Brewblox over- and under-shooting


Just updated to the new Brewblox yesterday. Tried setting the fridge to Fridge constant 7C for conditioning beer. At first it cooled too far, then seemed to come back up, only to cool again. Then I get home this evening to the fridge temperature being over 20C!

What is going on here? I really don’t understand why a setup which worked so well with the old BrewPi software suddenly becomes unpredictable and unreliable.

For cooling:
Kp: -50C, Ti: 2h, Td: 10m

Kp: 20C, Ti: 2h, Td: 10m

Any help greatly appreciated!


Those PID settings seem correct for controlling based on a beer sensor which is in over 20 liters of beer, but not for controlling based on the fridge sensor.

I see that the quick action to switch to fridge control mode contains prompts for Kp, Ti and Td to reconfigure the PID, but not suggested values. We’ll fix that in tomorrow’s release. Reminder @Bob_Steers.

What the quick action should do is:

  • Change input of heating and cooling PID to the fridge setpoint
  • Change Kp, Ti and Td to values appropriate for controlling fridge air temp:
    • Cooling: Kp: -10, Ti: 2h, Td: 5m
    • Heating: Kp: 10, Ti: 2h, Td: 5m

Did you use the quick actions?
Can you export your blocks (spark service page) so I can see why the cooler didn’t activate again?

BrewBlox is a lot more flexible in how it can be configured and this seems like it was not configured correctly, but I need more info to figure out why. Once correctly configured it should be very stable in controlling your beer.

Hello Elco,

Many thanks for the reply in the evening. I have set the PID settings as suggested. When I ran the fridge set point, it did suggest some settings, I cannot recall what they were though, but I set to what had previously been recommended to me. I did not know (and I could not see anywhere where it was explained) that these settings should be different depending on whether using beer- or fridge-constant. I don’t recall ever changing anything in BrewPi, it jsut seemed to work :slight_smile:

I have exported my blocks. Unfortunately I did not see that until after I saw the recommended settings, so I had already changed to what you recommended. Not sure if that will mess up what you were hoping to see. If so, sorry!

I am sure that it will. I just feel kind of lost as I don’t really understand what all of the settings mean. I have been happily controlling my beer fermentation without any knowledge of exactly what was going on under the hood as it were! It would be good if there was a Novice’s / Idiot’s Guide to all of this in the interface.

brewblox-blocks-spark-one.json (9.8 KB)

Thanks again!

Looking at your blocks, your PID’s still have as input the beer setting and not the fridge setting. That is probably why it didn’t cool.

We’ll discuss what to change tomorrow at the office and try to include it in tomorrow’s release.
It shouldn’t be so easy to configure it in a way that won’t work properly.
You will have to re-run the setup wizard after updating to the new release to get the updated quick actions.

Thanks! Not sure why it is using the beer setting. I did click the Apply next to constant fridge temperature.

The beer sensor was lying on the floor of the fridge next to the heater, which is why it was reading higher than the fridge sensor (at the top). As there is no fermentor in there right (two corney kegs for conditioning), the beer sensor was not in a thermowell. I have put the beer sensor on top of one of the corneys in contact with the metal lid now.

I did re-run the setup after updating. Not sure if that is why all my sensors and PIDs have -2 after their names now.

Kind regards,

Yes, probably, but I meant after updating to tomorrow’s release.
For a fresh start, go to the dashboard and from the top right menu delete the dashboard and from the Spark service page, remove all blocks.

But wait for tomorrow’s update.

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We checked and the release you had should already have all of the changes in the action needed to switch to fridge control. We only removed the confirmation.

Perhaps you clicked cancel on the query for Kp?

Try the new release anyway.
On the spark page, actions -> remove all blocks
On your old dashboard: actions -> remove dashboard

Then rerun the Wizard.

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I applied the update yesterday and so far so good!

I think that the previous version did prompt for settings, I probably kept my existing settings though. That could explain the initial issue, but why after these settings were corrected did it still not work is a mystery to me.

Whenever I change from fridge constant, to beer constant or fermentation profile, will I have to change all of these settings each time?


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The switcher now automatically adjusts your PID settings.

If you want to use different settings for eg. the cool PID when in fridge mode, edit the settings in the fridge constant action, and then apply.

That way, you can switch back and forth, without losing changes.