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Post by osx86apple on May 25, 2022 10:33:53 GMT
Hello everyone My first post, so hello! I’m from the UK and recently acquired a very nice BTH refrigerator from around 1938 I believe Have a couple of older fridges but this is the earliest, and I’m a bit of a newbie around this, so please forgive me :-) I’m currently in the process of carrying out some rewiring as it’s definitely not up to standard, however when I did a test run the compressor runs but I can’t see any cooling unfortunately even after a good half hour or so of running. The evaporator has been making noises occasionally meaning some refrigerant must still be present? No idea what it’s been charged with, BTH doesn’t appear to have a plate saying this? The compressor also changes tone occasionally when running which sounds like it’s then going start cooling, I’ve made a video of it running and would welcome some advice, thank you :-) youtu.be/CU-_1eiEnAk
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Post by turbokinetic on May 25, 2022 12:19:39 GMT
Hello everyone My first post, so hello! I’m from the UK and recently acquired a very nice BTH refrigerator from around 1938 I believe Have a couple of older fridges but this is the earliest, and I’m a bit of a newbie around this, so please forgive me :-) I’m currently in the process of carrying out some rewiring as it’s definitely not up to standard, however when I did a test run the compressor runs but I can’t see any cooling unfortunately even after a good half hour or so of running. The evaporator has been making noises occasionally meaning some refrigerant must still be present? No idea what it’s been charged with, BTH doesn’t appear to have a plate saying this? The compressor also changes tone occasionally when running which sounds like it’s then going start cooling, I’ve made a video of it running and would welcome some advice, thank you :-) youtu.be/CU-_1eiEnAkWow; that's a very unique design! It's hard to tell in the video, but it seems that the compressor is essentially the same as a DR Monitor Top. I can't see the top of the dome exactly though, to rule out the chance it is a scotch-yoke machine with a similar coiled condenser to a DR. Does your fridge have a condenser on the rear of the cabinet? Assuming it IS based on the DR design, those are much more finicky than some later designs. More than likely, the reason it's not cooling would be due to the float valve blocked; or not opening, and therefore not passing refrigerant from the condenser to the evaporator. This can happen from sitting a long time. Can you share more detailed pictures of the top, bottom, and electrical parts of the compressor area? Just to add; assuming this is a GE factory design; and not a custom built setup made from parts by an individual - it would have had SO2 (sulphur dioxide) refrigerant from the factory. Sincerely, David
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Post by osx86apple on May 25, 2022 12:54:52 GMT
Hello everyone My first post, so hello! I’m from the UK and recently acquired a very nice BTH refrigerator from around 1938 I believe Have a couple of older fridges but this is the earliest, and I’m a bit of a newbie around this, so please forgive me :-) I’m currently in the process of carrying out some rewiring as it’s definitely not up to standard, however when I did a test run the compressor runs but I can’t see any cooling unfortunately even after a good half hour or so of running. The evaporator has been making noises occasionally meaning some refrigerant must still be present? No idea what it’s been charged with, BTH doesn’t appear to have a plate saying this? The compressor also changes tone occasionally when running which sounds like it’s then going start cooling, I’ve made a video of it running and would welcome some advice, thank you :-) youtu.be/CU-_1eiEnAkWow; that's a very unique design! It's hard to tell in the video, but it seems that the compressor is essentially the same as a DR Monitor Top. I can't see the top of the dome exactly though, to rule out the chance it is a scotch-yoke machine with a similar coiled condenser to a DR. Does your fridge have a condenser on the rear of the cabinet? Assuming it IS based on the DR design, those are much more finicky than some later designs. More than likely, the reason it's not cooling would be due to the float valve blocked; or not opening, and therefore not passing refrigerant from the condenser to the evaporator. This can happen from sitting a long time. Can you share more detailed pictures of the top, bottom, and electrical parts of the compressor area? Just to add; assuming this is a GE factory design; and not a custom built setup made from parts by an individual - it would have had SO2 (sulphur dioxide) refrigerant from the factory. Sincerely, David Hi David, Thanks so much for getting back to me. Great youtube channel by the way, I’ve followed you for awhile now and they are really informative and interesting! So, there is no condenser on the back that I can see, I’ll gladly get some photos over shortly though detailing more on this. Looks completely factory in design and it came from a one owner household who had it in use up till 10 years ago, it’s been sat in their garage ever since they “upgraded” Kind regards, Mathew
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Post by turbokinetic on May 25, 2022 13:56:05 GMT
... Hi David, Thanks so much for getting back to me. Great youtube channel by the way, I’ve followed you for awhile now and they are really informative and interesting! So, there is no condenser on the back that I can see, I’ll gladly get some photos over shortly though detailing more on this. Looks completely factory in design and it came from a one owner household who had it in use up till 10 years ago, it’s been sat in their garage ever since they “upgraded” Kind regards, Mathew Hi Mathew. That's very cool that you got this from the original owners! Also happy you're enjoying my videos. I'm going to say there is a high likelihood that the system has accumulated some corrosion in the float valve seat area. This often happens when they sit unused. It's sometimes possible for this to be resolved by tapping on the float valve area with a hard plastic tool; such as a screwdriver handle. That is, if the corrosion isn't too severe. Unfortunately, often the only solution is to remove the refrigerant from the system and mechanically clear the blockage. If this is based on the DR machine, there is most likely a heater located in the oil sump of the machine. This is in place to keep refrigerant liquid from collecting there and impairing the lubrication of the unit. For that reason, it is important to see if it has a heater, and if so - to ensure that it is in working order. There are several threads about these heaters you can look up. If you want to try the tapping method, do it this way. 1 - Start the unit and allow it to run until the compressor housing is warm; possibly 20 or 30 minutes. 2 - Place a plastic bag of ice over the top of the float chamber, to ensure that liquid refrigerant has condensed into this chamber and filled it fully. 3 - Tap against the side of the float valve needle and seat area. Tap from alternating sides. Repeat with rising intensity until you hear flow going into the evaporator. 4 - Once it starts flowing, close up the door and let it run for several hours or until it cycles off. The picture below is my hastily-drawn and very crappy explanatory drawing of where to tap and place the ice bag. The part needing to be tapped is located inside the cabinet. It may be hard to get to, seeing how the evaporator is made in your fridge. It should be a piece of 1/2" brass tube, which reduces down to 1/4" copper tube and goes into the side of the evaporator at the lower left rear outside of the evaporator. I may be offline for the rest of the day due to work obligations but will check back as I can. Sincerely, David
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Post by osx86apple on May 26, 2022 17:46:54 GMT
Hi David,
Thank you so much for the information, it’s greatly appreciated.
