Reconditioning a WH31A

[HansR]

I had a WH31A performing badly on both T and H - resp. 12°C and 100% constant - and so I decided to get it inside and try some reconditioning.

Howto?

I put it beside my laptop in the outstream of the ventilator. T rose to 40 - 50 °C and H decreased to 15 - 20%. When a steady state was reached I had it there for a few hrs and put it back beside my new WN31A (which is exactly the same). I cycled this 4 times and it is almost back to where it should be. H is still 10% off, T is OK. Any improvements on the method? See screenshot:

Schermafbeelding 2022-10-25 140255.jpg

[mcrossley]

Sensirion recommend...

Baking: 100 – 105°C at < 5%RH for 10 hours
Re-Hydration: 20 – 30°C at ~75%RH for 12 hours

Not sure if the WH31 package would withstand that, but the bare cct board should be OK?

[HansR]

Sensirion recommend...

Baking: 100 – 105°C at < 5%RH for 10 hours
Re-Hydration: 20 – 30°C at ~75%RH for 12 hours

Not sure if the WH31 package would withstand that, but the bare cct board should be OK?

Ha, that was my first idea but I had the same doubt although I could do a test with the plastic (using the detachable battery protection lid).

But keeping the oven on 100+ °C for 10 hrs costs a lot more than having it beside the laptop and that is a legitimate consideration at times like these. I assume the energy prices in the UK are at similar levels as they are here? (currently there is a limit of I believe 0.7 € / kWh, it was 0.17 €) although it takes a bit more time (1 cycle per day) it seems to work with no extra costs.

Doing the bare board it would require soldering, but OK. Could be done yes.

[mcrossley]

I know what you mean, last time I did a Davis sensor I did it in the oven (electric, not gas please folks!), but only for a couple of hours, and it seemed to return to normal after that. I think it depends on what it is contaminated with and how badly to determine what temperature and for long it needs to be done.