Subcooling = Stacking Liquid Refrigerant (What Subcool really Signifies)

[@pmgodfrey]

Before even starting this video, I'd like to say this. I subscribe to MANY different channels on KZbin. Some in mechanical engineering, some in electrical engineering. A few other HVAC ones and others that have nothing to do with anything. This is, hands down, the channel where I learned the most and I'm not even in the HVAC industry professionally. I do own a bunch of units because I'm a landlord, but this helps me understand the process of what I'm paying for and helps me sometimes troubleshoot a unit. For this I am grateful. My hat is off to you guys both in the classroom and out in the field. Your work is very much appreciated.

[@HVACS]

Very kind of you to say. Thanks!

[@Flowtester1]

What are some good mechanical and electrical engineering channels to subscribe to.

[@pmgodfrey]

@@Flowtester1 -- This one, EEVblog, AvE, RODALCO2007, StuffMadeHere, HVACR You'll get a mix with those and KZbin will recommend others based on that criteria.

[@Flowtester1]

Ok thank you

[@N3X15]

@@pmgodfrey HVACR provides a good, practical window into any professional troubleshooting process, as well.

[@deanlhouston]

Way back in the day before I went to college and got an engineering degree, my old high school HVAC instructor explained subcooling (and superheating) in a way that a big dummy like myself could understand it. He first explained what sensible and latent heat were: Sensible heat being heat added/removed to change refrigerant temperature and latent heat being heat added/removed to change refrigerant state - and how until a state change is completed the temperature doesn't change. Once we understood that concept, subcooling is simply the sensible heat removed after the state change completed (condensed) and superheating is simply sensible heat added after state change completed (evaporated). You may have covered that prior to the video, but I found linking those two concepts really helped understand subcooling (and superheating).

[@roseelectronics4582]

But that doesn't explain the beautiful concept behind subcooling and superheating

[@raidone7413]

Thanks

[@bradjohnson2649]

Thank you for simplifying this concept. Sometimes we overcomplicate the process. 😀

[@bradjohnson2649]

Thank you for simplifying this concept. Sometimes we overcomplicate the process.

[@deanlhouston]

@@roseelectronics4582 But that IS the concept of subcooling/superheating. Now I think the concept you're getting at is "why its measured?" I just found it helpful when my instructor separated what superheating/subcooling IS from why its measured in AC/Refrig. Building blocks to understanding the bigger picture.

[@milanlipovic7349]

I’m glad you actually care about technicians I’m just starting in the industry and I think all companies should still teach their techs like you do thank you 🙏

[@lerch400block]

They really should hire an instructor vs a sales coach for a change. This is coming from a 19 year tech and rookie instructor.

[@SovereignTroll]

Finally a perfect statement. Stacking refrigerant. In engineering we would be "storing" the excess refrigerant.

[@armandorodriguez6447]

Star of DAVID 👍🏽

[@Stuart68505]

Low amount of subcooling can result from a lack of cooling by the condensing unit for many different reasons. (poor air flow, bad fan bearings, dirty condenser, unit surrounded by walls that are too close or vegetation, undersized condenser, low line voltage due to utility stress, damaged fan blades not moving enough air & other factors). So having insufficient sub cooling does not necessarily mean that more refrigerant needs to be added to the system. As I got near the end of this video, I realized that you did mention inspecting the equipment for cleanliness before analyzing sub-cooling. this video was very helpful with it’s in-depth discussion of sub-cooling. Thank you for helping me to get clearer on this topic.

[@larryproffitt4729]

Been in the field for many years and the way you explained subcool was simple, easy to understand and spot on. A excellent video. Wish I had you as a teacher back then.

[@P9rkour90]

I’m so glad I’m going to this hands on HVAC school. In my opinion, for me, I learn best hands on rather than reading through a book. Granted, the Schematics on the ac units help with wiring, nothings better than hands on learning. With that said, great video and you seem to be a great instructor!

[@ronnies779]

Your "approach" and logical explanations are by far the best I have ever come across. There is no reason your technicians should not all be experts in there field and because I don't hear many questions in your presentations, I would assume they all are. You leave little room for discovery by removing the mystery. This is what makes your presentations so valuable and is a rarity. I will definitely continue to watch your videos. Thank you! " Advancements are made by answering questions. Discoveries are made by questioning answers."

