Getting ferm mini fridge to lagering temps with STC-1000

[Justdrumin]

I built the STC-1000 at the beginning of summer and plugged in my mini fridge to it. It works GREAT for ale temps. I'm preparing to brew my first lager Monday and I'm trying to get it down around 32* or so to crash cool my starter. It's only getting down to about 7.6*c or about 45 or 46*F. The STC is set at 0*C, F2 is set at .5 and F3 is set at 5 min. I'm going to ferment my lager at 52*F, but when I go to actually lager, I planned to bring it down around 32*F. Any help is much appreciated and if it's already been discussed, I apologize, I did a google search and couldn't find much on it.

 

[Beernik]

If it's a fridge, it probably isn't built for cooling below 45F. The internal thermostat is probably governing the switching on and off of the compressor.

The way I got a mini fridge to lower temps was to bend the freezer plate down so it was flat against the back of the fridge, instead of a shelf at the top. This had the affect of making the whole fridge function as a freezer. But you have to be careful not to crimp or break the freon line.

On mine, there were four screws holding the shelf in place. I took out the front two and loosened the back two. Then I rotated (slowly and carefully) the plate down on the axis of the back screws and then tightened them back up when it was where I wanted it.

I'd include pictures, but my mini fridge is a fridge again and sitting in my wife's tattoo shop.

 

[ChrisL_]

The issue is your mini fridge will only go as low as the fridges internal thermostat will allow it, regardless of what the stc-1000 is set for. You can make sure the fridge setting is at its lowest possible setting, but for a fridge that may only be 4 or 5C. You might be able to figure out out to remove the internal thermostat and wire the stc-1000 directly to the fridge. I have no idea how to so that, but a goggle search on that might help. Problem is the fridge is only designed to chill down so low, no matter what the thermostat says the compressor may not be able to help get it to laggering temps.

 

[MangoMead]

Guys here in Thailand do this all the time to make fermenting fridges. You just have to use your controller to switch power on and off to the whole fridge. Then you set the built in thermostat to it's lowest setting.

When your controller decides the fridge is too warm, it switches the fridges power on and the internal thermostat will always start up the compressor. When it gets down to the temp your controller is set for the power goes off again.

Most people cut one of the lines from the power cord and put the controller in line there, run and secure the wires, mount the controller box on the outside of the fridge and run the temperature sensor inside through a hole drilled into the side of the fridge. If you wanted to be extra tricky you could wire up a project box with a plug to go to the outlet and a socket to plug the fridge into and just do the wiring inside the project box.

http://www.homebrewthailand.com/forum/viewtopic.php?f=5&t=33&sid=51f47016ff25607f377bb8232102b1a1

OOPS just realized I misread your original post, I'd say find the internal thermostat and disconnect it completely and connect the wires so the compressor will run all the time anytime there is power to the fridge. Then your controller should be able to bring the temp down to where you want it.

 

[Justdrumin]

OOPS just realized I misread your original post, I'd say find the internal thermostat and disconnect it completely and connect the wires so the compressor will run all the time anytime there is power to the fridge. Then your controller should be able to bring the temp down to where you want it.

This sounds like a great idea, but the only wiring I've ever done is wiring my STC. Lol. So how I do that is beyond me. I read somewhere about there being an adjustment screw on the thermostat. Does anyone have any experience with this? The post I read was very short and vague.

 

[Justdrumin]

"I know this thread is few months old so not sure if you found a solution to your fridge or not. I also have a haier mini fridge I turned into a fermentation chamber and was having a similar problem, my solution was a probe or thermocouple under the cooling coils covered by a piece of plastic. I removed the plastic piece and moved the thermocouple away from the cooling coils. I have got it down to 0 degrees since doing this."

I found this on another thread. I did it less than an hour ago and it's now down to 4*C and still goin. Keeping my fingers crossed that it keeps going. Thanks for your input guys.

 

[soulhere]

bump.

Goal: converting an Emerson mini fridge to a freezer.

1) First followed instruction to bypass the themostat:

"Unplug the unit. Locate the thermostat. There are 2 leads going to it. Remove them from the thermostat and connect them to eachother. Remove the thermostat and its temp sensor. Install your external controller and temp sensor. Boom."

from this thread https://www.homebrewtalk.com/showthread.php?t=78129.

Temp went down only to 25 or 30F. Aim is O.


2) Ordered an STC 1000 online to see if this would achieve goal. Installed according to diagram on this thread https://www.homebrewtalk.com/showthread.php?t=385792. All was working as stated. Set to -18.1.

First night temperature went down to -15C or 5F. Seemed like it was getting close.
Then went up to -8C and has not gone down below -10C or 14F. Too high.

Looking for ideas of what to do to see if I can get it to 0.

Reviewed some of this thread and starting question here though old thread.
THe internal thermostat is bypassed by a wire nut hooking the 2 wires together. there was a dial that was also the on/off so it is still in the fridge. I don't think this is impacting the temperature control since it went down to 5 right after install. Not sure why it won't go back down to 5 at least now.

 

[DurtyChemist]

bump.

Goal: converting an Emerson mini fridge to a freezer.

1) Temp went down only to 25 or 30F. Aim is O.

2) Looking for ideas of what to do to see if I can get it to 0.

Buy a freezer. A mini fridge won't get cold enough to be much below 30F. I know from experience. You're going to run the refrigerator 24/7 and it won't get any where NEAR zero degrees. Unless you're talking about getting to zero degrees Celsius.