As far as the evap icing, could this also possibly cause the accumulator to ice also?
I started pulling a vac at 2:30 and @ 3:00 this is what I ended up with
Vac.jpg (164.65 KiB) Viewed 2379 times
At 4:30 it was reading 190 microns
When I checked at 7:20 it had risen to 220 microns.
Should I once again puff in about 20 psi of refrigerant and do a leak check with the sniffer and then evacuate again? Also break the vacuum with a small amount of refrigerant, NOT room air?
Yikes!
I am not seeing accum icing. You are under vacuum, so I am not sure how anything could ice. Not sure how you could pull to 170 so quickly, must be a new pump with fresh oil. You did say you were using 3/8 hose tho so that helps, especially with cores removed.
In any event, you never break vacuum with room air.
Maybe you can clarify what you mean by accum icing
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I have to re-think what I said. Icing is caused by low pressure. The lower the pressure, the colder the object. Especially in the face of a high humidity environment, I suppose ice could form on the accum, but also on other components. The accum may be the most obvious.
If this is the case, it has no relationship to the icing John is referring to when the system is charged and operating in the summer.
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I don't see any icing in the photo. But to achieve a reading of 170 microns after only 30 minutes of pulling a vacuum seems extraordinary and makes me wonder whether the valve between the micron gauge and accumulator is closed.
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OK, guys, let me clarify what I got here:
All of my posts from before the hack are history and I’m kinda starting from scratch as to my procedure. Let’s back up to the beginning of this new inquiry starting here:
So, here I am back to a completely assembled system and am ready to evacuate again. My first question:
I want to pull the vacuum isolating my manifold gauge set, hoses, and vacuum pump as follows:
a. Connect an Appion MGAVCT 1/4" MegaFlow Vacuum-Rated Valve Core Removal Tool with a CPS VG200 Digital Vacuum Gauge attached, to the low side line connector beneath the Low pressure switch mounted on the evaporator with the schrader valve removed.
b. Use a 3/8” vacuum rated hose and a 3 CFM Two Stage Vacuum Pump.
I thought maybe run the vacuum for three hours and see if I can get below 160 microns. Would this be OK?
Forget all of the above.
Tbirdtbird, you suggested that I pull my vacuum from both sides. So:
I am using a New 3 CFM Two Stage Vacuum Pump with fresh oil and my Manifold gauge set connected to both the hi and low ports. I am not using the 3/8” vac line and I have a CPS VG200 Digital Vacuum Gauge connected with a tee to the low side adapter on the accumulator.
When I asked:
As far as the evap icing, could this also possibly cause the accumulator to ice also?
I was responding to the following statement from JohnHere:
An evaporator temperature of 25.8°F is pretty cold anyway and might cause evaporator icing problems under certain operating conditions. So I think that your concern about the pressures and temperatures are probably unfounded.
So there is no icing on the accumulator.
JohnHere, you said that to achieve a reading of 170 microns after only 30 minutes of pulling a vacuum seems extraordinary and makes you wonder whether the valve between the micron gauge and accumulator is closed.
I have a right-angle R-134a adapter connected to the port on the accumulator and the valve removed from the accumulator port because the adapter has a valve in it. I also went back and removed the valve from the tee where the gauge is connected.
Try to remember that everything in this system is new but the liquid line and the only oil in the system is the 3 oz in the compressor.
So, here I am back to a completely assembled system:
I started my evacuation last night at 8:00 pm and let it run overnight. When I checked this morning at 9:00 am, I am sitting at 110.
I watched it for 5 minutes and it had rose to 140.
It would seem you are OK. There is nothing shabby about 140 microns
The accum icing John was referring to was during operation, not during vacuuming. I think there was confusion about this, but it seems you are on board.
I am not so sure my comments about low pressure under vacuum make any sense, I was convinced that you were seeing icing on the accum that was not visible in the pic. But I have certainly not ever seen or heard of that.
To some degree you may be over thinking this.
Good luck and keep us posted
When considering your next auto A/C purchase, please consider the site that supports you:www.ACKits.com
OK, so should I go ahead and puff in maybe one can of refrigerant and let it sit until spring?
And when, where, and how should I add the remaining oil?
I was corresponding with another gentleman who says he has been in refrigeration his whole life and this is what he tells me:
Ok you have the two hand valves on the manifold closed and the micron level is stabilized at a certain number, say 350. With the hand valves closed remove the center hose, usually yellow from the vacuum pump and connect it to the refrigerant can. Open the cans valve pressurizing the center hose up to the manifold center tap. Loose the center hose at the manifold to bleed off the air in the hose to get just Freon coming out. Tighten the hose and invert the can, liquid charging and crack open both of the hand valves letting the refrigerant into the system. Get the pressure up to min 10 psig but more like 25 and then flip the can back over so its upright and let it continue to put more refrigerant into the system. This is to get the hose filled with vapor and not liquid. Shut off the hand valves. With the pressure in the system you can now remove the hoses from the suction and discharge lines and put the caps on them and let the system set till youre ready to charge it completely.
Sorry you had to repeat so much due to the hack. But I think you're just about ready to finish up now.
Remember that one micron is an extremely tiny measurement of vacuum and that anything below 500 microns is considered a deep vacuum in the trade. Additionally, a reading of 500 microns or below means that 99.99-percent of moisture has been removed from the system—in practical terms, virtually ALL of the moisture, as well as ALL of the air. If the system can hold 500 microns or below for 30 minutes or longer, which yours does, the system has no leaks under vacuum. However, under pressure, leaks are still possible but unlikely in this instance, I think. You evacuated overnight down to 110 microns, which rose to 140 microns after five minutes. I'd say that's an EXCELLENT evacuation, and you shouldn't worry about the slight variation.
However, we still have the question about how much oil to add, and where. It's unfortunate that you didn't put in all the oil before evacuation, but so be it.
The original information that I have for your car specifies 52 ounces net weight of R-12 and 7 fluid ounces of Mineral Oil. Of course, now we're converting to a somewhat reduced amount of R-134a, which can be addressed later. But the 7 ounces of oil (be it Mineral or PAG) is still a valid spec for your system. So you'll need to add 4 more ounces of oil someplace—PAG oil this time—either to your new R-4 compressor (if it will take all 7 ounces), or to make the process easier, introduce 4 more ounces into one of the service ports using the proper tool. The latter method will eliminate having to disassemble anything, which you don't want to do at this point.
After adding the oil, you can proceed to weigh-in the refrigerant—beginning at about 80-percent of the R-12 amount—into the well-held vacuum...if you can do so at your locale's ambient temperature. If not, add maybe a 20-percent charge and wait until Spring for the rest.
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