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Post by Travis on Dec 14, 2014 4:33:06 GMT
Chris, the SO2 is unpleasant, but nothing to be scared of.
Gill, I can find you a CK to fill that void in your life. ;-)
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Post by blackhorse on Dec 14, 2014 4:37:45 GMT
I'll be honest. The SO2 scares me. To be honest, me too. It's OK out in the shop, but for a daily user in the house, I'm not comfortable with it. A catastrophic failure seems unlikely, but if any natural disaster caused it to tip over and break a line, you wouldn't want to be trapped in the house with it, and the emergency services would likely consider it a WMD event, with all that entails. But fortunately that's an easy fix. The CK 134a conversion works great, but I'd use whatever the "environmentally sensitive" replacement is for R-114 if the float valve hadn't crapped out. R-114 was the freon answer to SO2, the characteristics are very similar, I bet it would sound exactly the same as SO2 does in the CK's and DR's, without the concern of "what if" a leak or accident occurred. But getting a TXV for 114 with the desired characteristics would be next to impossible; there are all kinds of choices for 134a. Fortunately the scotch yoke units work well under a wide range of conditions. But save me from POE oil. I don't think even a CK could take that kind of abuse......... |
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Post by blackhorse on Dec 14, 2014 16:31:41 GMT
I wouldn't say always - give it the right room temp and they run very quiet, even at the start of the cycle. But they can never be as efficient as a CK simply because of the heater drawing power all the time. I don't know if you can find one in the 1/2 inch diameter (the ones I have are 3/4 inch diameter) but the modern energy-efficient answer is a PTC heater. Fits in a well in the bottom of the compressor, like the high-side shell monitors. If I recall they are 44 watts stone-cold, but taper out to whatever is required to maintain oil temperature, as little as 2 watts in open air. More heat at low ambient, very little when the compressor is running and generating it's own heat. They aren't cheap, I believe about $22, but it seems to me some of the ones you had made ran well over that anyway. |
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Post by cablehack on Dec 14, 2014 23:16:23 GMT
John, you know it's not just the heater. The CK machines transfer more heat while drawing the same power, if I recall? 2-3 minute run times is something I don't think a size 2 CA machine will ever see with a 70F room temp. I suppose, it's not really fair to compare them as it's like saying a Model T will never be a Model A. Indeed the efficiency has improved over the evolution. The DR-2 varies from 300 to 450 BTU depending on the version. The CA-2 has 480 BTU and then the CK-2 gets 530 BTU. My point was that even if a CA had the same cooling capacity and cycling times as a CK, the heater would always be an extra drain. In practical terms it's only about 17 cents a day to heat both my CA's (25c/kwh). You can actually have a 2-3 min run time on a CA-2 if the temperature differential of the thermostat is set that way, but the problem is the off times are also short. This is why I had to go through the exercise of recalibrating my control, because it was doing just that. There's no change in actual power consumption though. 2.5 mins on & 9 mins off has the same kwh consumption as 5 mins on & 18 mins off. What counts is the actual duty cycle and the DR and CA can't compete with a CK on that basis. |
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Post by jhigdon2 on Dec 15, 2014 2:23:53 GMT
Well. I've had the 123 guenea pig CA running on a box for a few hours now. It ran for about 15 min. Cycled off. Now it's a 39 deg box and cycle times are 3.5 on, and 8 min. Off. Both tanks fully frosted. run amps are in the neighborhood of 2.38. Overall... not to shabby. Now it's time to optimize charge and experiment with different oil heaters.
