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Post by turbokinetic on Sept 29, 2018 14:17:35 GMT
Hi all I tweaked the charged some. I’d say it’s now roughly is at 1.3 or 1.4 L Run times have improved. 1.46 to 2.05 min on. The off times are a bit of a different story. The off times change a good bit. The best being 9 minutes off to the worst being 5.30 minutes off. It seems to be random. I’m ruling out the thermostat as being the issue right now. It’s differential is always the same, off 13 F and on at 24F. The Box temp is always 34/35F in a 72F room. With an empty box. If I shake the machine some as per what is the manual about the stuck float. The times improve but then start to get bad again. But will randomly Improve and then get bad again. So I think this is leading me back the float being worn out . Ugh . --- Also I did get a new temperature probe. I bought a fieldpieace on amazon. It seems to be pretty accurate and has two temperature probes so it allows me to get the box temp and evap temp without ever opening the door it’s pretty nice! I had some reward points saved up. So I got it for next to nothing! 😁 It's good that you're as scientifically as possible, ruling out things like the control being inaccurate. Nothing like knowing your measurement instruments are accurate and working correctly. I've been using an older analog temp meter for my testing, and it has been fairly consistent. I probably should send it off an have the calibration checked out, however. Thanks for keeping us up to date on your findings! Interesting stuff.
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Post by elec573 on Sept 29, 2018 16:36:36 GMT
Great AJ I think you have ruled out everything but the float!
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Post by ajc31980 on Sept 29, 2018 18:29:10 GMT
I was reading through cablehacks thread for cap conversion again. He says about how there is a hissing sound sometimes in the float when it’s worn. So I put my ear up close to the float and can hear a faint hissing sound after the compressor shuts off. I couldn’t hear anything with the higher charge. But with the lower charge it seems to be more noticeable but you really have to listen. So if I’ve done my home work correctly..... haha. That means I have a worn needle or seat. Or possibly there’s fragment of some kind in there messing up the operation of the float, idk what it would be though.
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Post by elec573 on Sept 29, 2018 20:47:43 GMT
AJ if you can live with it a while , I’d wait until 100 year fridge gets settled and then go see him .
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Post by ajc31980 on Sept 29, 2018 21:09:49 GMT
AJ if you can live with it a while , I’d wait until 100 year fridge gets settled and then go see him . Herb That’s pretty much the plan at this point. I think I’ve ruled out everything I can and pretty much narrowed it down. Unless somebody can think of something I missed ? I don’t have any problems waiting since mikes willing to help after he gets settled. The CA isn’t going anywhere. I’m probably going to just shut it down tonight and leave it sit. The good thing is that I’ve done most of trouble shooting already. Oh...... the torture of having to walk past it and knowing it’s not working right. Lol But good things come to those wait !
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Post by birkie on Sept 30, 2018 15:47:23 GMT
Hi all I tweaked the charged some. I’d say it’s now roughly is at 1.3 or 1.4 L 1.3L about the equivalent in volume to 2.8 lbs methyl formate, for what it's worth. I don't know what the nominal charge of the CAs is supposed to be. I spent a lot of time last year characterizing our CK, and can accurately predict its duty cycle for a given set of temperatures. At 34F in a 72F room, it would be at 15% duty cycle. I would expect a CA to have somewhere around 10-20% longer duty cycle based on rated BTUs, so something like 17%-18% would be about the right ballpark. The midpoint of your measured cycle times is 1.75 on and 7.25 off, that's about 19%. So it's close. I guess it depends, what is the average on time and off time? If you measure on and off times over the course of an hour, that'd probably give a better picture. If it's closer to "2 on, 5 off", that's bad. If it's closer to "1.5 on, 9 off", that's really good. So I'd say there is "reasonable suspicion" that something might be wrong with the float, but not "a preponderance of evidence" or "beyond a reasonable doubt" just yet. If it were mine, I'd keep it running, keep an eye on it, and see if it's possible to distill the signal from the noise to get the true average cycle times.
