Real bad moisture contamination that I cannot remove using the vacuum pump. Micron gauge tells you
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- Опубліковано 16 жов 2024
- Micron gauge can prove to you how bad the moisture contamination is.
Usually when it’s this bad leaving it on the vacuum pump for an hour will not get out the moisture down to a acceptable level even with the engine running trying to bake the system.
Now if I left it on the vacuum pump for eight hours for maybe 24 hours it will probably bring it down below 1000 µm. 
As vacuum level increases, don't think of it as you are sucking water vapor out the test port. Think of it as water molecules in random motion bouncing off the piping walls. What you extract at that point is a water vapor molecule that, by random motion chance, bounce out the test port.
By 'sweeping' with nitrogen, you initially, at higher absolute pressure of nitrogen, have a lot of nitrogen molecules heading for the exit door (test port). The few water vapor molecules get caught up in the nitrogen rush for the exit door and are 'swept' along to exit. This speeds up the process of getting water vapor out of system.
Reason for using nitrogen is you are not adding any additional water vapor, so each time you cycle with a nitrogen flush you sweep more of the water vapor molecules out of system.
It can take a long time to extract water vapor from PAG and POE oils. They like to absorb water in oil solution and give it up slowly at high vacuum level. Give it 30 minutes, or so, under vacuum to get a bunch of water molecules out of the oil so there is freed water vapor for the nitrogen flush to sweep out. Nitrogen will not help with getting the water molecules out of oil solution, only vacuum will do that.
I like to make it simple and not the book explanation
Describe it as your sweeping your broom, and your sweeping leaves out of your garage out the front of the garage door .
Gotta keep it simple .
Every now and then I’ll give the proper lab textbook explanation .
You’re definitely not going to get the moisture out of POE oil in 30 minutes .
When these vehicles come from a body shop that has opened up the refrigerant lines, and they leave the lines dangling in the air for anywhere from several days to several weeks, exposing the POE oil to the atmosphere
Other big problem they used refrigerant recovery, recycle recharge machines that they never change the dryer desiccant in the machine. It’s completely saturated with moisture, and their recovery cylinder is saturated with moisture and they pump it right back into every vehicle, if the vehicle came in and clean and dry it leaves highly moisture saturated after being serviced from dirty machines like this. .
I’ve shown many videos with the micron gauge after one hour two hours sometimes it takes 12 hours to 24 hours . On the vacuum pump before I could finally get the system dry enough to pass a vacuum decay test under 500 µm..
can u take the dryer thingie off the system and heat it up in an oven or smth to get the moisture out faster?
1: The plastic synthetic cloth that they use to hold the desiccant would melt before I could get hot enough to make a difference
2: my labor to do that would cost more than the entire condenser lol 😂
3: and all the Desikan BBs are coded in saturated with Refrigerant Toyota the fumes and the smoke that would be given off would make you choke and make the whole house smell really bad,
How would a shop move forward on a job that like this?The only thing I believe that could work is the replacement of drier, and a total flush of the system to include removal of the oil in the compressor. If I'm wrong please let me know what you would do. Thank you for the lessons
@@cdsfleetrepairs that would be correct by the book proper way step-by-step.
Unfortunately we live in the real world of peoples limited budgets and give them an option.
Bare minimum correct way.
Replace the receiver dryer and leave it on the vacuum pump for several hours.
Most people would have a heart attack at the price at least where we are in San Francisco California $185 an hour to $285 an hour depending whether it’s a private shop or a dealership.
In this case it just gets a refrigerant recharge
I'm having the same issue with my 2000 F350, there must be a leak, or if someone was in there before me didn't do something right. I recovered a little over 1lbs of refrigerant from the system but it should have 2lbs and some change in it, can't remember the oz off the top of my head. I'm only able to pull down to about 1000 microns on my gauges, cut off the vacuum and it spikes up and holds, vacuum down again, spikes up to a lower number. I know the gauges and hoses can pull down to around 280 microns, my cheap vacuum pump is rated for 150 microns, doubt the amazon listing is accurate 😝
Your hoses can easily pull down to 200 µm but when you turn it off just your hoses alone put slowly raise to 700 to 1000 µm by themselves.
Unless you have a brand-new steel recovery tank that has never been used as a test tank. You cannot trust anything unless you verify it first your gauge is your hoses any fitting adapters.
First you prove the tank by hooking up your micron gauge by itself to one port
Then you hook up your vacuum source to the other port
You leave your vacuum pump on overnight and then valve off the port hooked up to the vacuum hose this will leave your micron gauge open to the other port to the large 30 pound refrigerant tank
If the tank is good after a overnight vacuum it should come down close to the rating of the vacuum pump and hauled.
Now that you have a known good clean reference gauge which is your recovery tank you now hook up your hose gauge assembly to one port in and your micron gauge to the end of one of the hoses doesn’t matter if it’s the high side red hose or the low side blue hose and the yellow hose to one of the valves on your known good tank.
Then you draw with a separate hose on your vacuum pump to the other valve on the tank
Repeat the process overnight or 24 hours and then valve off the vacuum hose and let it sit and stand
This is the only way for you to differentiate and prove that is it is not your hoses or your gauges
but usually what I always see is the hoses engages going up to 700 to 1000 or more on most gauges and hoses.
Will breaking vaccum with nitrogen speed up the process to get it back down faster.
Yes
Definitely sweep with nitrogen between vacuum cycles to speed up the process.
Yes 👍 100%
Hey Tom,
Few days ago i recharge ac system in my car. All procedures based on your videos, deep vacuum, etc..
