Bypassing fridge thermostat. How?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Yorg

Well-Known Member
Joined
Jun 3, 2007
Messages
168
Reaction score
1
Bought myself a fridge, and have an external controller for it.
But let's say I want to lager at 0 Celcius / 32 F.
The fridge's own thermostat would turn the power off, and I would never get to 0.
So how do you bypass it?
 
Not sure if this is possible, and it would likely be dependent on the make and model of the unit, but I would also like to know how if it is.

Most people use freezers that have no problem getting down that low, most fridges can't quite get there.
 
It is possible you just have to know what you are doing and I can't help you with that. I want to do the same thing to a fridge that I have.

You have to find the wire that leads from the thermostat to the compressor and tie the power out into it from the controller.

Then you have to find a wire that is always hot to keep the controller on for the power in. If you do that you will by pass the thermostat but I have no clue where to find that when I attempt it Im going to be trying to figure it out.
 
I'm going to assume the stock controller works as a switch just like the external controller. It makes or breaks a connection. You should find two wires leading into the controller. Cut them both and wirenut them together. This effectivly turns the fridge into a deep freezer given no external controller.
 
Is it possible that the compressor on a fridge versus the compressor on a freezer simply wouldn't be rated to cool to temps that low? Or do you think/know that the compressors used in fridges and freezes are the same and just capped by temp control? With your fridge there should be heating and cooling specs. maybe could even pull the model number off the compressor being used and google it to find a spec sheet on it, Not the specs of the fridgedaire/whirpool/magic chef system. This would tell you what the compressor was capable of. as far as wiring in the controller look the the schematic included with the fridge manual and sub in the controller switch for the thermostat switch. If you don't understand electricity don't attempt yourself. People under estimate 110V because it's everywhere, It's still plenty to kill you.
 
OK, so I figured it out with my fridge. I'm using a Haier Wine Cooler, it fits a carboy just right.

My fridge's thermostat only allowed the compressor to run until the temp reached 40ish, with the lowest setting at 45, and let it warm back up to 48 before the compressor kicked back on. I found the wire leading to the thermometer, and discovered that it was right behind the backplate of the fridge. After removing the backplate and CAREFULLY bending it aside, I was able to detach the thermometer from the back of the unit.

I ran the thermo out from behind the backplate, took off the dome light and lined the inside with foil, and put it back on with the thermo inside the dome. Now, I have it so the unit will turn on and off with the help of a Ranco or Johnson control (haven't purchased yet). When it turns on, the light turns on, but doesn't expose the beer to any light because of the foil, and heats the inside of the dome light where the thermo is. Inside the fridge can get as cool as I need now, while the internal fridge thermo reads in the 90s.
 
Hmmm...I was trying to figure that out with an old fridge i'm about to purchase. It has a freezer compartment on top of the frindge compartment. Can I not just cut out the bottom on the freezer and the top of the fridge and make it one chamber. Then install a temperature control?
 
O.k I just did this on a fridge from 1956 and it was a nightmare but I finally got it going.

On my fridge on the back where the compressor is there was a relay that turned the compressor on and off.

This wasn't your run of the mill Relay it had about 8 wires going to it and was really confusing.

I decided to bypass the relay and use the love controller after many combination's of wiring I got it going.

So it is possible i'm thinking on a newer fridge it would have been a little easier.

I'm mounting the love controller n the door I will post pics after
 
I researched a lot, and was a bit worried about cutting the wires, but installing my temperature controller took about 5 minutes once I got to it.

The fermentor/kegerator I have is a Kenmore 5.7' model, no ice compartment, its part number is 9588.

This model has a digital display on the front, and control for the stock thermostat. To keep that and the light active you don't want to just plug the fridge into the controller.

So, after probing some wires and finding the compressor (which is conveniently inside a hatch/door near the back), I figured I could just wire the Ranco controller directly to the compressor. By keeping the other wires intact the rest of the fridge works the same.

