Digital Temp Controller w/Mini Fridge

Hey All, The other day I picked up a "defective" mini fridge that was being thrown out, figuring I would just use it as a heat only fermentation chamber, as I ferment in my garage during the winter where temps are usually in the low 50's. Turns out, all that's wrong with it is the thermostat. I can remove the thermo and short the two wires together and it fires right up.

My question is this, Would it be possible to simply wire a digital controller like the STC-1000 in place of the factory thermo, or would it be better to short the wires together and then wire the fridge to the controller separately?

I wired an ebay temperature controller in place of the factory one on mine... works like a champ.

https://www.homebrewtalk.com/f51/my-kegerator-build-frankin-mini-fridge-263926/

I also gutted the fridge and put it into my own cold box, but the controller should work either way.

How did you wire the temp control in? Did you run power to the temp control and splice the existing thermo wires into the cooling side, or something more involved than that?

digg1es said:

How did you wire the temp control in? Did you run power to the temp control and splice the existing thermo wires into the cooling side, or something more involved than that?

Click to expand...

That should be exactly how to do it. The controller provides the "goes into" and "comes out of" connections to a normally-open relay, so the user can chose what to route through it. In your case, instead of running line power through that relay, you can run your "turn on the compressor" signal...

Cheers!

I did just that... ran power to the controller and hooked the neutral from the compressor to the neutral and the hot to the controller. Got rid of the inside unit all together... minus the probe from the controller. I also hooked up a light bulb to the heat circuit since it sits in the shop and gets quite cold out there... hasn't kicked on yet this season that Ive seen but the compressor hasn't run in a while.

jtsims21 said:

I did just that... ran power to the controller and hooked the neutral from the compressor to the neutral and the hot to the controller. Got rid of the inside unit all together... minus the probe from the controller. I also hooked up a light bulb to the heat circuit since it sits in the shop and gets quite cold out there... hasn't kicked on yet this season that Ive seen but the compressor hasn't run in a while.

Click to expand...

Running line power through the relay is the "typical" way to use these controllers. But what digg1es was asking about, and what jtsims21 actually did, is to insert the controller into the existing thermostat circuit, and keep the original fridge line cord plugged into the wall...

Cheers!

That's exactly what I am wanting to do. I'll post some pics when I get it all wired up.

Please do post pics, I think what you are doing with hard wiring your freezer is easier than what I am trying to do with building a control box.

Hey digg1es, you ever wire the controller up?

I'm wanting to use a STC-1000. I'll cut a hole in the door for the controller, and take out the stock mini fridge unit. I notice 3 wires into the stock one, a "grey" a "light blue" and green. How would I wire these into the back of the Stc-1000, so I could keep the fridge plugged into wall, running the STC-1000 off of these 3 wires.......

Thanks for any info and help.

Yes, I did wire it up with just a little rewiring. My fridge has the same colored wires, so It's probably the same, but you should be able to check on the back of the fridge to make sure.

What I did was splice the green wire into the neutral 120 leg coming off the wall power.
Once you do that you should have both 120V hot (Grey Wire) and 120V neutral (Green Wire) where your thermostat used to be. I pulled out the thermo, but left the little case that clips into the wall to hide all my wire nuts and splices.

What you will want to do is split the wires coming out of your fridge wall.
Grey = 120V Hot - Split to 3 lines for inputs 1, 5, 7 on the STC
Green = 120V Neutral - input 2 on the STC
Light Blue = 2nd leg of cooling, input 8. This is the hot return to the compressor.
At this point your fridge should be up and running with cooling only. If you are wanting heat as well, wire the hot side of your heating element/heater to input 6, and the neutral to the green wire.

After that's done, you will have a built in temperature controlled fridge. The STC-1000 will now also act as a power switch for your fridge, so if you aren't using it, the unit can be turned off completely.

As a side note, all of the existing wiring in my fridge is 18awg, and I used 16awg for all of my wiring additions. I just bought a 25ft roll of one color, and color coded my wires with electrical tape to help it make sense.

I'll try to grab some pics as well.