How to Evacuate an AC system, Full Vacuum Procedure

Bryan goes deep into how to evacuate an AC system, covering the full vacuum procedure. He explains how to connect vacuum pumps, micron gauges, remove cores, and much more to show you start to finish how to pull a deep vacuum on any air conditioner or refrigeration equipment.
This video is a collaboration with Paul from The Engineering Mindset channel. Check out Paul's video on how a vacuum pump works here: • Vacuum Pumps Explained...
The goal of a deep vacuum is to get EVERYTHING out of the system, including non-condensable gases, oxygen, water vapor, and other contaminants in the air. There isn't really such a thing as a true "vacuum," which is the absence of molecules; however, the vacuum pump creates negative pressure, which forces molecules to move towards the area of lower pressure. We measure vacuum in tiny units called microns; one micron is equivalent to one-MILLIONTH of a meter of mercury column. Atmospheric pressure is equivalent to 762,000 microns, and the vacuum pump should pull below 500 microns.
Before we even hook up a vacuum pump, we need to make sure we have a clean, dry, and tight system that's free of solid and liquid contaminants. To do that, make sure your copper is sealed and that you are purging with nitrogen and flowing it while brazing. The system also needs to be leak-free before you connect the vacuum pump, and you can verify that a system is leak-free with a pressure test and a bubble test at joints. Eventually, the decay test will reveal microscopic leaks, which is normal.
For best results, use a modern two-stage vacuum pump, large-diameter vacuum hoses (greater than 1/4" and not a manifold or refrigerant hose), a core remover tool, and a high-quality vacuum gauge that reads in the micron scale. You also need to check the vacuum pump oil level and quality; change the oil if it's opaque or the level is low. Then, connect the micron gauge to the pump and pull below 50 microns to confirm that the pump is working. It's also a good idea to utilize the gas ballast when you're working on a potentially wet system. A system that's known to have water in it can benefit from the use of a heat gun to speed up the boiling process under low pressure.
To connect to the system, make sure there's no pressure on the system. Use the core removal tools to remove the cores from the system. From there, you can use a one-hose setup or two-hose setup to attach the pump. If you're pulling a vacuum on the evaporator and line set, a one-hose setup will suffice. However, a two-hose setup is ideal if you're pulling a vacuum on the entire system. After you remove the core from the side you're pulling the vacuum from, remove the end of the tool and connect the hose. Connect the hose back to the vacuum pump and attach your micron gauge to the system (as far away from the pump as possible); you can use a brass adapter with a core depressor to attach the micron gauge.
Then, you pull the system below 500 microns and isolate the system by shutting off the core remover tool. You will then do your decay test, where you make sure the system pressure doesn't rise. In general, pulling below 500 microns, isolating for 10 minutes, and making sure the pressure doesn't rise above 1000 microns will suffice; we pull below 300 microns and make sure the pressure doesn't exceed 500 microns in 10 minutes. However, the sensor in the micron gauge can be affected by refrigerant and can give strange numbers. (You can break the vacuum with nitrogen to stop that.)
There are some myths about pulling fast, deep vacuums. One myth is that you'll freeze water in the system, and the other is that you'll damage the oil by pulling too deep. POE oil actually requires a very deep vacuum, and you won't damage the oil unless you pull below 1 micron. You CAN freeze water in a vacuum, but there is usually enough heat in the HVAC system to prevent that from happening.
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschool.com/
The vacuum pump shown in this video is the NAVAC NRP8DI - www.trutechtools.com/NAVAC-NR...
Micron Gauge Shown is the BluVac Micro - www.trutechtools.com/Accutool...
Vacuum Hose Kit and Core Removers is the BluVac TruBlu Advanced - www.trutechtools.com/Tru-Blu-...
Core Depressor - S10767 - www.trutechtools.com/Accutool...
Watch More of our Videos:
Funny Videos from the Life of a Tech - • #BertLife
Pressure and Temperature Basics - • Refrigerant Compressio...
Make Flare Connections that don't leak - • How to Make Ductless F...
Air Conditioning Compressor Basics - • Air Conditioning Compr...

