Post a reply to the thread: moisture in system.. this ? always sparks good conversation..
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Originally Posted by timebuilder I think he is drawing the wrong conclusion form his experiment. It looks to me like he is able to pull gasses from the oil, not moisture. How do you know its not moisture? What do you think it could it be then?
maybe he had too much water in the bottle for such a short time it couldn't all be absorbed.
Originally Posted by PMARS2345 Check out this video on YouTube of a guy pulling a vacuum on a clear bottle of POE that came out of a new scroll compressor. http://www.youtube.com/watch?v=NzXO8...e_gdata_player I think he is drawing the wrong conclusion form his experiment. It looks to me like he is able to pull gasses from the oil, not moisture.
POE is definitely a cock sucker.. Had a bad burnout years ago and tried for days to clean it up. The only thing that seemed to work was heating and agitating the areas of the system with oil laying in them(crank case, seperator, suc line trap, and accumulator). After 2 days of runing, the oil tested ok in the field, but im sure a lab analysis would probably show that some moisture content was still there.
Thanks
http://sporlanonline.com/November%20...Cold%20WAR.pdf There is a start. There are many, many threads here on this topic. Use the search feature.
Quite a few statements on Poe oil here, any references to back then up? I'm nottt doubting what is said would like more info for learning?
Originally Posted by PMARS2345 Check out this video on YouTube of a guy pulling a vacuum on a clear bottle of POE that came out of a new scroll compressor. http://www.youtube.com/watch?v=NzXO8...e_gdata_player Means nothing. Yes, some moisture came out of the oil. After he's done, send that stuff out for an analysis and see what the moisture content is. You'll be in for a surprise.
Check out this video on YouTube of a guy pulling a vacuum on a clear bottle of POE that came out of a new scroll compressor. http://www.youtube.com/watch?v=NzXO8...e_gdata_player
Originally Posted by chuckcrj Bernoulli's Principle only applies if the velocity inside the pipe that has a small hole is so high that it starts drawing air into the hole and not letting any refrigerant out. Lets just take a low temp running R404a with a -15 evap temp, 20 psig, and a small hole in the suction pipe. The velocity would have to be extremely high to ever reverse the 20 psi gas leaving the pipe and start drawing in air. For a leak to leak gas out and suck gas in at the same time is completely impossible. You either have to take the pressure inside the pipe down to negative, or get the velocity so high it would create a slight vacuum at the leak(not gonna happen in a refrigeration system, velocity would never get that high). Maybe if you got the pressure down to .5psig you might have enough velocity to suck a little air in, maybe. Urban Legend. The more likely cause of getting moisture into a system would be having a leak in the low side and some intermittent restriction causing negative pressures at times, or a pump down system that is pulling down into a vacuum due to pressure switch set wrong. We need the Mythbusters!!
Bernoulli's Principle only applies if the velocity inside the pipe that has a small hole is so high that it starts drawing air into the hole and not letting any refrigerant out. Lets just take a low temp running R404a with a -15 evap temp, 20 psig, and a small hole in the suction pipe. The velocity would have to be extremely high to ever reverse the 20 psi gas leaving the pipe and start drawing in air. For a leak to leak gas out and suck gas in at the same time is completely impossible. You either have to take the pressure inside the pipe down to negative, or get the velocity so high it would create a slight vacuum at the leak(not gonna happen in a refrigeration system, velocity would never get that high). Maybe if you got the pressure down to .5psig you might have enough velocity to suck a little air in, maybe. Urban Legend. The more likely cause of getting moisture into a system would be having a leak in the low side and some intermittent restriction causing negative pressures at times, or a pump down system that is pulling down into a vacuum due to pressure switch set wrong.
Originally Posted by jpsmith1cm I was told that a drier is the only way to remove moisture from POE. You won't remove it with a vacuum pump, that's for sure. There are also issues with water causing chemical changes in POE oil and causing it to revert back to its component chemicals, namely acid and soap. Plugged cap tube, anyone? It will be interesting to learn more about this. We have a very small number of RTU's that use POE, so this is not an issue for us right now. Maybe I'll try to research the dryer aspect some more when I have time.
I was told that a drier is the only way to remove moisture from POE. You won't remove it with a vacuum pump, that's for sure. There are also issues with water causing chemical changes in POE oil and causing it to revert back to its component chemicals, namely acid and soap. Plugged cap tube, anyone?
1) Yes, a venturi can form and draw air with moisture into a system. 2) Yes, the moisture can already be in the oil, unless it is carefully contained and kept from exposure to moisture before it is placed into the system. POE is extremely hygroscopic. 3) Now, from what I have been told, a dryer cannot remove moisture from POE oil. In mineral oil, the moisture is merely entrained with the oil. In POE, the moisture bonds with the oil chemically, and that makes it virtually impossible for a passive dryer to remove it. At least, that's what I was told. I may be wrong.
Originally Posted by jpsmith1cm Do either of you understand Bernoulli's Principle? Also known as the "venturi effect" http://en.wikipedia.org/wiki/Bernoulli's_principle Study up I believe that it is possible, but would be extremely difficult to document and prove. Tranes without LPCOs and the "Green Slimer" when pressures get low. It does happen, in very specific circumstances. On resi gear, you can't place enough suction/LL dryers to clean that mess up. R11x and ERPing was trane's SOP during that rash.
Yes I remember Bernoulli's Principle from my industrial gas fitter's course, but I'm not sure it applies in a case like this. I can't think of any part of a refrigeration system that would form a venturi effect sufficient to overcome the force of escaping gas.
Do either of you understand Bernoulli's Principle? Also known as the "venturi effect" http://en.wikipedia.org/wiki/Bernoulli's_principle Study up. I believe that it is possible, but would be extremely difficult to document and prove.
Originally Posted by RuralSpaceman No way. I wouldn't believe that even if the unit somehow ran under water. Moisture has a mass and it moves by force like everything else. Until the forces equalize, moisture will stay where most convenient. Same thing I was thinking, but what do I know? Been doing resi all my life.
No way. I wouldn't believe that even if the unit somehow ran under water. Moisture has a mass and it moves by force like everything else. Until the forces equalize, moisture will stay where most convenient.
Originally Posted by bunny Always possible that the moisture was present in the POE and introduced that way.....POE does, after all, have a love affair with water. Much more likely. Evacuation doesn't remove moisture from POE. You need driers to do that.
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