[@manuelyberegaytan2068]

I've been working in refrigeration for about 7 yrs. This video is awesome because I never went to tech school. I work Low-Temp and Racks... Also any Hot-side equipment that comes my way... Keep up the good work guys

[@hvacservicementor]

This is super cool (see what I did there?) I have always thought of sub cooled liquid filling the condenser tube rows and stacking on top of one another. Never heard anyone else describe it like this. Bravo!

[@peterstencell804]

You are still fight . As lone as you under stand who cares .

[@bawlout9367]

this video was a god send along with the superheat video you guys put out. WHAT REALLY HELPED was the 3d models of the entire system running

[@willllo]

Obviously this could just be 1 school but if this is how well this is taught in the US its insane to me. My qualification in the UK was just that, a peice of paper. I learned absolutley everything on the tools from very good technicians as an apprentice. School was Brazing, Elthrapy diagram, leak test, Charging to the specified charge weight through a rig. That's it. Wild how so simply you cover the depth of this so it's understandable to guys starting out. Took me a couple years on the tools with guys in practice to learn a lot of what you explain in your videos which should have been taught in school. I'm lucky too because most don't have decent techs teaching them at work.

[@gregscheyd4131]

VERY VERY COOL EXPLANATION , BRYAN !!!!! THANKS IMMENSELY !!!!! IM NOT AN HVAC TECH OR APPRENTICE , NOR WILL I EVER BE . I M 65 , I LIKE TO DRINK COFFE AND BEER , AND LEARN,ABOUT EVERYTHING TRADE AND TECHNICAL THAT MAY GO WRONG WITH MY WIFE'S AND MY HOUSE ..... the way I figure , you should not own ANYTHING you do not understand and BASICALLY KNOW HOW TO FIX !!!!!! ....to that end , you helped me alot : thanks again ......

[@miltonbradley4249]

All your teachings are are great we'll done and to the point. As an engineer I love your style it flows with thousands of hours of experience and wisdom in your teachings

[@asweetdealfleamarketstore8889]

Heres a respectable thought, this teacher has been awake loner than the whole class, and is probably the most tired, nevertheless he came punctual, provided a wealth of information. Kept the class awake, sought a challenging question. Taught himself in the process, extinguished questions and alleviated concerns, provided reassurance and implanted confidence. Thumbs up to you for going back home tired..

[@jameswasher3938]

All of these sessions are SO VERY GOOD!

[@nickthadon9894]

1 thing you should of added is checking delta T to make sure getting target temps thank for making these vids

[@jeffreyrex8232]

Just sent this to the apprentice. Told him to subscribe to this channel for much learning 👍🏻 Clear and concise. Doff my cap to you sir.

[@AJISFREAKENAWESOME]

Man I would love to be in this classroom. I’m in the automotive industry. Managing now, but I’m so interested in every other industry and this classroom just seems like a pool of knowledge. Maybe one day.

[@newkidontheblockism]

Come to Florida and I’ll hire you

[@mikelain13]

Wish my previous employer took the time to train me like this. Thank you for the lesson.

[@bikerbobcat]

Same. The techs and I ask for it all the time (especially for installers to save us embarrassing install warranty callbacks) and it just doesn't happen. The "cost" of education clearly rolls downhill, too.

[@f1reguy587]

I’m finding the employers education bad here too, it’s like it’s protected information...that or he doesn’t wanna be superseded... however the refrigeration side is less complicated over the huge amount of electronic knowledge needed...

[@maxclark11]

An amazingly simple concept made amazingly complex in this video.

[@jw77019]

There are people who think refrigerant needs to be added every year as though it gets consumed. I think this is because especially in cars for a long time there were lots of leaks. My parent’s Carrier system installed in 1979 never had anything done except the filter changed. We sold after they passed away and I often wonder if it’s still going. It was installed by the best company in town with all the ducts running through the basement. Of course all the ductwork was replaced with new, but they left the original diffusers that were put in for the gas furnace when the house was built in 1955. It’s seems logical that air conditioning would need to be discharged from high on the wall or ceiling, but those long diffusers that usually ran the length of the windows at the baseboard level worked perfectly

[@NestorHVAC]

Man I would love to be in that classroom!!! Keep the videos coming!!!

[@jeffreyrex8232]

Ahhh RTFM! Always my first port of call when speaking with other tech’s 😉

[@gregscheyd4131]

WHAT IS RTFM ?????

[@mropie428]

Thank you for the videos and all the knowledge that you have given all of us

[@6057noel]

I like this channel. Very educative. Explained in detail.

