Guide to set internal chest freezer thermostat to >32F; Eliminate external control

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Just wanted to say thanks again for this info.
I have fine tuned my temp and it is holding great now. I wanted to change the temp a few degrees and tried with the large dial knob that lets you fine tune it when the freezer is operating normally, however I got large temp swings and couldn't get the temp I wanted. I then tried adjusting the temp by only turning the course adjust screw you mentioned and can set the temp perfectly. So if anyone else is having problems don't touch the large dial and only use the course adjust screw. My screw works out to be about 2 degrees warmer for every one full turn clockwise (screw in).
 
My freezer is swinging widely, 30's to 50's... I ended up going back to my controller to keep it tighter.. It could be because its in my hot garage?

I'd be interested in what kinds of temp swings this translates into for the beer itself. I suppose it might be different for one gallon vs. five, but were these readings with a probe suspended in the air?
Also, have you taken readings the same way with while using your external controller t-stat to see what kind if swings it shows?

Agreed - you need to be reading some average temperatures, not the air temperature. Tape the probe to the fermentor, or stick it in a small glass of water. Oh, is there anything in the freezer? You need some mass in there to get the temps to average out.

Think about the A/C in your house. Your thermostat may be set to 76F +/-1F, but the air out of the vents is ~ 60F. That's normal, not a problem at all. It's not a 17F swing - the 'stuff' in the room will be 76F +/-1F.

Since a fridge is small, and normally packed with a lot of 'stuff' and little air (compared to a house), the air will normally be much colder than the 'stuff' during a cooling cycle - it has to to overcome the mass of all that 'stuff'.

-kenc
 
Well yeah, the compressor only turns on or off, producing very cold air until the desired temperature is reached, then turning off. It's not capable of adjusting how much it cools the air by... temperatures are maintained strictly by how long the compressor cycles on and off for.

Because of this, I have a tiny bit of ice on my freezer walls at times, despite being set to 70° right now - but the beer itself (according to the thermostat with the probe attached to it) remains at a very stable temperature.
 
I have a datalogging RTD thermometer that I will stick into a 3 gal keg of water and see what kind of fluctuations I get this weekend! That will tell the tale!
 
Temperature swings?

Two words.

Thermal Mass.

As has been noted, refrigeration equipment basically runs at one speed--high.

The chest I converted to a fridge has something over 100# of water in bottles at the bottom (you never see stuff at the bottom of a 35" deep box...) All refrigeration equipment keeps a more eve temperature with more mass and more insulation.

I currently am monitoring the unit with 2 external alarms, the external controller and the thermometers inside the box. All reading air temperature.

Seldom do all of them match, but the external is set to keep a 33-37 degree range, which it does well. The other thermometers range from 32 to 40 depending upon their location.

An internal circulation fan would probably even things out, but the swings I'm getting are fine, stuff that needs to be colder goes near the bottom, stuff that shouldn't freeze on top.

Now that I have about a week of data, I'll move a couple of the sensors into bottles of water, here I expect the swings will be far less.
 
I just picked up (free) an older Amana chest freezer. Not sure of the year, but here is some info:

DSC02046.jpg


It's got to be 10-15 cf as I can easily fit 6 corny kegs, 5lb CO2 tank and probably a 30 pack inside. Cleaned it up and plugged it in and it works great. I dug into the thermostat hoping to find a coarse adjustment screw and found this:

DSC02047.jpg


There are tiny screws inside the "cut in" and "cut out" holes. I assume if I turn those counterclockwise, it will run warmer? Turn both the same amount? Some insight would be helpful.

I just picked up an old amana... havent tore into it yet but wanted to know if you had made any headway with this one?
 
OHIOSTEVE said:
Mine absolutely has no screw. so a mini digital controller will have to be bought. Took it apart today, and there is nothing.

I have the same "cut in" "cut out" on my Whirlpool EHH-180F.

I have a diagram inside the service plate. I'll add a photo of it in a moment.
 
Sorry I didn't get a photo of table. I couldn't get the camera to shoot the text properly. I'll type it out below. Hopefully someone can make some sense of it.

Thermostat Calibration
(Not cabinet temperature)

Cut In (degrees)F Cut Out (degrees)F
-----------------------------------------------------------------
Warm (No. 1) +3 +-1(degrees) -10 1/2 +-2 1/2
Normal (No. 3) -2 1/2 +- 3 -17 1/2 +-3
Cold (No. 7) -8 1/2 +- 3 -25 1/2 +- 3(degrees)

Well length 23"

Note: Thermostat altitude adjustment not required on chest freezers

(Looks like the forum is killing my spacing and formatting. Hopefully it still make sense.
 
