How To Check Superheat & Subcooling On An HVAC System

[@iceyaj3167]

throughout all the HVAC tech guys on youtube, you're the only one who makes it easy to understand. Thanks for the info!

[@hediervarelamedina987]

The video is respectable and the truth is that in the little that there is agreement that the pressure gauges should be installed with the unit turned off and what I did not see was the bleeding of the hoses, so they say that it is not important to bleed to remove any air that may exist within them and thus prevent contaminating the system. For the most part, the video is respectable.

[@JohnDiMartino]

In the beginning of the video, he explained that the hoses were low loss. They were Schrader valves inside the holes that held the Freon so there’s no need to do that.

[@trex9194]

My area is new to cooling since we never had the need. We have nothing but swamp coolers. I've been working with our northern branch JR and you explain it better than any of them! I ordered the service book! Thank you!

[@alexjustasu2637]

your explanation very clear and very easy to understand at least I find good HVAC teacher by video.100% like

[@cacornett58]

I learned HVAC on my own reading books ( yes we had books in my day) an my dad taught me alot too. He was in HVAC engineering at the VA hospital Cincinnati. Taught me how to use gauges and other thigs. But I knew nothing about super heat and sub cool. Maybe they didn't use it in the old days, I don't know. I love what you are doing for DIYers like me. I need to know how things work and HVAC is one of my interests. Thank you . Well done!

[@mark2020]

I got to say I watched a lot of KZbinrs and for some crazy reason you're the only one that really explains it very well. I feel they all understand it but there's these obvious steps that they're not realizing the novice doesn't get. Very good work for such a young guy Thank you!!

[@OnRappel]

Dude, I watch a lot of HVAC channels and you channel is the best by far! Keep up the good work!

[@diyhvacguy]

That’s so much! That means a lot to me

[@deanmartin1966]

I don't think you had enough of a heat load in the house to properly check the charge. That's probably why the chart didn't help. Crazy to see that B vent installed in the wrong direction. Chance for CO2 leakage from the flue joints on the furnace? I would of also checked the Delta T just to make sure you had around 17-20 degree split. I was taught to check the outdoor ambient temperature in the shade and not directly in the sun. I love Craigs channel too. He is one of the GOATS of Hvac.

[@hliz8818]

I thought the X on the chart means over charge

[@jollyscaria1922]

Tion

[@jollyscaria1922]

Air.... Atfirstlestus understand the structure and propwrties of air is a mixture of gas wich is invible odourless tastelss..air surronding the earth is 400miles thick air divided into severallayers air sea levl to 30.000 feet is called at mosphere and from 30.000t0 50.000feet (10) miles is called

[@reaperinfinite8427]

Delta T is to subjective to use as a definitive measure method. Superheat only, subcool only, fan speed and static pressure check to nail it home

[@UncleMerlin]

Hello, I am a Vietnamese and follow your KZbin channel a lot. I really like the way you share with everyone, it's very easy to understand and very approachable, I really like the HVAC jobs but I can’t find a job because my English is not good enough to communicate with the customers

[@Frank_Techguy]

Excellent video on explaining Superheat & Subcooling on a HVAC system. Keep up the good work.

[@dogbyte555]

I am trying hard to understand this concept. You measured 17 degrees of superheat which makes sense. Your calculation for target superheat is essentially zero, or possibly negative superheat, which would be impossible. It would appear that there must be a problem with either the wet bulb temperature reading, or the dry bulb temperature reading. I suspect the wet bulb reading. I am not an HVAC tech, I am just trying to analyze this logically. Thanks very much for making this video.

[@TanveerKhan-hj9lp]

Thank you Sir for uploading this videos , I learn alot from your videos

[@georgewashington687]

Another great video, explained all the details as to what you were going to do, the steps as you performed them and showed all the steps in calculating the results. You do a good job and thanks for all you do to inform those wanting to get into the field and for those like myself who just want to know all aspects of HVAC because I find it very interesting. I like troubleshooting and I did that in my career as an electronics technician for the Air Force and later for the FAA. I am now retired but continuing to expand my knowledge base. Keep up the good work. BTW, today I noticed my compressor was making an unusual sound, it was not running at a steady RPM but sounded like the speed of the compressor was oscillating. I made some voltage and current checks and found the start winding to be only 2 amps whereas the run winding was 26.3 amps. This is a 5 ton unit. I pulled the power and checked the capacitor. The fan capacitor was right on 5 mfd but the run capacitor was only 17 mfd when it should have read 60 mfd. Also it was a leaky compressor, the resistance drop across the herm contact to common was 17 k ohms. I had a spare, put it in and the start winding current went to 7.5 amps and the run winding current dropped to 20.5 amps.

