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Post by cablehack on Jun 6, 2016 23:51:24 GMT
I can hardly detect MF by odour when purging, so use condenser temperature to know when purging is complete. The key things are to do it slowly, and follow GE's pictorial instructions exactly; i.e. 3 mins bleed, 1 minute wait, and only have the valve open just enough for the gas to bubble through the oil, then things will go to plan. The first thing is to get the pressure up so the condenser is working above atmospheric pressure. I use trays or saucepans of boiling water placed in the evaporator. Once the compressor dome and top of condenser start to feel warm, open the valve very slightly and see if there's any bubbling through the oil. If not, continue heating the evaporator until it does. When purging is under way, keep feeling the top and bottom of the condenser. You'll notice the warmth gradually moves further down the condenser as the NCG's leave the system and make way for the warm refrigerant gas. Once the bottom of the condenser seems to feel as warm as the top, I'd stop there in the case of cap tube machines. With float valve equipped machines such as yours, continue on for just a little bit longer (maybe only one or two more 3 min purge sessions are needed)until you feel the float valve starting to warm. I did a Youtube video of purging my CA-1 here which may help understand the procedure www.youtube.com/watch?v=_hkBczJdBawThe CA-1 has a direct connection between the condenser outlet (bottom connection) and the float valve chamber inlet, unlike the CA-2 which has additional tubing around the cabinet top for added condensation area. This means that for CA-1's the float valve will warm sooner than a CA-2 once the warmth has reached the bottom of the condenser. In practice it's easier than it sounds - once you're used to the set up and procedure it becomes the kind of thing you can do while you're getting your dinner ready. In summer with an ambient temp of 25C or more, you usually don't have to even heat the evaporator.
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Post by ckfan on Jun 7, 2016 4:45:44 GMT
Well, I did it. I think I got the terrible gasses purged. It is already acting better. I'll post more tomorrow. It's late for me!
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Post by ckfan on Jun 7, 2016 14:47:14 GMT
Thanks to everyone who gave tips and support. The process went just fine. I think that this little CA may still have some life in it. I think I went a little overkill with the heating of the unit though. I wrapped the condenser with blankets because I was having trouble getting it warm. Seriously, I couldn't get any heat out of it and the compressor was rattling like crazy. It sounded poor. Once I wrapped it up with a blanket it started to warm up quickly. I then put a pan of hot water in the evaporator which was basically room temperature. Keep in mind that I still have the unit off of the cabinet. It is on a crate so the evaporator is in mid air. Once I put the hot water pan in the condenser started to really warm up. I took the secondary screw out, put oil in, got my friend drew to time me and hold the flashlight, and I cracked it open. I had to push quite a bit to get it open but I got it open. A little too much at first, it blew a lot of oil out but I quickly dialed it back to a slight burble. It really was easy after that. Just measured the temperature of the condenser, motor, and float. Unfortunately I may have skewed up the results. I could never get the top and bottom of the condenser to match up. The top was always much hotter than the bottom. The float eventually got to the same temp as the bottom of the coil but it took a long time. I must have went through the bleeding process 10 times or more. I lost count. I hope I didn't do it too much but I just couldn't get the temps to match. I think that might be because the poor girl got so hot so quickly. I took the blankets off after the 4th cycle and boy was it searing hot. Hopefully I didn't do any damage. It just happened so quickly. Going from barely enough heat to searing hot in a matter of a few cycles. I read the temp of the case 140! The top of the condenser coil peaked at 135. The bottom was 90 and the float 85 for the first few purges. This got down to 125, 120, 95, 93 respectively at the end of the process. I would have kept going since the frost was getting better but I smelt the Methyl Formate all of a sudden. I had been trying to waft it to my nose before I smelled it for the previous cycles. So hopefully I didn't loose that much refrigerant. It definitely has a distinctive smell. I kind of like it. Didn't take my breath away at all. It just let me know, hey you big dummy! Quit letting out my juice! So, I sealed it up and took some pictures after a few more minutes of running. The compressor was much more quiet now. It didn't sound like a tractor with an engine that has a rod knock...it just sounded like a well tuned tractor now. I think that is because it was under such a heavy load. I think the frost line looks pretty good. As you can tell, the left header was completely frosted. The right header was only starting to frost on the very rear. The rest of the evaporator was completely frosted. The lowest temp reading I got was 11. The highest I saw on the right header was 29. So, what do you all think? Am I done or do I need to give it another go? I'm sure it would get a lot more frost if it were in the cabinet. Oh, and a side note. It was the 3rd or 4th purge cycle before I heard the float open. I could hear it open pretty regularly after that. I'm not sure if I should be hearing it "spurt" like it was or if it should be more of a constant, quiet process like my CK is. To view the photos in this post, please follow this link: drive.google.com/open?id=0B8_jm7K-ahMaR0N5STBQYlNTLW8
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Post by cablehack on Jun 7, 2016 23:10:00 GMT
I'd wait until it's on the cabinet before deciding to do any more, but sounds like you've purged by the right amount. The warm room air circulating around the evaporator doesn't give a true idea of the frost pattern - you'll need to wait until it's in the cabinet and the temperature has stabilised to see that. The float valve can be noisy under load on the initial pull down of temperature. I'm curious what the story of the oil heater is also.