With three twist connectors and a couple snips it was all done. I just cut an extension cord in half and hooked the white and black wires to the compressor, the green to ground, then plugged it into the Ranco controller.

The other connections that were on the compressor, I just made sure were intact, except for the control lead (a red wire from the control board).

Done. Do it. The fridge was off by about 5 degrees, so I am happy I just decided to control the fermentor this way instead of turning the fridge on and off to do a diactyl rest!
 
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.
:mug:
 
So I'm trying to do this to my fridge as well. I have a Danby 50 bottle wine chiller that goes to 41F. I would like to get it to 35F using a temperature controller & bypassing the internal thermostat.

I've attached a photo of what the compressor compartment looks like. Does anyone have any tips or suggestions for me?

Its called Danby Silhouette DWC512BL

20151231_091335_resized.jpg
 
So I'm trying to do this to my fridge as well. I have a Danby 50 bottle wine chiller that goes to 41F. I would like to get it to 35F using a temperature controller & bypassing the internal thermostat.

I've attached a photo of what the compressor compartment looks like. Does anyone have any tips or suggestions for me?

Its called Danby Silhouette DWC512BL

I did this with my kegerator successfully by following youtube videos. maybe search around for your model or a similar one? I doubt the thermostat is that different across various fridges. For mine, I just had to take apart that "Colder/warmer" dial and locate some screw in the back. Turning that a mere 30 degrees or so was enough to freeze my beer.

Just a word of caution, before messing around with it, UNPLUG the unit. Take a lesson from my dumb electrocuted ass
 
This is what my circuit diagram looks like.

I have googled it and there are some people describing the process for Danby kegerators but I couldn't find anything for the wine chiller.

Couldn't I just take the thermostat out somehow and leave it at room temp so it will always COOL and then the external controller will shut it off when it gets to my desired temp?

Could it be that simple? If so - any suggestions on where to look for thermostat?

20151231_095105_resized.jpg
 
This is what my circuit diagram looks like.

I have googled it and there are some people describing the process for Danby kegerators but I couldn't find anything for the wine chiller.

Couldn't I just take the thermostat out somehow and leave it at room temp so it will always COOL and then the external controller will shut it off when it gets to my desired temp?

Could it be that simple? If so - any suggestions on where to look for thermostat?

I think I found some. The thermostat should just be inside the adjustment thing. Mine looked exactly like these videos once i took it apart

 
Last edited by a moderator:
bosster01,

Looking at that picture the unit that you have is a refrigeration cycle not an electrical cooler (like the chepo wine units I have!). :mug: The 41°F limit appears to be a control limit not a thermo limit of the cooling capacity. 35°F MIGHT be possible, or the thermo limit could be somewhere between (dependent on ambient).

An external temperature controller simply uses its own temperature probe to determine if the fridge/freezer/wine cooler needs to be cooled and turns it on if it does. Therefore the fridge/freezer/wine cooler itself always has to be set to a lower temp then the controller, or the controller will just turn on the unit but no cooling will happen.

You have the options of attempting change the coolers controls or trick the cooler into cooling. Changing the control range will likely be difficult, unless it is mechanical. I would look at two options:


  1. Locate the temperature probe that the cooler thermostat uses to control the cooler. Can it be easily moved? If so relocate the temperature probe outside of the cooler. That way the cooler thermostat is always saying that it needs to be cooled. Hook up the temp controller like normal, since the cooler always wants to be cooler anytime the unit is turned on by the controller it will start cooling.

  • Locate the thermostat that controls the cooler. It should have several wires attached. There may be a wiring diagram inside the unit somewhere. (2) wires should be the input power wires. (1 or 2) should run to the temperature probe. (1 probably) should run from the thermostat either to a relay, board or directly to the compressor/fans.

    If you need to pull out a multi meter, BE CAREFUL, figure out which wires are the input wires (+120V and "ground"), figure out what happens when the thermostat says the cooler needs to be cooled. Most likely the thermostat will open an internal relay and allow +120V to the wire that is controlling the compressor/fans. Wire around the thermostat so that anytime the cooler has power the compressor/fans turn on. Hook up the temp controller like normal, since the compressor is now hard wired anytime the unit is turned on by the controller it will start cooling.