[@EngineeringMindset]

Great video, Bryan. So many good tips!

[@theprocessor8023]

TEM you see that's the way on speaking english.

[@TheMaster5150]

Same with yours Paul. You and Bryan are one of my 5 go to channels. Keep up the great work guys, it's appreciated more than you know👍👏

[@rajendramakwana]

Nice to see you both "The Engineering Mindset" and "HVAC school" together i follow you both, you both doing great job and its very informative helpful, to the point and accurate

[@jonathanboyd292]

They h TY up Stui r Hugh juju I

[@lilyyang6129]

Great work guys👍

[@RayMainBagpiper]

Holy Cow !! All I wanted to do was to replace the AC compressor on my Volvo. I've discovered a whole universe just based upon air conditioning. completely overwhelmed.

[@WillieMakeit]

Good shit ain't it

[@ezekiellackey3439]

Welcome to the world of hvac. We take our vacuums serious.

[@keithglynn9237]

Don't be overwhelmed, it's a lot easier than you think. Just take your time replacing the parts and have a local repair facility do the leak check, evacuation and charge. You'll save a lot of money and feel good about doing something for yourself.

[@thecargotsold]

@@keithglynn9237 i want to replace my HVAC. I am confident I can learn how to. Thanks for that tip

[@LynxStarAuto]

Mvac is nothing compared to hvac. Mvac is bottom of the barrel of this world.

[@shawnmeyers6412]

I'm going to be working in "startup" for hvac and this video; was so much more in depth than anything else I found online. This man took the time to explain every process of how to do it. At the same time explains why you do what you do. While everyone elses videos. they said some really wrong information that I lowkey at first thought was like okay its part of the job. This man with his videos basically called out these other "hvac tutorial lessons" and made them look like a work of fiction. I will be working my way down the entire playlist of 88 videos. Thank you so very much for your time, your explanations, and your brain power to help others succeed. Thank you sincerely. I'm a man who has earned everything himself no hand outs.. so this makes me feel respected as a newcomer trying to learn the trade, versus the other guys making me feel like i can ignore real problems and move on to get paid for doing a crap job. You are certainly a cut above.

[@jdewitt-pn9kr]

Page is called HVAC school for a reason

[@timwall1309]

Thanks for posting this video, we just did some training with our team this morning and used your video as part of the training. Our entire team was very impressed. One comment was that it is difficult to find a video that mimics the process we have as a team. Thanks again and keep up the great videos

[@justinnegrete6803]

Man you go in deep into hvac then my instructor ever did i have a epa universal and i still learning alot more with each of your videos

[@elgringoec]

Yes he's terrific! I'm not an HVAC tech, I just walked into that test and got my universal.

[@gptech2444]

This is one of the greatest technical videos I've seen, period.

[@rickytruong5994]

Wow, excellent video. Thank you for the intuitive video! I should have watched this video before my first system evacuation lab.

[@Alphamales4Trump]

If every inspiring HVAC student watches your VERY WELL DONE INSTRUCTED VIDEOS they would be LIGHT YEAR'S AHEAD of the CLASS. GREAT JOB.👍🏻

[@markthompson4099]

Like WOW Bryan you are one of the most intelligent tradesman tech that I have ever seen. Nice balance you do not waste a word and speak with data and useful information. Great video.

[@JohannnesBrahms]

It is so appealing to hear you explain things. Someone as brilliant as yourself (in any field, not only HVAC) who cares about sharing your hard-earned knowledge and wisdom is truly inspiring. I am someone who does not work in HVAC and still I love to watch and listen to your videos. You are a great teacher.

[@jollyscaria1922]

Thankyou gues shering good

[@user-hx5vh9uh2n]

Same here I’m an electrician but am enjoying this

[@rudysilva8291]

I agree 100 percent if it wasn't for you.having great mentor s makes all the difference in the world. Thank you so much for sharing your knowledge

[@mike-yp1uk]

The little connections and how to adapt to every set up was awesome. No to mention the depth of detailed technical info.

