Author Topic: I Really Need Help with my Johnson Controls A419.  (Read 7738 times)

Offline patrickswayze

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I Really Need Help with my Johnson Controls A419.
« on: July 11, 2012, 07:09:06 PM »
Hey guys i just received a Johnson Controls A419 Unit this past weekend from Amazon and today i plugged it in to my Haier Chest Freezer for the first time. I plugged in the following for the device

Setpoint: 63'F
Differential: 1
Anti-Short Cycle Delay: 1
Temp Offset: 0

I have the probe suspended in the middle of the freezer. The freezer itself is set to its lowest setting. The problem i am having is that when my control turns off the freezer at the 62-63'F mark it keeps dropping slowly all the way down to 51'F or so. I WANT TO RIP MY HAIR OUT this is soo frustrating. Please, can anyone help me out here, why is this happening? It should be only a degree or two off from my setpoint.

Offline tom

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #1 on: July 11, 2012, 07:26:44 PM »
It may continue to cool a little bit, but that's a lot.  How big is the freezer?  What else is in the freezer?
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Offline patrickswayze

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #2 on: July 11, 2012, 07:32:04 PM »
Right now their is nothing in the freezer as i am testing it out before brewing this Friday. The freezer is 7.1 cubic feet. I plugged in the A419 when the freezer was off. Should i have connected it when freezer had already been cold, so the air would be relatively universal?
« Last Edit: July 11, 2012, 07:57:09 PM by patrickswayze »

Offline aa7yy

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #3 on: July 11, 2012, 09:01:21 PM »
So I had to pour a glass of wine to think about this. If you left your freezer unplugged and put the probe inside, what would the temperature be ? If you come back with any number under 63 then I think you are expecting your freezer to be a heater. Not sure that works. Seems that even if you tell the freezer to shut off at 63 the coils and condenser are still cold.  So if so, how about the light bulb in the paint can to heat it up and skip the freezer ?

Plan B, drop the setpoint way down and use it for lagers. Not sure you need a freezer for ale temps.

But if I knew what I was talking about I would probably be drinking homebrew.

Offline patrickswayze

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #4 on: July 11, 2012, 09:42:55 PM »
My temp in San Diego is around 86'F and was about 78'F in the freezer before plugged in. Im just asking for some assumptions or personal experiences to help me in why when the freezer turns off at my setpoint temp but the temp still drops so dramatically after the freezer has been turned off. Probe location? Should i place a glass of water in the freezer and place the probe in it? The manufacuter is no help so im trying to get help from the community who has first hand expeience. This is prolly the one post i meed the most help in! Please! If it sounds like i am begging, its cause i am

Offline tschmidlin

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #5 on: July 11, 2012, 11:16:35 PM »
I would guess it's probe location.  You're in the center of the space, and the cooling is coming from the walls.  By the time it hits 63 in the center the walls are much colder, so it drops further as the heat evens out in the space.

First, put some stuff in it - an empty space like that makes the compressor work much harder.  At the very least put some water jugs in there.  The more stuff in the space the more it will even out.

Don't put the probe in water to begin with, that will just make it worse because you're waiting for the freezer to suck the heat out of the walls, which pulls it from the air, which pulls it from the water until the water gets cold enough.  That's going to take a long time and the walls will be even colder.

Basically, put stuff in it and leave it alone.  Given time it will even out and it will work as expected.
Tom Schmidlin

Offline narvin

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #6 on: July 12, 2012, 05:02:39 AM »
Air temperature is going to fluctuate very quickly. The walls will stay cold after the freezer shuts off, cooling air near the sides and causing convection currents that show fluctuations on your probe reading.  Even with a fan to even things out, you're never going to be able to keep the air temperature around 63 without cycling the freezer on and off constantly, and this will break your freezer pretty quickly.

You don't care about air temperature; you want to maintain the temperature of your beer, so tape the probe to the side of your carboy (or use a thermowell).  5 gallons of liquid has a lot more thermal mass, so the freezer will run for longer periods of time and then shut off for longer, and your beer temperature should only fluctuate 1 or 2 degrees.
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Re: I Really Need Help with my Johnson Controls A419.
« Reply #7 on: July 12, 2012, 07:41:38 AM »
Is there a reason why you'd want your freezer on the coldest setting versus the warmest?
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Offline EHall

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #8 on: July 12, 2012, 07:43:01 AM »
Sometimes I need help with my johnson control too...  ;)
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Offline patrickswayze

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #9 on: July 12, 2012, 11:27:17 AM »
Is there a reason why you'd want your freezer on the coldest setting versus the warmest?

Not sure if this was for me but i have it on the warmest setting possible

Online beersk

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #10 on: July 12, 2012, 12:17:21 PM »
Is there a reason why you'd want your freezer on the coldest setting versus the warmest?

Not sure if this was for me but i have it on the warmest setting possible
Yes and no, it was sort of a general question.  Not intending to hijack the thread.
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Offline patrickswayze

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #11 on: July 12, 2012, 12:23:04 PM »
Is there a reason why you'd want your freezer on the coldest setting versus the warmest?

Not sure if this was for me but i have it on the warmest setting possible
Yes and no, it was sort of a general question.  Not intending to hijack the thread.

No worries, im actually curious about this as well

Offline Slowbrew

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #12 on: July 12, 2012, 12:58:05 PM »
Setting the freezer's thermostat to the coldest guarantees that you won't have any contention between the internal and external controllers.  It really shouldn't matter in a freezer since the idea behind the appliance is to freeze things but it is basically standard practice on control systems to set the controller being overridden to the max setting to avoid issues. 

Paul
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Offline tom

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Re: I Really Need Help with my Johnson Controls A419.
« Reply #13 on: July 12, 2012, 01:11:59 PM »
I think it will equilibrate after a few cycles.
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Re: I Really Need Help with my Johnson Controls A419.
« Reply #14 on: July 12, 2012, 01:49:58 PM »
So essentially it doesn't matter...

Does the front of y'alls freezer get warm when it's running?
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