John's Cheese Cave #6 - Small GE 4.3 cf Fridge Freezer

[Cheese Head]

OK, either my 16 year old fridge was on the fritz or the Johnson Controls, so I bought a GE 4.3/4.5 cubic foot small fridge with tiny freezer from WalMart.com here in USA. Shipped all the way from Chicargo by FedEx in original shipping box, tiny dent in front door.

Older style, with compressor, no fan, no drain (just drip tray), just radiant cooling into fridge from coils around small aluminium freezer compartment. Also no automatic defrosting, so I expect I'll have to manually defrost every 3 months.

Plugged it in and running on warmest setting on thermostat for three hours, rats, warmest is 41F / 5 C, too cold for cheese aging, two choices, try and fix thermostat or use external thermostat, almost same price as the fridge, so I'd like to try and adjust the thermostat.

I unscrewed the thermostat cover and it's basically an adjustable switch with electrical positive, negative, and earth, and a small tube with loose white plastic insulation. This small tube attaches to bottom of freezer with a 3 in / 8 cm un-insulated extension after where connected that is dangling in mid air.

The best info I could find on the tube "thermometer" is here which says:

Usually, the thermostat is a capillary (very small) tube filled with a gas. This tube is then connected to a diaphragm. As the temperature in the fridge increases, the gas in the tube expands (PV=NKT) & pushes on the diaphragm, which in turn operates a set of contacts. These contacts will in turn, operate the compressor.

Here are some pictures of the thermostat and mostly copper tube thermometers which they call capillary tubes.

I searched on fridge capillary tubes and found this good info which says sensor is via tube clipped to freezer.

So I think:

• The tube is the thermometer and it is filled with a gas that expands/contracts depending on temperature which operates a diaphragm in the thermostat to switch the compressor on/off.
• Either the length of the copper tube of the amount of gas or the thermostat was calibrated for normal fridge temperatures and to not allow warmer temperature, probably for legal health reasons.
• I could adjust the thermostat internally to switch at warmer temperature but it is a closed device which I could break dismantling.
• I can't adjust the length of the copper tube or amount of gas inside.
• I can adjust how much cold the tube senses. The third link above says that your fridge could get too cold if the sensor detaches from the freezer and thus it sees warmer fridge conditions and thus keeps the compressor on. Conversely, if I put the tube more in contact with the freezer, it should make the gas in the tube colder and thus switch the compressor off at a warmer temperature, my goal.

Does this all sound right or am I missing something? Anyone else have ideas?

Anyway, I've just done that and will report results later. If this doesn't work I could remove the white plastic insulation.

[Cheese Head]

More snaps . . .

[linuxboy]

Have you thought about building your own thermostat?

http://sites.google.com/site/aliask/fridgethermostat

http://www.craig.copperleife.com/tech/thermo/

[Sailor Con Queso]

How about just moving the existing thermostat INTO the freezer compartment to fake it out?

[Cheese Head]

Reading this morning was 40F but saw that my sticky tape holding extension to thermometer tube to freezer plate had detached, presumably as slightly icy.

linuxboy thanks for the idea, but I'm not electrically knowledgeable.

Sailor, even better idea, so I just unclipped the thermometer from the outside of the ice box and wrapped tube so that inside the end is inside the "freezer" box compartment but it won't easily reach the same clip spot. I put the word freezer in quotes as it isn't much of a freezer basically just a U shaped compartment with presumably aluminium plate with built in coils for freon or whatever compressor fluid and just a flap on front which air can easily circulate from, a 1/2 in / 1 cm gap at back between U and back plastic wall where it can also circulate from, and 1/8" gaps along both tops of U where it attaches to plastic roof, again where air can easily circ out of. Within 10 min of typing this the temp had dropped to 37F, because I think the thermometer tube is not attached to the wall and is just dangling in air which can easily circulate and thus the thermometer is now reading too warm and trying to pump down the fridge colder.

I'll try to think of a better way to connect it to inside wall.

Another idea is to seal the freezer space better and thereby faking the thermometer into thinking it is colder than it really is.

Also, when I unclipped the thermometer, I noticed it has an opaque white plastic sleeve on it, presumably as a temperature dampener. Tonight I'll try removing that.

