The biggest difference between a kegerator and a keezer is that the kegerator begins life as a refrigerator and the keezer starts as a freezer. The critical difference is that the temperature controller built into a refrigerator is meant to keep temps above freezing while a freezer’s temperature controller is meant to do the opposite. While the slushy beer at Epcot was interesting I did not think that it was something I wanted to duplicate on a regular basis at home.
A common solution is to use a plug-and-play temperature controller like the Johnson Controls model available at Northern Brewer. I thought that this solution was a little “hacky” and decided to go with a cleaner, hard wired solution.
I procured an Elitech STC-1000 digital temperature controller from Amazon. The price seems to be stable at just under $20, but sometimes this spikes or availability goes into the toilet. You can find similar temperature controllers on eBay, but I actually had a hard time finding one that was the right voltage and it was often no difference in price so I felt the extra hassle was not worth it. As I said in my first post about the keezer build, everyone will make slightly different choices that make this an essentially custom build.
The key thing to remember when buying a temperature controller like this is that you get the model designed for 110 volts as opposed to the higher voltage model. In the U.S. your household current and freezer are likely to be 110 volt alternating current.
A version of this temperature controller exists that displays the temperature in Fahrenheit as opposed to Celsius, but the cost difference was substantial and the availability was spotty. For under $20 I figured that I could deal with converting to the accepted world temperature measurement.
The compressor and wiring in the back of my small—5.1 cubic foot—chest freezer was already exposed. Some freezers may require you to remove a grill to get at this wiring and others may actually have the wiring hidden in such a way that would require some minor surgery. If you require cutting into the skin of the freezer be very careful to not nick any coolant lines because if that happens you will be left with a very large piece of junk on your hands.
I did not have any problem cutting the power cord off of the freezer because it was free and the cord would be easy to replace in the even that I want to turn this back into a freezer at a later date. You can mount the temperature controller in a special cut out or build a bracket, but I kept the wiring simple and easy to remove.
The other reason that I mounted the temperature controller here was to keep it out of the cool and moist air of the keezer compartment itself. I have seen builds where the controller is mounted in a cutout on the collar. Given that the STC-1000 does not appear to be sealed for this type of application I chose to keep it at room temperature. Again, a personal choice.
As you can see by the picture below the temperature controller just sits inside the compressor bay:
The STC-1000 can actually handle temperature control for both heating and cooling. In this build I will be dealing with just cooling because I do not intend to create a lagering cellar. Again, this is a simple build and you will probably make different choices.
It can be difficult to find straightforward wiring diagrams for a cooling only STC-1000 that is hardwired, but below you will see how I wired the device:
I do not claim that this is entirely proper and I would not follow my instructions for fear of burning down your house. This is the internet and you can find information to suit your needs as you see fit.
I reused the cord from the freezer and cut jumper wires from that same cord to ensure that my wire was properly rated, etc. You could use supplemental wire, but I figured it was cheap and easy to make do with what I had in the basement at the time.
I grounded the refrigerator using the existing ground wire from the cord, bypassing the STC-1000, because the temperature controller does not have a provision for grounding. Also, please make sure you use wire nuts that can accommodate three larger wires. I cannot tell you the number of times I have seen people try to smash heavier gauge wires into a small wire nut meant to splice two small gauge wires.
After every wire nut was tightened and all the wires were checked I plugged things in and it all worked.
The setup on the STC-1000 is a little convoluted, but easy to follow with the instructions included in the box. For a test I set the cool temperature at 2.5 degrees Celsius or about 36.5 degrees Fahrenheit. Since I do not have any beer in kegs ready to dispense I might be adjusting that in the future. Right now when it is below zero—in terms of Fahrenheit—here in Iowa that might be okay, but come summer when the temperatures move toward triple digits I might want to go even colder.
One thing to make sure happens is that the unit actually cycles the compressor in the keezer on and off. When you initially power the unit a delay will be set because the STC-1000 comes from the factory with a compressor delay set to 3 minutes. This is programmed to prevent the compressor from cycling too rapidly and wearing out prematurely. I left the setting alone because I figured that at higher than freezing temperatures the cycling should not be an issue. Just wait out the few minutes and make sure the compressor starts operation. I waited until the unit cooled the keezer down to the set temperature to ensure that it would shut off. Everything worked clean from the first try.
That’s the beauty of homebrewing, you are always tinkering.
In my next post I will discuss the construction of the collar and the mounting of some hardware. See you then!
My Green Misadventure 