Probe Placement Issues

[ctevans1]

Hey all,

I converted my Kenmore 4 cu ft fridge to a kegerator a couple years ago, and have still not nailed the temperature. It's close enough to keep the beer fresh, but I can't seem to nail the 36* - 38* I'm looking for.

I use a JC A419 controller and have moved it all around the fridge. Either it gets too warm and foams like crazy, or it freezes the keg. I recently read putting the probe in a cup/glass/container of water will even things out, so I did that, and set it for 35*. The water in the container was holding steady at 35*, but the beer ended up being at 44* and foamy.

What size container of water should the probe be put in? Maybe the one I used was too small and cooled too quickly? Should I strap and insulate the probe to the bottom of the keg? This is really starting to get to me after two years, and I'd really like to get it figured out!

Thanks!

[KillianBoy]

ctevans1,
For sure a small glass of water will not react the same as a keg of beer, but I think more information is needed for an educated guess as to what to do to help you.
Understand foam and temperature are 2 different problems, you can balance warm beer and not have foam but if too warm or too cold you can't balance beer, but if you don't balance you will always have foam.
So this is a small cold plate mini refrigerator with no air circulation?
Are you trying to balance beer? (using v/v and temperature of the beer to set PSI)
What are your other settings? (Differential, cut-in or cut out, unit thermostat set to max?)
How long is your line, ID, through door, tower or remote dispense?
Glass is of 2nd, 3rd, etc of consecutive glass, room temperature? Calibrated thermometer?
What was the coldest beer you got, what glass was it and where was the probe and setpoint of ETC?
So you really have to solve your problems one at a time, if you can get 40 degree beer you might be able to balance so you don't have foam, without balance, no matter how cold, you might have constant foam.
Check out my newbie thread, main point is you need air circulation to get beer temperature on the 2nd glass, no air circulation it may take several glasses to get actual beer temperature (depending on your dispense method).
KB

[ctevans1]

Thanks for the reply.

I have a small fridge with the cold plate bent to the side, two CPU fans circulating the air (they are powered separately, and stay on all the time), 10 ft 3/16 ID hose going through copper tubing up the tower.

So since I posted my question, I moved the probe to the only place I hadn't tried it yet; taped to the side of the keg near the bottom. For the first time, the beer is making it's way down to 36*, but only if I leave my setpoint at 32* (cut in with 4* diff, so it shuts off at 28*).

On my first pour, I fill about 1/4 of a pint glass and dump it, then continue to fill a full pint with near perfect head. From there, it pours beautifully unless there is a break of 1.5-2 hours, then I start the process over. I'm not really looking to get a tower cooler, so I think I will just be content with losing 1/4 pint every so often.

I will take a look at the thread you directed me to so I can hopefully pick up a few more tips.

Thanks!

[KillianBoy]

ctevans1,
Thank you for keeping membership updated about your problem, copper up tower is helpful but no replacement for a tower cooler, warm faucet/shank and tower will cause your initial foam (low PSI to v/v will also cause this).
You are doing it partially right, if no tower cooler, pour off a bit, then start your 1st pour (beer poured on foam will cause more foam). But foam is just beer agitated, it is still beer and still can be consumed, throwing away foamy beer is throwing away beer, just wait a bit and it will be beer.
You don't have to create a weather system, just circulate air, try 1 fan, maybe at 6 volts and see. point airflow bottom to top.
Placement of probe is usually not tricky, you usually try to keep it out of airflow and if you place in water, you have to keep the differential way lower than air.
Logically speaking something is wrong with cut-in, differential setting of 4* and setpoint of 32*. Logically, the beer temperature should be right in the middle of setpoint and diff point, so by all laws your temperature should be 30 degrees.
Wait a week and see where your beer temperature goes, if it slowly gets colder than 34 degrees, then setting is right (change the setpoint warmer), if stays near at 36-34 degrees, then you are at cut-out (cut-out at setpoint 32*, cut-in at 36*). Some members like diff at 2-3, compressor goes on and off more often but temperature is more stable.
Adjusting PSI, ETC isn't like adjusting the volume on an stereo, it takes a while to see any difference, patience is your friend.
To avoid 1st glass foam, you need to hook up a properly working tower cooler, once set up, take fan out and you should be good. And try to balance beer with a calibrated thermometer.
KB

[ctevans1]

After exhaustive reading of forum after forum, I believe I have two separate issues.

One, I do in fact need a tower cooler. When I originally built this kegerator, I drilled a hole only big enough for the copper tube to fit through, but now I realize that even though it hasn't hurt any, it's just not doing it's job. When this keg is dead, I will drill out the hole to the ID of the tower and build a tower cooler with one of my two fans.

The other is the pressure vs. temp. I only keg IPA's and DIPA's, whether homebrewed or store bought, so at a desired temp of 36*, 12 PSI is a good starting point. I have 10 feet of 3/16 ID hose, so I will start cutting it down a foot at a time to find my personal "sweet spot".