[Cheese Head]

OK, so I had problems with this cave last summer where humidity went up to very high and I had a big puddle of water in top plastic drip tray resulting in a couple of big goudas hitting the garbage as I didn't identify the problem early enough.

This fridge is in attached garage and I assumed the problem was due to a combination of very high ambient humidity outside the fridge and that this fridge is sealed and does not draw air from outside (just had radient cooling from freezer coils that you can see in picture).

Anyway, it's winter here now and air in garage in cool and humidity ambient lower and again I have the same problem, this time resulting in my 4 oiled goudas getting blue mold spots. This is my third cheese cave fridge (first 3 were cooler boxes), 1st was small chest freezer that did the same thing as sealed, second was an old 220 volt Toshiba forced air and thus very low humidity but it died, and this is third.

Questions:
1) does anyone else have small cheese fridge like this one that is also sealed, not forced air and are they in a high humidity location and do they have the same problem?
2) Does anyone have an idea how to lower humidity in my fridge? My current solution is to switch off the power and just leave it to go up down with temperature in garage which will vary with the weather.

[acstokes]

John,
I know Houston probably has as high a humidity as any place in North America, so my experience in NC may not be applicable to your situation. However, here goes:
1) Did you ever get your thermostat fixed so that your temperature is in the 50-55F range or is it still around 37F? You will get more condensation the lower the temp.
2) In your pictures it appears your cheese is out in the open without overhead protection. Perhaps a sheet of wax paper or other loose water repellent covering would divert any droplets over the sides of your cheese so they fall to the bottom of your fridge.
3) I place my cheeses in plastic boxes. The boxes keep any droplets above from falling on the cheese plus less air exposure means less total moisture to condense within the boxes. I keep the box tops partially open to control cheese exposure to humidity, but the box tops are slanted so that any droplets that do form are on the underside and run to one end of the lid and fall off at the end of the box. The cheeses are on a mat and/or cookie rack so they are above any water that may accumulate on the box bottom.
4) Large sponges could be placed in the drip tray to soak up any water that forms there. You would need to wring out the sponges regularly.
5) If you're trying to decrease the overall humidty of the fridge to less than 80%, I don't have any suggestions for doing that other than using some type of desiccant.

Hope one of these ideas helps your situation.

Fred

[Cheese Head]

Fred thanks for thoughts and ideas, replies:

1) Sorry forgot to mention that I gave up on trying to "hack" the built in thermostat and replaced my broken Johnson brand external analog thermostat with a Johnson digital one which I'm currently using with this fridge and which works great.
2) The plastic drip tray in the picture catches the drips from the freezer compartment and when they build up enough overflow eventually run down the back onto the bottom but not out as it's a sealed type unit. So I'm good there. FYI some people who tried vertical freezers with a layer of coolant wires just below each shelf did have the problem of condensation dripping onto their aging cheeses below.
3) Good standard method for hobby scale cheese makers like both of us, good point on drips running to one end as lid slanted.
4) Good idea on sponges, I'm going to try that, while I don't think it won't stop my problem, it will give me an easy way of ridding the excess free water!
5) This is my real problem, reduce the humidity or buy a new fridge for cheese cave. I don't know where to buy desiccant and is there a way to regenerate it because if I had to keep buying new for the next several years I'm probably better off buying a forced air very low humidity type fridge and fighting the low rather than high humidity. I remember when I had the same problem with a previous sealed chest freezer that I bought someone said to put a bucket of dry salt in to act as a desiccant. Maybe I've got to try that.

Thanks again!

[acstokes]

I don't know where to buy desiccant and is there a way to regenerate it because if I had to keep buying new for the next several years I'm probably better off buying a forced air very low humidity type fridge and fighting the low rather than high humidity. I remember when I had the same problem with a previous sealed chest freezer that I bought someone said to put a bucket of dry salt in to act as a desiccant. Maybe I've got to try that.

One more idea: Cat litter can be bought that uses silica gel as a dessicant. Silica gel is much more effective than salt. Maybe a tray of this would work.

