What is normal for a temperature hysteresis (or "dead band") in a wine fridge? I am seeing 5F and more. It is a Vinotemp VT182. Long story short I modified it to become a beer fermenting chamber and added heating capability. Due to it being winter out here it is operated in heat mode right now and the original controller is still used to measure and regulate temps. I didn't hack the micro controller part of it (yet ...). Currently it is set to 65F. Heat came on at 63F or 64F and now it's topped out at 69F, still heating. Since the heater is wimpy that means it may be always on until it gets warmer outside. No problem, just got me to wonder why the hysteresis is so large on these. In case someone wants to know what's currently in there: American Wheat, Honey Porter, IPA and Pale Ale. It sure beats having all these buckets standing around in the downstairs room and having to run the pellet stove just for the fermenters. -- Regards, Joerg

Air temp in a fridge is notoriously variable, both in temp due to hysteresis, as you observe, and also in location inside the chamber. 5 deg for a typical fridge is pretty good, the controllers are not all that smart, in general. It is usually assumed that the liquids in the fridge hold at least the liquid at a relatively stable temp, due to the high heat capacity. So put more beer in ! -- Regards, Adrian Jansen

Slightly OT: Wine fridge temperature hysteresis?

Mar 05, 2017 24 Replies

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Mike Perkins 9 years ago

The hysteresis might have been set to take into account the nature of the cooling radiator in much the same way the mechanics of the bimetal sensor set the hysteresis.

My point is that the hysteresis was in part negated by the position of the sensor, which as you say is next to the heat exchanger.

Sorry, but hysteresis is hysteresis, whether through a mechanical switch or electronic means. I accept if you have access to the code then obviously you can make an equivalent of an 'accelerator heater' and save a component.

Mike Perkins Video Solutions Ltd www.videosolutions.ltd.uk

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Joerg 9 years ago

However, the hysteresis was still huge when I test ran it in cooling mode and the cycle times were very long. It just does not make sense.

Well, for the heating situation I'd have to make an "accelerator cooler" and that is no small feat. Would require a peltier which dissipates to some other farther away part in the fridge. Plus power.

Regards, Joerg http://www.analogconsultants.com/

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makolber 9 years ago

no, you just set up the small heater next to the sensor such that the heater is ON when the cooler is OFF.

You can then easily adjust the system hysteresis.

Also the term used is "anticipator"

mark

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makolber 9 years ago

which is simply a small resistor ACROSS the contacts

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Joerg 9 years ago

There are no contacts here, it's all electronic. I could place a small heater resistor near the sensor. Except then the temperature display will be off but I could probably arrive at a cheat sheet for that. More cables though.

Regards, Joerg http://www.analogconsultants.com/

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