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A/C Fermentation Chamber Build

I’d like to build a fermentation chamber using 2" rigid insulation and a small 110 v. window a/c unit I have on hand. I’m also thinking of building a dual temp controller using an STC 1000. My first question is will I have to use a relay to handle the amp draw of the a/c unit? Also I have read that I’ll need to eliminate the built in temp controller on the a/c unit, I understand that part. Some people have posted that the cooling coils will freeze up with very little suggested in the way of preventing this. One poster mentioned using a computer fan?? Would like to know if anyone here has done this and how it worked out. My main reason for doing this to be able to lager.

I don’t do electric. I don’t know your budget. But there’s a turnkey item made for this purpose called a coolbot. Here is the link.. Might have the info regarding the freeze problem.

$315 is way beyond what I wanted to spend. I can buy the STC 1000 for less than $15 on Amazon and then I just need a few other components, which I already have on hand. But thanks for the idea always good to know all of the options.

What i have been seen. A box with a old fridge they took the door out. Or build a box where you put two compfans. And a ice jug. They say it will stay cool all day

A window air conditioner would probably draw more current than an STC-1000 could handle. But, you can run the output of the COOL terminals of the STC to the coil terminals of a relay to switch a higher amperage circuit (120 V or 240 V). Here’s what I use to switch 240 V for my kettle:

The window a/c probably draws about 8-10 amps but likely 2-3 times that on start up. I know I have a relay at home but a contactor is probably more in order to handle the surge, Thanks

Couldn’t a simple Johnson temp controller be used? Some kind of heat source touching the ac unit’s sensor like a light bulb, heating pad or whatever to fool it into thinking it is not cold enough. It would be plugged into the controller the same way you would a fridge. The only problem I see after that is the fins icing up.

Or, just git a chest freezer and a controller? I have that going on now and very happy with it. I have yet to put wheels under it to make it way more portable, very soon! Sneezles61

I’ve thought of that too. I was just trying to get this project done on a shoestring. I had everything I needed except the $15 controller. Also this is going to have to go into the basement and plan A would be very lightweight. I use the plastic conical fermentor our hosts sell on their site, which is quite tall and wouldn’t fit in a chest freezer. I also have buckets and could use those with a chest freezer. Lots more to ponder I guess.

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look at I believe he has info on the webpage about building his. If not you could drop him a PM and he’d likely be happy to give you some ideas.

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I pm’d Greg at mullerbrau and he rplied with some useful advice. Thanks to you and Greg.

Cool. Keep us posted on your progress. I want to build one too.

I’ve finished the bulk of my shoestring fermentation chamber project. I just need to order the controls. I’ll be using an STC 1000 Dual channel controller and a 30 amp contactor to handle the startup current draw of the window a/c unit. It ain’t pretty but I think it will work. So far I’ve got $2.00 invested for a tube of PL400 construction adhesive. Should be well under $40.00 for the whole thing. All of the other materials were things I had on hand. The brackets inside are for a Fast Ferment conical fermentor.

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