Johnson Temp Controller Kegerator Issues?

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jbay76

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Folks,
I'm super bummed and could use some help. I have this kegerator that has had wild temp swings. I bought a Johnson Temp digital temp controller to get my temp w/i +/-1 degree. I set it at 38, and 2 days later my kegs are at 46, WTF. I have the probe taped to one of the kegs. What settings should I be using? Would that even help? Anyone had these same issues?
Thanks
J
 
Also, I'd check the start delay setting while I'm at it (ASd). This affects how frequently the controller will allow the compressor to cycle. I have mine set to the max (12), which means that it will not allow the compressor to kick on sooner than 12 minutes from the previous cycle. This is to prevent the compressor for turning on and off too frequently, which will shorten the lifespan of your kegerator.

I'm still not sure as to the best way to set the probe. Currently I have mine suspended in a large mason jar of water at the bottom of the kegerator, as leaving it in the open air would cause temp readings to differ drastically from what is actually inside the keg (air temp changes much faster than liquid temp). I'm not sure how this compares (better or worse) to taping it to the side of the keg.

Does anyone know the best method for setting the probe? Is taping it to the side of the keg a good way to measure the keg temp?
 
Hi Folks,
I have the differential set at 1, I like my temps within a tight range. I have not messed with the ASd, so I am sure its at the default setting of 1. I'll check that and change it to 12. I also placed the fridge's dial temp controller to its coldest setting. from my understanding, and I do this with my fermentation fridge, you attach the probe to the item you want to measure. So, from that P.O.V., I have mine taped to the keg nearest the door. This is the one that'll be the warmest.

Back to the ASd. If its set to 12, and the fridge temp exceeds my differential limit, the compressor won't turn on until the ASd limit has been reached, correct? So, in theory, setting it at the max can allow the beer to warm up beyond the desired range, correct?
 
Back to the ASd. If its set to 12, and the fridge temp exceeds my differential limit, the compressor won't turn on until the ASd limit has been reached, correct? So, in theory, setting it at the max can allow the beer to warm up beyond the desired range, correct?

Theoretically, yes, but I'd be real surprised if your fridge warmed up very much in 12 minutes.
 
OK, so an update. I have the thermostat set at 33 ( I wanted to bottle) but the beer comes out at 38. I've taken everyone's input to use, so now I think I am just going to make peace with this P.O.S. Kind of bummed.....oh well.
 
jbay76 said:
OK, so an update. I have the thermostat set at 33 ( I wanted to bottle) but the beer comes out at 38. I've taken everyone's input to use, so now I think I am just going to make peace with this P.O.S. Kind of bummed.....oh well.

How long was it set at 33 before you bottled? What kind of dispenser (tower, coffin box, cobra tap, etc)? Do you have a circulation fan in the kegerator?
 
Hunter, I set it at 33 this morning, but forgot...I was abit oversampled from last night. I do have access to a fan, but have not wired one in because I do not know how. But, how would that explain the digi thermostat reading 33 on tha keg when the beer pours 38? I'll report back tomorrow then to see if an additional 24 hrs does the trick.
Cheers
J
 
Hopefully a bit more time will make the difference.

I only mention the fan because without air circulation, the top of the kegerator tends to be several degrees warmer than the bottom due to the whole hot air rising/cold air sinking dynamic. I was wondering if maybe the beer temp was increasing as it was leaving the keg and traveling through the warmer beer lines/tap tower at the top? I'm just throwing out guesses here, I'm no expert on thermodynamics. I've yet to actually measure the temp of my dispensed beer and compare it to the reading on the temp controller. I'll try to remember to do that later and report back.
 
Huh... My kegerator is set to 39 degrees (with the temp probe set in a large jar of water on the bottom), but the beer is coming out at 49 degrees (according to my analog thermometer). The 10 degree differential is a little alarming. Not sure if its warming up when passing through the coffin box/tap (cooled with 2 circulation fans drawing from the kegerator), if my the way I have my temp probe set is flawed, or if either my temp controller or thermometer are miscalibrated. I'll have to do some more tests to find out.

Your thread is making me question everything about my kegerator :p

In the mean time, I guess I'll just lower the SP a bit so my serving temp is in the low to mid 40s...
 
Hunter,
I have my probe taped to the top portion of the keg, and each keg has a micromatic temp/volume sticker running the height of the keg. So far, the sticker is more in line with the beer temp once served. The draft tower has insulation in it, so I would think the temp differential would be small between whats in the keg and in the line, but I could be wrong.

Though I am still toying with this thing, I consider this thread a success if it made you re-evaluate your setup and validate/invalidate previous beliefs. Ultimately, if we are carbing for a particular temp, and our pouring temp is 5-10 degrees warmer than it should, the carbonation is now off-mark. I'll check my beer again tonight and report back, maybe the temp has gone down and it just took a sh*t ton of time.....don't know.
Cheers
 
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