Unfortunately work has taken over since yesterday and won’t be able to get round to looking at it again until tomorrow or the weekend, however, I will keep you posted on an update as soon as possible.
Fingers crossed it’ll work! :-)
Kind regards, Mathew
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Post by osx86apple on Jun 1, 2022 15:37:52 GMT
Hey,
Sorry for my delayed response.
Managed to get a re-wire sorted today before running it for too long, and it’s now properly grounded!
Compressor has been run for a good hour, and no cooling as of yet unfortunately. The compressor seems to run consistently, and isn’t getting warm - however occasionally the tone/running will change/smooth out and you can start to hear refrigerant moving, but this seems to only last 10 or so seconds, any thoughts ?
I have tried to be as forceful as I can with the float, but it hasn’t changed anything as of yet, although at the top of the float I can hear something moving around when I tap it?
Apologies, I’m learning as I go :-)
Forgot to add, this doesn’t appear to have a heater at the bottom either.
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Post by turbokinetic on Jun 1, 2022 17:24:19 GMT
Hey, Sorry for my delayed response. Managed to get a re-wire sorted today before running it for too long, and it’s now properly grounded! Compressor has been run for a good hour, and no cooling as of yet unfortunately. The compressor seems to run consistently, and isn’t getting warm - however occasionally the tone/running will change/smooth out and you can start to hear refrigerant moving, but this seems to only last 10 or so seconds, any thoughts ? I have tried to be as forceful as I can with the float, but it hasn’t changed anything as of yet, although at the top of the float I can hear something moving around when I tap it? Apologies, I’m learning as I go :-) Forgot to add, this doesn’t appear to have a heater at the bottom either. Interesting. Can you give us a picture of the very top center of the compressor dome? There is a linkage with float ball inside the float housing, which is moving when you tap on it. The change in sound may be due to, every now and then, a drop of refrigerant comes through. It is looking like it's probably suffering from a corrosion blockage in the float outlet, sadly. Or it has a lot of air in the system.
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Post by osx86apple on Jun 1, 2022 18:28:16 GMT
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Post by osx86apple on Jun 1, 2022 18:29:17 GMT
Sorry trying to add photos on my iPhone and post at the same time was not easy for me lol.
I’ve tried to get as close to the centre as my phone would allow, hope these shed any light ?
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Post by turbokinetic on Jun 1, 2022 18:45:56 GMT
I was hoping to see if this machine had any lines coming out of the top; or if it had the "bump" in the top as in the US-built GE Scotch Yoke machines. Yours looks to be different in that it has no bump, but also no line coming from the top! Still have no idea what mechanism it is. In spite of that, I continue to think that the most likely problem is corrosion blockage at the float; with a second most likely problem being air trapped in the system. Either of those issues will necessitate opening the system and recharging afterwards.
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Post by osx86apple on Jun 1, 2022 19:01:02 GMT
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Post by turbokinetic on Jun 1, 2022 20:00:17 GMT
It's not a terribly hard job to fix the blockage if that is what it is. The only Monitor Top which we know for 100% sure is not compatible with R152A is the CA machine (for methyl formate) which has to have a low pressure / vacuum refrigerant. All the high-side float SO2 units such as yours will work with R152A; assuming you follow proper procedures to evacuate and charge it.
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Post by osx86apple on Jun 2, 2022 7:42:24 GMT
Thank you.
I’ve seen a some methods or evacuating the So2, any thoughts on what would be the best method? It’s currently in my garage, so away from my home thankfully!
Also, having looked at the hermetic kit I believe the Bristol spline key is missing unfortunately, but the rest looks complete. Looks like I need to get a .216, as the service port looks identical to the GE.
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Post by turbokinetic on Jun 2, 2022 10:51:20 GMT
Thank you. I’ve seen a some methods or evacuating the So2, any thoughts on what would be the best method? It’s currently in my garage, so away from my home thankfully! Also, having looked at the hermetic kit I believe the Bristol spline key is missing unfortunately, but the rest looks complete. Looks like I need to get a .216, as the service port looks identical to the GE. Yep, they call that key a '0.216" Old Style' Bristol key. Apparently there are two different profiles they used. The kit needs to have the "L" shaped key; plus a "bit" style key which goes in the tool its self. As far as getting rid of the SO2, you can roll the fridge outside and "let it go" on a windy day; or you can arrange a bucket of an alkali solution to neutralize it. There is always a little more coming out of the oil and other internal traps, for a long time after initial release of the charge. This happens until it's been placed under vacuum to remove all traces.
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Post by cablehack on Jun 2, 2022 23:54:51 GMT
The BTH fridge uses a different compressor to the U.S. and Canadian produced Monitor Tops, even though externally it looks the same. That's one reason why it operates from 240V without a transformer.
Unfortunately, I can't open the file but I recall it showed the internal design. Perhaps karlbrighton can help?
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