Stirring Unit not working

Hey all!

After some troubleshooting, I couldn’t find a way to get the stirrer in our pioreactor running.
The screws don’t touch the fan / the fan is spinning, the fan is plugged in PWM1, adjusted the rpm from 550 to 200 ppm, but I always get this error message:

Any idea?


Hi Sara, welcome!

Did you have a look at our stirring troubleshooting guide yet?

Yip, currently the distance between the fan and screws is about 0,5mm & the fan is potentially able to spin.
However, it does not even start to spin. Would it be worth sharing pictures?

Pics would help!

Sorry I don’t quite follow:

So the fan does not spin when you start the stirring activity?

Yip, it won’t even start. When manually activating the stirrer, I get the error message instantly.

There should be enough space between fan and vial holder.

Yup that all looks good. Here’s two things I’d like you to try:

  1. When you start the stirring activity, can you confirm that the “PWM intensity” section in the Pioreactor card has a non-zero % for channel 1? Like in the image below:
    Screenshot 2023-07-18 at 12.10.48 PM

  2. To confirm that it’s the fan and not the HAT: can you change the [PWM] section in the config to use a different channel for stirring? The following example changes stirring to use PWM channel 2:


Hit save. Now change the stirring wiring to connect into PWM channel 2. And try starting stirring again from the UI. Let me know if this works.

We do check each PWM and fan for problems before we ship, but something may have still occurred during shipping. Perhaps a connection become loose.

@sara_m did you get a chance to try this again? BTW do you hear a small hum when you start the stirring?