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

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well this is sorta old...but it came to me in an email...


i modded my oven with a 200ohm resistor on the temp probe to go lower, but i got the idea from pizza affectation's doing it in series(?) with high ohm resistors....just find the temp probe and then short the leads off it with a high ohm resistor if you want it to go higher.....


(and no i didn't read all 15 pages, just thought i'd share)
 
There are not only no resistors in a mechanical thermostat, there's no electronic components at all, save for the switch inside the pressure sensor...

Cheers!

you mean like my cheapo analog temp controller, with the copper and all that...my oven has a two wire temp probe......would have thought a modern freezer would have something similar....
 
I think what Daytripper was getting at is that most economy fridge and freezers use a capillary tube thermostat. The large part of the tube sits in the compartment, and pressure is raised and lowered on the other end in the thermostat in direct relation to temperature. Higher temps cause more pressure, and it expands a small chamber in the stat, tripping the microswitch, turning on the compressor. The knob that you are moving adds/removes opposing spring pressure to give the system some limited adjustability. The silver thing coming off the back of the stat pictures shown is not a wire, it's the capillary tube. If you cut into that, you opened up the stat system and rendered it useless to measuring temperature.
 
Hi all, thanks for a great thread with lots of usefull info. I recently bought a Electrolux EC2230AOW1 chest freezer to cool my corny kegs in, but i cannot get it above freezing temp.

I am unsure if my thermostat has this magical screw. I see on most pictures in this thread the coarse adjustment screw is located on top, next to the knob, or on one of the sides under tape/stickers. I could not find any screws on the outside of my thermostat, but there is a screw on the inside of it, accessible through a crack on the bottom. I have tried turning this screw to the very end (both CW and CCW) and waited 24 hours to check the results, but it does not seem to make any difference.

Should i try dissasembling the thermostat to get a better view on the inside? Could this screw be the one? See pics attached. Could not find the modelnumber, but it seems to be from a Company called Danfoss.

Hope this thread is still alive, any help would be deeply appreciated.

http://imgur.com/gallery/kbWAfPI
 

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Look in the small hole, next to the adjustment knob shaft.

Use a good light........If see a small screw in there, I'd say that is the one.

Don't screw it all the way out.
Make small adjustments, and measure what you did, then make more adjustments.
 
Look in the small hole, next to the adjustment knob shaft.

Use a good light........If see a small screw in there, I'd say that is the one.

Don't screw it all the way out.
Make small adjustments, and measure what you did, then make more adjustments.

Thanks for the reply, good to see this thread is still going!

I looked at it once again, but im now 100% sure there is No screw in that hole. I turned the adjustment knob shaft and looked from every possible angle.
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The only screw that makes sense to me is the one i talked about in my post, the one on the inside. I did get a better look at it if it helps, see pics. Also i found these two very small (what appears to be) screws on the side, can it be one of theese?

Are there freezer termostats without the coarse adjustment screw? This might not have a temp range as suggested in this thread. If not, what are my options? Buying a New thermostat, or maybe its better to go with the external temp controller?
 

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The one with all the threads pictured, is probably it.

"Normally", the ones without a coarse adjustment, are digital thermostats.

Your call, on "screwing" with it, or the ext. temp controller..............Both will work, messing with the mechanical thermostat takes a little more dialing in.

The one I had tweaked, was for the Wife's "cheese cave", and worked great.........She no longer makes cheese, so I tweaked it back where it was originally..........Take a sharpie, and record the turns in or out when finalized, so if you wish to return it to original.
 

Thanks to the OP for posting! This saved me the cost of a temp controller so i figure I'd post how I got mine working.

Just bought a GE 7cuft Freezer Model FCM7DUAWW.


Shot of the Thermostat:


I unscrewed the side vent and pushed in the clips to pop out the themostat.


Once the themostat was dangling out I found the set screw. In this pic it's the top screw in that oval on the side.