If when bypassed the compressor runs 100% of the time but the set temperature is never reached then the set temperature is below the thermo limits of the cooler with the current ambient temp.

Jason
 
This is what my circuit diagram looks like.

I have googled it and there are some people describing the process for Danby kegerators but I couldn't find anything for the wine chiller.

Couldn't I just take the thermostat out somehow and leave it at room temp so it will always COOL and then the external controller will shut it off when it gets to my desired temp?

Could it be that simple? If so - any suggestions on where to look for thermostat?

bosster01,



  • Locate the thermostat that controls the cooler. It should have several wires attached. There may be a wiring diagram inside the unit somewhere. (2) wires should be the input power wires. (1 or 2) should run to the temperature probe. (1 probably) should run from the thermostat either to a relay, board or directly to the compressor/fans.

    If you need to pull out a multi meter, BE CAREFUL, figure out which wires are the input wires (+120V and "ground"), figure out what happens when the thermostat says the cooler needs to be cooled. Most likely the thermostat will open an internal relay and allow +120V to the wire that is controlling the compressor/fans. Wire around the thermostat so that anytime the cooler has power the compressor/fans turn on. Hook up the temp controller like normal, since the compressor is now hard wired anytime the unit is turned on by the controller it will start cooling.

Jason



I see you added more info that I didn't see when I posted. For the second option I gave, bypassing the thermostat, use this ****ty drawing :tank: as reference.

Untitled.png
 
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.
:mug:

You make it sound simple....... and it is. Folks here have a tendency to make mountains out of molehills. I personally would not connect the two leads together where the thermostat was, but tie into my external controller there, as I want my light, etc to work. The really quick and dirty way is to simply adjust the internal to max (most fridges will max out far colder than you want), and control power from the wall through the external controller.
 
You make it sound simple....... and it is. Folks here have a tendency to make mountains out of molehills. I personally would not connect the two leads together where the thermostat was, but tie into my external controller there, as I want my light, etc to work. The really quick and dirty way is to simply adjust the internal to max (most fridges will max out far colder than you want), and control power from the wall through the external controller.

The wine cooler that bosster01 is discussing has an electronic thermostat that is control limited to 41°F.
 
You make it sound simple....... and it is. Folks here have a tendency to make mountains out of molehills. I personally would not connect the two leads together where the thermostat was, but tie into my external controller there, as I want my light, etc to work. The really quick and dirty way is to simply adjust the internal to max (most fridges will max out far colder than you want), and control power from the wall through the external controller.

So is this an option for me or not? It would be nice to have my light work!
I just bought a DIY temp control (dual stage) from a local homebrewer who sells them fro 40$ with everything.
 
I see you added more info that I didn't see when I posted. For the second option I gave, bypassing the thermostat, use this ****ty drawing :tank: as reference.

I'm going to start unscrewing the things on top to see if the thermostat is hiding in there like in the video that was previously posted!

Thanks everyone, appreciate all the help.
 
Okay I believe I have identified the temperature probe - it was sitting right behind the dial deal where i can change the temp.

So 1 idea that was discussed was to put the probe outside to trick it into thinking its hot.

One problem.

When my temp controller shuts off the wine chiller when it turns back on again it goes to a default of 53 degrees - so it won't chill unless my basement is more than 53 degrees - which it typically is.

Just one flaw that I noticed. IDK if having it set to 53 degrees decreases the amount of "cooling" itl'll do if the probe measures say 60 because it's sitting outside.

I'm going to take apart the temp control module thing I'm assuming the thermostat is hiding in there.

Here's a photo of the probe - hard to take the photo sorry for poor quality.

20151231_131814_resized.jpg
 
Okay so here are the new photos. You can see that the probe deal is attached with a white clip.