[@miker252]

In 1969 my collage Electronics Tech instructor was retired from the FAA. He used a big flight simulator schematic for our final exam problem. I never took a job as an Electronics tech, but no matter what I was working on, I could always use those troubleshooting skills especially large Air Conditioners and Chillers.

[@samygold100]

It's great to find a free ebook copy of this book online😊

[@loudroarTV]

OMG! Thank you for clarifying and helping on what to look for when troubleshooting. I have some experience with working on small appliances and auto air conditioning, but never on my home ac. I appreciate the tips!

[@connorcoutant2059]

Thank you for this video. I’m an apprentice currently trying to figure all of this out, very helpful! 😄

[@giantkillin8278]

getting into advance stuff but will add it to my study list.!! thank you

[@92fsoakcreek]

Thank you very much. I learned more in this one video than a month surfing the internet. Im looking forward to putting my first DIY mini split together next month. :)

[@diyhvacguy]

If you need any help check out our Patreon membership at Patreon.com/diyhvacguy Cheers man.

[@jackl9922]

I enjoy your detailed explanations. I have a variable speed unit (Carrier) and supposedly is has to be running wide open. I’m thinking there is probably a maintenance setting in the thermostat, but I’ve been reluctant to go into the ‘secret’ menu for fear of causing a problem. I have helped others with simple systems, but afraid to touch mine.

[@jeremyg8568]

Most systems start on hi then ramp down as they approach the target temp you have it set at. You can simply sett the temp to the lowest setting available so the ac will push to it's maximum. Most thermostats have a manual fan control function built in but it can be turned off in the set up menu.

[@Honestandtruth007]

Clear and thorough Explanation, Thank you brother 👍👍

[@jin8684]

Great video! I just want to clarify that the EPA is a certificate and not a license :)

[@robavis4906]

great info. Thank u i always wondered how u are supposed to know what the guage readings should be.

[@enduringpromise]

A few things to note. When disconnecting the hoses and dumping the refrigerant back into the low side, the lines should have been purged of air. This step should have been done when first connecting the hoses. The next thing to note is never wear cotton gloves which can absorb refrigerant and increase the injury if the fingers or hands come into contact with the refrigerant. The third thing to note is when connecting and disconnecting the refrigerant lines is place your hands and fingers in such away that when refrigerant leaks out that your skin will never be in contact with the refrigerant which can cause a VERY serious injury. I do mean serious. His gloves had a protective layer on the fingers which would protect him.

[@HomeImProveMentHow]

*Hey bro, You are really going above and beyond which is Excellent💥👍🏻.* From one "youtuber" To another. I am new here to your Channel, I don't know much about air conditioningAnd heating units, But I see that you really care, About helping People understand, That's really good of you! Thanks again, I look forward to hear from you , bye for now, God-bless, My name is Ken.

[@diyhvacguy]

Thanks man! That means a lot. Best of luck with your channel!

[@nhojcam]

thanks for your videos, man! i'm just starting to buy basic equipment. i have a POS amana 3.5t ac and air handler. it's only 2.5 years old and already failing (leaky low pressure switch due to poor design). i have always been a trane / amer. standard guy, but the crappy equipment i have came with the new house i purchased in '22. actually, it was almost a deal breaker, but i decided to look past it. i KNOW that i will be replacing this equipment within the next 3 to 5 years, maybe sooner. so.... i can at least feed it some r410a when the a-coil freezes up. i'm sure that leaks will be a common theme going forward. at any rate, thank you soooo much for your videos.

[@transmitterguy478]

Great video, I work on my own system and value this video as a refresher course. Thanks.

[@bryanspears2045]

the "X" area of the SH chart is the temperature that are at or near zero Superheat. So the system is under charged or low air flow

[@johncottrell7901]

The book you're using clearly explains the situation you experienced on the superheat chart. You CAN NOT assume the system is charged properly because you're in the X's on the chart. The book explains it: "This means that the Target Superheat is too low to set the system to because the Target Superheat would be below 5° F."

[@aaronclark1599]

You have to read the dry bulb temperature down below about 6" away from the bottom.. you can't read it at the top of the system because what you're getting is cooled air coming off the condenser fan

[@johncottrell7901]

The dry bulb reading is the ambient being drawn into the coils on the condenser. The location vertically is not important. The probe must be far enough from the coils to prevent radiant heat from the coils and the probe must not be in direct sun.

[@carsonsmith5871]

Thank you sir, very much appreciate all your hard work and great videos.

[@glendurant911]

Hi there, i love your videos and please keep up the great work with basic explanations and tips,This makes you the King of H-vac.

[@aaronclark1599]

I use the field piece prh2 and it's the most reliable tool..

[@AntonioHaywood-fc4rw]

Heat pumps are known to have txvs (thermostatic expansion valve )

[@luisprado9323]

Easy to understand. Thanks for your tech video!!

