Bypassing fridge thermostat. How?

[Owly055]

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!

The entire assembly is the thermostat and display, the transformer is part of the assembly and reduces voltage for the components on the display and electronic thermostat. The schematic makes things pretty simple. We have red wires and we have black wires, we have a board with buttons and a display. When removing the entire assembly there should be 3 red wires and three black wires, plus two blacks to the sensor which are probably smaller or of a different appearance. We also have a member who really has absolutely no business trying to do this. It's not rocket science, but it does call for someone with at least a rudimentary understanding of systems, and of electricity.

Unfortunately this project requires either tracing wires back and understanding what you are looking at. or testing live power, which is not something someone who is timid or unskilled with electricity should be doing. It's a job that requires hands on help in this case, by someone with some knowhow... that cousin, brother in law, neighbor, etc who knows what he is doing and how to do it safely, and without destroying anything. Who has the experience to secure everything before testing and to wear dry leather gloves. Who doesn't need to be told that the green wire can be used to determine which wire is hot, and the hot wire can then be used to identify the neutral (of the other color).

It's a simple job, and one I made the mistake of assuming anybody should be able to tackle, but I come from a different generation where "can do" was the norm. Where we grew up doing things people today would consider irresponsible and dangerous. I've been playing with things electrical for over 50 years, I've built my own boats and bicycles, and quite a few vehicles and machines of various types, rebuilt engines and transmissions because nobody told me I couldn't. Built inverters (not from plans, but from an understanding of the principles) so I could buy 3 phase equipment. I've built and flown my own aircraft. I've been caught in rip tides swimming off the coast of Kauai and Oregon a number of times, and made my way back on my own safely. I have hiked and backpacked for long distances (max 250 miles in one trip), often in bear country without carrying any "protection", kayaked in white water, etc. I've worked with and owned drilling rigs, handled explosives, hunted and fished, etc. I've done lots of plumbing and electrical work, built buildings. I can fix a well, dig in a septic tank and drain field, fix a leaky roof, assist a lamb or calf being born......... or any other animal probably, fix and operate about any kind of heavy equipment from a backhoe or excavator (I've owned both), to a scraper, rock crusher, crane (I own one now), large loader or forklift (I own both), rebuild a gas or diesel engine of any size (largest was a D8 Cat engine), and I began brewing beer and wine in 1969 (approximately). I tend to assume most people experiment with many things while growing up, but we seem to be transitioning into a society of specialists of ever narrower focus. For example, the electricians I know specialize in AC and are lost working with DC... which makes no sense to me. People in the construction trades do framing OR roofing, OR hang and finish sheetrock, insulate, OR pour concrete, OR do finish work, OR paint........ and seldom cross the lines. People who cook for a living usually can't fix their own car, deal with plumbing, or electricity. Carpenters don't understand structural engineering, and engineers don't understand carpentry. Mechanics follow flow charts blindly, with zero understanding of systems. And more and more people are doing work that I simply cannot understand as "work"....not producing anything identifiable as a product....... I seem to have become an anachronism. My good friend who is also a welder......but unlike me is ONLY a welder often chides me for my "do it yourself" mindset. "Do what you are good at and hire someone else to do that" is his frequent refrain..... and his mindset, which is carved in stone. I wasn't raised that way, and haven't lived that way. My friends, neighbors, and customers are farmers and ranchers, most of whom think the way I do........

H.W.

 

[bosster01]

The entire assembly is the thermostat and display, the transformer is part of the assembly and reduces voltage for the components on the display and electronic thermostat. The schematic makes things pretty simple. We have red wires and we have black wires, we have a board with buttons and a display. When removing the entire assembly there should be 3 red wires and three black wires, plus two blacks to the sensor which are probably smaller or of a different appearance. We also have a member who really has absolutely no business trying to do this. It's not rocket science, but it does call for someone with at least a rudimentary understanding of systems, and of electricity.

Unfortunately this project requires either tracing wires back and understanding what you are looking at. or testing live power, which is not something someone who is timid or unskilled with electricity should be doing. It's a job that requires hands on help in this case, by someone with some knowhow... that cousin, brother in law, neighbor, etc who knows what he is doing and how to do it safely, and without destroying anything. Who has the experience to secure everything before testing and to wear dry leather gloves. Who doesn't need to be told that the green wire can be used to determine which wire is hot, and the hot wire can then be used to identify the neutral (of the other color).