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Post by Travis on Jun 8, 2016 0:13:58 GMT
The oil heater was done by me some years ago.
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Post by ckfan on Jun 8, 2016 15:30:20 GMT
The oil heater currently draws 6 watts according to my Kill-A-Watt meter. I think that means that it is one of those drain heaters that keeps frost from building up. Correct me if I am wrong about that Travis. Like I mentioned earlier I think that 6 watts will be good enough since the machine will always be kept in a conditioned environment.
I started the unit up after work last night and it sounded much better. No rattle that I could hear. I had left the heater plugged in all day. I did notice though that it was kind of sluggish to cool off. I'm not used to these unit though so maybe it will act better once it is housed in its ridiculously tiny 4.7 cu ft. cabinet.
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Post by Travis on Jun 8, 2016 18:40:29 GMT
Ray,
You're being unfair to it. A CA unit will not cool your house.
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Post by ChrisJ on Jun 8, 2016 19:29:05 GMT
My Kil-A-Watt always says 9 or 10 watts when the heater is actually drawing 12.
A 12 watt heater has served me well even when the kitchen was in the low 60Fs due to us making modifications to the boiler.
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Post by ckfan on Jun 8, 2016 20:47:41 GMT
My Kil-A-Watt always says 9 or 10 watts when the heater is actually drawing 12. A 12 watt heater has served me well even when the kitchen was in the low 60Fs due to us making modifications to the boiler. I figured that my meter is actually under selling what the heater is actually drawing. So, that raises the question...if I put it on the cabinet, it sounds quiet, and it has good frost lines and cycles properly I shouldn't have to worry about putting in a larger heater right?
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Post by ChrisJ on Jun 8, 2016 21:11:28 GMT
My Kil-A-Watt always says 9 or 10 watts when the heater is actually drawing 12. A 12 watt heater has served me well even when the kitchen was in the low 60Fs due to us making modifications to the boiler. I figured that my meter is actually under selling what the heater is actually drawing. So, that raises the question...if I put it on the cabinet, it sounds quiet, and it has good frost lines and cycles properly I shouldn't have to worry about putting in a larger heater right? Oh boy........I'm going sound like Travis, please, forgive me. If it's quiet and not bitching, leave it alone. If you get a rattle from time to time, especially on startup or when the room is cool, you would want to try a larger heater. My CA form A never rattles. It sounds a little louder when I start it after defrosting, but never chatters / rattles etc. It sounded awful before I put a heater and a cap tube in it though so it's not that it never rattled before, it's just when things are proper CAs seem to be very quiet.
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Post by cablehack on Jun 8, 2016 23:03:39 GMT
You can measure the resistance of the heater element if there's any doubt about the power meter readings. Power is the square of the mains voltage divided by the resistance.
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Post by ckfan on Jul 1, 2016 14:50:19 GMT
I wanted to give an update on the little CA that I bled a while back. It seems to be a lot quieter now vs before I bled the NCG's. However, I am not positive that is is completely correct. I want those of you who know and love your CA to chime in here and tell me if I am correct in assuming that something isn't right.
Let me first start off by saying that this little guy will cool off the cabinet no problem. It will get down to around 38 degrees or so after a few hours of running, no problem. However, there are a few odd things that I have noted.
