Tuning BrewPi settings


Is there any information on tuning PID settings? I am in the middle of my second fermentation with my new BrewPi Spark set up. This is in a new fridge (full height), with a 40W tube heater at the bottom. When heating, it goes a fair way over the set temperature before coming back down.

My control algorithm is attached.

Any help appreciated


BrewPi Control.txt (6.8 KB)

Can you post a screenshot with the the fridge temperature and setting?

It might also help to move your fridge sensor closer to the heater.

Sorry, Elco. That would have been a good idea! :slight_smile:

The chamber temperature probe is around the half-way point, height-wise, maybe slightly higher. I have a PC fan at the bottom by the heater bowing upwards on one side to keep so airflow within the chamber.

I am also experiencing a similar issue so am following this thread.

Your heater seems to overshoot the target fridge temperature a bit.
Without knowing your current settings, this will be a bit of a guess. I would:

  • Decrease heater Kp, increase heater Ti (at least 7200), heater Td at least 120.
  • Set beer-to-fridge Ti to a big value, like 14400.
  • Set beer-to-fridge Td to something bigger to account for the lag in the beer temperature.

Your beer temperature still rises after the fridge temperature has dropped below the beer temperature. This could be because your fridge sensor is far from the heater. Moving the fridge sensor towards the heater will improve this.

Thanks, Elco.
I have done what you suggest with the settings. I will have to wait until my next brew or until I can put water in to test.