As for probe placement, having it on the side of the keg is working out okay, but I really want to have the controller set to what the actual beer temp is. So I am re-trying the probe in a larger vessel of water (a 22 oz bottle) to see if that is more accurate than the side of the keg.

I'll definitely check in when I have any concrete info to share. It may take some time, though, as my poor little kegerator is battling a very warm California summer.

[djc]

The long beer line is not contributing to foam, the only thing being too long will do is make a slow pour. It is helping you in that it gives you the ability to dial up the pressure to properly balance the system. Being too short will cause foam.

I'd say you should leave the line alone until you have the foam under control.

[KillianBoy]

yup, ditto what djc says, what part of "PATIENCE is your friend" don't you understand.
Why do you want to change something that is working, in favor of something that YOU THINK MIGHT work, given time to work, what I said should do the trick. Understand, water is water 6 oz. or 22 oz. don't think it will make a difference.
JUST WAIT A WEEK AND SEE IF YOUR SETTING WORKS, if you want to see if an EQUAL mass can get your temperature right, then put an equal mass in kegerator ( if you think this sounds ridiculous, try it on our side).
If you have v/v of beer that is store bought then balance, if you have a home brew, set to 12 and see what happens, no matter what tower cooler will help with 1st glass foam.
KB

[ctevans1]

Well, like I said in the OP, the main issue of not being able to maintain a desired keg temp has been going on for two years. I make small adjustments and let it cycle for up to two weeks before making changes, so, yeah, patience is a good friend of mine.

The foaming issue is new; only the last two kegs, which is why I doubted a tower cooler since I never needed one before. I am more inclined to think I do need one now, though. I just re-read what I wrote last night, and I was all over the place and didn't convey my thoughts very well, as I plan to build a tower cooler and test for at least a whole keg before considering messing with the hose length.

I do appreciate the input. I think that patience I have is just starting to run out. I'll have to muster up some more.

[djc]

Ditch one of the fans as KB said, and if you can run the remaining one at lower voltage. The fridge you have is 4 cubic feet and some of those little fans flow 20 - 30 cfm. You might be trying to flip your air volume 10 to 20 times a minute. That's way over kill.

[ctevans1]

Do you think it will affect it negatively? Or is it just not needed?

[KillianBoy]

ctevans1,
Both actually, sometimes too much positive pressure can cause cold air to run away. Most make do with 1 fan at 1/2 strength, 2 at 12 volts is overkill and can cause problems and so not really needed.
If you have beer at 36 degrees and it stays that way, what is the problem?, why change to something that might work? when you have something that is working right now, why change when you finally got the beer to temperature. The only problem I see with 36 degree beer is that it is too cold.
Again I would leave everything and wait, if beer gets colder, I would change setpoint, logically your beer temperature should be between setpoint and cut-out, anywhere else something funny is going on, make sure the thermostat on the unit is set to maximum cold or bypassed to run full on all the time without ETC.
KB

[djc]

I'd go a different way, and say maybe it doesn't work that well and since there a few things that are closer to standard practices he should make those fixes.

[ctevans1]

Just a quick update. Still having the probe to the side of the keg, I have had my controller set to cut in at 30 with a 2 degree differential. The beer finally reached, at last pour, 35*, so I can now try and see if I can maintain a good 38*.

I built and installed a tower cooler, but had to have to door open and the tower removed for 15 or so minutes, so I will let that settle for a few days before trying to get any real data.

I do have one question for you guys, though. Going back up a few posts, I mentioned I was considering cutting my beer line shorter, and you both agreed that I shouldn't. I have been reading up on balancing a direct draw system, and every formula I have seen says my line should be more like 3.5-4.0 feet. Now, I have no problem with leaving it at 10 feet, but couldn't all the extra line cause excessive foam as well? I have been a mechanic for 15 years, so I'm all about solving one issue at a time, so I'm not grabbing my hose cutters just yet. Just wondering if the tower cooler doesn't do the trick, could the long hose possibly be the culprit?

[djc]

The longer line will not cause foam, it will cause slow pours that are foam free. The line length should be the last thing you adjust, and all you need to do is cut back in 6" increments until you are happy with the fill rate. I'd also stop reading whatever reference says you can go with 3.5-4 feet. That would pour like a fire hose. You don't need to use formulas for a short draw system, balance to the temp and volumes of CO2, and from there cut back the line to get the speed.

[KillianBoy]

ctevans1,
If you find your flow slow then cut back a little at a time to find the right flow, unless it is a trickle I'd leave it alone till you get the temperature issue solved. If longer line means more foam there wouldn't be any long draw systems using pure CO2, don't worry about those resistance tables, short draw systems are funny that way.
Could be the ETC and the unit thermostat are fighting for power, even if you have the unit thermostat set at maximum, it may not be getting to the ETC temperature to turn it off. You could try and use unit thermostat alone and see how cold unit gets at max temperature. At the same time monitor the compressor on/off cycles, if the unit turns off at maximum, you may have to bypass the unit thermostat to run 100% while plugged into a wall socket.
If the unit turns on and off at maximum, see if it will work without the ETC.
KB