Johnson Temp Controller

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flabyboy

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Quick question. I just received my Johnson temp controller for my kegerator project and am wondering if any of you had to open up the box and change around any of the jumpers inside. The menu buttons seem pretty straight forward and it is factory preset for cooling purposes.
 
I changed mine around, but I was using to to heat a freezer in the winter. I think that if you are using in cooling mode you should be fine. The other jumper is for cut-in/cut-off, and I think most people use the default.
 
I'm using mine to keep a cheat freezer in my house between 40-45 degrees. Should be good not touching it then.
 
You're going to want it set to cooling and to cut out. You'll want the set point at 40 and a dif of 4 or 5 to keep it between 40 & 45.
 
So have my setpoint at 40 and my DIF at 5 and the temp dropped to 35. Do I need to set the SP to 45 if I want the temp between 40-45
 
Now I have the SP at 45 and DIF at 5. The freeze kicked in at 45 and I went to look at the temp 10 mins later and it's 35. WTF
 
You're going to want it set to cooling and to cut out. You'll want the set point at 40 and a dif of 4 or 5 to keep it between 40 & 45.

In this setup, the freezer will turn ON at 45, and turn off at 40. The freezer will turn on at the SP + Differential, which is 45. It will turn OFF at the SP (Cut-out).

The Cut-in and Cut-out is what they controller will do when the SP is reached.

Keep in mind that even though the freezer has turned out, there is a chance that the temp could drop a degree or two as the cold soaks into the freezer.

And a small fluctuation in air temp is not a concern. It's the temp inside the fermenter that matters, and it will be more stable, as it has such thermal mass to not lose or gain temp as quickly.

I really suggest you re-read the manual a few times. There is a small section that should give a visual example of how the cut-in and control mode work together. It's not hard to understand if you can "see" it.
 
JC_Modes.jpg



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Hmm... Strange. I never had a problem posting images before, and a cut/paste works in a browser. Maybe I stayed up too late last night and now my brain is not working properly...
 
In this setup, the freezer will turn ON at 45, and turn off at 40. The freezer will turn on at the SP + Differential, which is 45. It will turn OFF at the SP (Cut-out).

The Cut-in and Cut-out is what they controller will do when the SP is reached.

Keep in mind that even though the freezer has turned out, there is a chance that the temp could drop a degree or two as the cold soaks into the freezer.

And a small fluctuation in air temp is not a concern. It's the temp inside the fermenter that matters, and it will be more stable, as it has such thermal mass to not lose or gain temp as quickly.

I really suggest you re-read the manual a few times. There is a small section that should give a visual example of how the cut-in and control mode work together. It's not hard to understand if you can "see" it.

I always forget the terminology. I've been using one of these for a couple of years now. I know what pins to put the caps on to make my fridge and my heater work the way I need it to.
 
I always forget the terminology. I've been using one of these for a couple of years now. I know what pins to put the caps on to make my fridge and my heater work the way I need it to.

I'm not even familiar enough to get it straight right away. I usually have to re-read the book.

And I HATE that they put jumpers on the INSIDE. If I wanted to change it (which is very likely living in a state with a 120F temp swing each year) I have to undo the 4 screws. I'm seriously considering installing small switches into this thing. I mean, it's not even the waterproof housing!
 
I'm not even familiar enough to get it straight right away. I usually have to re-read the book.

And I HATE that they put jumpers on the INSIDE. If I wanted to change it (which is very likely living in a state with a 120F temp swing each year) I have to undo the 4 screws. I'm seriously considering installing small switches into this thing. I mean, it's not even the waterproof housing!

I completely agree. Having to undo the stupid screws all the time is such a PITA. I've actually stopped using my heater most of the time just so I don't have to switch from heat to cool so often.
 
Thanks for your help. Right now I have it set to cool with SP of 40 DIF 5 and cut-off. It kicks in at 45 and cuts out at 40. Unfortunately the freezer continues to cool even after it cuts out. I have nothing in there right now. Just testing it out. I'm sure it will be better when 3 full kegs are in there
 
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