[@danielkeene-lopez3527]

This is great. 5 years in the industry and I love learning ways to make my job easier and systems last longer

[@jb0579]

Dude - perhaps the easiest to understand tutorial on the web. Good on you sir - awesome post!

[@ericneal8582]

THIS is how you know someone knows their stuff. They explain complex things in a simple way. Thank you!

[@jollyscaria1922]

Aircondeshion systom 2methad self evcacuom methad evertiveing typed vacuom -0to-30 ppint methad vacomed colde chergeing methad very good shering methad vacuom pump using micro mercury cul methas psi using ..

[@davidgordon295]

Excellent video Bryan . As the head on engineering at Javac I meet lots of seasoned technicians that don't know half this stuff . keep up the good work.

[@rodgraff1782]

Bryan, Great video explanation on how to properly set up equipment for evacuation. I once had to evacuate a low temperature drier used in a leather tannery. We had to install a new coil, which the factory had pressure tested with water. Multiple evacuations and multiple oil changes over several days just to get the coil dry. It also helps, when dealing with a wet system, to do partial evacuations, breaking the vacuums with DRY nitrogen which, will soak up some of the moisture. Also slow DRY nitrogen purge, before evacuation is started will help speed things up. Not all nitrogen is DRY. I once used up a small nitrogen cylinder, and opened the valve an inverted it when it was empty, and water ran out!

[@jericosha2842]

I keep rewatching your vids to beat this stuff into my head. Thanks so much for sharing this clear and detailed information for free.

[@HVACS]

Glad it was helpful!

[@howardleopold9887]

Excellent teacher, and fully detailed. Couldn’t be better!

[@grashoprsmith]

Awesome video. This is the type of content this industry has needed

[@emmaa427]

Your vacuum pump is a "beast"...I can't belive how fast it's pulling vacuum!!!!

[@dane1234abc1]

I am a retired electrical engineer. I designed radio & TV antenna systems, microwave links, and did human exposure to radio frequency energy safety studies. I like learning about other systems, plus it helps understanding my house's central AC system. Excellent tutorials, thanks for explaining terms and why it matters.

[@95827tube]

😊

[@Intense_Cloud]

Sounds interesting. Where can i learn more about effects (if any) of exposure to radio freq energy? Thanks

[@YouTubeCommunists]

Can you tell us how we block millitary/ harrp frequency emf? They are frying us ALL to death...Please help!

[@fyx812]

Well Presented Video, great narration and equipment explanation. Process procedures revealed without a condescending attitude, also common errors exposed, with helpful remedies. 10 out of 10....Great JobGuys

[@WillieMakeit]

U need to be commended for your collaboration efforts you are making with other channels on KZbin. Thank you very much

[@Ruby8881]

this channel is a blessing, thank you, bro!

[@condor5635]

Bryan you are the man. Your delivery and knowledge on this subject of HVAC is second to none. I am a big DIY guy who has done most DIY stuff except AC refrigerant type work. Probably never will but at least I know what it’s all about. I understand everything you say and it is clear you have great knowledge and passion for this subject. Great delivery. Thanks

[@grim789]

These videos are such a blessing my online HVAC course goes through a book that doesnt explain these concepts well at all. Thank you for taking the time to break down these topics its tremendously helpful.

[@tle2507]

Thank You! I'm an Electronics Technician and have been working in the field since 1997. I was falling in love with HVAC because of your passions plus knowledge and how you were explaining step by step. You have reiterated how importing larger size hoses and how to connect micron gauges away from the pump and checking no leakage before the services step done. Thanks.

[@erikholmes8069]

I greatly enjoy your videos. It’s nice to see a a young man making the industry better one Conversation at a time.

[@HVACS]

Glad you enjoy it!

[@moralatu]

Great video Bud thanks for all that time you spend on doing this videos

[@dandaman2226]

Nice Brian.... same micron guage and procedure I use! Although after evacuation I always pre charge the line set and evap coil with a little reefer before opening the service valves.

