This man has taught me more than school every did.My hats off for you sir.

I really like watching this man explain, in common sense terms, what is going on and what he is doing....The videos are always excellent.

great refresher, felt like I was back in school again, keep up the good work Professor Grayfurnaceman

Another superb run-through for how to adjust charge in an R410A split system with a TXV. I’m finalizing the charge in a similar system right now. It has a brand new condensing unit, but I am still using the existing evaporator and line set. So I knew additional R410A would need to be added to the pre-charged amount which was already in the new condensing unit. It required about 3 LB to be added. I think I’m getting close to the right amount now, but will make one more test of subcooling, indoor supply vs. return air temperature split, and superheat exactly like what is shown here in this video.

You said you were gonna do a video on recharging-subcool-superheat ect, and you kept your promesse. Thank you so much. It changed few things in the way I was doing it like taking the low pressure temp after the evaporator for superheat.instead of outside. If ever you have some trick to solve slow leak, you would make my day. Thank you

Just like I learned in school... Although there wasn't any creation called R410a back then. We had it easy with r22, blended refrigerants are a pain... Lol. Good video as always Gray. Thanks for all the knowledge you pass along to all of us.

Actually is one the better videos addressing this topic than many I have seen in the past.. great job.

Thanks for your help in making it simple to understand!

I did residential for 7 years, I'm currently working for the last 7 1/2 years in big commercial equipment. I started looking for any videos HVAC because I always believe that in this trade is always something new to learn and I found one of your videos and I was hooked. I wish I would it have an instructor like you when I first started in this trade, thank you sir!

I am fresh out of School green horn. I very much like these videos has reminders and when I get stuck not rembering exactly what to do. Practice and "learning opportunities".. thanks again for very straightforward information.

Sir ....ur the man.... i wish there was utube when i was in school or better yet u were the teacher...i learn alot from ur videos....thank you so much ...really appreaciated!!!!

Super helpful. Very good details and explanation.

Love that manifold …..did some refrigeration many moons ago . We didn’t have that , had to do all the superheat and sub cooling by math , wonder how much it cost …thanks a lot for the video ! You explained and a few minutes what it used to take weeks to grasp

Thanks for the videos I'm currently studying to become a Hvac technician and your videos really help me a lot

Thank you very much for your teaching I’ve been learning allot from your videos, I feel that I’m better technically,God bless you for your teaching thanks again for taking your time to make this videos

thanks for all you do! You are a very good teacher.

thanks for sharing your knowledge. I value your experience. thanks

I personally, have a lot of problems in charging system with the TXV & Receiver. I think this give me a lot more clear than before, but if you have more example of charging, please post it. I am so grateful that you are sharing your experiences. John

Love your VDO easy to understand thanks

Good video. I appreciate your candidness about recover and refill vs. top off. It is first I have seen with that viewpoint. As a DIY guy, this means I just need a decent manifold set, a scale, temp probe(s), and jug of 410a. I will leave the other tools to the professional when it is time to have serious repairs performed. My unit has been serviced 2 times, 2 diff techs. Neither one found a leak, both ended up charging it up and that was it. Strange observation on my part - it appears to leak when it is powered off for an extended period of time. Crazy.

Excellent Vide and information. Thank you for sharing !

Nice video. Thanks!

20° is a bit high across the coil. May want to increase the fan speed a notch to increase efficiency. Great video and information 👍.

thanks Mr. Gray

thanks Mr for your time great job

Paul.... If a R410 unit is low when testing on a service call or check up, that means the R410 is unbalanced with concerns to oil mixture. R410 requires the precise mixture for it to cool properly and oil sufficiently. Only if the unit is brand new and just requires a top up then can you just add. Otherwise the system (by manufacturer specs) requires you to recover and start from 0 if the unit is found to be low

I have one of those SMAN4 gauges along with the wireless sensors and transmitters. No need for any math, once set up, it reads the superheat and subcooling in real time. This allows me to very quickly zero in the correct charge and squeeze out the highest efficiency the unit is capable of.

Good stuff dude.

awesome explanation sir!!

Excellent video probes that when u have the time and the dedicated tools the charge would be pretty close to perfect.....One must be careful about Microchannel Cond. Units that can be overcharged very easy running most times into Overcharged High Head Situations specially on 94 degrees temp summer days....tnks

I cant wait to get my certs in. I always wanted to do this type of work. thanks for the great video's. this is way better then the typical schools I see people going to

Thank you for the info.

Good video as always, but I wish you would show where your probes are placed for your various measurements. As it is, some parts are confusing without that context. It would also help to mention alternative ways to get the saturation values without a digital gauge set.

Awesome video well explain

Great video.

good lesson

Question: So on my new Ruud 3.5 ton AC with "N" coil, using 34 ft of (3/8 liquid & 7/8 vapor) lineset. I know to add .6oz per foot over 15 ft. but was curious if it was necessary to add extra 410a to account for the copper elbows? I have three 7/8" elbows and then 2 long hand bends for the 3/8". Cant determine if they are telling me I need to do this no matter what or just if I have a long lineset and high vertical rise which I do not have. Lineset goes 8 feet up from AC service valves to ceiling then 22 feet straight to furnace room and then 3 feet down with the 2 elbows to connect to coil. Manual states, All units are factory charged with R-410A refrigerant to cover 15 feet of standard size interconnecting liquid and vapor lines with a required field installed filter drier. I have installed the filter drier inside before coil and coil also has TXV installed with bulb of course at 10 o'clock position on vapor line also on outside of cabinet.