It's a simple job, and one I made the mistake of assuming anybody should be able to tackle, but I come from a different generation where "can do" was the norm. Where we grew up doing things people today would consider irresponsible and dangerous. I've been playing with things electrical for over 50 years, I've built my own boats and bicycles, and quite a few vehicles and machines of various types, rebuilt engines and transmissions because nobody told me I couldn't. Built inverters (not from plans, but from an understanding of the principles) so I could buy 3 phase equipment. I've built and flown my own aircraft. I've been caught in rip tides swimming off the coast of Kauai and Oregon a number of times, and made my way back on my own safely. I have hiked and backpacked for long distances (max 250 miles in one trip), often in bear country without carrying any "protection", kayaked in white water, etc. I've worked with and owned drilling rigs, handled explosives, hunted and fished, etc. I've done lots of plumbing and electrical work, built buildings. I can fix a well, dig in a septic tank and drain field, fix a leaky roof, assist a lamb or calf being born......... or any other animal probably, fix and operate about any kind of heavy equipment from a backhoe or excavator (I've owned both), to a scraper, rock crusher, crane (I own one now), large loader or forklift (I own both), rebuild a gas or diesel engine of any size (largest was a D8 Cat engine), and I began brewing beer and wine in 1969 (approximately). I tend to assume most people experiment with many things while growing up, but we seem to be transitioning into a society of specialists of ever narrower focus. For example, the electricians I know specialize in AC and are lost working with DC... which makes no sense to me. People in the construction trades do framing OR roofing, OR hang and finish sheetrock, insulate, OR pour concrete, OR do finish work, OR paint........ and seldom cross the lines. People who cook for a living usually can't fix their own car, deal with plumbing, or electricity. Carpenters don't understand structural engineering, and engineers don't understand carpentry. Mechanics follow flow charts blindly, with zero understanding of systems. And more and more people are doing work that I simply cannot understand as "work"....not producing anything identifiable as a product....... I seem to have become an anachronism. My good friend who is also a welder......but unlike me is ONLY a welder often chides me for my "do it yourself" mindset. "Do what you are good at and hire someone else to do that" is his frequent refrain..... and his mindset, which is carved in stone. I wasn't raised that way, and haven't lived that way. My friends, neighbors, and customers are farmers and ranchers, most of whom think the way I do........

H.W.

Thank you for the very tangential post. In this thread you can see I repeatedly admitted I have no knowledge in this department. I was hoping that this was a simple fix that could be clearly explained in a concise manner. Clearly that's not the case.

ANYWAYS
My workaround is as follows in a stepwise clear to understand fashion for future readers.

1. Remove the 4 screwed that hold the LCD display to the top of the wine chiller.
2. Identify the temperature probe (seen in page 2 of this thread) which is attached to the circuit board using a small white clip thing. It has 2 black wires with the end being a sensor.
3. Unscrew the screw that connects the temperature probe to the display.
4. You will see above the LCD display there is open insulation
5. Put a blunt object such as a screw driver into the insulation making sure not to hit anything like a coolant line etc.
6. Then place the temperature probe inside that hole you made with the screwdriver.


This will cause the fridge internal thermostat to believe the temp is like 65/70 depending on ambient temp. As the fridge starts cooling it will get warmer from heat produced by the fridge components in that section. Now attach your external temp controller. Set it to desired temp. It now is capable of cooling to 30F with ease.

Thanks for the help.

 

[day_trippr]

Wow. Someone really needs to get laid. Or something...

Cheers! (Just sayin'... )

 

[bosster01]

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 as reference.

Now that I'm looking at this diagram I'm starting to understand I think. So I have 3 black wires and 3 red going into the LCD display.

I could figure out how to identify which red is which & which black is which, but what I don't understand is after I splice the wires together which one gets plugged back into the circuit board?

I get the diagram just unsure how it relates to the circuit board since I don't simply have wires that I can just attach.

I was so confused before because I didn't understand that this whole circuit board thing was the thermostat I thought the transformer was the thermostat.

Do I simply connect the 2 reds from the left side of the thermostat with the third red which is the "output" on the right side? And then splice those 3 together and plug it into the circuit board? <<< im basing left / right on the circuit diagram not the photo of the wires

And then do the same for the blacks?

-Wish I could just hook the compressor control right up to my external temp controller so that whenever my temp controller tells it to turn on it just turns on the compressor.

 

[jddevinn]

bosster01,

I, and a lot of other members here, have a large amount of technical background and often answer questions with assumptions assuming the poster has a reasonable background in the subject. For example when I said to "cut wires per my ****ty drawing" I assume (wether I should or not) that you are going to cut, solder back, and heat shrink the wires.:fro:

It looks like the system you have is more complicated than the chest freezers most people are using for keezers. The section of wiring diagram that you photographed and I commented on is just the cooling section of the electronics. The power supply from the wall is 120V. The transformer on the board takes the 120V and turns it into a low voltage power, probably 12V. This low voltage power runs the display and apparently the thermostat contained in the board (and maybe the fans). When the thermostat tells the unit to cool it activates the relay (black box) to allow 120V power to the compressor and fans (?).

