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Post by cablehack on Apr 13, 2015 1:49:04 GMT
Shock horror! The ever faithful and reliable CA-1 actually needed a purge, so I took the opportunity to make this video www.youtube.com/watch?v=_hkBczJdBawGiven the machine had been open for five months, 18 months of running without needing a purge is pretty good and nothing to complain about. I was drawn to the need to purge as I'd noticed that the cool weather rattle was now accompanied by 'something extra' in the sound it made. The high pressure rattle caused by NCG's, is slightly different to the cold weather rattle - something that is only learned by experience. Also, the cycling time had deteriorated; only 9 minutes off. Short cycling like that made me think the evaporator wasn't fully frosted...and sure enough after a defrost to remove the chunks of ice hiding it, the frost line had fallen considerably. All is happy again and even the cold weather rattle is now much less. While capillary tube converted machines do allow a longer NCG build up than those using the float valve, eventually the NCG's do get down to the evaporator, displacing refrigerant, and thus causing the lowering frost line. |
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Post by ChrisJ on Apr 13, 2015 2:27:32 GMT
I'm curious if that NCG in your machine was due to the high temperatures your machine sees?
If I'm remembering correctly, you do not have air conditioning and the temperatures were well above 100F for a while?
My understanding is besides moisture, temperature and time also cause it to break down. The higher the temperature, the shorter the time it takes but it seemed like if it's always in a cool environment it may never happen.
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Post by ChrisJ on Apr 13, 2015 3:30:04 GMT
Is it just me, or was your suction line also frosted near the end of the video?
Also, do you continuously do the sniff test to make sure methyl formate isn't escaping? On my CA-2-A machine after it sat for a year I ran it, got it good and hot and cracked the valve and instantly got methyl formate so I assume that means I'm leak free at least?
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Post by timeswelding on Apr 13, 2015 3:31:38 GMT
Thanks for the film, Cablehack. Very informative.
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Post by cablehack on Apr 13, 2015 3:59:32 GMT
The high temperatures are only for a few days per year; 36C (97F) was the highest inside the house last summer. That would have been for less than 5 days though. Normally, summer room temp would be around the mid 20's (~75F). From now, for the next 7 months things remain cool/cold, under 20C, 15C mid winter.
I think you're right that high temperatures accelerates break down - after all, as a refrigerant it is having to work harder. (However, the CA-1 is under much less load than the CA-2, being smaller and having better cabinet insulation)
GE statistics of where NCG purge call outs were required would be of great interest. One could anticipate those in warmer areas requiring more frequent purging.
One thing I remember reading about refrigerants was that the continuous evaporation and condensation of refrigerant really stresses it, so molecular bonding had to be sufficiently strong to cope with this. This is why so many things were tried without success.
Although they regretted doing so, I'm glad GE was impatient and released MF fridges onto the market without sufficient testing. We wouldn't have seen them otherwise, and I do prefer the unusual.
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Post by cablehack on Apr 13, 2015 4:14:06 GMT
Is it just me, or was your suction line also frosted near the end of the video? Also, do you continuously do the sniff test to make sure methyl formate isn't escaping? On my CA-2-A machine after it sat for a year I ran it, got it good and hot and cracked the valve and instantly got methyl formate so I assume that means I'm leak free at least? Yes, the suction line was frosted, but only for the duration of purging. It quickly settled after so now the frost line is back to normal, just above the bottom of the tank.' I do sniff the gases just in case MF should appear before I expect it, but it does make itself evident in little droplets. With the sewing machine oil I used to use, it actually reacted with it so was quite obvious. Most of the time I stop purging before the MF makes itself evident - I'd rather have a small amount of NCG than risk losing refrigerant. Not that I can't add more - but the question is how much...and that's a tedious experiment. If your CA-2 emits MF from the charge valve straight away after a year, it's clearly leak free. This would also suggest that it's using the machine that causes MF breakdown...it's not breaking down just sitting there. Which is good because my stockpile of MF won't be deteriorating. It's going to be interesting to see how it goes once you have the CA-2 in normal use. |
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Post by thedman on Apr 28, 2021 2:06:06 GMT
What size wrench is required to open the purge port?
Donald
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Post by turbokinetic on Apr 28, 2021 12:41:41 GMT
What size wrench is required to open the purge port? Donald Donald; the tool which opens the service port is a Bristol spline wrench; 0.216" old style. These are getting hard to obtain unfortunately. |
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Post by thedman on Apr 30, 2021 1:45:23 GMT
I purchased one from Max Gain this morning. The gentleman said they have about 30 left and when they're gone, they're gone. So, I'm sharing...
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Post by montman on Sept 6, 2021 17:55:51 GMT
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