It took around an entire week to get the temperature set high enough. I first turned freezer to the warmest setting. Then I screwed the set screw in(clockwise) 3 turns, let the temp stabalize over night. Repeated that over several days. Eventually I got to a total of 11 turns and the freezer temperature was sitting at 48 degrees F at the warmest setting. I wanted the temp down around the upper 30's so I put the thermostat back into the freezer and used the front dial, raising the setting up(cooler) little by little to adjust the temp a little cooler. It didn't take much and I got the temp down to 38 degrees F when the dial was at the 1.5 setting.

It takes some time and patience to get the temperature correct since the freezer has to adjust temperature overnight. But if you take your time and let the temp adjust lowering it little by little then it can be done. =)

Goodluck and Cheers!

I have the same model GE as these two posts so I know it should work but could not get the freezer above 28 with the adjustment screw. Ended up going back to a temp controller.

But then I thought on it for a month or so and wonder, does the thermostat need to be reinstalled or at least level for adjusting? Mines in the basement at a steady temp and I wasn't worried about the kids messing with it so I just left it dangling cockeyed // while I worked on adjusting it. Would it not work because the thermostat was not level?
I'm not sure on the mechanics of these things but I thouht of it when I replaced an old mercury dial thermostat in the house...
 
The one with all the threads pictured, is probably it.

"Normally", the ones without a coarse adjustment, are digital thermostats.

Your call, on "screwing" with it, or the ext. temp controller..............Both will work, messing with the mechanical thermostat takes a little more dialing in.

The one I had tweaked, was for the Wife's "cheese cave", and worked great.........She no longer makes cheese, so I tweaked it back where it was originally..........Take a sharpie, and record the turns in or out when finalized, so if you wish to return it to original.

Thanks for the advice, you were right. This must be the magic screw. Unfortunately, in my feeble attempts to tinker with it, i have rendered the screw unturnable. The screw head is now mangled, and it is very hard to sort this from the outside, so i would have to disassemble the whole thing.

I think at this point i might be better off just buying a new thermostat. Does anyone know of any thermostats that are better suited for this purpose out-of-the-box? Or where i might aquire one. Or if you think there are better options, im all ears.

Attached is a pic of the screw and its mangled head, hope No one else makes the mistake of using suboptimal tools

<Edit>: The screw is stuck very far turned clockwise if it makes any difference. This seems to have made the temp colder by what litte measures i have gotten so far.
 

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I know this thread is old (but not dead) and long...but question. I have a mini fridge that right now I'm using for cold crashing - but it's not getting very cold inside (45f - ambient is 85 in the garage - maybe my ambient is to warm). Would (assuming I have not refrigerant, evap/condense issues) setting the t-stat to the coldest setting effectively mean run constantly....and then would an inkbird be a good choice to keep it at say 38f? Should I bypass the internal t-stat by just wiring the two wires (not the green ground) together?
 
From experience the lowest setting on a fridge thermostat will not force the system into some kind of "run compressor forever" mode. It'll still have a temperature "floor", and I'm guessing it'll be pretty close to that 45°F.

I would try bypassing the t-stat because it's usually quite easily done, then see how the fridge reacts. If it'll get down to your cold-crash target (fwiw, mine is 34°F) then it should work well with an external controller. Otoh, if it still won't go much below 45°F, there may be other limiting issues in play...

Cheers!
 
From experience the lowest setting on a fridge thermostat will not force the system into some kind of "run compressor forever" mode. It'll still have a temperature "floor", and I'm guessing it'll be pretty close to that 45°F.

I would try bypassing the t-stat because it's usually quite easily done, then see how the fridge reacts. If it'll get down to your cold-crash target (fwiw, mine is 34°F) then it should work well with an external controller. Otoh, if it still won't go much below 45°F, there may be other limiting issues in play...

Cheers!

Thats my plan this weekend. The other thing I noticed is that it cycles every 15 min or so. I don’t think it’s overload switch because the compressor is only pushing 160f. Hardly long enough for the cold plate to get fully cold (it will if day I leave the door open to make it run). If I’m thinking the t-stat is probably just bad. If it’s not the t-stat then it could be low on refrigerant but I wouldn’t think that would make it cycle...
 
