GE Combination Cold Control

[rp2813]

Below is a picture of the original cold control out of my '57 GE Combination refrigerator/freezer.

 

Can anyone advise on what the raise/lower adjustment is for?  At the bottom of the hole to the right of the adjusting guide is a screw.  I don't know if this will adjust the set point, or if it's the altitude adjustment.

 

 

 

[goatfarmer]

I "believe" it's cut in temperature. The temperature at which it starts.

 

[rp2813]

Thanks Kenny.

 

I'm debating on whether to mess with the screw at all.  The removal and installation process has its trials so I prefer to avoid having to extract it again.

 

 

 

[hydralique]

The only thing that would make sense to me is that it's to adjust the "float" between turning the compressor off and then on. The main thermostat allows adjusment of the approximate temperature the system maintains, but this will vary somewhat as once it shuts the system off it will then let the temperature rise a few degrees before turning it on again. Too little float between the shut off and turn on temperatures and the system would constantly short-cycle, but too much float is undersirable too. Unless you think there's a problem I wouldn't mess with it as there's no much way to determine how much affect a little tweak will have until it's all installed again.

 

[rp2813]

Thanks.  I think I'll leave things as they are and re-install.  I pulled the module because I thought it was faulty, since after defrosting, or introducing a moderate amount of room temperature items (such as a 12-pack of beer or soda), the compressor cycles off before the set cabinet temperature has recovered.  It can sometimes take more than 24 hours for my "control" cup of water to reach its prior temperature from before warmer items were added.  Everything that was already in the refrigerator becomes a few degrees warmer, while the newly introduced items become steadily cooler.  I know some of this is basic physics, but it still seems odd that recovery would take so long, and that the cold control would be receiving a message to cycle off when contents' temps indicate further cooling action is still needed.

 

Is this a typical recovery situation in a refrigerator where a fan isn't circulating the air?  Is it a quirk of the system GE used on the Combination models?  I ask the latter question because a NOS Gemline replacement control hasn't improved the recovery process, is turned up to a rather high (colder) setting, and cabinet temperature isn't as cold as with the original control on a lower (warmer) setting.

 

[arbilab]

Where is the thermal sensor? If it's reading the freezer it has no idea what load you've put in the fridge.

I've never seen a thermo with a hysteresis adjust besides furnace fan controls.

 

[rp2813]

The capillary tube runs along the back of the serpentine evaporator in the fresh food section.  Supposedly the cycling should be such that cooling is called for when the evaporator temp is 37 degrees or higher, and cooling stops when evaporator temp is -23 degrees.

 

Here's a picture.  The small dark (on the left portion) tubing that is clamped along the top of the coil is the sensor.

 

[hydralique]

I wonder . . .

What would happen if you got a small computer cooling fan - usually these are 5v or 12v I believe - and placed it in the box  with a suitable exterior power supply? Or perhaps a little battery operated fan? If the reason for slow response is stagnant airflow, which makes sense to me, then you should see a difference with a fan.

 

[arbilab]

Ah, measuring evap temp rather than box temp. That about half explains insensitivity to load, no fan explains the other half. Ya think?

 

[roto204]

Supposedly altitude adjustment

Ralph, the Gemline sheet outlines how the screw works (the new control has one too) and outlines a very detailed table for how to compensate for altitude based on degrees rotation of the screw.  I'm not sure this will accomplish what you're looking for in terms of kicking down the temp or reducing the "swing."

 

Optimum refrigeration temp range is supposedly 37º to 41º, which sounds like what that has been maintaining in both iterations of the cold controls; the older with less dial-crank; the newer with more.  I too wonder if this is just sort of the "nature of the beast," and that due to no active circulation of air, it just takes time for it to gravitate back to where it belongs...?

 

[rp2813]

Yeah, I'm thinking it's the nature of the beast.  If you're using the evaporator to tell the cold control what to do, the temperature of the actual interior becomes somewhat incidental.  I honestly think this GE system just functions this way and there's nothing that will change it.  Well Nate, at least we gave it our best shot, and we still had a good day's worth of appliance fun and GMC brake system diagnosis.

 

I really do love this fridge and have lived with this behavior for over a year now, so I can continue to do so.  It would hold at 37 degrees nicely until room temperature items got introduced, and if it takes a day to recover, meh, it's just the drinks fridge, not my daily driver with milk in it or whatever.

 

The small fan is a good idea.  When we had an RV, we got a small fan for the refrigerator, battery operated and intended for that purpose, and I do think it helped.

 

[arbilab]

Just never let beer or soda supplies get lower than 3 days and you'll be fine.