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Post by ajc31980 on Oct 1, 2018 7:52:30 GMT
Hi all I tweaked the charged some. I’d say it’s now roughly is at 1.3 or 1.4 L 1.3L about the equivalent in volume to 2.8 lbs methyl formate, for what it's worth. I don't know what the nominal charge of the CAs is supposed to be. I spent a lot of time last year characterizing our CK, and can accurately predict its duty cycle for a given set of temperatures. At 34F in a 72F room, it would be at 15% duty cycle. I would expect a CA to have somewhere around 10-20% longer duty cycle based on rated BTUs, so something like 17%-18% would be about the right ballpark. The midpoint of your measured cycle times is 1.75 on and 7.25 off, that's about 19%. So it's close. I guess it depends, what is the average on time and off time? If you measure on and off times over the course of an hour, that'd probably give a better picture. If it's closer to "2 on, 5 off", that's bad. If it's closer to "1.5 on, 9 off", that's really good. So I'd say there is "reasonable suspicion" that something might be wrong with the float, but not "a preponderance of evidence" or "beyond a reasonable doubt" just yet. If it were mine, I'd keep it running, keep an eye on it, and see if it's possible to distill the signal from the noise to get the true average cycle times. The tag on the back says. 2 1/4 lb for MF. But from reading though this thread. monitortop.freeforums.net/thread/430/guenea-pig-ca?page=2It’s mentioned that R123 is roughly twice the weight Of MF. So I’m figuring just like he did. It’s probably best to go by volume. I had shut it off last night before going out and pulled the plug. I had to let it sit most the day for the heater to do its work. ( till I couldn’t hear any bubbling in side the compressor) I probably won’t be able to get a good average on run times till tomorrow night after work. I’ll post back tomorrow night with results or later in the week. My work weeks and hours are a bit crazy. Thanks AJ. :-).
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Post by ajc31980 on Oct 5, 2018 13:11:29 GMT
Hi all I let the ca run for a day and the times stayed pretty much the same. I’d say the average was on 3 to 4 min and off 5to6 min. And the frost line fell pretty low .... So I started bumping the charge back up very slowly. Less than 100 ML at a time. Figure 100 ML is 0.20LB. For R123. The amounts that I Added at a time where roughly 0.09 lb. give or take a little for that. I was using my kitchen scale. I’m going say the current charge is roughly 1.5 L. Given that I’m sure I lost some in vapor between recovering and charging. The current run times are 2.48 min on and 8.09 off. And it’s been holding that time pretty steady in a 72/73 F room with a box temp off 34 to 37 F for the last few days. It shuts off when the evap temp is 11F and the box temp is 34F. Turns back on when the evap temp is 24/25F and box temp is 37F. If I bump the charge up at all. Both The on off times times decrease by almost a minute. If I lessen the charge the times start to get erratic again and the box temp will start to rise as well as the frost will start to drop. Plus I found that the temp between the bottom center off the evap can be up to 5 F warmer then the side where thermostat temp probe is mounted with a lower charge. With the higher and current charge it’s only about 1F difference between the bottom center and left side where the thermostat temperature probe is during pull down . The temps become even after things are stabilized. So I think I’ve found my happy medium.. haha. And I’m very glad that I now have a good thermometer with dual temp probes ! Makes diagnosing this patient so much easier! Ha! This is my current frost line. From other evaporator pics I’ve seen in the forum this looks pretty normal to me. I’m going to leave it run like this for a wile and just keep an eye on it and see how things go. I’m thinking this is about as good as it’s going to get as far as the charge goes. I’ve also noticed the the thermostat is a bit touchy! If I turn it up or down and then return it to 5 on the dial. The on and off temp can change up to 4F. But the differential is always the same . if I don’t touch it. It will hold its current on/ off temps just fine . So I’m just not going touch it any more lol. Next weekend I’m planning on changing the wiring and the insulation. Does anyone have any recommendations on insulation ? And what actually holds the inner lining in place ? I can’t imagine that heavy inner lining is just held up by the black strips on on the front of the door opening. Is there some kind of extra support on the bottom and on the sides holding it in position? Or is it just resting on the cardboard insulation? I think I read in another post that is does just rest on the cardboard but can’t seem to find that post right now. Thanks AJ
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Post by turbokinetic on Oct 5, 2018 13:21:34 GMT
Looks like you're making some nice progress on dialing in the charge amount needed for this machine. Lots to be learned that is for sure!
When you re-insulate, be sure the foamboard (or whatever you choose) is tightly in contact with the cabinet liner. That will prevent air circulation around the outside of the liner, bringing with it moisture and corrosion.
When I did my Frigidaire, I used the "low pressure" expanding foam to fill in the corner gaps. This low pressure foam is supposed to not "bow in" window and door frames. I figured it would also not deform the cabinet.