[@sterlingarcher46]

Bryan this new series of videos are fantastic mate , keep up the good work 👍

[@MECENGINEERS]

very good explanation of the topic.. kindly make a video explaining the copper piping when the indoor and out door units are at different elevations. Thanks

[@mdelgado6080]

Awesome video great refresher

[@texture6]

The compressor compresses vapor gas refrigerant and an overcharged system (condenser) results in high head pressure and reduces the amount of work the system can perform. Because of compression, a saturation compression instead of a vapor gas compression.

[@acrepairnearme]

Great video lesson.

[@zyxnix]

Good stuff. Gotta recheck my system. Hope I did'nt over charge it. 🙂

[@magoh08]

Lmao

[@Garth2011]

This is also a good reason for manufacturers to make high quality data plates that will not fade or oxidize etc. over a 20+ year period of time. We have seen many of them that have faded or were losing all of their "font" paint or the like and the data is not legible without having it "x rayed" with methods to restore what was printed or etched on those data plates.

[@ltherealist3729]

I had a condo in the wall box unit with all the temps and pressure looking good but the sub cooling stayed around 1 with a TXV inside a aqua therm air handler and only had about 12 degrees Detla T. I couldn't figure out why.🤷🏾‍♂️

[@kevinmithnick9993]

Thumbs up from Colombia

[@ronie1337]

Bryan, Thanks for the info.

[@D2DNYAC]

Good video thank you I like the + 4 degrees to outdoor ambient rule of thumb for liquid line temperatures, I will be experimenting with that 🤔.. so In summary what youa are saying is to gain more sub you need to finish condensing earlier and to loose sub finsh later?

[@brianthomas736]

What app? Info please I’ve been in the field for 32 years, while some of this content is elementary, i still learn something every time, or at least I’m reminded of stuff i forgot. Great stuff

[@davejohnsonnola7908]

HVAC School app. Tech tips. Podcasts. Videos. Calculators and more.

[@craigspicer4296]

Oh the the days at Tafe Tech collage lol. Love the delivery lol.

[@hubercats]

Another excellent video. Thank you!

[@thetruthserum2816]

If you had an IR thermal camera, would you be able to see the liquid stacking in the condenser coils?

[@jbaker8871]

Really great class. Im interested on your approach vrs ambient rule of thumb. Could you go more in depth. Also mid and low temp would be great to hear. My weakness and what i hear is not consistent.

[@nunyabusiness6746]

Did I hear him say digital manifold ? This guy seems like he knows his stuff but as an old timer I personally have to comment on some of the advantages of good old fashioned analog equipment, like the PT is right there on your gauges, no need to have to study an instruction manual to learn how to use the thing, and more importantly, watching that needle is good a real time indication of system operation, for example a pulsating needle can indicate a sticking valve in your compressor which no digital meter can show, same goes for your clamp amp, and most importantly I have still have money for a12 pack, the only digital I like is my Fluke 12 voltmeter which has an excellent Cap. checking function, i’m just hoping the thing lives longer than me because it’s no longer replaceable.

[@grashoprsmith]

How does low outdoor ambient conditions affect subcooling? I'm imagining a situation where the load at the evap stays consistent (like a server room), but the outdoor ambient is low that day and a PSC motor is, more or less, moving the same amount of air over the condenser.

[@hvacservicementor]

Subcooling remains remarkably consistent throughout the fairly wide range of outdoor ambient the unit is rated to operate within. Server room units will have liquid receivers and head pressure controls which behave a little differently than a standard residential AC.

[@peterstencell804]

That guy summed it up very well.

[@joebalenzano6623]

Question: If system is overcharged what effect does it have on the llt? If a system is undercharged, what effect does that have on the llt?

[@nyimachoenyi4997]

Great video !! Thanks for sharing.

[@tmst2199]

I would have loved to be in Orr's class when he asked "How do you measure subcooling?" Uh, with a thermometer?

[@teeteewasherwhirlpool9156]

Hi Bryan,so I work in a place that has some of the condenser unit sits in a confine concrete wall area,and usually has 3 to 6 condenser and roughly 6" to 10" apart from each ither and majority of them has only a inch from concrete wall.so when it gets 106° outside temperature, the temperature around these condenser units climb up to 118°. So my question is,because of ambient temperature so high,will a subcooling on my condenser change? And if it is,what can I do or what is the best way to solve the high readings on my high side pressure? I appreciate the videos and an answer..have a bless day..

