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.
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.
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.