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Post by ChrisJ on Jul 10, 2016 0:00:58 GMT
How many kwh is that per month? 40? What size heater are you using?
I think I had noticed my CA-2-A16 uses around 30-35kwh a month with a 12w heater in my kitchen which is usually between 70-72F but 40 wouldn't be a surprise in an 80F ambient.
Was your CK in an 80F ambient when you kept track? You'll notice a huge difference between a 60F ambient and an 80F ambient.
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Post by timeswelding on Jul 10, 2016 2:00:20 GMT
If the CA has an empty cabinet while the efficiency is being monitored, I'd think that would drastically increase its energy usage. Just a thought.
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Post by allan on Jul 10, 2016 3:41:00 GMT
The ambient temp in the room is about 80 degrees. I had nothing in the cabinet but the chiller tray. I also had opened the door for a few seconds to check on the frost before I started timing it. A good test on that machine would be to place a thermocouple sensor under the clip with the thermostat sensor. If the float seat is in good shape you will be able to see low Evap temps on pull down of about 8 degrees. If a worn seat is letting more liquid flow through into the Evap, then the compressor is unable to move the extra volume of vapor from the Evap and temperatures will be higher. Cablehack will buck me but I don't think the non condensibles hold the float down. The float appears to work on liquid levels and the reason it won't open when system has too much non condensibles is that the NCG displaces the liquid and prevents an adequate supply of condensed, liquid MF. Once the NCG is gone the condenser is able to provide a constant liquid flow. When the liquid level rises physics demand that the float, if it is not liquid logged must rise.
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Post by ChrisJ on Jul 10, 2016 5:13:33 GMT
Allan, what happens if the gas inside the float is much heavier than the NCG surrounding it? wouldn't that change how the float behaves?
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Post by allan on Jul 10, 2016 15:12:23 GMT
Allan, what happens if the gas inside the float is much heavier than the NCG surrounding it? wouldn't that change how the float behaves? I don't think so. Another way to look at it would be how does the float distinguish between NCG and MF vapor. The float tank is mostly full of gas (un condensed MF vapor) during normal operation with liquid displacing the bottom 1/3.
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Post by ckfan on Jul 10, 2016 16:53:48 GMT
Oh my! Looks like a real discussion has started. So I guess I need to determine what the evaporator temperature pulls down to so that I can determine if the float seat is worn. Interesting.
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Post by cablehack on Jul 11, 2016 0:36:58 GMT
Cablehack will buck me but I don't think the non condensibles hold the float down. The float appears to work on liquid levels and the reason it won't open when system has too much non condensibles is that the NCG displaces the liquid and prevents an adequate supply of condensed, liquid MF. Once the NCG is gone the condenser is able to provide a constant liquid flow. When the liquid level rises physics demand that the float, if it is not liquid logged must rise. I don't have any problem with that. I just use the "float held down by NCG" explanation because it's what is illustrated in the GE notes and is a simple way to describe it, and for the purposes of purging a fridge it's adequate. Of course, like all of the CA quirks, there's a lot more detail if one wants to get into it.
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Post by cablehack on Jul 11, 2016 23:12:42 GMT
Further thoughts re NCG's & the float valve: Having used a float valve for a year, the effect of NCG's was noticeably different to when a cap tube is used. With the float valve in operation, the effect was more profound and more sudden. The rattling would begin earlier and the frost would drop more rapidly. With the cap tube in operation, the fridge can run for months with half the condenser full of NCG's before the falling frost level occurs. And when it does start falling it occurs maybe over a week rather than a day or two. So, on that basis, it does appear that the NCG build up, by whatever mechanism, does actually affect the float valve. With no float valve, it appears the effect is to simply displace the liquid refrigerant, rather than shut off the flow.
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Post by hilomonster on Jul 17, 2016 18:29:44 GMT
What's up? This is a timely discussion as I went thru my first round of bleeding a CA2A. I did really well for the first 30 min and then I was distracted by a neighbor and went off track. I thought maybe I bled some MF as well. But after reading thru this thread I may be in good shape afterall. Probably overthinking it a bit. For now, decent frost line. Much better than pre-bleeding frost line. Paying attention to the run cycle. After bleeding for 1 hour, the machine ran for 30-35 minutes without cycling off. I turned it off and back on. Now it's cycling on/off again but with varying cycle times. Hmm. It's fun though. I appreciate the discussion and levels of experience. Jesse
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Post by allan on Jul 17, 2016 22:07:13 GMT
Further thoughts re NCG's & the float valve: Having used a float valve for a year, the effect of NCG's was noticeably different to when a cap tube is used. With the float valve in operation, the effect was more profound and more sudden. The rattling would begin earlier and the frost would drop more rapidly. With the cap tube in operation, the fridge can run for months with half the condenser full of NCG's before the falling frost level occurs. And when it does start falling it occurs maybe over a week rather than a day or two. So, on that basis, it does appear that the NCG build up, by whatever mechanism, does actually affect the float valve. With no float valve, it appears the effect is to simply displace the liquid refrigerant, rather than shut off the flow. Do you think that high ambient temperatures contribute to NCG production? My everyday heavy use at work CA2 form B is well over 2 years now on a cap tube and the frost lines stay very stable. Just for checking I have slightly opened the bleed screw a couple of times, the last time about 4 months ago and I instantly get the sweet smell of MF. No NCG. But this machine never sees above 75 F. Any ideas?