[@XRPBull4Life]

Great Tips and explanations for beginners and refreshers for the old timers too. Carrier doesnt advocate running your refrigerant lines underground though. i use CRTs on both sides of the unit and attach the 1/4" hoses to the side ports on the Appion CRTs that i have removed the cores from and pull from both sides into a 3/8" and the yellow 1/4" hoses attached to the Vacuum Pump, with the Micron Gauge attached to the Vapor side of the unit on the end port of the CRTs. In doing this i can isolate the system with the valves on my hoses and do the standing test and then once i know the system is good i can reopen my valves continue to pull a further vacuum. Close the valve on the CRT that is attached to the Vapor side and remove the Micron Gauge and then immediately replace it with the core that i had removed from the condenser and either critical charge the system before i release the refrigerant in the condenser. Basicly i can replace the cores and do what is needed without having to mess with anything other than taking a micron gauge off and switching it with the core all the while pulling an even deeper vacuum. My systems are always pulled down to 89 Microns and end a (seven minute standing test - Carrier Specs) between 180-230 Microns. Great Video though loved the detail and how much you know about this trade. Just wanted to lend my opinion on the hose setup and how its a little more convenient and will still end with the same result.

[@vernroach3413]

Most excellent explanation and instruction....I'm semi retired, in my 70's, still working the trade, not as often as I used to, but still humping and I'm still learning...This video, helped me get better...My thanks to the gent that make it.

[@gracida6]

still humping? what does that even mean, pretty lame way to talk

[@vernroach3413]

@@gracida6 Humping is an old expression of laboring for a trade...Not knowing what it means says a lot about you bud...Not very worldly in short.

[@sirius6beta]

Straight to the point - well explained. Appreciated!

[@bayouflats5054]

I really appreciate your tutorials. I stumbled on a nifty procedure to help eliminate moisture in a system I’d like to share since your speaking on the subject of nitrogen and moisture; I had a situation where line set had been cut at condenser for a change out and left open- uncovered overnight and it rained hard that night. I had installed a site glass with moisture indicator ring and reached a vacuum of 500 microns, but my moisture indicator was still very pink( high moisture content). I tried multiple evacuations as per described in this video and frantically searched forums. It was the end of the day now, as I’d removed and replaced the 3rd floor apartments inside and outside units by myself. In desperation, I charged the unit with 200 psi of nitrogen and let it sit overnight ( I didn’t run across this exercise anywhere I looked). The following morning, I pulled a vacuum again and in very short time my moisture indicator went to green ( dry ). Pulled to little over 300 microns and all’s well. Cheers!

[@damron2]

thank you i have been in commercial hvac for 25 years and have always evacuated the same way. through my manifolds. i have been working on trane wshps recently and it takes a 1 ton 6 hours to get to 800 microns and that is with triple vacuuming it. now with your way i can do it in 10 mins and get 250 microns

[@mhoush]

I freaking love this video... Great job 👍!

[@ChrisHVAC]

Good info there! When it's time to replace my 1/2" Appion vacuum hose I'll try the blue ones.

[@special_k-hvac]

I forgot how much but when I bought my appion half inch hose the difference was significant. Regardless it will take years for a hose to take a dump if taken care of

[@HVACRTECH-83]

The appion ones are much better. That's what I use. They will last forever if you take care of them. Just replace gaskets periodically and lube them w vac pump oil before you hook them up

[@vick07esco]

I’m currently going to school, your videos and a couple of other channels are really helping me out understand the information apart from the lectures and in class labs 👍💯

[@kerrydavis2919]

That's a great demonstration of the difference in vacuum at the pump and in the system! Excellent video!

[@josepeixoto3384]

That is in a dynamic situation; if you stop the pump,(that becoming a static situation then),both readings will be the same; also, an experienced technician will do that while vacuuming ,and interpret the rapidity of the equalization of both pressures to look for obstructions in the system; but *rush* jobs do not allow for that....

