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Johnson A419

Just bought one. Hooked it up to a upright freezer I also just bought. In order to achieve 60 degrees in the freezer I have to set the controller at 54. Is this a normal thing? I was under the impression If you set it at a temp it would be within a degree or two. Is there something I am missing or don’t understand.

I’m not sure what the default setting is, but if you press the menu button and switch to the ‘dif’ setting, change it to 2. That will have your freezer kick on if the temp differs more than 2 degrees of what you set it at. You could probably set it to 1 but I wouldn’t want to cycle the fridge so often.

edit - it could also have to do with where you have your probe placed.

Already have the diff set to 2. Is it common for these units to not read entirely accurate.

probe comes up through the drain hole of the freezer and is in the right hand corner

Is the probe hanging in the air or resting against the side of the freezer?

The best thing to do is either use a thermowell or tabe the probe to the side of the fermentor with some sort of insulation over it (plastic sheeting, zip-top bag, bubble wrap, etc.). That way the controller will monitor the temperature of the beer rather than the air temperature in the freezer and can keep it from cycling off (or on) too soon.

It’s fine to set the differential to 1 degree - just be sure to also set the anti-shortcycle timer.

That all being said, you can successfuly control fermentation temperature by measuring the temperature of the air in the freezer, but it requires some experimentation. In my opinion, it’s simpler to just monitor the beer temp.

Also, it sounds like you are doing a dry run to test out your gear, the temperature will be quite a bit more stable when you’ve got 5 or 10 gallons of beer sitting in there.

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