We attempted to recondition the sensors using the reconditioning procedures in the datasheet. This did not work for us. It seemed to only improve the sensors by 2%. 

Are there any other methods to reconditoning these sensors? Is there any known eratta or other issues not listed in the data sheet? 

[kgoveas]

Hi rob,

Which reconditioning method did you attempt?

Regards,

kgoveas

[rob]

We have attempted all 3 methods on multiple boards.

Rob

[handytech]

Could please also confirm that you have followed all the recommendations of BME280's HSMI manual, and especially that you protected the hole in the sensor's lid from any contamination during the process (e.g. solder flux, cleaning agents, sprays, etc.)?

Are you using our recommended BME280's sensor API?

Could you please share more details about the sensor used as reference/ground truth? Since relative humidity depends on temperature, it would be useful to also share both temperatures of BME280 and reference device.

[elrhoul]

Dear Rob,

We need some specific data to investigate your issue, can you please share your email address with me via private message on this forum, I will forward to right people to follow-up on this,

Thank you.