[@leonardpearlman4017]

Hey, this is great! This is long for a KZbin video, but short and very snappy for a LECTURE. I feel like I'm back in school, in a good way. I'm here for general technical interest, have worked with vacuum systems in general, and also Neon. Slowly becoming aware that what we're doing when making a Neon tube has some overlap with what people are doing with the HVAC vacuum pumps there.... I've been looking at that gear my whole life and never really understood what people were trying to do with those gauges. Now halfway through one video it seems surprisingly clear! I'm sure this is a simplified presentation and don't want to mess it up, (but) at 18:30 or so, talking about slight rises in pressure, there are little leaks of course, but then there are "virtual leaks" which are not in software, no! They are what we deal with all day in Neon, or in other high-vacuum work. It's well known that when you exhaust something with a mechanical pump your troubles have just begun! So, a quick evacuation can remove the bulk water, but there's still LOTS of water sort of stuck to the surfaces inside the system, and it takes some force to get it out. Either LOTS of heat (you hint at this with the heat gun), or electric discharge (as in Neon processing) or TIME. So you could evacuate a system for a long time with a high vacuum pump, and it WILL "harden" in time. This information is a few generations old now, but not widely advertised. Anyway, the time for a system to degas itself under high vacuum might be DAYS if there's no heat involved. SO, trying to put all that into like one sentence: It might be that if you do everything right, clean and tight, fresh oil in the pump and everything... there will be some rise in the vacuum and NOTHING is leaking. Hey, don't you guys have "dryers" in the system to take care of these last few molecules? Anyway, I thought that might be good news, and also it's just something that's a big issue in my own life right now. Thanks for this dynamic and clear explanation! I'm going to finish the video now.

[@harrystrohm7614]

Bryan thank you for this video & intro to Engineering mind.

[@elgringoec]

Bryan is such an excellent teacher!!! Blessings!

[@RJMaker]

Wow, One of the best evacuation procedure videos I've seen in a long time. The ONLY thing I would add (sorry if I missed it) is to clear the air behind the "ball" on the ball values by actuating them (close and open) a few time when

[@rickbraden4272]

That's was i was told once by Ritchie Engineering tech support.

[@416RG]

God bless you and your channel honestly, and everyone else whos involved. Thank you.

[@TheNYgolfer]

Concise with no stuttering or searching for words. A sign that he understands the subject very well. Every question I have ever had on this subject was answered. Brilliant job!

[@robinkelly1770]

People don't deliberately stutter just to annoy you. Some of the worlds best educators have a speech impediment...

[@Dancing_Alone_wRentals]

Amazing video. Easy to follow and fun knowing what is going on with each step. That said, I doubt I could do this.

[@conradhomestead4518]

Excellent presentation. Clear and concise. Thanks for sharing!

[@earljacobs6238]

Whew! need to see that again. Thanks

[@nitojr4846]

This helps out so much. I just started to learn about this and you explain it so well. Very understanding

[@andersonferreirasaraiva1889]

Sou Brasileiro, e essa é a melhor aula que eu já assisti sobre vácuo, muito completa, des do início teórico até a prática final. Parabéns, muito boa a aula.

[@eikkaheikkinen]

Thank you! This made so much sense.

[@AdventurewithSonny]

Another great video ! Thanks Bryan

[@Oscarbm1234]

You guys are on a roll.

[@ericksonalagadan]

I have finally found a great teacher. GGWP. Commended

[@jeremydefreitas9753]

Really informative detailed videos, thanks , as with all your videos.

[@workinprogress008]

Great video, Brian. I little tip. Those oil quarts are meant to be held and poured from the other side. So it doesn't "glug glug glug" when it comes out.

[@HVACS]

Yes, I always forget that

[@renemartin2788]

Best video ever. This guy is from another planet. Kudos

[@amgonzalez429]

Best video i have found on pulling a deep vacuum.

[@Caderic]

This is collegiate level information...presented in a professional, clear way!

[@ericgass9790]

It's actually elementary level information. Day one shit!

[@Caderic]

@@ericgass9790 Elementary..."I do not think that word means what you think that word means."

