Keezer Temp Controller Using the STC-1000

We recently added a keezer to our arsenal and the person we purchased it from was controlling temps by adjusting the internal thermostat.  We wanted a bit more control over the temps for storing and serving our beers so I built a temp controller to add to the keezer.  A match made in beer heaven.

If you’ve done a bit of looking around at temp controllers you’ve likely seen the STC-1000 mentioned, it’s the go to device for those that don’t mind a bit of DIY.  If you have at least some mechanical/electrical abilities this is very easy to build and total cost is only around $40.00.  The project can be completed in about an hour once you gather everything up.  You ready?  Let’s do this.

STC-1000 Temp Controller Completed

STC-1000 Temp Controller Completed

KEEZER TEMP CONTROLLER BUILD INSTRUCTIONS

Parts List:

  • STC-1000 temp controller  Make sure to get the one rated for 110v and NOT 220v or 12v DC!  (At the time of this post you can get one for $17.92 via Amazon.com, shipped free with a Prime Membership)
  • STC-1000 Temp Controller with FAHRENHEIT display Just added to Amazon, no more messing around converting from Celsius! UPDATE PLEASE READ!  This is not the same as the °C version of the STC-1ooo.  The °F version and only control heating or cooling, it cannot be setup to control two outlets at the same time for simultaneous heating/cooling.
  • Duplex Receptacle Outlet
  • Duplex Receptacle Trim Plate
  • Project Enclosure (I used the 8x6x3 from Radio Shack)
  • Power Cord (I used a 15′ cord and cut pieces from it to use for the internal wiring. You can also use an old computer power cord.)
  • Wire nuts
  • Spade wire connectors (optional)

Tool list:

  • Pencil
  • Ruler or other straight edge
  • Wire cutter / stripper
  • Fleshlight (Just checking to see if you’re reading all of this.)
  • Dremel or other cutting tool
  • Flat and Phillips screwdrivers
  • Electrical tape
  • Drill and bits

Instructions:

  1. Lay out all your parts and make sure you’ve got everything there.
  2. Mark the outline of the STC-1000 and the wall receptacle on the lid of the project enclosure and cut them out.  REMEMBER, you want the inner dimensions of the STC-1000 cut into your enclosure!
  3. Mark and drill holes on the front and back bottom sides (does that make sense?) for the power cord and temp probe to come out of the box, you want these on opposite ends of the enclosure.
  4. Break the hot side jumper tab off of the wall receptacle, this allows you to control each outlet independently.  This is much easier to do before mounting and wiring… trust me.
  5. Mount the STC-1000 and the receptacle in your enclosure.  Attach trim plate over receptacle.
  6. Cut and strip the ends of your power cord.
  7. Run power cord and temp probe into the holes you drilled in the enclosure.
  8. Using the wiring diagram below, wire everything up.
    • On the STC-1000, terminals 1, 5 & 7 are connected via wire nut to the black wire on your power cord.
    • Terminal 2 will connect to ‘cold side in’ on the receptacle.
    • Terminals 3 & 4 will be for the included temperature probe
    • Terminal 6 goes to one hot side connection on the receptacle for your heating control.  Make a note of which outlet you wire for heating and cooling.
    • Terminal 8 goes to the other hot side connection on the receptacle for your cooling control
    • Connect the other cold side connection on the receptacle to the white wire on the power cord.
    • Connect the green wire on the power cord to the ground on the power receptacle.
  9. Wrap electrical tape around the power cord and temp probe to use as a stopper inside the enclosure.  This will prevent the cords from being pulled and damaging your wiring.
  10. Making sure all connections are secure and you have no crossed wires, gently lay the lid with the controller and outlet back on the enclosure.  Plug in the enclosure to verify it powers up.  If you have an outlet tester or multimeter you can set the programming and test each outlet as well.
  11. Place the lid back on the enclosure and secure it with the 4 screws.
  12. You. Are. Done.
STC-1000 Temp Controller Wiring Diagram

STC-1000 Temp Controller Wiring Diagram

Temp Controller Wiring

Temp Controller Wiring

Break off the tab connection these terminals.

Break off the tab connecting these terminals.

So there you have it.  You’ve just built a temp controller you can use on your keezer to keep your brews right where you want them or in a fermentation chamber for lagering.  Add a heat wrap and kick it up for those Saisons and Belgians.  Oh yeah, the STC-1000 only reads in Celsius and since I’m an AMERICAN I don’t know how to read that crap.  I solved the problem of reading in this Commie temperature scale by printing out a Commie-to-‘Merica conversion chart and attaching it to the controller box with gravity.  I’ve included the chart below if you’d like to use it, it prints nicely on business card sheets.  You’re welcome.

