Temperature controller question

I am thinking of trying to turn a chest freezer into a keezer, and want to install a temperature controller. Before doing so, I want to make sure I know what to do. I have looked on this site, and many other places on the net and seen demonstrations and videos of how to make a keezer, but have not been able to answer some questions around the temperature controller :

Currently, the freezer has its own thermostat (I have it set to -19C / -2F). The freezer is plugged in to the mains wall socket.

If I buy a controller, I plug the controller into the mains wall socket, I put the probe (attached to the controller) into the freezer and my question is around connecting the controller to the freezer : Do I

1 : Plug the freezer into the controller (ie the plug that used to go into the mains socket now gets plugged into the controller, so the freezer gets on/off power when the controller allows it to, or :

2 : keep the freezer plugged into the mains wall socket as before, but connect the thermostat from the freezer to the controller somehow so that the ffreezer thinks it has a new thermostat (the controller)

In 1 the thermostat is set to -2F which is way colder than I ever need it, so my thinking is that when my temperature gets above my desired temperature (set by controller), the controller allows power to the freezer, and because my desired temperature is higher than the -2F setting on the freezer thermostat, it powers up and tries to cool the freezer down to -2F. When it hits my desired temp (say 45F) the controller cuts the power to the freezer, and this cycles continues.

In 2, there is always power going to the freezer, but the governer is now the freezer thermostat, which is wired into the controller.

Option 2 seems much more complicated to me than option 1, and I am not that experienced with this stuff.

Can someone let me know which way it works (hopefully there are controllers that operate like option 1) and if option 2 is my only bet, does anyone have a good resource or link to explain how to actually do this at home?

Many thanks in advance.
Murray

i just start to have a discussin on the site. i hope i can learn much from this forum.

Option 1. Plus, make sure that your controller has a compressor delay option which is set to at least 5-10 minutes (depending on how old your freezer is). This will avoid having the freezer cycle on/off too rapidly and burn out. Might also want to change the temp range to about 1F (so if you want your beer at, say 40F. You set it to 39.5 +/- 1) which will let the freezer work longer sessions with less start-ups.

Also, make sure you're installing the probe ON one of the kegs (tape it there, and put a folded up paper towel around it to insulate it). This will allow you to control the temp of the beer, rather than the temp of the air in the freezer. Typically, by the time the air gets to 32F, liquid in the freezer is in the twenties.

You can actually do it both ways, but option 1 is easier to do, and easier to revert back. And it seems you're more comfortable with that option, so you might as well just stick with it.

Option 2 is possible, but I'd never recommend it.

you guys have made my day. I was dreading getting a complicated reply with loads of electronic work necessary. Next question : Any ideas on what temperature controller and probe I should buy? I work off 240V mains here in the UK, and ideally want to buy form the UK

I have seeen the Johnson controls temperature controller on many US homebrew sites. It looks like exactly the thing I need, though I cannot find it in the UK. Given that the US operates on 120V mains voltage, and the UK operates on 230V mains voltage, would I be able to use the unit in the UK if I ordered it online and bought it from the USA?

Go take a look at the "eBay aquarium temp controller build" thread... you can get a 220v model and it'll be like 1/4 the price of a similar-functioning Johnson.

If you are afraid of wiring like me, there are step by step instructions, with pictures for wiring the "ebay" aquarium controller in the Ebay controller with cheap wal-mart parts (or something like that. I think it was started by Misplaced Canuck.

It is really simple and cheap. I have two controllers, the Johnson and the Ebay. If I would have known how simple it was to build the Ebay controller I would have gotten two and saved about $70.

Yeah... it might seem intimidating, but it's actually really simple, and I promise that *anyone* can do it.

This is the thread:

I am a wiring idiot and I was able to do it. I used the controller with heat and cool, but you can get one that is cheaper that only controls the cold.

https://www.homebrewtalk.com/f51/ebay-fish-tank-controller-build-using-wal-mart-parts-261506/

Awesome, thanks very much everyone. I have just bought one online at eBay. Now let's see if we can get it all working!