1. Idea would be to splice those wire and extend it to be long enough to sit outside of the fridge. Downside to that was in previous post (the default is 53F) - so when temp controller shuts it off the fridge will be trying to cool it to 53F instead of 41F. UNSURE if this matters or if there is a away around this.

2. Idea from jddevinn is to adjust the wires as he described.. I'll just have to figure out which wire is which - any tips appreciated.

3. I just tried disconnecting the probe from the white clip and when I do that the display says E1 and the fan will spin but the compressor doesn't come on. I was hoping disconnecting the prob would just make it chill indefinitely but it doesn't seem to be the case.

So long story short just curious what everyone thinks I should do?
And do you think the metal thing in the pic is the thermostat?

Thanks for all the help! Can't wait to start lagering.

20151231_132942_resized.jpg


20151231_132958_resized.jpg


20151231_133014_resized.jpg
 
So is this an option for me or not? It would be nice to have my light work!
I just bought a DIY temp control (dual stage) from a local homebrewer who sells them fro 40$ with everything.

It's an option if you have a suitable thermostat with a delay built in so the fridge will not snap on and off on short intervals. I've never had a fridge where I couldn't access the thermostat fairly easily. The thermostat of course is right behind the adjusting knob, and can usually be accessed right there. The compressor is normally underneath, and you can if you are clever do it all from underneath. You will have hot and neutral lines all down there. If you find the hot wire from the thermostat to the compressor, you can cut that and feed it from your thermostat. It should be easy to trace which is which, as the neutral goes back and connects to other neutrals, and the hot goes only to the thermostat. You can simply cap off the supply from the internal thermostat. No matter how you do it, it's not rocket science. Working from underneath is a pain, but if you're creative, it should not be that difficult. laying the fridge on it's side is probably the easiest way to access wiring underneath. I've replaced the thermostat in my fridge ( GE ), and it will have a neutral line connected, and a hot from the thermostat. You can simply cut and cap this wireproved extremely easy.......that's how I personally would approach it....... and I intend to install an STC 1000 eventually because factory controls suck!!

H.W.
 
It's an option if you have a suitable thermostat with a delay built in so the fridge will not snap on and off on short intervals. I've never had a fridge where I couldn't access the thermostat fairly easily. The thermostat of course is right behind the adjusting knob, and can usually be accessed right there. The compressor is normally underneath, and you can if you are clever do it all from underneath. You will have hot and neutral lines all down there. If you find the hot wire from the thermostat to the compressor, you can cut that and feed it from your thermostat. It should be easy to trace which is which, as the neutral goes back and connects to other neutrals, and the hot goes only to the thermostat. You can simply cap off the supply from the internal thermostat. No matter how you do it, it's not rocket science. Working from underneath is a pain, but if you're creative, it should not be that difficult. laying the fridge on it's side is probably the easiest way to access wiring underneath. I've replaced the thermostat in my fridge ( GE ), and it will have a neutral line connected, and a hot from the thermostat. You can simply cut and cap this wireproved extremely easy.......that's how I personally would approach it....... and I intend to install an STC 1000 eventually because factory controls suck!!

H.W.

I don't have a dial, I have buttons. I still think I found the thermostat though based on my picture above.

I guess I just don't have a good way of understanding which wires I should mess with.

OR if I should even mess with the wires at all because maybe I can just extend my probe to outside the fridge - so that it'll cool it.

My goal is the easiest/most reversible repair possible to get the job done.

Thanks again for the help.
 
I don't have a dial, I have buttons. I still think I found the thermostat though based on my picture above.

I guess I just don't have a good way of understanding which wires I should mess with.

OR if I should even mess with the wires at all because maybe I can just extend my probe to outside the fridge - so that it'll cool it.

My goal is the easiest/most reversible repair possible to get the job done.

Thanks again for the help.


The one big red wire going to the transformer is probably the power in, the other is probably power to the compressor. The small red is the evaporator fan according to the diagram.