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Post by ChrisJ on Dec 15, 2014 3:08:22 GMT
Well. I've had the 123 guenea pig CA running on a box for a few hours now. It ran for about 15 min. Cycled off. Now it's a 39 deg box and cycle times are 3.5 on, and 8 min. Off. Both tanks fully frosted. run amps are in the neighborhood of 2.38. Overall... not to shabby. Now it's time to optimize charge and experiment with different oil heaters. Let's see some evaporator pics! |
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Post by allan on Dec 15, 2014 3:51:36 GMT
Well. I've had the 123 guenea pig CA running on a box for a few hours now. It ran for about 15 min. Cycled off. Now it's a 39 deg box and cycle times are 3.5 on, and 8 min. Off. Both tanks fully frosted. run amps are in the neighborhood of 2.38. Overall... not to shabby. Now it's time to optimize charge and experiment with different oil heaters. Let's see some evaporator pics! Sounds good! Yes let's see some pics |
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Post by cablehack on Dec 15, 2014 4:19:59 GMT
Very promising so far. It wouldn't surprise me if a tweak of the charge gets the off times into the +10 min area.
One thing I am curious about with R123 (and R11) is how it might react with moisture for those machines that have been contaminated.
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Post by jhigdon2 on Dec 15, 2014 4:35:25 GMT
Well. I've had the 123 guenea pig CA running on a box for a few hours now. It ran for about 15 min. Cycled off. Now it's a 39 deg box and cycle times are 3.5 on, and 8 min. Off. Both tanks fully frosted. run amps are in the neighborhood of 2.38. Overall... not to shabby. Now it's time to optimize charge and experiment with different oil heaters. Let's see some evaporator pics! |
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Post by jhigdon2 on Dec 15, 2014 4:40:08 GMT
Evap it frosted clear to top of both tanks but it's only been running for 4 or 5 hours now and humidity is so low today its barely visible right now. I'll take a pic and see if frost shows up.
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Post by jhigdon2 on Dec 15, 2014 5:05:06 GMT
I just snapped some pics of evap. It seems that the frost line on the rt side tank has settled down a bit since this afternoon. Maybe chris can help me post them.
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Post by ChrisJ on Dec 15, 2014 13:50:46 GMT
Here are John's pictures. It does look like the right side settles in the usual spot though, I assume in between cycles the upper half defrosts and the lower half stays frozen due to liquid level? Attachments:
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Post by blackhorse on Dec 15, 2014 14:43:22 GMT
I assume in between cycles the upper half defrosts and the lower half stays frozen due to liquid level? I believe so. When running the upper half of the tank is cooled by the vapor moving through it and a certain amount of bubbling and splashing, but it's not as cold when it's stopped, so after several cycles we get the usual frost line about where the liquid lies. That's my take on it, it's like that with various refrigerants and evaporators. Some day, someone with a true artist's skill level needs to make an evaporator out of lexan or "transparent aluminum", so we can actually see what goes on in there while it's running. Tint the oil bright green so we can tell the oil from the refrigerant. Think what we could learn then! |
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Post by ChrisJ on Dec 15, 2014 15:17:35 GMT
You know that pisses me off. Scotty gave them the formula for that in what, 1986? But do you see it anywhere?  On a serious note, why does the left tank stay frosted all of the way up and yet the right tank only half way or a little less? Shouldn't the liquid be equalized on both sides during off periods? |
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Post by blackhorse on Dec 15, 2014 19:07:16 GMT
You know that pisses me off. Scotty gave them the formula for that in what, 1986? But do you see it anywhere? On a serious note, why does the left tank stay frosted all of the way up and yet the right tank only half way or a little less? Shouldn't the liquid be equalized on both sides during off periods? No you don't see it anywhere; it's transparent!  I'm thinking they are keeping it a military secret. The current generation of stealth aircraft are indeed completely invisible. It usually takes 30 years for military tech to be revealed to the public, so another couple of years should do it. The frost line is level; your floor is tilted.  Differences in internal distribution? Remember that liquified gasses always move to the coldest point (lowest pressure), so tiny differences in temp or loading? It just seems to me that every time it comes up, a full charge is described as one side frosted to the top, the other half way up. All of them I have seen have the crossover tube well above the liquid level, curved in the middle to be even higher; there isn't going to be much flow from one side to the other during off times. It seems like they made it that way deliberately, though I have no idea why. |
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