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Post by nd1933 on Aug 17, 2023 20:58:31 GMT
Hello! I recently purchased my first monitor top, a CA-1-B16 as a repair project for my 1933 home. It starts, gets cold, and shuts off in about 20 minutes or so. At that point it won't restart on its own, but will if the power switch is turned off and then back on, though it won't run for as long (say 5 minutes or so before the same thing happens).
After reading up a bit, I went ahead and started purging the NCGs, which has definitely allowed it to get colder and run quieter, but the main problem still persists.
Any insight as to what I should be looking at would be greatly appreciated. Thank you!
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Post by cablehack on Aug 17, 2023 23:30:38 GMT
Some things to check first - 1) That the evaporator is evenly frosted up to at least a quarter of the way up the header tanks; higher if it's coming down from room temperature. 2) What the temperature is at the bottom centre of the evaporator when it shuts off after the initial 20 min run, and also when it shuts off 5 mins after resetting it. The most accurate way to do this is to freeze a temperature probe to the evaporator, but a point and shoot infra red thermometer works well enough.
What I'm getting at here is to make sure the actual refrigeration system (i.e., compressor/float valve/evaporator) is working properly first. This is because the thermostat (called "control" by GE) can only operate correctly if the evaporator temperatures are correct. If all is good there, then the control will need to be looked at. Also, since you're new to CA's, make sure the oil heater is working, because quite often they're not with original fridges. To do this, either plug the fridge into a power meter and see that it draws about 12W with the switch off, or with an ohm meter, measure across the plug pins also with the switch off. The resistance should be around 1000 ohms. |
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Post by turbokinetic on Aug 18, 2023 13:11:57 GMT
Hello! I recently purchased my first monitor top, a CA-1-B16 as a repair project for my 1933 home. It starts, gets cold, and shuts off in about 20 minutes or so. At that point it won't restart on its own, but will if the power switch is turned off and then back on, though it won't run for as long (say 5 minutes or so before the same thing happens). After reading up a bit, I went ahead and started purging the NCGs, which has definitely allowed it to get colder and run quieter, but the main problem still persists. Any insight as to what I should be looking at would be greatly appreciated. Thank you! One thing you need to confirm is the current draw of the compressor while running. It sounds like the compressor may be tripping the overload. Turning the control off and back on resets the overload if that is tripped. Another possibility is that the control is internally gummed up and it's just not able to trip on when the evaporator warms up. It may be in need of cleaning and oiling the moving parts of the control. Do you have a Kill-A-Watt meter? Sincerely, David |
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Post by nd1933 on Aug 18, 2023 15:39:39 GMT
Some things to check first - 1) That the evaporator is evenly frosted up to at least a quarter of the way up the header tanks; higher if it's coming down from room temperature. 2) What the temperature is at the bottom centre of the evaporator when it shuts off after the initial 20 min run, and also when it shuts off 5 mins after resetting it. The most accurate way to do this is to freeze a temperature probe to the evaporator, but a point and shoot infra red thermometer works well enough.
What I'm getting at here is to make sure the actual refrigeration system (i.e., compressor/float valve/evaporator) is working properly first. This is because the thermostat (called "control" by GE) can only operate correctly if the evaporator temperatures are correct. If all is good there, then the control will need to be looked at. Also, since you're new to CA's, make sure the oil heater is working, because quite often they're not with original fridges. To do this, either plug the fridge into a power meter and see that it draws about 12W with the switch off, or with an ohm meter, measure across the plug pins also with the switch off. The resistance should be around 1000 ohms. Without using a thermometer, it feels like it's getting cold evenly to the touch, and quite high up the evaporator. I don't currently have a good probe or IR thermometer yet, but I'll plan to get something soon. I'll also check the resistance on the heater today. |
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Post by nd1933 on Aug 18, 2023 15:45:31 GMT
Hello! I recently purchased my first monitor top, a CA-1-B16 as a repair project for my 1933 home. It starts, gets cold, and shuts off in about 20 minutes or so. At that point it won't restart on its own, but will if the power switch is turned off and then back on, though it won't run for as long (say 5 minutes or so before the same thing happens). After reading up a bit, I went ahead and started purging the NCGs, which has definitely allowed it to get colder and run quieter, but the main problem still persists. Any insight as to what I should be looking at would be greatly appreciated. Thank you! One thing you need to confirm is the current draw of the compressor while running. It sounds like the compressor may be tripping the overload. Turning the control off and back on resets the overload if that is tripped. Another possibility is that the control is internally gummed up and it's just not able to trip on when the evaporator warms up. It may be in need of cleaning and oiling the moving parts of the control. Do you have a Kill-A-Watt meter? Sincerely, David I was looking through the service manual last night and thinking that the issue sounded like the overload ("motor protective device" in the manual?) tripping. I'll plan to buy a Kill-A-Watt meter today and will let you know what that reveals. |
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Post by cablehack on Aug 19, 2023 23:33:43 GMT
Interesting thought re the overload. I discounted that only because my CA's will stall and/or be very noisy well before it trips. In fact I've never actually had one trip because I've turned it off manually within a few seconds. But yes, the power consumption will reveal if it's something to do with that.
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Post by nd1933 on Aug 20, 2023 4:14:54 GMT
I'm getting 0W of draw when plugged in and switched off. Read the resistance as well and came up with 2MΩ+. Does this indicate a toasted oil heater? cablehack & turbokinetic, thank you for the help so far. |
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Post by cablehack on Aug 20, 2023 4:39:38 GMT
Yes, the oil heater needs replacing. That's going to lead to having to also replace the wiring from the heater to the relay box, since the original is rubber wire which will have hardened and started to crumble. On that note, it's probably a good time to rewire the whole thing.
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Post by nd1933 on Aug 20, 2023 5:11:11 GMT
Got it. I saw your replacement with the pair of wirewounds - looks like fun. Rewiring won't be a problem as I've put in quite a bit of time with hifi repairs. The wiring to the relay looks quite bad, so I'll feel a lot better having everything replaced.
Do you happen to know if the CA and CK have relatively similar topography? I was just looking at ckfan's post about rewiring.
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Post by cablehack on Aug 20, 2023 6:00:23 GMT
Yes, you can use ckfan's wiring guide since the routing of the wiring is the same. The main difference is the connections to the control and power cable are via screw terminals with the CK and locking plugs for the CA. The oil heater has a separate cable. Be careful of avoiding any strain on the tubing to the evaporator when accessing under the cabinet top. Just to give you an idea of what it looks like, this is my CA-2 after rewiring www.flickr.com/photos/13469158@N05/7104514065/in/album-72157633054818403/ |
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Post by turbokinetic on Aug 20, 2023 13:00:31 GMT
I'm getting 0W of draw when plugged in and switched off. Read the resistance as well and came up with 2MΩ+. Does this indicate a toasted oil heater? cablehack & turbokinetic , thank you for the help so far. Yep, your heater is open-circuit. These need a good heater to minimize refrigerant collecting in the oil. Many have been getting heaters from Phoenix Thernal Supply https://www.phoenixthermalsupply.com/ They don't have it listed on their online shop, but you can call or e-mail them. The heaters are specified by dimensions and ratings. Order the following: Cartridge heater, 120V 20W, stainless steel, 12mm diameter, 2.5" long. It should be a stock item. There is a LOT of rewiring info on these. As with cablehack and ckfan, I have done a rewiring video. It covers a CK machine, which is similar in how the rewiring job is done. Be aware that the position and configuration of the terminal pins is different between the CA and CK so be sure to note everything carefully. monitortop.freeforums.net/thread/2320/ck-rewiring-video-start-finish Sincerely, David |
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