The first thing is the watt draw. When I first start the unit up the watt draw seems outrageously high. I know that all fridges start off with a high watt draw when pulling down a warm cabinet but it seems a bit too high. 220 is what is starts off at. It stays there for a good while until the evaporator gets nice and frosty. BTW, the frost on the evaporator *looks* correct. The headers both have frost and so does the underside and the sides of the plate leading up to the headers. The left header gets completely frosted and the right one frosts up all the way near the back and it tapers off towards the front but it still goes about a quarter of the way up the header. After the unit settles down the watt draw is about 170-180. That seems more normal to me.
I've also noticed that the condenser coil only gets warm on the top half. There is a very big difference between the top and bottom halves. The bottom half is about room temp but the top half gets quite warm. Is it possible that there are even more NCG's in the system? I bled it until I caught a whiff of Methyl Formate, I am sure of that (very noticeable). The float valve is also about room temp. For an unfair comparison, my CK also has a difference between the top and bottom halves but it isn't as pronounced.
One thing I have not noticed since the bleed is rattling. Even at start up there is just the slightest hint of a rattle but it smooths out after a few minutes. However, the compressor is still pretty noisy when running. It almost sounds like a sort of liquid sputtering sound. Its not an alarming sound, not like the rattling that I heard before the bleed. That made it sound like a worn out Russian tractor. No, this sounds more like a gurgling sound. I don't know if this is "normal" or not.
I just want to make sure that I am treating this old girl right. It sure is different compared to what I am used to in the old Sulfur Dioxide machines. Thanks in advance for giving me your opinions!
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Post by ChrisJ on Jul 2, 2016 1:40:46 GMT
If not working hard, I've found my condenser will be cool at the bottom. But during an initial pull down, or even if I have the door open for a bit the entire condenser will be nice and warm, 90+F
Sounds like you need to do more bleeding but let's see what cablehack says.
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Post by cablehack on Jul 4, 2016 8:09:37 GMT
220W is not unreasonable during the initial temperature pull down, and 170-180W is normal by the time it starts cycling. The frost pattern sounds OK too. As your machine has the float valve in operation, an excess of NCG will become apparent earlier than one with a capillary tube. So, it would seem that you're on the right track with the purging, and the high frost would seem to indicate you haven't lost any methyl formate.
Now, the next thing is the condenser temperature. A trap for the unwary can be that in normal operation, with a stabilised cabinet temperature, there can be a large temperature variation from top to bottom of the condenser. In a cool room, the condenser might not run warm at all. This doesn't, in itself, mean there are NCG's. The evaporator needs to be under load to test for NCG's. So, load the compressor with a container of hot water and after the compressor has been running for say 20 mins, see how the temperature variation is then. In other words, prepare the machine as you would for purging. If the bottom of the condenser still remains much cooler after running under load for a while, then it's worth trying another purge.
Room temperature, and change in room temperature, play a huge part in how the CA performs with regards to things like frost level and rattling sounds, so anything peculiar is not necessarily cause for alarm. It's when the something peculiar does not go away when the room temperature has reverted to normal for a couple of days, that it needs investigation. The CA's can appear to do strange things if the room temp drops below about 18C. In colder temperatures there might be a brief rattle for a few seconds after start up, but even in my 6C kitchen in winter, the CA-2 runs silently for the remainder of the compressor on time. The important thing is these unusual aspects of behaviour (as compared to fridges using other refrigerants) don't affect the actual refrigeration performance.
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Post by ckfan on Jul 4, 2016 17:04:45 GMT
Cablehack,
Thank you so much for that information. For the record, I tried to run the unit yesterday and got pretty different results. I ran it for an hour in an 80 degree Fahrenheit room (26 degrees Celsius). After an hour it was still sort of noisy but not terrible. The watt draw was 230. Even more curious was the evaporator. It was just cool enough to be sweaty. The bottom of the condenser was cool again.
Just the night before I showed the unit to my friend and let it run for 5 minutes. The evaporator was starting to form frost already. This leads me to believe that something is causing erratic behavior of the float valve. Hopefully it is just more ncg's but it could be a worn valve I suppose.
I am going to try the hot water trick tomorrow and see if more gasses need to be bled. To be continued!
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