Celsius to Fahrenheit Conversion Chart

Celsius to Fahrenheit Conversion Chart

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32 thoughts on “Keezer Temp Controller Using the STC-1000

  1. Pingback: How to make super sexy tap handles. | The Mostly Harmless Brewing Co.

      • Great article!-Hope you can help me with my stc 1000 install on my nostalgia krs2100 kegerator-i just want to remove the analog thermostat (it has 1 black, 1 white, 1 ground) attached to it. The 110 power cord/plug from kegerator plugs into 110 wall outlet then it runs into the transformer…into the compressor then comes out and runs to the thermostat (1 white, 1blk, 1 grn)-where/how do i wire in the stc 1000? Can i just cut the 1 white 1 black and wire right into the stc (this is what i want to do so i dont have to touch the kegerator cord/plug)? if so, which wire goes where. Thank you for helping me if u can!

      • I’m not 100% sure and since we’re talking about electricity I’d hate to say something I’m not 100% sure on. Is your kegerator running now and you just want to add digital control? If so you could just build tis as is and plug the keezer into it.

      • Yes it is running now, just wanted to swap the analog for stc 1000 digital thermostat. Just thought u might know but i really appreciate your response. Thank you.

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  3. Very, very awesome! I was hating the fact that I’d have to spend $70-100 on one of the Johnson Controls units, and am very happy I found this!

    I just wish there was a controller that had two cooling outputs, as I’ll have a keezer for my kegs, and some sort of other chamber for fermenting in South Carolina. Oh well…guess I’ll just have to build two!

  4. How much clearance did you have in a 8x6x3? I ask because the product details for this unit say 4.3 x 3.5 x 2.5 inches and by the look of it it looks like the length is the 4.3″ Just curious how a 4.3″ deep unit fits in a 3″ deep box … unless I’m just way over thinking this, which I’m sure I am since you clearly had no problems fitting that in the box. Thanks for the great (and clear) write up, extremely helpful, can’t wait to get mine built!

    • There’s very little clearance. On the back of the STC-1000 there’s actually a removable plate that protects the wiring, on mine I had to remove that to get it in the box. Not a big deal IMO as it’s still protected since it’s installed in the project box.

      • Sounds good, I was a little nervous to move ahead with this considering those dimensions so thank you for the reply. I have everything else I need, just waiting on the controller to get here. In all this will cost me $30, way better than the $80 I almost spent on the Johnson controller … thank God for google!!

  5. Thanks, this is my next step in gathering part for the keezer. I was not sure about this because of the “dual” stage capability. I understand that it doesnt; need to be connected to both a cold and heat source to work. is that correct ?

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  8. What amperage is your Chest Freezer? We are about to build a TC using your guide, but we have a concern. It is the 110v version of the stc-1000 and we have a freezer that pulls 15 amps. Is this going to be an issue?

    • I’m not sure what the rating is. I looked at the specs online but can’t find anything specific. The only reference they had to amps was when referencing the use of an extension cord they said it had to be UL listed, 120VAC, 3-wire grounded and rated for at least 15 amps.

  9. When you use this for cooling, do you simply turn your freezer temperature down as low as it will go, or do you actually go in and bypass the freezer’s own thermostat so that it runs continuously – no matter what – when the STC-1000 tells it to?

    • Hey Chris, the STC-1000 has a temperature probe so when you plug the freezer into the controller it will turn it on/off as needed to maintain the temperatures you have set. Hope this answers your question!

    • Yes. Check your freezer/fridge to see what amperage it draws and make sure all your hardware and wiring can handle it.

  10. Way back to the fellow with the Kegerator who wanted to swap the analog factory equipped with a digital…..I am in the same boat…..my analog temp controller is not working properly so I assume I cannot build an external STC-1000 box and plug the Kegerator into it and expect it to work……I would think the internal analog still has control and I have issues with it maintaining proper low temps. The analog is $75 to replace and I thought the STC-1000 could be retrofitted in it’s place….but can’t figure out how I decommission the analog and let the STC run the show….any help???? I will call Edgestar tomorrow. Thanks Jim

    • If the freezer is running but it’s just not staying below freezing then the STC-1000 might work out. I’m not sure how those are wired internally as far as bypassing the analog, do you have the know-how to just straight wire the freezer and allow the STC-100 to take over?

      • I do if I could understand the Kegerator wiring which I can’t seem to find even in the owners manual…maybe my call to Edgestar will help. thanks

  11. The Kegerator has 3 wires running to the current internal analog thermostat. 2 that I know are 110V. I called Edgestar…useless party line that says they have no circuit diagram for the Kegerator nor can they help. The 3rd wire is a blue wire and I wonder if it should connect to one of the cooling terminals (don’t need heat control)…I can’t trace it to the compressor..I assume the STC just turns power off on the unit until temp raises if it’s over cooling. Again, I need to get the analog thermostat out of the circuit in that it’s bad. Are there experts from STC that can help??

  12. Hi Excellent DIY Project… but I have one Doubt… if I have a Freezer… and I wanted to use it to fermentation chamber (usually 60/63 F), on which outlet should I connect, on the cool or heat… tnx..

    • You would plug the freezer into the cool side. If you uses a heat source as well it would be plugged into the heat side. I have a small ceramic heat lamp in mine that I use for the heat.

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