[@burnardhayes8995]

How can I join the class and would I get a certificate when done

[@JP-zz5rm]

It’s a program , you would have to complete the entire program to actually receive the HVAC certificate and you would have to study and take the EPA test ( 100 questions total ). My program was 10 months long , M-F 5pm-10pm.

[@Ivan-qq6dj]

Question, why AC BLOWER IS SPIN8NG THE OPPOSITE WAY. changing cap, won't spin the proper way,can reversing shaft will correct it,or reversing wires. Need a opinion,please kindly. Thank you for your help, have a blessed day

[@larkhill2119]

Have you checked the fan is on the correct way? single phase motor or multi phase. Also if the motor was ever disassembled was the coil replaced the same way as before?

[@paulmorrow8372]

The cap has two wires on it. If these are reversed the fan will run backwards

[@larkhill2119]

@@paulmorrow8372 Not sure why you think that will work? start and run capacitors do not care which way round they are connected. However worth adding check the circuit because if its wrong the capacitor can hold full charge and it bites take care.

[@tomoliver8498]

I ran across motor spinning the wrong way on 2 different heatcraft motors new out of the box. I replaced them however I believe the wires in the motor were reversed specifically the wire that goes to the capacitor and the line wire that the capacitor gets power from because reversing those two wires changes direction of rotation.

[@thunnasalbako6095]

Very informative. And I would like to ask could you please show me how to measure the sub cooling and super heating in practically? And please let me know if it's possible to apply on the freezer which is set for minus 18degree Celsius and how I could apply or doing that? Hope I can get positive answer Thank you very much for you kinds information Once again

[@shahzadyousaf110]

Hi, Is there a way to find the Saturation pressure inside the evaporator with the air side information? like the indoor temperature and the CFM information?

[@wmdayman]

Fantastic explanation

[@michaelcostello6991]

Interesting discussion. Thank you.

[@DrHarryT]

One thing I have noticed is that it is common to run the liquid line through the attic with no insulation.

[@ryanduhaime9086]

Hi Brian. On a new install (ac). My sub cooling was low (4) and had 0 superheat with a adjustable txt. Should I have added refrigerant to correct my sub cooling first, and then adjust the txt to correct superheat. I wasn’t sure to I ended up doing both a little at a time but curious what you would have done. Thanks best videos out there

[@Garth2011]

This may be a reason why newer condensers are so large/big as to stack refrigerant with lots of condensing room plus slower fan speeds will do the same work as the faster speeds had.

[@joseramonherreramendoza9260]

Thank you so much for such a great info... keep it up...

[@RP-mt6bp]

How do you use the Clausius-Clapeyron equation to calculate the saturation pressure?

[@kasranoor613]

can receiver affect on subcooling temp, do we set subcool differently with a system that has a receiver, how do we adust subcool in water-cooled condenser? would approach temp to be different with water-cooled condenser compared to air-cooled one?

[@bardia8225]

Please help me understand how subcooling is done? I know the purpose of subcooling and i have a decent understanding of thermodynamics but no one ever mentions how the subcooling is done practically. Is it basically by manipulating the pressure slightly to ensure that the refrigerent is sufficiently "cooled"? So that the pressure increases slightly after the liquid passes the condenser to ensure that the refrigerent is below the saturation level? or is it simply by dimensioning the system in a way that the saturation temperature of the refrigerent is lower than the ambient temperature?? I know how subcooling and superheating is done in a turbine because there we can actually mnipulate the high temperature and low temperature sink, but in refrigeration cycle, we can only play with the pressure so no one really explains how subcooling and superheating is actually done?

[@seek3n]

I hvnt seen a factory installed head pressure service valve. And when I add undercharged refrigerant the liquid line pressure will always go up along with approach temperature from negative to positive. I always go with subcool superheat and ctoa. Please help!

[@edyburkay]

14:00 """Subcooling is a differential number between Tci-Tco "" . Subcooling is not the differential between condenser inlet and outlet, it is the differential of Tsat-Toutlet. Am I getting something wrong here or did theacher just explain it wrong? Thanx in advance.

[@jaymanuel4126]

Good day sir, im jay from the Philippines, is there a minimum and maximum range for superheat and subcool? I will use for troubleshooting.. thank you sir..

[@gregs9555]

Good presentation, thanks!

[@Suicaedere666]

Thank you B-Orr⚡️

[@kingjiren3681]

Sir does this apply to like r290 equipment

[@alklapaxida850]

gona check that with a flir on the condensor coil ..

[@markspazianijr1143]

What should subcooling be for a Pentair Ultratemp 120 pool heat pump?