[@ericgass9790]

It means exactly what I think it means.

[@LDriggs]

just watched this video again. Such a great step by step video. Thank you

[@MrYournamehere4202]

Jim Bergmann was my teacher at the career center...Pretty cool to stumble on to this video and hear his name

[@alimamybangura3620]

Thank you for the video, it is very helpful .

[@logicalrat]

Lots of good information, will pass it along

[@benplatt3325]

It's nice to here someone with knowledge and Intelligence !!

[@Automotive_Solutions]

That was very well explained. Thank you 👍

[@norsephoenix9940]

I have been doing HVAC for 15 years and this video blew my mind! Very insightful, thank you for the knowledge sir! Can you please tell me where I can get the hose and clamps for that set up? I have never seen this at a supply house and it is very effective!

[@vdarr1]

WOW! Perfect explanation!!! I will be installing my Airhandler and Condenser in my Mobile Home! Just in time:)

[@toujayecarter9745]

I am about to show my hvac students this video. We our going over Refrigerant System evacuation, refrigerant system charging, and trouble shooting air conditioning system. I hope this video will be beneficial for them.

[@irinkukaushal8590]

Detail explanation on vaccum good this is very helpful for hvac service

[@Hambxne]

thanks for the badass video bryan

[@Thebytedoc69]

As always, great job. Thank You 🙏

[@herbertw.lewis1115]

Thank you so much Learned a lot.

[@rkdehkiani]

Excellent presentation, Thanks

[@mohamedmahfouz1813]

Great video, Thank you so much

[@andrewsomers9042]

Wow! By far the best video on this subject, thank you!!

[@amersingh2557]

Brilliant video and very detailed information.

[@ghostbear35]

Awesome videos. I heard you say in one of them that you were in Florida, so I went and looked up Kalos Services and got excited when I saw you had a 352 area code. Unfortunately , you don't service my area (Citrus County). Bummer. But again, awesome videos! I certainly appreciate all the information.

[@plumber919]

Great video! Very thorough.

[@MinnesotaHvAc]

Well I presented this system to the managers yesterday. This will be upfitting 20 to 30 techs.

[@DKhoe539]

Wow wow wow the amount of good information. Great job 👍🏻

[@TitaniumZX]

Great info all around. Thank you for sharing!

[@fermin0614]

Wow what a great explanation thanks is always good to have a refresh and check for tips really good explanation

[@YANGNIMOG]

This is the greatest tutorial of HVACR video. Thanks.

[@wb3213]

Great vids ! Thanks for the info

[@kennethgarcia3350]

very well informed.. thank you

[@janicesmyth2183]

thank you for sharing! You're very knowledgable. I could never make use of this information but my grand children will as they are in the trades.

[@arzaq915]

Completely clear, thank you

[@heatpump8566]

This is a master class, thanks

[@sanigarba3846]

I definitely want work with you, I wish I will work with you because your knowledge is really awesome

[@mikebarnes3464]

Thanks for the video!

[@StevO3]

Thank you for explanation. Really thorough.

[@redukas123456]

Thank you, perfect video to learn.

[@roddeperalta4605]

I got my epa 608 lic from LATTc and it’s been a while. Very interesting video and I want to learn more deeper To be A GOOD HVAC TECH

[@Lwjdejong]

Thank you very very much man!! I needed al this information

[@CarlosHernandez-gy2kl]

Very good video, learned a lot from it.

[@TheChefjustice]

Nice Video...clear voice and the the tutorial is easy to.understand. Thanks very much😀😀😀

[@ibrahimsiradvancedresearch]

Awesome. Life-saving video.

[@garyray9277]

Very nice video and well explained , I would like to see - how and when one should vacuum one side of the unit.- High and low side of the unit.... thanks if you can and thanks even if you don't want to... thanks again. you do good work!!!

[@gtplumbing2004]

You,, my friend, are a badass, great info, perfect teaching video.

[@HVACS]

Glad to help

[@jtr82369]

Thank you so much for this info