[@JRhodes88]

Just an FYI; The low loss hoses you link on your page are not low loss.

[@betomusik]

Thank you doesn't seem enough.

[@Akadectra]

Thank you for this very interesting video 👍. Greetings from Bavaria/Germany 👋👋

[@jessevasquez8323]

say bro I know you did not do this install and the subject is cooling SH and Sub Cool charging methods but i just want to mention that before you leave the residence its a good idea to check the type b venting for the furnace. the venting is incorrect check the flow direction on the venting the arrows are pointing towards the furnace.

[@diyhvacguy]

Yes that all got updated 👍🏼

[@jessevasquez8323]

@@diyhvacguy Awesome videos!

[@matth.4932]

What about purging air from the yellow manifold hose before letting the suction side pull the liquid freon from the red manifold hose. Doesn't the Freon go into the yellow hose as well and gets mixed with any air in the yellow hose? Shouldn't you open red and purge the air out the yellow since you already purged the blue side? And then open the blue side to suck only freon in?

[@mr.troubleshootingtech3930]

Wow! Thank you so much; this was very helpful, I appreciate you!

[@ReyValle-wh4jh]

What is the name of that book ? Please share

[@PosterityOf1776]

His website has the name and link to Amazon. A/c service pro LLC.

[@EdwardChuck-s3s]

Can u make a video for the glove which is safe deal refrigerant

[@karynasmith6026]

thanks for this video, i did not see you purge the gauges? can u please explain me why ? im interesting to learn

[@diyhvacguy]

Check out our membership where you get access to special members only educational videos. If you hit join at our Home Screen you will see the tiers there, we upload videos frequently to help people learn hvac. I believe I did purge but it was a while ago I created this video. Cheers man

[@steventhecaveman]

This video is awesome man thank you!

[@alexx479]

This helped so much, thanks 🙏

[@carlitozway2799]

I will be waiting for the video about the EPA license...

[@scottnewlin1]

Same!

[@valberde61]

He has not made that video yet. Or I just can’t find it

[@bobrylander2132]

This is a great video, but shouldn't you bleed the lines first? A considerable amount of these type videos skip this set.🤔

[@Side_Show]

Does this book have superheat and subcooling charts for reefer units? I work on trucks/trailers with 404a.

[@derekprreira3214]

Hey bro, with regards to superheat I understood if the system is undercharged or overcharged or Ok through the target superheat. What about subcooling, how can we know if the system is overcharged or undercharged or ok, kindly advice

[@smokex2d309]

What do the X's in blue squares shown in the book on the temperature page mean? ​

[@mannyfresh8504]

Sooooo… thank you for sharing. My question. What happens when the Manufacturer does not have a subcooling on tag…? Does 11 deg always suffice? I’ve been given an opportunity to maintain and service packaged units for a school. The units there are in pretty bad shape and i Noticed they don’t share a target subcooling. When i open the blower chamber, i see TXV’s at the evap coil. Thanks

[@GregLobb-l2n]

Great instructor

[@mcd5082]

Great video thanks for sharing

[@majorshong4951]

Thanks man! Super helpful videos!

[@Soulkking]

Does this also apply to marine hvac systems, specifically the tx valve/ piston part, a lot of marine systems use tx valves and my boss tells me to use the superheat method😭.

[@tommyatt8193]

is this the book that you sell on your Amazon site with the Refrigerant Temp?

[@Kevin-mm6xm]

You don't have enough heat load to properly charge that system. 53 wet bulb equates to 64 F at 50% RH which is not enough load. Outdoor dry bulb was reading 82 F so not even very warm either depending on where you live. To get the heat load up open doors and windows and let some of that 82 degree warmth into the house for a better super heat setting, which by the way, is a Goodman recommended setting of 8 degrees, plus or minus 1 degree. As to the low temperature load, here is a quote directly from the HVAC School: "On a fixed orifice system, the superheat will drop with the load. It can drop so much on a fixed orifice system that the superheat can easily be zero when the system is run outside of design conditions, resulting in compressor flooding." That's why all the X's on your superheat charging sheet. You're out of range for proper charging.

[@diyhvacguy]

Very good info. I will keep this in mind on future videos. Thanks for sharing your knowledge!!

[@Kevin-mm6xm]

@@diyhvacguy No problem. I posted about the TXV bulb on aluminum. This is not good at all. Galvanic corrosion having steel to aluminum will eat the aluminum. Attach only to copper which has much less galvanic corrosion potential than aluminum. I like your videos and appreciate the time it takes to make one but if I can help you in some way I will.

[@gregoriocampo]

Great video.

[@Samlol23_drrich]

Any idea how these electronic units do wet bulb? Cause all they really measure is temperature. Is there a formula? Like wet bulb= dry bulb- 10 degrees? That’s what it seems like.