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Post by cablehack on Jul 17, 2016 23:27:09 GMT
Do you think that high ambient temperatures contribute to NCG production? My everyday heavy use at work CA2 form B is well over 2 years now on a cap tube and the frost lines stay very stable. Just for checking I have slightly opened the bleed screw a couple of times, the last time about 4 months ago and I instantly get the sweet smell of MF. No NCG. But this machine never sees above 75 F. Any ideas? Just going on experience, I think there may be some connection with room temperature and the frequency of purging needed. Generally, my CA-1 needs a purge only in summer, although somewhat unusually I did have to purge it a few weeks ago with winter at its coldest, but I think the NCG's had been in it for quite a while. It was when I defrosted it that my attention was drawn to this. Also the off times had dropped to 10 mins, whereas 16 mins is the norm. The frost line looked OK before defrosting, but this was deceiving because after I defrosted it, it was quite low. After purging, the frost line is now higher than I've ever seen it during winter. This along with a few other things I've noticed over the past few years makes me think that not all the NGC's are removed from the system during one purge session. My CA-2 isn't a good example given its unusual circumstances. However, roughly speaking, it is more stable through winter. One could come to the conclusion that the harder the fridge has to work, the more NCG's it produces. One thing I have wondered about is how the Sigma Aldrich methyl formate compares to what GE used in terms of NCG production.
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Post by cablehack on Jul 17, 2016 23:43:00 GMT
What's up? This is a timely discussion as I went thru my first round of bleeding a CA2A. I did really well for the first 30 min and then I was distracted by a neighbor and went off track. I thought maybe I bled some MF as well. But after reading thru this thread I may be in good shape afterall. Probably overthinking it a bit. For now, decent frost line. Much better than pre-bleeding frost line. Paying attention to the run cycle. After bleeding for 1 hour, the machine ran for 30-35 minutes without cycling off. I turned it off and back on. Now it's cycling on/off again but with varying cycle times. Hmm. It's fun though. I appreciate the discussion and levels of experience. Jesse If the frost line is above about half way the right side header tank after purging, it probably has enough refrigerant. The frost line will then drop once the cabinet temperature stabilises, if the room temp is reasonably cool, and if the door is opened infrequently. In other words, the frost line level reflects how hard the fridge is working. It should never drop below the bottom of the header tank. Purging puts a lot of loading on the machine because the evaporator temperature is raised to much higher than in normal use. And, if the machine has been purged with the cabinet at room temperature, that has to be cooled back down as well. So, a long run time afterwards is not unusual. However, if the long run time persists, and the cabinet never really gets down to temperature after a day (assuming satisfactory door seal) it could indicate a worn float valve. The best way to test this is by measuring the evaporator temperature. Aside from that, CA's (especially with the 7 cu. ft. cabinet) are very influenced by room temperature, and changes in room temperature, so it's necessary to take that into account, and make your observations over a couple of days before deciding that something might be wrong.
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Post by hilomonster on Jul 18, 2016 19:57:08 GMT
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Post by hilomonster on Jul 18, 2016 20:06:25 GMT
The two photos above are of the frost in the CA. One photo shows full frostation just after bleeding for 3rd round. The other photo shows frost line about 10 hours after bleeding.
10 hours after bleeding the cooling unit temp was 18F and bottom of cabinet temp was 30F.
Aside from right header w/o frost line the unit seems to be running well.
I replaced the oil conditioner but I think the older heater wires are probably to crusty. I was trying to avoid removing the top but it looks like I may have too in order to replace oil conditioner wiring.
Regarding the bleed I did it in 3 stages. First stage roughly 35 min. 2nd stage roughly 30 min. I did a 3rd stage about 12 hours later for 45 min. At that 45 min mark there was a noticeable change in bubbling of oil. I shut valve and did catch a very distinct chemical smell.
Any advice is welcomed. Many thanks. Jesse
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Post by ckfan on Jul 18, 2016 20:10:18 GMT
Sounds like you are on the right track. I think that the evaporator simply needed some time to "settle in" with the cabinet. Hence why the first photo shows no frost on the right header but the second photo looks perfectly fine.
The wiring on these old CA's are notorious for being in poor shape. At least you were able to get the new heater in to test it though.
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