I just picked up an old amana... havent tore into it yet but wanted to know if you had made any headway with this one?

I have an old chest freezer that has the same thermostat and wondered if you guys had made any progress.

I am going to try to change the 'cut in' and 'cut out' screws to warmer settings. They should control the range of temperatures the freezer will allow before the compressor comes on, the delta T if you use another controller.

My hope is that if they are turned enough, they will be a coarse adjust for the freezer. I hope to try this weekend, and will let you know if I have any good or bad results.
 
Hi Guys, I picked up a Magic Chef 7.2CF chest freezer yesterday, model is MCCF7WBX. I am having a very hard time finding an coarse adjustment screw, it seems like all the mechanicals are in a plastic box, and its not really accessible through the front, I have to take the side panel off.

Here is a picture, any help? I'd rather not buy an external controller, my wife hates this hobby already.

2011-07-16%2009.46.37.jpg
 
Hi Guys, I picked up a Magic Chef 7.2CF chest freezer yesterday, model is MCCF7WBX. I am having a very hard time finding an coarse adjustment screw, it seems like all the mechanicals are in a plastic box, and its not really accessible through the front, I have to take the side panel off.

Here is a picture, any help?

It's going to be on top ( or bottom) of the adjustment knob that your thumb is on. Remove that top screw and see if that piece will slide out.
 
Hi Guys, I picked up a Magic Chef 7.2CF chest freezer yesterday, model is MCCF7WBX. I am having a very hard time finding an coarse adjustment screw, it seems like all the mechanicals are in a plastic box, and its not really accessible through the front, I have to take the side panel off.

Here is a picture, any help? I'd rather not buy an external controller, my wife hates this hobby already.

2011-07-16%2009.46.37.jpg

Post number 54 is mine and I did this mod on the same keezer
https://www.homebrewtalk.com/f51/gu...liminate-external-control-249612/#post3015206

you need to remove it from the plastic housing. the coarse set screw is on the side with the green wire.

-=Jason=-
 
Wow that was a PITA, but I think I got it. I screwed the coarse adjustment all the way, then backed it off just a tad. Ambient temp is 43*F and a glass of water is 38*F, does that sound good for a keezer temp? I would like beer to be around 40*F, but I guess I can't complain, this was free.
 
Just gotta say thanks for this post, very accurate! I yanked the adjustment knob off of my spare beer refrigerator yesterday (came right off, no issue) and saw a little screw beside it, woohoo!

Initially I cranked it counterclockwise about 1/4 of a turn, that did nothing. Fridge was at 43f air temp inside this morning, my test bucket with 2 cups of water was at 38f. I popped the knob off again, this time turned it clockwise about 3 full turns, compressor turned off right away (yes, did this plugged in, rebel yell!). Now, 8 hours later, my water is at 50f, air temp around 52f.

Still warming it up to see how high I can go, but at least I know I can lager in here, which is AWESOME! I'll see if I can get this to about 60f top end, then turn the screw back (with the dial set to the 'warmest' temp) until the compressor turns on. This way I know that at 1 on the dial, I'll be at cool ale fermenting temps, then see what turning the normal adjustment dial to full cold does.

My hope is to vary between 48 and 60 just using the normal dial, but that's probably too good to be true.

One downside is my freezer is warming up bigtime...like the fridge compressor affects the freezer temps. So I may wind up having a freezer that's at normal fridge temps, and a fridge that's at fermentation temps, until I do a lager down to 48 or so and the freezer goes below 40, and all my bottles freeze up. Must remember to remove them then ;)

Wicked though, this saved me like $100 easy, fantastic!
 
Flomaster, did you adjust your coarse adjustment screw all the way? What is your temperature on your magic chef? Mine is too cold at 33-32*F.
 
Flomaster, did you adjust your coarse adjustment screw all the way? What is your temperature on your magic chef? Mine is too cold at 33-32*F.

yeah mine is turned all the way as far as I can turn it. I have my fine adjustment dial on the front turned all the way to the left and then just a 1/4 turn or so to the right. I have my temp probe in a vile of starsan sitting in the keezer just monitoring the temp its been at 1.2°C so I just turned my fine adjustment dial all the way to the left to see how warm it will get.

-=Jason=-
 
i made a ferm chamber out of a dorm fridge. the thermostat knob is on the right side, right where the door closes, and there is a probe running from the knob up to the freezer plate. any info on how to do this with a dorm fridges so i can get it in the 60-65 range?
 
Anyone with the cut-in/out screws figure it out?

I have been trying mine. I turned the screws (both) 4 turns warmer and let it sit. The temp was at 10F after about 12 hours. I turned them 3 more times warmer this morning and will check late tonight.