Fred

[tananaBrian]

Most thermostat circuits that control motors ALREADY have a relay in them.  It seems to me that if this is so, then you could use a regular home-type thermostat to control the fridge, e.g. a mechanical bimetal spring type where you've wired the 2 wires from the fridge thermostat to the house one instead.  I've got one of these small fridges too (paid $25 used), but haven't taken a close look at it yet.  My plan is to take the door off and extend the length of the fridge so I can age cheeses and also retard dough when baking overnight bread or maturing sourdough doughs and what not.  I have one of those external thermostats from William's Brewing Supply, but don't know if I'll use it or not.  I'd like to come up with a system that both heats (light bulbs for heat) and cools (fridge compressor on/off) as necessary.  Our garage conditions vary quite a lot over the space of a year.

In any case, your simple fridge thermostat probably has 2 wires going to it, one of which continues on to a relay, the other coming from a power source.  If it's 115 VAC power, you'd replace it with a 115 VAC home type thermostat (usually sold for in-floor heat systems), else the standard low-voltage type would work. 

Brian

[susanky]

1) Sorry forgot to mention that I gave up on trying to "hack" the built in thermostat and replaced my broken Johnson brand external analog thermostat with a Johnson digital one which I'm currently using with this fridge and which works great.

John
Regarding the digital thermostat you used.  That link goes to the Ranco digital thermometer which I've seen recommended.  So I got one.  But it could not just be plugged in like the other one.  It had to be wired to the fridge (I had to get someone to do this for me... I'm not that talented).  Is there a digital one that the refrigertor can simply be plugged in to?  Or did you have to wire it?
Susan

[bmckee561]

Johnson makes a controller that you actually plug the refridgerator plug into and place the sensor inside the box.  You then put the refridgerator thermostat on the lowest setting it will go to (coldest) and let the new controller do the work.  They are pricey.  I would suggest using a PID controller which is about the same cost or maybe even a bit less.  Wiring is not a big deal if you have some skill and knowledge.  If not, get a friend or electrician to do it and give them some of your cheese. 

Here is a link to a post that shows the PID controller and a link to the supplier:  https://cheeseforum.org/forum/index.php/topic,5625.0.html

Salute!   

[Cheese Head]

OK now this is getting very convoluted, I resurrected this thread as I have a problem of excess humidity resulting in water puddling in drip tray and as 100% humidity getting mold on my cheeses, but people are discussing how to re-wire this small fridges internal thermostat which is where I started this thread, my bad.

@tananaBrian, good idea about replacing this fridges simple manufacturers thermostat with a cheap household furnace type thermostat, I hadn't thought of that and I gave up and ordered a new pre-wired external digital Johnson one as linked above.

@susansky, I was also not talented enough to wire mine. As bmckee561 replied, the answer is yes. The second link you quoted shows a picture of my Johnson digital one that I ordered pre-wired. I think you are referring to the second link's post where I linked to a company in USA called Rancoete.com. That's the on-line store that I bought mine from, they sell Ranco brand digital ones pre-wired and also my pre-wired Johnson brand digital one. My choice was personal in that I recognized the Johnson brand more than Ranco and the webpage said the Johnson would do 220V which would be good in case I go overseas again. It's slightly more expensive than the Ranco's and as a PID as bmckee561 recommended, but's it's simple to plug in and then you have to make a couple settings. If you order a second one be sure to ask them to set it to run a fridge as mine came in default mode to run a heater.

@bmckee561, thanks for ideas on PID, I hadn't thought of that when I ordered the Johnson last February.

[steampwr8]

I have an older model of the same fridge labeled for Kenmore. I had the same issue and came up with a simple solution that worked.

I took a terry dish towel and lined the drip tray with it. It would wick up the water. After a day or two, you'll know when, as you go to flip your cheese just change the towel. This would get the Rh down in the 70% range.

I also took a small 4" fan on a dimmer switch, didn't need it running full blast, and put in the cave for some air circulation. That allowed the towel wick to dry some and get me in the 60%+ Rh.

If you buy another compact cave go for a wine cooler. It take the same "freezer" coils that actually carry the cold freon and stand them vertically against the back wall. The condensation then runs down a drain to a drip pan under the unit. Then you have the same problem as all of us, too little humidity.

[steampwr8]

As I was typing I had a small epiphany. We could drill a small hole in the drip tray and put a pipe nipple in the hole. Then add a bit of plastic tube  and drain the water away much like the wine cave.

May mean we have to drill an exit hole in the box, but hey whatever works. I want to drill one anyway for the capillary tube on the controller.