 

[rp2813]

Good advice regarding beer and soda supplies.  The fridge stays fairly well stocked, but when I introduce twelve or more soda cans and twelve bottles of beer, my control cup of water can rise from 37 degrees to as high as 45 degrees before it starts to drop again, and it can be 36 hours before the control cup is back down to optimum beverage drinking temperature.

 

I'm going to try measuring only the interior air temperature and see what that tells me.  I know my control cup is going to be influenced by nearby cans or bottles that are room temperature, so the more accurate way to gauge recovery over those 36 hours could come from monitoring air temperature instead.

 

[jamiel]

...and I think that's why this design did not win out over the fan forced (Westinghouse's Cold Injector) refrigerator.

 

[redcarpetdrew]

I wonder...

I'm glad to see you still like that GE. It really did find a good home. I was thinking (one of my more dangerous actions...) that taking a light plastic tube or something of the like and wrapping the cap tube so it takes a little longer to reach temp might affect things? Hmmm... gotta give it a little more thought...

RCD

 

[combo52]

COLD CONTROL ON GE COMBINATION REF

Ralph the ref temperature should recover faster than yours is doing. When you put a large warm load in the ref it should run constantly for hours if necessary to cool everything down. You can test the thermostat by clamping a thermometer where the capillary bulb clamps to the evaporator and check the temperature when the TS cuts the compressor off. I believe the cut off temp is more like -2 or 3 degrees not -23 if the coil actually got down to -23 everything in the ref would be frozen and that doesn't seem to be the problem you are having. I have often had success adjusting the cut out setting on thromostats in unusual cases like this. Just do a 1/4 turn at a time and keep track of exactly which way you turn it in case you have to go back.

 

[rp2813]

John, thanks for your input.  I agree with you that the compressor should be running constantly until proper cool-down has been achieved.  And yet, even with the replacement cold control installed I'm witnessing the same behavior, and am having to crank the control up almost as high as it will go in order to achieve 40 degrees.

 

I've attached a shot of the chart on the Gemline replacement control instructions.  Mine is part #GC-402.  This is where I got the -23 information from, and I presume the "Mid," "W," and "C"  and their related "On/Off" sub-columns mean mid-range, warmest and coldest.

 

This chart is labeled "Figure 1" but the reference to "Figure 1" in the instructions doesn't provide an explanation on how to interpret  the information it provides.  I think it's saying that when the control is set to the warmest setting, it will cut the compressor when the capillary reaches +3 degrees instead of -11, and when set to coldest, it will cut out at -23 instead of -11.

 

[rp2813]

Update

I put the old cold control back in today. Once everything was buttoned up, I turned the fridge on and set the dial to the middle. That was at 2:15 PM. I quickly loaded it up with all the contents that had been pulled out last weekend. It's now 8:15 PM and the fridge has not stopped running. The serpentine evaporator coils have a nice thick and even layer of frost on them. The cabinet temp is down to 45. This is the first time I've witnessed such proper behavior from this refrigerator. When Nate and I were pulling the old control out last weekend, we found compromised wiring near one of the terminals on the control. That has been fixed, and I'm wondering if it has anything to do with the improvement in operation. We'll see how it goes as the night continues. It may require some tweaking over the next few days, but I'm feeling confident that proper operation may have been restored.

 

[hydralique]

Yay!

Beer should not only be served cold, it should get cold fast!

 

[rp2813]

Beer!

I think I take after my Uncle Frank, who spoke of beer in code:

 

KC/KC: Keep 'em cold and keep 'em coming, and CBC: Could be colder.

 

I'm keeping my fingers crossed that this fridge is now capable of making him proud.

 

[rp2813]

I'm Declaring It Fixed!

The fridge ran straight through for 11 hours, up until 1:15 AM. I wanted to go to bed, and with cabinet temp down to 37, I backed off the thumb wheel to make sure the fridge was going to shut off at some point. I only had to turn it a small amount. This morning the cabinet temp was 39. I'll continue with tweaking the control over the next few days to get beverages at a nice cold drinking temperature. The fridge is finally operating as it should. I don't know what to attribute this to, other than the compromised wiring near the one loop type spade connector that could have been causing intermittent problems. Both connectors have been replaced and the original control module is working flawlessly.

 

[arbilab]

Even in my fanned Hotpoint it takes a case of beer ~36 hours to reach temperature.

 

[rp2813]

Yeah, I was on the wrong track with using liquid temperature instead of air temperature to measure initial cool-down.  But even so, it wasn't until after removal and re-installation of the cold control that the fridge would run continuously until it reached set cabinet temperature. 

 

Yesterday I monitored temperature swing and it's currently 35 at the low end and 38 or 39 on the other.  That's right where I want it, and my test cup of water is holding at a steady 37 now.  I can't ask for more than that.  The fridge is behaving perfectly at this point.