Johnson A419 chilling too much, user error?

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Jukas

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Folks,

I have a Johnson A419 controller jumped in factory default settings that I'm using with my brewhemoth conical to control the pump for the IC. I have it configured with the following settings.

SP: 66F
SF: 1
OFS: 0
ASD: 1
DIF: 1

What I'm expecting is that the controller will try and keep the temp at 66F with a differential of 1F, so when it hits 67F it will turn on the plug until the temp reads 65F and then shut off with a minimum 1 min delay between cycles.

What I'm experiencing however is that once it hits 67F it will actually chill all the way down to 63F before shutting off. Am I misinterpreting how this controller works, or is it indicative of an problem with it?
 
Is it set to cut in or out at set point? What I do is set it to cut in at set point, change the sp to one degree above the desired temperature and keep all the other settings just like you have them
 
ASD of 1 min is pretty low. I usually set mine for 15 min or so.
The cut-in/cut-out toggle switch at the top, inside the unit. U need to open it and switch a jumper.

Also, I highly recommend adding a fan that turns on when the circuit is hot. I use the vornado fans since they are easy to aim, have a high/low toggle, quiet, are small and in a shielded case
 
ASD of 1 min is pretty low. I usually set mine for 15 min or so.

It's controlling a submersible aquarium pump that runs ice-water through the IC. I left it at the default 1min because A) it never seems to try and run that frequently anyways B) it's not controlling a compressor where your worry about the time between on/off.

The cut-in/cut-out toggle switch at the top, inside the unit. U need to open it and switch a jumper.
Also, I highly recommend adding a fan that turns on when the circuit is hot. I use the vornado fans since they are easy to aim, have a high/low toggle, quiet, are small and in a shielded case

I'm confused as to why I would switch the jumper as I believe it's currently set to cut in. If I set it to cut out, wouldn't that be to control a heater or am I misunderstanding the purpose?
 
It's controlling a submersible aquarium pump that runs ice-water through the IC. I left it at the default 1min because A) it never seems to try and run that frequently anyways B) it's not controlling a compressor where your worry about the time between on/off.



I'm confused as to why I would switch the jumper as I believe it's currently set to cut in. If I set it to cut out, wouldn't that be to control a heater or am I misunderstanding the purpose?

You need to check and see what it is actually set to as that is going to make a difference in your set point. Cut out is more apt for using the heat mode but it can also be used for cooling as well.

Here is the manual http://cgproducts.johnsoncontrols.com/MET_PDF/125188.PDF
check out pages 5 and 7
 
Oh, I missed the IC pump part. Ya 1 asd is fine and nevermind the fan comment.
Its possible that your ic contains a lot of coolant and alot of thermal mass? When you refresh the line with cold water by turning on the pump, it takes time to balance out between the wort and the IC. Are you sure that the controller actually has the green light and pumping when it goes to 66 and lower and its not just the system balancing after the large amount of cold is added?
 
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