You need to either physically or carefully with a multimeter trace the lines to determine what wire does what. You need to manually power the compressor, the condenser fan and the evaporator fan. Fans may be 120V or may be low voltage.

The condenser is the heat exchange coil on the outside of the cooler.

The evaporator is the heat exchange coil on the inside of the cooler.

You can start by locating the physical equipment and trying to trace the wires. 120V and low voltage wires will be noticeably different in size.

 

[jddevinn]

-Wish I could just hook the compressor control right up to my external temp controller so that whenever my temp controller tells it to turn on it just turns on the compressor.

If you cut the two wires that I identify as +120V and neutral going to the compressor. Turn the unit on and determine which is which you can wire an extension cord directly up to these two wires and power the compressor directly.

You will also need to determine if the fans on the condenser and evaporator are 120V or low voltage. If 120V you can wire them directly to the same source. If low voltage you will need a transformer.

 

[bosster01]

-Wish I could just hook the compressor control right up to my external temp controller so that whenever my temp controller tells it to turn on it just turns on the compressor.

If you cut the two wires that I identify as +120V and neutral going to the compressor. Turn the unit on and determine which is which you can wire an extension cord directly up to these two wires and power the compressor directly.

You will also need to determine if the fans on the condenser and evaporator are 120V or low voltage. If 120V you can wire them directly to the same source. If low voltage you will need a transformer.

Thank you very much for the detailed diagram and explanation! Your willingness to help is much appreciated. This second option seems much more technically simple for me to accomplish on my own. I've attached photos of where I took apart the compressor control/power switch assembly.

To make sure I understand instructions: I should cut the two wires (120V & Neutral) and attach them to extension cord. I've cut my extension cord and I have 3 wires - 2 blacks and a green. I assume green is the ground/not going to be used.

So question - does it matter how I attach the 2 wires (neutral/120V) to the extension cord? like in terms of neutral vs power etc or can I just try both ways and see if it works?

Also - in terms of the condenser/evap fan - are you saying that I need to somehow wire those to the new extension cord as well? Or can I just plug both the new extension cord and old power cord from the wine chiller in at same time?

Once again thank you so much!

 

[jddevinn]

Thank you very much for the detailed diagram and explanation! Your willingness to help is much appreciated. This second option seems much more technically simple for me to accomplish on my own. I've attached photos of where I took apart the compressor control/power switch assembly.

To make sure I understand instructions: I should cut the two wires (120V & Neutral) and attach them to extension cord. I've cut my extension cord and I have 3 wires - 2 blacks and a green. I assume green is the ground/not going to be used.

So question - does it matter how I attach the 2 wires (neutral/120V) to the extension cord? like in terms of neutral vs power etc or can I just try both ways and see if it works?

Also - in terms of the condenser/evap fan - are you saying that I need to somehow wire those to the new extension cord as well? Or can I just plug both the new extension cord and old power cord from the wine chiller in at same time?

Once again thank you so much!

I'm sorry to tell you this.... but now that you have pictures of the wires exposed there is more than the (3) wires I expected going to the compressor. These could be doing something or they could simply be using the pump connections as jumpers for the fans. You are simply going to have to get a meter and do some exploratory work to see what wire does what.... I don't think I can help much more without having my hands on the cooler.

Yes the fans need to turn on. This (and most other) refrigeration/cooling cycles work by pushing a coolant (with the compressor) around in a loop. In the evaporator the coolant evaporates the evaporation requires heat. This heat is transferred through the surface area of the evaporator inside the fridge, as a result the interior temperature drops. The coolant then is condensed inside the condenser, this releases heat that is expelled into the environment through the surface area of the condenser. In this design the fans are required by the heat exchangers.

 

[Owly055]

The fans have to run with the compressor. The evaporator fan is what transfers the cold from the evaporator to your refrigerator, and the condenser fan is what transfers the heat out Without them the pressure relationships and efficiency would really suck.

The simplest system by far would be to just tap into the power cord, and switch the entire thing on and off (presumably down underneath).......... how much trouble is it worth just to have a light that comes on when you open the door? ........... The KISS principle. I would say either do it this way, or tap in at the existing thermostat. Remember, those wires at the thermostat all lead down underneath...... except perhaps the evap fan. Ultimately you have to run both fans and the compressor, so you are going to have to either get creative, or get crude........ those are your only choices. I personally would forget the idea that I would ever want to restore the unit to original...... why would you? It's only a refrigerator. I'd cut wires and pull them down, or splice and feed them down for the evap fan, identify the "culprits".... hot and neutral, gather all the neutrals together, and gather all the wires the same color as the hot except the actual hot wire, and switch the hot with the thermostat. It really is a no brainer once you identify the actual hot wire. I assume a DC guy designed this, so the red is probably the hot and the black neutral, though AC should be black hot and white neutral. As far as lectricity, I'm AC/DC.... I go both ways when it comes to electrical stuff.

