Hi
Started a New brew a couple of days ago and noticed today that the brewpi heats every time the temp is a bit to low. Never seen it before. Normaly the temp from fermentation heats it up and the fridge cools it down. Its the old arduino brewpi and it has worked fine for several years. Anything I can do?
Increase the minimum time for switching between heating and cooling, on the bottom of advanced settings.
On the bottom of advanced settings I have “Trigger rotary encoder at every …” and I know its not that one 
Anything called ‘dead time’ ? Have not used the Arduino version for quite a while.
No. These are the settings under advanced settings/Control constants
Temperature idle range top
Temperature idle range bottom
Heating target upper bound
Heating target lower bound
Cooling target upper bound
Cooling target lower bound
Maximum time in seconds for heating overshoot estimator
Maximum time in seconds for cooling overshoot estimator
Beer fast filter delay time
Beer slow filter delay time
Beer slope filter delay time
Fridge fast filter delay time
Fridge slow filter delay time
Fridge slope filter delay time
Use light as heater
Ah ok. I looked at your chart again. Your fridge temperature continues to drop long after you stop cooling.
You are probably cooling the back of the fridge beyond what is needed and you have overshot before that cold reaches the sensor. Try moving the sensor closer to the back of the fridge.
Thanks, I’ll have a look when I get home
Have a beer in the fermentor for about a week. How does my graph look? Seems a bit strange at the end of the graph?
You’ll have to zoom in on that last part. Can’t give much feedback from this data, I need to see when it was cooling and heating.
I think you should try a higher kp and longer ti
Pid kp? Where do I find ti?
Right, arduino version. Lower Ki, increase Kp. The theory is that with kp too low, you’ll have the integrator increasing and decreasing to provide the action, which is slow. If the proportional part does more work, this is not needed.
Thanks 
By how much? Ki is 0,25 and kp is 5
Try doubling Kp and halving Ki. Reduce Ki further if needed.
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