The only issue I may have is the temperature swings. If the screws aren't linear, the range that the freezer is on may be too large. Only one way to find out. If it doesn't work, I can always turn them all the way back and use an external controller.

BTW, my freezer is a Montgomery Ward 8060 (8.4 ft3).
 
My frigidaire will be delivered this weekend. Can't wait to tear it apart, lol. No really I was on this site looking for what controller to get, now it looks like I may not need one, good stuff thanks.
 
Got this set with my kenmore 8.8. I turned the screw all the way to the right then used the knob to fine tune. worked perfect!
 
i made a ferm chamber out of a dorm fridge. the thermostat knob is on the right side, right where the door closes, and there is a probe running from the knob up to the freezer plate. any info on how to do this with a dorm fridges so i can get it in the 60-65 range?

I'm trying to do this with an old mini-fridge as well. For mine, I took apart the thermostat inside the fridge and found a screw on the opposite side from my thermostat knob. After adjusting this screw, I can definitely adjust the range of temperatures but sadly, I can't see to hit ~60 degrees. My fridge will either turn on (34-40 degrees) or turn off completely. I may try to play around with it more but for now I'll give it a rest since I also use it to cold crash my beer.
 
I have an OLD Frigidaire by General Motors freezer. Probably late 60s - early 70s. Would this thing have a coarse adjustment, ya think? I know the thing works, but I haven't used it yet. Got it for $25 at an estate sale. :mug:

I'd like to use it for my beer fridge in order to free up my current beer fridge for cold crashing. I can't use the freezer for CC because I can't take the shelves out - the coolant lines are built into the shelves.
 
I have an OLD Frigidaire by General Motors freezer. Probably late 60s - early 70s. Would this thing have a coarse adjustment, ya think? I know the thing works, but I haven't used it yet. Got it for $25 at an estate sale. :mug:

I'd like to use it for my beer fridge in order to free up my current beer fridge for cold crashing. I can't use the freezer for CC because I can't take the shelves out - the coolant lines are built into the shelves.

It wouldn't hurt to check. This kind of sounds like a universal concept on thermostats.

How built in are the coolant lines to the shelves? One of the mini-fridges I had to tear apart had coolant lines attached to a metal shelf. I realized I could pry it apart by using a screw driver to bend some metal tabs around the coolant lines. Afterwards, I simply used some cable ties to bunch up the coolant lines to the side. If this is the case with yours, I'd give it a try.
 
I just picked up (free) an older Amana chest freezer. Not sure of the year, but here is some info:

DSC02046.jpg


It's got to be 10-15 cf as I can easily fit 6 corny kegs, 5lb CO2 tank and probably a 30 pack inside. Cleaned it up and plugged it in and it works great. I dug into the thermostat hoping to find a coarse adjustment screw and found this:

DSC02047.jpg


There are tiny screws inside the "cut in" and "cut out" holes. I assume if I turn those counterclockwise, it will run warmer? Turn both the same amount? Some insight would be helpful.

Ran out of patience with this freezer and sold it for $50. I now have my eye on a 5 year old Haiar 5cu ft freezer on craigslist. I shouldn't have a problem with this one, I would think.
 
I wanted to try this out and was wondering where the screw is going to be. I have two little boxes with wires going into them. One on the compressor(first pic), and one all alone(second pic). Which one should i try taking apart? Thanks for the help.

CIMG0075.jpg


CIMG0074.jpg
 
Hermish said:
I wanted to try this out and was wondering where the screw is going to be. I have two little boxes with wires going into them. One on the compressor(first pic), and one all alone(second pic). Which one should i try taking apart? Thanks for the help.

I would say the second pic. Try to find where the thermocouple attaches. In the second pic if that is where the dial attaches to fine tune the temp for normal operations them that is where the course adjust screw is located. Just don't adjust the round dial once you start adjusting the course adjust screw or you might have a hard time fine tuning the temp. Sounds wrong but for some reason for me the normal knob screwed things up for me.
 
Just want to get another thanks to the OP! I'm pouring brew now pretty consistently at 38 degrees. Saved me at least 50 bucks and some electrical work.
 
I would say the second pic. Try to find where the thermocouple attaches. In the second pic if that is where the dial attaches to fine tune the temp for normal operations them that is where the course adjust screw is located. Just don't adjust the round dial once you start adjusting the course adjust screw or you might have a hard time fine tuning the temp. Sounds wrong but for some reason for me the normal knob screwed things up for me.

I'm not sure if this changes anything, but the knob in the second pic spins on its own. Seems to be like a timer for the freezer to turn on and off.
 
subscribed....

Awesome write-up. Now I am going to have to start building a keezer...

Oh, honey... where is the checkbook? :)

-Redbeard5289
 
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