Another Johnson A419 Controller question

Hope this is the right forum vs. beginners forum.

I just put my first carboy into a 5.0 Holliday Freezer I have hooked up to the Johnson controller. I am running into the problem of it sitting at too cold of temps.

The controller is set Set Point 65 degrees
Differential is 1
Set to Cut-in so should be cutting off at 64

It seems to be holding consistently at 62 degrees and I would prefer it to be at 63 at least. I understand it will continue to run and make the surrounding air cooler but it is holding at 62 the whole time.

Probe is taped to carboy and covered with a sock (didn't have any bubble wrap)

Any Ideas on how I can get this straightened out? Maybe change it to cut-out?

Thanks again

To me the easiest mode to understand is to set to Cooling Mode and Cut-Out at Set Point. Then add a degree or two of Differential and call it a day.

In any case, there's always the chance that the probe is off by a couple of degrees. The only way to know that is to put the probe and a known accurate thermometer in the same test solution and check that they either agree, or note which way/how far the probe is off. Once you know that you can use the OFFSET setting to adjust the controller, or you can just manually adjust your Set Point to account for the difference...

Cheers!

Hving issues with mine too. I set mine at 68, when the freezer turns on, it cuts off at 66 or 67,,,,,,then next thing the temp is down in the 50's, WTF!

The reason is because of thermal mass in the freezer coils itself.

What happens is the compressor turns off when the controller tells it to....but there is still really cold freon in the coils that cool the freezer....they will still absorb heat from the freezer space (i.e. cool) until things equalize.

Remember what is important is your beer temp.....so set your temperature like you have it set and watch your actual beer temp (you have a fermometor on your bucket/carboy right?). If you set your freezer for 67F.....but your beer is maintaining 65F...but you want it at 67F....then you now know your offset temp to set your freezer needs to be 2F higher than the temp you want your beer at.

So, in this example, if you want your beer at 67f....you would set controller to 69F....knowing that the average temp of the freezer will end up at 67f over the long term.

Also....if you have an empty freezer...it will be worse...the temp swing after it shuts off because there is nothing in the freezer (i.e. 5 gallons of beer)...to help absorb the extra coolness.....

If you know you are getting a constant 62 but want 64 raise the temperature setting on the controller two degrees. It should stabilize at 64.

ok thanks.....my freezer is empty. But once I start using it to ferment,,,,should I also have another carboy in there filled wilth water? kinda like a full refridgerator is more efficient than an empty one?

Your fermenting carboy should be fine......

So the empty freezer is definately the reason for the huge swings....you still may need to adjust temp higher on setpoint....but not so much....

Just monitor it once you have beer in there....but if you make changes to setpoiunt give it a day to equalize and settle before making another change

Just affirming the above and adding my experience: I turn the freezer on early in the brewday and it will fluctuate pretty widely. But once the carboy is in there, it is much more stable. Still some fluctuation, but not nearly as wide.