A few things can cause short cycling, if that's what's going on. Low refrigerant/suction pressure. Evap fan not pushing air past the coils, iced up coils. Bad door switch;. If the door is leaky, and you have an empty fridge, there is no mass to hold temp. I had a fancy upright freezer that had solid state control over defrost timing cycle, board issues caused short cycling. I would bypass the Tstat, if your evap line inside is not even getting cold pretty much immediately, then you have other issues.
 
I have a number of these refrigerators running. When the thermostat is set as cold as possible, and you have a digital control running the refrigerator line cord, they will chill down to about any temperature you want. Mine are old 4.4 cu ft Sanyos (no longer in production) and can hold a lagering temp of 34F degrees in a 98F California garage all summer long. When they can't hold the lagering temp they are still good for fermentation chambers set at 50F for lagers or mid 60s for ales. About the only time to toss them is when they begin icing up. Usually not worth the expense of a recharge unless you can figure doing it yourself. At $75 Craigslist, just drop in another unit.
 
Here's what the thermostat looks like on my Magic Chef 10cf chest freezer. I set the normal temp control dial to its midway point them used the coarse adjustment screw seen in the pic to bring the temp range up. Nothing scientific, I just screwed it in 4 or 5 full turns and let the freezer run overnight. Got pretty lucky. It was right at 37 degrees.

View attachment 27359
I wonder if you put the fine controller at it's lowest setting then adjusted the course to 40. Could you then use the fine controller to adjust up for fermentation?
 
what's the "norm" on direction of adjustment? in or out to raise the temp range?
 
what's the "norm" on direction of adjustment? in or out to raise the temp range?


From page 1 of the thread, post # 16 or so:


"The direction you turn is dependent on the particular thermostat you have. It could be left or right. The diagram is just for the concept. Here is one way to find out; If the freezer is at temperature and the compressor is off, unplug the unit and turn the screw a few turns in each direction and listen for the thermostat relay to click on. When it does you know the direction you were turning when it went on makes it colder. "



;)


Ya' gotta' play with it...........( That's what she said.........)
 
close call...I just did this method, but had not read the thread entirely. I have a 7.0 cu ft magic chef.
I unscrewed the screw too much and couldn't get it to catch the spring nut again. I had to take apart the entire thermostat...which wasn't that hard. It was getting it back together again that was a pain. Methinks they put it together in an assembly jig with the gas cylinder unpressurized then add gas and crimp the end (of the in-freezer side).
Oh well..my flathead screwdriver just nicked but didn't puncture the gas cylinder (bellows).
Waiting to see if it freezes my beer... 🤞
 
welp...i turned the screw all the way out and reassembled the best I can...still got down to 5F...froze the beer line, although I don't think it froze the keg...
probably just going to install a temp controller then.
I don't want to drill my collar as I've just finished it today and got the sealing beautifully done!
I have a spare Johnson controller, so I may just yank out the temp bulb from the thermostat and jam the Johnson temp bulb in it's place (under the compressor hump I think it sits "inside" the insulation adjacent to the inner freezer wall.
 
My Sanyo 4.4 cu inch refrigerator will freeze a keg... I closed the door with the thermocouple probe hanging outside the unit ... so it kept cooling and cooling finally to the point of freezing... Ice beer anyone?

CC990849-CB27-4965-85DA-551C9DF3A460.jpeg
 
I tried this adjustment on a 2.6cuft Magic Chef like this one I plan to use as a small beer cellar.
Magic Chef 2.6 cu. ft. Mini Fridge in Black, ENERGY STAR HMBR265BE1 - The Home Depot

Coarse adjustment screw was the side to the right of the fine adjustment dial. Default was about 37F when set to the 1. Did a few turns CCW and the temp went up to 42F after a few hours, did few more CCW turns and no change after a few more hours, so did a bunch and the temp went colder and started forming ice in the jar of water I had a thermometer in. The spring was compressed quite a bit.

I backed the coarse adjust screw all the way out clockwise and the temp went back up and is holding at about 52F. I would of liked it to get a little warmer but it is close enough for me.

Not sure why it initially started getting warmer when the adjust screw was turned CCW then got colder, but it seems to be holding a warmer temp OK for now adjust CW.
 
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