[@ATeamAdam]

Great lesson

[@efrainfajardo8360]

Good information,thank you.

[@hhn2002]

enjoyable to watch. thanks.

[@habibhoward7159]

Lmao everyone is still sleep....hi from lehigh valley Pennsylvania! Just started my own company after 8 years working for someone ......man the freedom is so good

[@Respect.The.Grind..]

I’m from the valley , been doing hvac in Washington state the past two years. I’ll come install for ya when I move back

[@thermocoolofficials6499]

Hi Sir.Please advice.Why my sytem with 410a refigerant in it. The discharge pressure is 410 psi but the suction pressire is 70 psi only that if normal should be around 100 psi.

[@davidb2438]

Sounds like liquid line restriction

[@scott5654]

Excellent ‼️

[@timbunner8855]

Saturation is when all the liquid in the evaporator has change state from a liquid to a vapor. Condensing is when all the gas has condensed to a liquid in the condenser coil. There is no saturation process taking place in the condenser coil is condensing.

[@milanlipovic7349]

When are you going to add line set to the app?

[@asweetdealfleamarketstore8889]

Ok 1:54-1:55, look at his eyes drop in the empty answers. 😅 good morning 😂

[@magoh08]

😅

[@jamesmooney5348]

Thanks

[@kingjiren3681]

They ask for like 4ozs in some system's that I would use a lot more that that if I would use 134 or 404

[@AdrianButler86]

Excellent. Thanks

[@rafaeljaquez9214]

I think if you were my instructor when I went to school I would have had a better understanding

[@davejohnsonnola7908]

If my instructor had been half as good, I might have gone into the field 25 years earlier. Now playing catch up.

[@jorgecolon6705]

If subcool is the way to go then why does a piston rely on superheat charge method & txv rely on subcool?

[@Jaker788]

For one, superheat method doesn't work with a TXV because it's adapting it's orifice to keep superheat in a range. Not sure why subcool isn't used for pistons, maybe you need to get superheat in the correct range for safety of the compressor, since it can't adapt the pressure drop into the evaporator like TXV can, it's fixed. It's more variable of a target, but for ice machines and whatnot, you're probably better adapting the charge to the environment it's in than subcool, assuming it's indoors.

[@bretwalley4673]

I measure subcooling and superheat with a testo 550.

[@robertmyers6859]

GREAT JOB

[@HughesManHVAC]

Great video

[@DWAYNE2ism]

adding a heat exchanger to a system will add to system efficiency?

[@thealeons3179]

I work on low temperature Chillers. We run a sub cooler on the liquid line after the condenser. This is typically a brace plate heat exchanger. It has a TXV on it, so it acts like an evaporator. The liquid line refrigerant runs through the sub cooler heat exchanger and is pre-cooled before it gets to the main TXV or metering device. This will allow you to run a much colder evaporator temperature. In some cases all the way down to -80 F

[@justinperry68]

How do you check sub cooling on a ductless? When only one port? Say in Ac

[@sotistudent3759]

teacher is a funny guy

[@jamesfitzsimmons381]

Would had loved to have worked for you Bryan

[@donnierobertson3088]

Nice job and video

[@TonyGioMusic]

I also prefer to yeet the refrigerant into a new system.

[@mrcrux213]

Hi Bryan ! The time and dedication that you put on these classes is priceless. But if you keep changing the technical names on the concepts that are universal concepts found in technical data sheets that are not just in the English language but in Spanish or any other language around the world you might confuse many techs that watch your videos. When they see your video it might limit there technical vocabulary when looking at data sheets on the job. In my case being a bilingual tech I find many people from different Spanish speaking countries that they call the same concepts in different ways because they learned from someone that didn't know the technical name. I understand and like your videos but you might be misleading your techs by not using proper technical vocabulary.

[@mohammadqamar1854]

Thanks sir

[@jollyscaria1922]

Vrey good explaning thankyou gues shering welcome gues guied gues

[@stevekaufmann8109]

you should make your students learn on analog gauges

[@DB-zh3ti]

You don't need to remember all the numbers, you just need to know where to find the numbers.

[@logzz6373]

Thanks 💪🏾

[@marcoselgaucho1106]

Your voice when you said i don’t remember numbers🤣🤣🤣

[@BaronVonSTFU]

With it being 0 degrees out, my rack condenser is stacking A LOT of refrigerant. Like all of it....

[@peterstencell804]

It must have a head master on it 😉 that's there job.