The whole project is really pretty simple. You need to find someone who has some basic understanding to help you, and you have to commit, in other words "this is going to be a kegerator, or fermentation chamber, etc, and I'm not going back with it". We are after all only talking about a $200 unit here.

H.W.

 

[bosster01]

Thanks for the advice. I will work on tracing the wires this weekend. Appreciate all the help! I'm going to have a friend come over with a multimeter to determine which one is the hot.

 

[Jayhawk79]

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.

I realize this is an old thread, but this message addresses exactly what I'm trying to do. The thermostat in my fridge has the two leads Bobby is referring to, but also a ground on the thermostat housing. My plan is to remove the stock thermostat all together and wire the two contacts directly so that the compressor will run when the unit has power. The temp/power will be controlled by an external thermostat. In this case, do I need to do anything with the ground wire that was attached to the stock thermostat? Should I screw it into the metal frame of the fridge, or leave it out of circuit?

 

[day_trippr]

Either is fine. It was only there to ground the thermostat housing...

Cheers!

 

[SleepyBeer]

Sorry to reprise an old thread, but it has good info. I have a Danby kegorator, and there was instructions on the the web to add a resistor into the wires going to the the thermometer sensor thing in the fridge. I ended up adding 2 and could get the beer to 28 degrees (so awesome) any more and it would freeze.

Now I have an huge old Kitchenaide refrigerator coverted into kegorator with room enough or a corny keg for home brew and a commercial keg. But it only got to 40 degrees at best. From this post I put the thermometer thing (i think it is called something else) outside the fridge door and got it down to 32 F. So thanks for that tip. I also put a regular computer fan in there to help even out the cooling.

Was looking for some other solution as the temp probe is just hanging out by the taps which stupid looking, and prolly letting cold air out a bit. plus it is probably running 24/7 now, and they may overwork the compressor, IDK. Has anyone tried adding resistors into these temp probes?

Also it looks like the cold air enters the freezer then kinda passively goes to the lower compartment. The temp control just swings open a baffle there. Was thinking of putting a computer blower (not a fan) there to usher more of the cold in.

 

[marc1]

Sorry to reprise an old thread, but it has good info. I have a Danby kegorator, and there was instructions on the the web to add a resistor into the wires going to the the thermometer sensor thing in the fridge. I ended up adding 2 and could get the beer to 28 degrees (so awesome) any more and it would freeze.

Now I have an huge old Kitchenaide refrigerator coverted into kegorator with room enough or a corny keg for home brew and a commercial keg. But it only got to 40 degrees at best. From this post I put the thermometer thing (i think it is called something else) outside the fridge door and got it down to 32 F. So thanks for that tip. I also put a regular computer fan in there to help even out the cooling.

Was looking for some other solution as the temp probe is just hanging out by the taps which stupid looking, and prolly letting cold air out a bit. plus it is probably running 24/7 now, and they may overwork the compressor, IDK. Has anyone tried adding resistors into these temp probes?

Also it looks like the cold air enters the freezer then kinda passively goes to the lower compartment. The temp control just swings open a baffle there. Was thinking of putting a computer blower (not a fan) there to usher more of the cold in.

I completely cut out the divider between the fridge and freezer on my fermentation fridge. I control temperature with an inkbird that the whole unit is plugged into.

 

[SleepyBeer]

Thanks. Already moved the temp prob outside the unit, with occasionally got the beer down to low thirties but mostly about 40-42 degrees. So I was going to cut a hole and put a blower from freezer to the lower refrigerator part. I had a $4 computer blower already, wired it to a 12V transformer that I have in my box of old transformers.

When I got to looking in the fridge, and saw toward the back and on the sides, colder air was coming in via 2 slit vents. The more obvious vent in the middle with a closable baffle, I surmised, was actually a return vent. So I just duct taped my blower to that middle vent, forcing a lot of air right into the return vent. The air coming in via the other 2 side slit vents increased dramatically.

The next day, fridge was a nice 30 F, and freezer was also a little warmer upper 20's instead of 10-12 range. The next day, fridge was 27-28, and beer was starting to freeze in the lines. So happy that the fridge can get to my desired range.

Will add an external temp control like the inkbird next. Wondering if I should connect it to the whole unit's power supply, or just my little blower motor or both? Also, still considering what to do with the temp probe permanently.