nana
5 Cubic Foot
Posts: 70
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Post by nana on Aug 15, 2017 21:11:54 GMT
If I understand it correctly, the 39* cut in means that when the temperature gets to 39 it will turn on, no matter what the dial is set on. So the dial is there to set the lower limit of the temperature in the refrigerator. If it needs a new thermostat, (And I'm beginning to think it does--I went down to check it just now while I'm waiting for the guy, and it was back down to 10 degrees. I haven't touched the dial in two days, or even opened the door since yesterday) why would that 39 degrees be so important? Isn't the whole function of a thermostat to keep something at a certain temperature? If a new thermostat was set to keep things between, let's say, 34 and 38, wouldn't that be just fine?
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Post by birkie on Aug 15, 2017 21:15:37 GMT
The digital thermostat I used allows you to set the differential and the temp. That way you can allow your frost to melt. Indeed, so does the analog. But no way to anchor the cut-in to 39 degrees that I know of. Unusual/custom control logic sounds for which there's nothing off the shelf soubds like a perfect job for a thermistor paired with a tiny 8-bit microcontroller. The most complicated part of that sort of setup is the power supply.
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Post by blackhorse on Aug 15, 2017 21:52:13 GMT
If I understand it correctly, the 39* cut in means that when the temperature gets to 39 it will turn on, no matter what the dial is set on. So the dial is there to set the lower limit of the temperature in the refrigerator. If it needs a new thermostat, (And I'm beginning to think it does--I went down to check it just now while I'm waiting for the guy, and it was back down to 10 degrees. I haven't touched the dial in two days, or even opened the door since yesterday) why would that 39 degrees be so important? Isn't the whole function of a thermostat to keep something at a certain temperature? If a new thermostat was set to keep things between, let's say, 34 and 38, wouldn't that be just fine? The point is, the cabinet needs to go to 39 degrees, regardless of the low temperature you set, because that refrig has no "defrost". If it doesn't rise to that point the ice won't melt off adequately. Not that I'm getting my shorts in a twist over "38" vs "39", rather that when you set it lower the top temperature will come down along with the bottom temp. But you can buy constant-cutin replacement thermostats. Johnstone lists 4, cutins at 37, 38 , 41 degrees, with different cutoff temp ranges.
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nana
5 Cubic Foot
Posts: 70
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Post by nana on Aug 16, 2017 1:22:24 GMT
The guy was here, gave it one more adjustment just to see, but he said he was going to try to find me a new thermostat. He did explain a little more to me about how the fridge works, which I was gald to have my little bit of knowledge I've gleaned from all of you to be able to follow along. He said the thermostat was designed to measure the coil temperature, not the air temperature in the cabinet. The coils themselves can get as low as 20 below zero (!), and when the fridge turns off, the coils start to warm up, and the frost can melt off, then when the coils are at 39, it turns back on. He said even when functioning properly, there will be a bit of a temperature range in the cabinet, but more in the way of 32-38, which would be fine by me. We discussed putting in an air temp thermostat, but he said it may not let the frost melt off the coils completely, in which case I'd have to be manually defrosting the coils when necessary. Not what I want to be doing. So he said he was going to look for a new one. The thermostat itself did not have a model number that we could see, and judging by how long it took him to find the gasket, the sooner I help him out with that, the better. Which means asking you once again for even more advice. I sure hope you're not tired of all my questions just yet!
#1 Am I better off trying to find a 1959 GE thermostat, or going for a modern replacement? and #2 If a modern replacement is the way to go, which would you recommend and where to get it?
He seemed to think these fridges were pretty tightly designed. You can't just throw any old thing in there and expect it to work. If these thermostats had a rep for being difficult, I might be better off with a modern one, but then I'd worry about it not being right for the design. Yikes!
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Post by coldspaces on Aug 16, 2017 4:16:05 GMT
My 1986 Gemline catalog lists the GC-116 as a direct replacement control and the GC-402 as the universal control.
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Post by jake on Aug 17, 2017 22:57:52 GMT
Your repairman sounds very knowledgeable! He is correct. You have a cycle defrost model. What that means is that during the off cycle the cooling coils at the top of the fresh food compartment should defrost. In order for that to happen they must be allowed to rise above freezing (+32°F). So this is where the constant cut in type thermostat comes into play. When you adjust the thermostat dial you are only changing the cut out (shut off) temperature. The cut in (turn on) temperature always remains the same. Above freezing. The thermostat feeler tube is clamped to the cooling coils and senses the coil temperature, not air temperature. In a cycle defrost fridge there is more of an air temperature swing then in a conventional fridge. But the temperature of your food varies very little because of the food's density.