A/C system work generally very good, i checked every day temp. out of duct ( im driving all time, with thermometer :D)
What puzzles me. One day in similary ambient temp, and similary air vent settings in car, my temerature out of dash is
around 2-3-4*C, in other day in similary condition, cant go down below 6-7-8*C. I found that this difference in temperature
move binding with humidity%. So. Is there any way to calculate "how much" ( don't know exact word do describe)
power of cooling is absorbed is removing out of delivered air to evaporator between
scenario no.1 ambient 20*C and RH35%,
and scenario no.2 ambient 20*C and RH85% ?
I mean... how much heat transfer is "blocked" by moisture in air?
and what phenomenon is it related to? Thats why moisture in air have a latent heat, which need to be reject
as resublimation or freezing?
Yes, there is math formulas for this. This is what we learn in class when we go to school in HVAC design..
Moisture is your latent heat ( heat you cannot measure with a thermometer) but there’s much more energy in the conversion of a substance going from a gas to a liquid and then back from a liquid turning it into a vapor, a gas takes much more energy. BTU, Then sensible heat. ( heat you can read with a thermometer.). Changing the same substance changing one foot of air, for example or even better yet 1 pound of water to change 1°F takes one BTU of energy. For example, changing 1 pound of water into 1 pound of vapor or steam. Takes 970 BTUs..
So the energy the capacity the BTUs that would have been available to chain sensible heat that you feel that you can measure the capacity of your evaporator will be used up by higher humidity changing vapor into water . After the energy has been used, changing vapor into liquid water then whatever energy absorption capability is left over is what you will feel as sensible heat..
I think that’s my Lemans way of explaining it without using math formulas .
On UA-cam, some really good videos were produced by professional instructors on this topic they made several videos each of them explaining it a little bit differently every time and there’s always new pieces of information that make you understand it better from each instructor
Ty Brenneman @ LOV2hvac
Brian Orb @HVAC School
Greg @ HVAC School LLC
If you search their names, and then put in the phrase latent heat or sensible heat. With the search, it might bring up their videos on the topic..
Videos on superHeat from the same individuals also do some explanation .
Here at Laney College, Oakland, California, my son, and I attended we took all three major simultaneously over five years
Residential, heating, and air conditioning
Commercial refrigeration
Building automation
Everything about all the math formulas to do with designing a system, and figuring out exactly for every pound of the air that flows at what temperature and what humidity you can figure out exactly how many BTUs that is needed that will be used in latent heat and sensible heat . And it even changes when you go up in altitude from sea level to Denver Colorado where are your 1 mile high the weight of air is less. So you have to calculate in the actual weight of per cubic foot of air.. because for every cubic foot of air there’s less mass. So you have to move more of it to get the same amount of work done as if you were on sea level.
@@coldfinger459sub0 thanks for the quick reply. Just watched Bryan hvacschool's video...
interestingly, RH% will determine the humidity relative to dew point,
but the warmer the air, the lower the RH and the higher the water content in the air could be,
compared to a higher RH% at a lower temperature.
...Then what happens to the water content of the air when we have hot air in a closed heated car,
and suddenly it starts to cool the interior? Huge amount of water will trying to condense, but where, evaporator cant
condense infinte amount of water and drain it outside car. I wonder if there is any relationship between fast temperature drop
in hot car cabine,
and does what happens to moisture then have an impact that many people have, for example, a headache after starting the air conditioning?
Should we use recirculation or air from outside first, when starting car and AC on hot interior temperature?
@@apachechoice2538 because you only watched one video on that topic you only got a few pieces of information about that topic from one presenter.
The things that you were thinking about and you’re trying to come up with answers, you’ll get the rest of the information by watching the other videos on the exact same topic by different presenters they all give different little pieces of the puzzle.
Not all the information is available in one video it would be way too long .
There’s a reason the schooling on this topic is 2 1/2 years long . You’re not going to get it watch in just a couple videos..
If you watched every video produced by four people I recommend . I gave you a list of three people. I forgot to mention (HVAC service mentor.) I forgot his name.
There’s also a Jim Pytel he’s instructor in a university or college.
That makes five there’s many more but I’m going to give you.
If you went back two years and watch everyone of all of their videos.
All the topics covered all the math, the formulas, the physics, the science.
You would have completed what it is the equivalent of only the first semester in a high-quality certified accredited HVAC program.
That would be watching every video produced by these five people going back two years.
Guys, in the automotive industry, have not a single clue cannot even fathom in the tiniest imagination how somebody can literally spend 2 1/2 years on one topic.
The HVAC industry is a extremely large wide vast industry that covers many areas. Certain individuals can go their entire life just in one branch of the HVAC industry and still be completely clueless about geothermal completely clueless about hydronic’s, completely clueless about chillers or building automation and many other branches that are all branched off of the-based information of understanding the basic principles of moving heat and the simple math formulas of your first semester. The difference between automotive, HVAC and commercial and industrial HVAC..
I’ll give you a visual scenario I like giving this one
You’re inside the ghetto and there’s a little drug dealer on the street corner with his baggy pants hanging down he’s wearing a cheap gold necklace maybe as a gold tooth with a wild hair do and he selling five dollar nickel bags to homeless people and drug attic’s on the corner.
(this describes the automotive industry )
Then the contrast, if you remember the movie, Scarface. With Al Pacino.
When he goes to visit the big drug lord, down in Columbia, living in the mansion, the Villa, like he’s a king with more money than Fort Knox 😂
(this describes commercial and industrial Hvac)