Originally Posted by Crabnut
Anyone else run into kegs that seemed to persistently freeze in keezers? This is really annoying when I go out to have a beer, and one or more of the kegs are frozen up far enough so as to not feed. I have tried adjusting my temps up, and am at an ambient air temp in the keezer around 45 degrees, while still having problems with the kegs freezing. It seems especially true on the step, but is even happening when the kegs are on the bottom. Any ideas would be helpful. so far no luck with placing a styrofoam pad under the kegs, but I am willing to try anything to keep the beer flowing...
What is happening with your kegs is that ice is forming on the bottom and blocking the dip tube. It doesn't take much ice at all to block the tube completely. This can occur even when the freezer is set considerably above freezing temperatures. The evaporator coils are typically located in the walls of the chest freezers. The walls will get very cold while the compressor is running. The coldest air will be near the bottom of the freezer and there can be a substantial temperature difference between the bottom of the freezer and the top. Your taps and beer lines will normally be located near the top of the freezer where the air is warmest. If you have a collar on the freeze with taps, the shanks and taps will also be much warmer than the bottom of the freezer. The result is that even though the beer coming out of the taps is not all that cold, the lower portion of the kegs will usually be much colder and possible to the point of freezing. Often the warm beer lines and taps will cause the beer to warm quickly and this can lead to excessive foaming problems at the tap.
I solved this problem by installing a muffin fan to circulate the air inside the freezer. I mounted the controller probe directly in the airflow of the fan. Now, my taps and lines stay cold and the kegs stay at a uniform temperature from top to bottom. I have the controller set to 40 F with a 5 degree differential. Out of curiosity, I timed the compressor cycle recently to see how often it ran and what the on/off durations were. With the ambient room temp at 74F, the compressor was on 37% of the time and off 63%. This while the beer stays at a very stable temp. I want to repeat this test using several different differential settings in order to find the optimum to minimize power consumption. Using a fan will cause the compressor to run more frequently, so it's a trade off on how uniform you want the kegs, beer, lines and taps to be vs power usage. I chose to have stable beer temps at the expense of using a little more power. I run the fan continuously. I've tried it with the fan cycling on with the compressor, but found that having it run full time works the best. A bonus is no foaming problems at the tap too. I like that a lot. The fan installation was a huge improvement at a very low cost. Since then, I have installed fans in all of the freezers I use for fermentation and lagering. The fridges I use already had fans in them from the factory except for a small one that I did a retrofit on.