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nana
5 Cubic Foot
Posts: 70
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Post by nana on Aug 17, 2017 23:10:07 GMT
Thank you Coldspaces. I'll let him know!
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Post by jake on Aug 18, 2017 20:40:08 GMT
You can Google the part numbers Coldspaces gave you and see what pops up. Gemline has been out of business for a number of years but other companies have bought up their old inventory. That's how I found the spare thermostat I have for my Frigidaire. I'd suggest getting the thermostat and just have your repairman install it. That'll save him some time and possibly save you some money as well.
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Post by jake on Aug 18, 2017 20:42:30 GMT
There's a GC-116 on eBay right now! $18.99 free shipping.
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Post by jake on Aug 18, 2017 20:48:54 GMT
Make that 4 on eBay. Just put "GC-116 gemline" in the eBay search box and they'll pop up.
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nana
5 Cubic Foot
Posts: 70
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Post by nana on Aug 21, 2017 15:05:58 GMT
I was pretty busy all weekend, we had our grandkids for a couple days and yesterday I was a little bit under the weather. The fridge had been kind of holding in the 40's to 50's in the cabinet, but the freezer had been nice and frozen. This morning I finally got ahold of the guy to give him the thermostat replacement info and to tell him about the new problem it was having. The last time I checked it was Saturday morning, and it seemed fine, just not cold enough. I did get one of those probe thermometers so I didn't have to keep opening the door. Sunday I was a bit sick and I didn't check it, so sometime between then and now it started to get really warm. The freezer thawed, no frost anywhere, cabinet up to 58 degrees, which is only a few below ambient temperature, and the few things I did have in the freezer had mostly thawed. The fridge kicks on, runs for a few seconds and kicks off again. I unplugged it and called the guy. He said it sounds like the compressor. Uggghhhh! I think I may be in a lot deeper than I wanted to be here. What bothers me most is all this trouble was supposed to be solved by having a professional fix it up BEFORE it came to my house.
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Post by birkie on Aug 21, 2017 15:25:28 GMT
Does he think it's kicking off because it's triggering the overload? Does it consistently just run a few seconds and kick off now? If you keep it plugged in, does it do that over-and-over again?
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Post by coldspaces on Aug 21, 2017 15:51:25 GMT
Sounds like a bad start relay if your lucky. You can't expect the repair man to see the future and know which old parts is going to go out next. He can't see inside of things like compressors and relays.
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Post by blackhorse on Aug 21, 2017 16:38:02 GMT
Sounds like a bad start relay if your lucky. You can't expect the repair man to see the future and know which old parts is going to go out next. He can't see inside of things like compressors and relays. I'm going more with this than the compressor. Really, it's pretty rare for a compressor to just up and die without some causative event. It happens, but it's a lot more common for it to be a relay, capacitor (if it has one), mouse-chewed-wire type event, bad electrical connection, water (you did say the basement floods, right?). Particularly these old compressors, they were a lot more durably designed than the newer 3rd-world knockoffs. A statistic thrown out there a lot by the warranty dept of companies is that about 90% of "Bad" compressors they get back are mis-diagnosed, (with the intent that they aren't about to issue you a credit for replacing it). That said, bad wiring, lightning, improper repairs, etc can damage a compressor. But working fine and then blowing up seems less likely than something else being at fault.
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Post by jake on Aug 21, 2017 21:17:37 GMT
I agree. Sounds like a bad relay or possibly the condenser fan motor quit. If the fridge hasn't been used for awhile the contacts in the relay may be stuck. Or if you have a starting capacitor it may be bad. You have a starting and a running winding in the compressor motor. That's why you have 3 wires going to the compressor. Start, run, and common. When the thermostat kicks on the compressor the compressor begins to run on the start wire. As the motor comes up to speed the relay switches to the run wire and the compressor continues to operate on that and the common wire for the remainder of the cycle. On some older fridges if you listen closely you can even hear a "click" as the relay switches from start to run.
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