To put it in place, I replaced the short plastic straw on the foam can with a long piece of hose. Then, inserted this hose into the corner void space. As I injected the foam, I pulled the hose out so that the corner void was filled from the bottom up, leaving no voids. This was a way to ensure that no air circulation would occur in the insulation space.
I'm sure there are other equally effective methods, as well. I think you're right that the cabinet liner does sit on the bottom cardboard, with support also given by the Textolite strips. If you have to shim up the foam board on the bottom to get the liner in the correct position; be sure the foam shims are on the bottom, between the insulation board and the outer cabinet shell. That way the liner will be flat against the insulation and not having an air gap.
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Post by ajc31980 on Oct 7, 2018 2:02:20 GMT
Looks like you're making some nice progress on dialing in the charge amount needed for this machine. Lots to be learned that is for sure! When you re-insulate, be sure the foamboard (or whatever you choose) is tightly in contact with the cabinet liner. That will prevent air circulation around the outside of the liner, bringing with it moisture and corrosion. When I did my Frigidaire, I used the "low pressure" expanding foam to fill in the corner gaps. This low pressure foam is supposed to not "bow in" window and door frames. I figured it would also not deform the cabinet. To put it in place, I replaced the short plastic straw on the foam can with a long piece of hose. Then, inserted this hose into the corner void space. As I injected the foam, I pulled the hose out so that the corner void was filled from the bottom up, leaving no voids. This was a way to ensure that no air circulation would occur in the insulation space. I'm sure there are other equally effective methods, as well. I think you're right that the cabinet liner does sit on the bottom cardboard, with support also given by the Textolite strips. If you have to shim up the foam board on the bottom to get the liner in the correct position; be sure the foam shims are on the bottom, between the insulation board and the outer cabinet shell. That way the liner will be flat against the insulation and not having an air gap. David Thank you for all the advice on re-insulating the cabinet. I’m probably going to use foam board for the cabinet. That’s a very good idea using the spray foam to fill in the corners ! Something I also need advice on is what to replace the top insulation with ? Mine has some kind of brown ? Or dark looking insulation in the top. I’m not sure what it’s made of. And from what I can feel through the heater plug. It feels a little on fragile side. I don’t think it’s fiberglass. I’m thinking may I just stuff the stop with pink fiberglass insulation. Also what would be a good replacement for the non-ox-Id cloth that’s sealing in the insulation around the top of the lining ? Thanks AJ
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Post by ajc31980 on Oct 7, 2018 8:36:07 GMT
Just had a thought. How long should it take for the system to stabilize after its shut down and is defrosted ? I can hear bubbling and or refrigerant moving for a long time after I shut it down. (This is in both the evaporator and condenser) For at least an hour if not more . It was the same when the machine was charged with MF. Isn’t the float suppose to stop the flow ? Unlike a capillary tube that keeps passing until things are stabilized? Just thought. Maybe it’s the nature of this system. I know the 1947 GE doesn’t take near that long to stabilize after shut down. But they are 2 totally different animals. Thanks AJ.
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Post by cablehack on Oct 7, 2018 22:40:07 GMT
Isn’t the float suppose to stop the flow ? Not when the needle and seat are worn, which yours appears to be. In that respect, it's working a bit like a capillary tube, albeit an incorrectly sized one.
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Post by ajc31980 on Oct 7, 2018 22:56:32 GMT
Isn’t the float suppose to stop the flow ? Not when the needle and seat are worn, which yours appears to be. In that respect, it's working a bit like a capillary tube, albeit an incorrectly sized one. Thanks cablehack for confirming that ! I wish it would have came to mind for me to mention it earlier on in my posts. It just sorta hit me all the sudden .... The last machine I worked on used a cap tube and I was used to hearing refrigerant moving after shut down. This would be first that I’ve had that uses a float. I’m slowly getting the hang of things haha. So back to plotting out a cap tube conversion. Thanks again AJ.
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Post by elec573 on Oct 9, 2018 1:56:58 GMT
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Post by ajc31980 on Oct 9, 2018 7:25:30 GMT
Hi thanks for that link herb . It helps with the insulation part and the top strips. That CK turned out really nice ! I was going to tackle the insulation this weekend when things were looking up, but now that’s it’s pretty much been confirmed once again that the float has issues, I’m going to wait. No point in redoing the cabinet insulation and seals if it’s not cunning correctly. But the info in that thread will be handy when the time comes. Thanks AJ.
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