Cannot set temperature below zero about fermentrack HOT 4 CLOSED

Thank you for reporting this! Interestingly, I dont know how long this bug has been out there but I stumbled across it myself on this side by accident two days ago when trying to investigate a different issue for someone on HomeBrewTalk.

The issue is entirely in the display on the device - not in Fermentrack. If you change the device from Celsius to Fahrenheit you will see that it will drop below 32 as expected. Make sure that your control constants are set such that the minimum temperature is lower than 0 as well to make sure you can chill below 0 if that is what you would like to do.

from fermentrack.

Ah interesting, I was trying to edit the control constant minimum temperature and after saving and then returning to the setting page it would return to the absolute value and loose the negative value. If I get time I'll have a look through the flow of setting the control constant and see if there's anything there.

Just adding this screenshot of the settings page to illustrate (has been set to -10°C):

The device display is showing all negative values as absolute value, but is definitely respecting the negative value and allowing the fridge to actually go to negative temperatures.

from fermentrack.

It seems everything is being reported by the device in absolute values, even the log has interesting results with the temperature hitting zero and immediately 'climbing' at the same rate as it was falling:

from fermentrack.

I'll close this issue here as it's not fermentrack but rather brewpi-ESP that has the issue.

from fermentrack.