What I would do is cut all three red wires, leaving enough to connect back with wire nuts if you decide to. I would then plug the fridge in, and use a volt ohm meter to determine which is the hot wire. Use the green (ground) wire as your neutral for testing. Once you determine the hot wire, both other reds should be connected to the output of your thermostat so the evaporator fan runs whenever the compressor is on. The control you have is designed to run the fan longer than the compressor, hence the two leads. This results in a bit better efficiency, but older fridges didn't do this, and it obviously isn't necessary.

The green wire of course will connect to something metal in the body of the fridge.


H.W.
 
The one big red wire going to the transformer is probably the power in, the other is probably power to the compressor. The small red is the evaporator fan according to the diagram.

What I would do is cut all three red wires, leaving enough to connect back with wire nuts if you decide to. I would then plug the fridge in, and use a volt ohm meter to determine which is the hot wire. Use the green (ground) wire as your neutral for testing. Once you determine the hot wire, both other reds should be connected to the output of your thermostat so the evaporator fan runs whenever the compressor is on. The control you have is designed to run the fan longer than the compressor, hence the two leads. This results in a bit better efficiency, but older fridges didn't do this, and it obviously isn't necessary.

The green wire of course will connect to something metal in the body of the fridge.


H.W.


Here is a better look at the thermostat - this is definitely the thermostat right?

And the wires there are 4 in total. Could you please provide me with step by step instructions - sorry for my lack of knowledge :) I really appreciate your time.

I'm starting to think it would be simpler to simply extend the sensor probe and tape it to something hot on the fridge so that the compressor will always run? Do you agree or is there a flaw in my idea? My plan would be to splice speaker wire and then just tape the probe to a hot part.

20151231_142642_resized.jpg


20151231_142657_resized.jpg


20151231_142713_resized.jpg


20151231_142725_resized.jpg
 
The one big red wire going to the transformer is probably the power in, the other is probably power to the compressor. The small red is the evaporator fan according to the diagram.

What I would do is cut all three red wires, leaving enough to connect back with wire nuts if you decide to. I would then plug the fridge in, and use a volt ohm meter to determine which is the hot wire. Use the green (ground) wire as your neutral for testing. Once you determine the hot wire, both other reds should be connected to the output of your thermostat so the evaporator fan runs whenever the compressor is on. The control you have is designed to run the fan longer than the compressor, hence the two leads. This results in a bit better efficiency, but older fridges didn't do this, and it obviously isn't necessary.

The green wire of course will connect to something metal in the body of the fridge.


H.W.

So then I don't mess with the wires that are actually attached to the thermostat? I just cut all 3 reds > find out which ones hot > attach the 2 other wires to the output of thermostat?? what is the output (which wire) > then what do I do with the hot wire?
 
So then I don't mess with the wires that are actually attached to the thermostat? I just cut all 3 reds > find out which ones hot > attach the 2 other wires to the output of thermostat?? what is the output (which wire) > then what do I do with the hot wire?

I was mistaken........ as a glance at the schematic shows........... There are more wires there than I realized......... This is spread out over too many posts to put it all together easily, and there are unfortunately only two wire colors, red and black, which adds to the confusion.

Black is normally the hot wire on AC, not red..... I wasn't seeing them in the photos, but a look at the schematic shows that you have red and black as neutral and hot or hot and neutral??? who knows which? Who cares. You also have red and black to both the fan and the compressor, and black and black to the sensor. I would look to determine which wires go to the temp sensor..... presumably smaller black wires. You don't need those obviously. I would first check to see what they've done with the color code.... is black hot (standard), or red? Check all the reds and all the blacks against the green with your VOM. One wire will be hot. Mark it. Then test it against all the wires of the other color to see which is the neutral. The neutral will give you a 120 volt reading against the hot wire. Mark it. These are your two supply wires.

Assuming you have identified the sensor wiring, and set it aside, gather all 3 neutrals with a wire nut. Then run the hot wire to the relay points in your thermostat, and gather the other two wires of the same color, and run to the other side of the points. The result will be that the thermostat will turn both fan and compressor on and off together.

