Kegerator Issue

So I just set up my 4912. However I noticed a huge problem that I created. I have a cooling fan running cold air up into the taps. The problem is that it was causing to much cold old from coming off the back plate that creates the cold. That in turn caused the fridge to run constantly. Eventually the heat seaped through the walls (from the sides of the fridge), and caused it to heat up inside instead of cool down.

It looks like Im gonna have to let the compressor completley cool down before I can run it again. At the moment it does cool down to 36 degrees, but the lines are still too hot, so it just heats back up a minute later. At least I didnt kill the motor before I noticed what was going on.

Back to the drawing board on the air moving device.

I have 3 lines going up into my tower. The tower is insulated and it works fine. First couple seconds of the very first pour may be a bit foamy, but it settles down after that. Try it for a few weeks without the fan and see how it goes.

Like Ed said. Keep a small fruit juice glass near your taps and just run your first 1 second of brew into it to omit it from your glass.

For the time being, I have removed the fan. However my fridge seems to run quite a bit. I think this is due to the fact that there are no radiant lines outside of the fridge. This means that the copressor side of the system is still touching the walls of the fridge creating heat on the inside. Im hoping though that after the beer itself is cooled to 36 degrees, it should have to run as often to remain cool.

As it is it seems to run for about 30 seconds on, and then about a minute off. I have a house fan blowing on the compressor to aid in cooling the system off.

On a technical note, I had my friend help me with the wiring. We removed the original thermostat in its entirety. We connected the power side of the electronic thermostat directly to the copressor. Last I put the Temp Sensor in the exact location where the original sat. I set electronic sensor to 38 degrees, with a 5 degree variance. It runs to 38 degrees, and shuts off. At that point it continues to cool to about 36 degrees (from the residual coolant in the plate). After sitting at 36 degrees for about 10 seconds it rises up to 43 degrees in relativley short order and starts the cycle again.

I have kind of a wild guess, but to first understand your problem, it sounds like you are putting warm beer in there. And as it is trying to cool it down it is getting too hot on the sides and warming it back up.

From what I understand about a normal, newish at least, fridge. There is a set run/rest duty cycle. In most cases the fridge can drop the internal temp from room, to where it is set within this cycle. But when you put a giant dampener on the system (like 5 gallons of liquid) it takes a lot longer to cool it down, so the fridge drops the temp somewhat and stops before the compressor gets so hot that it can't maintain that temp while turned off. After the system returns to normal it does it again and over a while it drops it to the temp you want, and with the system now dampened in your favor you are fine. I could be off the wall here, but that is how I though they worked, and how I would design it.

I would guess that in the process of replacing the thermostat you removed all that logic. So the system is running longer and getting past the sweet spot when it should turn off. So it can't hit the steady state and will just run until it dies or you turn it off.

Well what most people do is crank the internal thermostat to max, and then use an electronic control unit. This essentially bypasses the mechanical thermostat. The only think I have done different is completley removed the mechanical thermostat since it isnt used anyways.

The fridge does work, it just cycles semi frequently. I think that has a lot to do with the fact that a) the compressor lines are internal. So there isnt alot radiating that heat away, b) my house is easily 85+ degrees as it is, and c) the fridge is only 4.9 cubic feet, so things happen much faster than on a say 18 cubic foot fridge.

Im mostly trying to get opinions on whether it runs to much, or is just fine.

Note: I timed the fridge. It seems to run for about 1:12 and then is off for about 3 minutes. Im thinking its just very noticible how often it cycles because the digital timer has a very loud relay, and I hear it every time it clicks on and off.

Try removing the keg from the fridge and seeing if the compressor still cycles frequently. With nothing in the fridge but air, it should be able to sit for a good long time without cycling the compressor.

What thermostat are you using? If your thermostat is too sensitive, it will come on every time the temperature shifts one degree for more than a few seconds, and conversely it will shut off as soon as the ambient air in the fridge reaches the desired temperature. That would mean that it's going to take quite a long time of cycling on/off before you get stable temperatures, as you chill the outside of the keg and then it warms up again quickly from the relatively warm beer inside. There may be some sensitivity/time delay functions you can adjust on the thermostat.

SixFoFalcon said:

Try removing the keg from the fridge and seeing if the compressor still cycles frequently. With nothing in the fridge but air, it should be able to sit for a good long time without cycling the compressor.

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I agree with SixFoFalcon, the problem is that you have no buffer. The original fridge thermostat is designed to work with ambient air temp, but your new controller is not. It's a much more accurate and faster responding system. I also have a digital controller for my kegerator and I keep the tip of the control probe duct taped directly to the side of one of the kegs, ensuring good contact. The fridge will stay on until the keg has gotten down to the right temperature and not shut off before that.

Fridge compressors aren't designed to switch on and off frequently and I suspect that is where your heat issues come from.

Interesting ideas. Technically speaking I have 5 degrees of buffer. Should I set it to 10 or 15 until the keg is cooled next time? At this point I do know that the keg is in fact cooled. Also I can see that my co2 tank has finally dropped to 600psi and holding which is what I gathered was the consesus for a properly cooled fridge.

That little bit of warm beer you pull out to get the cold beer into the line - give it to your dogs, they will love you for it.

I found no need for the extra work of a tower fan...and I have a big tower.


Plenty of insulation should be adequate. I used a half-spent roll of paper towels stuff up inside, and ran the lines up through the cardboard tube. Even with a small halogen light over the tower that gets pretty hot, the beer never shows any signs of warming up.

There is so little beer in that limited length of very narrow beverage line, that I'd be surprised if there is any real benefit. My first pour foaming issues is due to the CO2 bubbles settling at the top of the line. Like Ed said...I have a beer "spitoon" nearby to capture that 1st Oz.

5 degrees of buffer (deadband) should be fine if you either have the control probe taped tight to the keg or immersed in a pitcher of water in the fridge (though the pitcher of water is not a good long-term solution as it may cause frost problems). I have 4 degrees programmed in on my controller.

I don't keep my CO2 tank inside my kegerator so I'm not really following you on the 600psi thing, but I would deem a fridge to be cooling properly if the keg is at the temp you want it to be at and the fridge is not cycling on and off more than once or twice every couple hours or more if not disturbed.

I got, I got it.

Yes, you are all right. Having the temp sensor in the ambient does not work at all. I put the sensor in a glass of salt water (for now, will fix with freezer gel and a spent liquid yeast bottle tonight).

However there is something that I found out that is very very very important. The compressor seems to have a built in timer that only allows it to run so long. The only problem is, if you remove power to it, and that return power, it trips it and allows the compressor to run all over again. Thus allowing it to get way overheated.

So now compound all the issues I was having, and I now see my problem.

The ambient air was causing my sensor to go off and on resetting the trip inside the compressor causing it to get way way to hot.

Lesson Learned, having the sensor imersed in water isnt just a nice idea, its an absolute must.