[@dross902]

nice walk through !!

[@eddieochoa6636]

Can you make a video how to measure , delta T

[@robertcopeland17]

I have a 4 ton split with a fixed orifice/piston. I’m in Southern Louisiana and our days are 97 to 101 without the heat index. I own the Fieldpiece charge and air temp measurement kit. I cannot hit target superheat without possibly damaging unit. I can get to 13 but sub cooling is in the 40’s. New filter, condenser and evaporator coils are clean. I’m thinking I need to install a TXV so this system can handle the heat load on these hot days. Any suggestions?

[@kencrane6420]

Do you use an old "beater' set of gauges for r22 systems?

[@diyhvacguy]

Nah, I use one manifold for both. Just let out the refrigerant in the hoses if I’m connecting to a different system then the last one i checked.

[@ice4278]

What happened to the video on how to get the EPA license

[@nbctcp3450]

1. how to find target superheat for single split aircond R32 in Celcius 2. do u hv chart for it

[@Keepithonest7]

How important is it to insulate the small copper line

[@worldtran5511]

great video. A lot of info.

[@SM-vs4ro]

One thing I never heard anyone talk about. If your hoses are full of 410 refrigerant and you hoof up to R22, what will that do? Do you have to purge the hoses before hand?

[@diyhvacguy]

You just let the 410a out of your gauges before hooking up to the new unit 👍🏼 then if you are adding refrigerant just purge all your hoses after you connect.

[@yellowstoic7678]

Bro, you need an amazon affiliate link for Canada. I just bought 1.7k worth of stuff to get into hvac. I'm a Plumbing and heating tech.

[@SaresMLee]

Hi sir, I didn't get it. What's going on with your SH. It's not in the list, what I'm gonna do in this case? Thanks

[@Franklinveterinarycenter1of4]

Beer can cold approach almost destroyed my compressor; lazy tech didn't even hook up the gauges....I was curious and watched. I clean evap and condensor coils and change filter regularly. Unit kept having problems, 2nd tech came along within the week and said, too much refrigerant and took some out. He hooked up to digital gauges like yours. 1st tech charged $74 for 15 minutes worth of stupidity. 2nd tech charged $125. 1st tech lives 3 miles away and 2nd tech lives 30 miles away. needless to say, first tech will not be back. I can't believe he did that!

[@diyhvacguy]

Yea it’s just a rule of thumb. Not accurate at all that way but just something my mentor taught me. Haha

[@craigm5601]

Thanks great knowledge

[@williamchapman9150]

Thanks

[@maddog5814]

What does it mean if the chart doesn't list target super heat? For example outdoor temp is 105F, indoor WB is 60F its not even listed on the chart. I have a fixed orifice R-22 system and based on my readings my SH is 12 degrees when on the chart it's just X

[@ingdan6786]

Good video

[@eddieochoa6636]

Great video!!!

[@georgeyang6631]

Is your tube has switched off by itself

[@robertgalvan5612]

Wht fin comb do u use?

[@MrInkotime]

Do you need different guages for r22 and 410? Or just different lines?

[@diyhvacguy]

Same gauges and hoses can be used for both. Just make sure to clear remnant refrigerant from your hoses before you hook up to a different system! Cheers

[@MrInkotime]

@@diyhvacguy what's the best way to clean the hoses?

[@joshm2243]

​@@MrInkotimeNitrogen

[@jaimedpcaus1]

Very nice!

[@arealmaintenanceandrepairl1103]

What if you don’t have a target SH

[@1foulman]

Thanks!

[@diyhvacguy]

Thanks so much! 🙏🏻

[@richardtoney2441]

how to get epa freon certification?

[@diyhvacguy]

You can find that video in our hvac training videos membership. Just click the join button at our main channel homescreen

[@armantrans3390]

Excuse me how can I get EPA license

[@cheezycheddar211]

Why is your office 90 degrees? 💀

[@bobb.6393]

It's a sweatshop at night.

[@abeyoder2631]

Your 90° elbow on the fluegas exhaust is installed in the wrong direction....

[@alfredosauceda2605]

👍

[@reaperinfinite8427]

Only mistake I see is using a fieldpiece! 😂

[@kumudiniwasanthi1952]

Super .if you can send me that book for me

[@diyhvacguy]

amzn.to/47IQlF6 Here you go

[@MantuChaurasiya-g8t]

hello friends how are you

[@andy-ti9zf]

i bet most guys are using the beer can cold method.

[@diyhvacguy]

Probably so

[@baskorobas7550]

Kurang memahami.........

[@carlitozway2799]

Great 👍!

[@luismontoya5189]

This is for R22......too.....?

[@eddieochoa6636]

Great video

[@Bqe001]

Great video.

[@manueldacosta6539]

Great video