You have three reds that matter, and three blacks that matter. The only wire you really need to identify is the hot from the mains since neutrals are all common. There is no guarantee which color is which...... Red and black are normally L1 and L2 on 240 volt AC. Black and White are normally hot and neutral on 120 VAC. Red and Black are normally positive and ground on DC. Electrical engineers get goofy sometimes, so you really can't tell what they did here.

Note that the green wire is ground obviously, and ground and neutral are common back at the box, so we know that green will register as a neutral when testing..... It's the ONLY thing we know for sure.

The wires from the thermostat to the thermostat should be left alone...... I'm asssuming the removal of the thermostat or bypassing of it. Please label your wires if you intend to "revert"

H.W.
 
Thanks for the help OWLY

Unsure if you can tell from the photos but all of the wires are connected using clips to the circuit board. There are 2 black wires attached with a clip to the circuit board that then attach to the sensor.

In all honesty your instructions are very detailed but I think I'm too dense to understand them. I don't want to go cutting the wires and messing it up without a clear plan that I can understand.

I think I'm going to just use speaker wire > extend the sensor probe > tape it to a hot part of the fridge.
-This way whenever my temp controller turns it out the fridge should kick in the compressor because the outside temp will be warmer than the inside temp.

Because I don't understand your instructions.
I have 2 red wires leaving the thermostat that are attached to clips in the circuit board separately.

I have 2 white wires that are attached to a clip together (coming from thermostat).

I then have numerous red wires that independently attach to the circuit board and a black or 2 if I'm remembering right.

I don't see how I can use your instructions. You use words like "relay" idk what a relay is :(.

I'm not criticizing your instructions I appreciate the effort greatly!
 
That is a transformer. Not a thermostat...

Cheers!

Wow! Thank you sir. So I definitely shouldn't be messing with that I'm assuming.

I guess the thermostat must be behind the fridge then... I posted a photo of the back earlier on page 2.

I do know for sure that i have correctly identified the temperature sensor because when I hold it in my hand the temp goes up (above room temp temps).

Any tips on where to search for the thermostat then? Or do people think I should just extend the sensor and put it on somewhere hot so whenever the fridge gets turned on by the temp controller > it'll be tricked into cooling?
 
I have yet to see a picture of a thermostat in your sub-thread.
Go back to the "dial thing" you referred to earlier and take a picture of it...

Cheers!
 
I have yet to see a picture of a thermostat in your sub-thread.
Go back to the "dial thing" you referred to earlier and take a picture of it...

Cheers!

Hi

There is no dial there it's an electronic button display. All I've done so far is identify the temperature probe, then take apart the LCD display to take photos of what I thought were the thermostat.

This is what it looks like. I unscrewed the LCD button display thing to find the probe/transformer and circuit. I also unscrewed the light which only had a light in it.

Other than that I've posted photos of the back of the device/compressor. Could the thermostat be back there?

20151229_170853_resized.jpg
 
I suspect the thermostat is up in the area of the display.

On page three where you see all the wires and the transformer that's the photo of the digital display taken apart etc. Nothing in that looks like the thermo to me but idk....

I was thinking about unscrewing the back of the fridge tomorrow to see if I can see it back there.

Appreciate the tips.
 
If this shot is the back side of the thing with the digital display, that relay (the black rectangular thing) indicates the thermostat function is in that unit.

attachment.php


It's digital, of course, so you're not going to see the capillary/bulb/pressure switch of a mechanical thermostat.

So if you wanted to continue your pursuit, you need to figure out how to take over the function of that relay...

Cheers!
 
If this shot is the back side of the thing with the digital display, that relay (the black rectangular thing) indicates the thermostat function is in that unit.

attachment.php


It's digital, of course, so you're not going to see the capillary/bulb/pressure switch of a mechanical thermostat.

So if you wanted to continue your pursuit, you need to figure out how to take over the function of that relay...

Cheers!

That is the inside of the digital display. I will take a better look at the black box tomorrow!

Maybe it comes apart to give us an idea how to bypass it.

Thanks again
 

Latest posts

Back
Top