Inkbird controller - WTF is hysteresis temperature?

[crosschk]

Got a new wifi inkbird today (old johnson controller may be for sale)

What is hysteresis temperature setting for?

 

[Whisky River]

Hysteresis is the range that the temperature will change before the controller activates to correct it. So if you have it set for 65f with a 3f hysteresis, the controller will kick in at 68f to begin cooling (or heating). You can often set it for a smaller range but then you increase the rate at which you are cycling on and off, which might not be great from a reliability standpoint depending on your equipment.

 

[crosschk]

Hysteresis is the range that the temperature will change before the controller activates to correct it. So if you have it set for 65f with a 3f hysteresis, the controller will kick in at 68f to begin cooling (or heating). You can often set it for a smaller range but then you increase the rate at which you are cycling on and off, which might not be great from a reliability standpoint depending on your equipment.

Thanks

 

[Whisky River]

Thanks

I should add, that’s all just my understanding from what I’ve learned here. Others may have more a more definitive explanation.
Either way, good luck with the new controller, would be interesting to hear how it works out.

 

[crosschk]

I set for 3 degreees either way....seems to be stuck in 1 degree or less if that's possible

 

[passedpawn]

In cooling equipment, hysteresis essentially adds a time delay so that the compressor isn't "short-cycled". You do not want to rapidly turn a compressor on/off. In the example above, 3° of hysteresis means the fridge will start cooling when the temperature goes OVER 68, but won't turn off until it goes UNDER 65. So there is that 3° that induces a time delay.

 

[doug293cz]

In cooling equipment, hysteresis essentially adds a time delay so that the compressor isn't "short-cycled". You do not want to rapidly turn a compressor on/off. In the example above, 3° of hysteresis means the fridge will start cooling when the temperature goes OVER 68, but won't turn off until it goes UNDER 65. So there is that 3° that induces a time delay.

View attachment 782747

Controllers like the InkBird ITC-308, also have a "Compressor Delay" setting, which prevents the compressor from restarting before the set number of minutes has elapsed. IIRC the max is 10 minutes on the 308. It should be set for the max delay when running a refrig/freezer. You want at least a little hysteresis so that measurement "noise" doesn't rapid cycle On/Off (although the compressor delay also prevents rapid cycling of the cooling output.)

I typically run with 1°F hysteresis, and 10 minutes delay. If you have a heater in your ferm chamber, you want it to be low wattage (less than 50W), or you will have too rapid cycling between heating and cooling.

Brew on

 

[Bobby_M]

Agree. The compressor delay is what saves short cycling but other than that, the desire is to keep the band narrow as long as the compressor delay doesn't forbid it. 1F for me.

 

[crosschk]

My fermenting chamber is a standup freezer. Hardly ever goes in the cool zone. I have a paint can heater to keep it in the 68-72 range all the time.

I bottle condition in there as well.

Thanks for the info guys

 

[crosschk]

My next question is what is the cooling back temp, is that the same as the hysteresis but for heat?

 

[jerrylotto]

Controllers like the InkBird ITC-308, also have a "Compressor Delay" setting, which prevents the compressor from restarting before the set number of minutes has elapsed. IIRC the max is 10 minutes on the 308. It should be set for the max delay when running a refrig/freezer. You want at least a little hysteresis so that measurement "noise" doesn't rapid cycle On/Off (although the compressor delay also prevents rapid cycling of the cooling output.)

I typically run with 1°F hysteresis, and 10 minutes delay. If you have a heater in your ferm chamber, you want it to be low wattage (less than 50W), or you will have too rapid cycling between heating and cooling.

Brew on

Not if you take your temperature reading from a thermowell or tape the probe to a keg. I don't really care what the air temperature is - I'm only interested in the wort temperature.

 

[doug293cz]

Not if you take your temperature reading from a thermowell or tape the probe to a keg. I don't really care what the air temperature is - I'm only interested in the wort temperature.

What's this have to do with the discussion? Nothing was said about where temps are measured. OP wanted to know about hysteresis in controllers. Hysteresis, and compressor delay have the same definition and purpose no matter where you put your temp probe.

Brew on

 

[jerrylotto]

What's this have to do with the discussion? Nothing was said about where temps are measured. OP wanted to know about hysteresis in controllers. Hysteresis, and compressor delay have the same definition and purpose no matter where you put your temp probe.

Brew on

Has a huge impact on the behavior of the controller. Ambient temperature can swing widely but wort temperature rises and falls much more gradually.