Thanks for the video. You cover a lot of great details to watch out for. I am curious what the specific advantages of a TXV are over a fixed orifice for the evaporator. It would be interesting to see a video on an r-22 superheat charge with a fixed orifice.

thank you sir for teaching

Good Video

Great video gfm..

you charge to superheat at evaporator outlet if it's a cap tube metering device. subcool for TXV. good video GFM.

I'm curious to learn what would my subcooling look like with a bad TXV.

Great job save me a semester of school lol

thank you

thank you...

Good stuff

Great vid Gray. Listen Gray I'm thinking of purchasing a set of digital manifold gauges like your using. Are you up to date on which unit is a good unit to purchase at this time......?

I'm still a fairly new tech (3 yrs. exp) and still learning the more specific technical details for individual units and systems. I would like to ask, when the information is not present on the unit,for example, older unit with faded tags or new one with missing paperwork. How do you go about finding out the exact specifications for what the unit should run at,as far as subcooling/fan cfm/or static air pressure? Thank you for your time and good video.

Best video! even better then school haha Question what's the best target SH and SC?

+grayfurnaceman, thanks you Sir! You are sharing great knowledge! 👍

Great video and good thorough explanation! So the greater the efficiency the less you add to the ambient to get total condensing saturated temp? Like in a standard unit it's ambient plus 30 so in these high efficiency units it's plus 20? With every passing year the standard is getting higher. Will that mean that eventually we will be adding less and less to the ambient? Thanks for your wisdom!

Great video. I do have a question. I thought if you were charging by superheat, you should attach the temp probe near the suction service valve. Thanks for the video

What’s the problem with charging by superheat, it worked for me for the last 43 years, TXV, PISTON, or CAP tube, cuts no ice, besides any installer worth his salt will put a sight glass after the dryer if it’s a TXV system ! Anyways I can judge operating conditions with my hand on the suction line, I don’t need a temperature probe unless i’m diagnosing a problem. Forget subcool just make sure of your gauge readings, and look for telltale problems that needle will show by its movements, like a pulsation that may indicate a sticking discharge valve, oh i’m sorry I see you have one of them modern digital manifolds that won’t show things like that, oh well maybe it’s also a radio to keep you entertained while your working. Also your liquid line should be warm to the touch, NOT HOT, and NOT COLD, one could indicate a dirty condenser, the other a plugged system and be careful, Carrier likes to sandwich two coils together on some of their units and they get dirty in between where you cannot see ! Never cared much for Carrier and I can’t stand Trane.

Hey mate, I saw another video of a guy adjusting the superheat (on a walk in cool room) by adjusting the TXV. This is incorrect right? The only way to do it is what you have done in this video by adding refrigerant to get the correct sub cooling..? Also I always thought it was bad juju to charge a system with liquid or is it ago to do it by adding slowly?

Very good video . I have Question pls If he charge with sub cooling when there is a TXV and by wet b dry b on the super heat with non TXV . In what category fits units with capillary metering device. And one more q. If I was to do sub-cooling calculation on a R410a split in cooling mode do I doit in test mode ? Full fan run speed? 18 Celsius set temperature? Thank you

on a new out side unit with nu22b add charge low side or high side? apt maintenace techs do different sides what is correct.please help thank you gfm

Bravo.

hi, doesn't that affect the compressor when adding liquid into the low side like that? thanks.

So with TXV the superheat should always be no more than 15 psi if the valve is working right, even if the charge is low?

That was a very helpful presentation thanks a lot! 3lb charge does make me curious as to what leak you repaired because that sucker was dry.

r410a system ( with fixed orifice) with equalized pressures of around 200psig. But once compressor starts the low side drops to 50 psig while the high side goes up to 300psig. I checked superheat was like 80F and subcooling was 2F. Does this mean the system has leaked out all the refrigerant? Does the 200psig equalized pressures means there's refrigerant in the system? thank you.

what brand digital thermometer are you using? not the fluke, the black one.

how do you like those gauges? was thinking of grabbing a set

i read about "target" subcool and confuses me, and i read about return wet bulb temp has to be considered on the equation also, can you make a video on that?

what do you mean by comparing the ambient temperature to the condensing temperature?

I got a question I'm pretty new to the Hvac field...in class we're currently doing a recovery and a vacuum and the instructor told us to buy out own gauges so we can get used to using them.....now my question in your opinion which digital manifold is good for a beginner but also good enough to have out in the field price is not really an issue.....thnks

I know this is a training video probably at your house but would it not be good to mention that if a tech gets to a R410A unit and its found to be low on refrigerant that the unit should be recovered and all new freon put back in so that the right amount of mix is in the unit?. just a thought

What do you do if your unit does not have a subcooling chart? Is there a standard? I have an ICP Heil PGAD30D1K7 and cant find a manual or subcool chart. I am getting 10 degrees with the probe and gauges. Thoughts or help is greatly appreciated and Thank You.

do you like the fieldpiece gauge? im thinking of buying one... any review would be nice.

What about adjusting TXV when subcool is correct and superheat is high?

thanks man..... these r410 cylinders come with a dip tube... so is necessary to keep the cylinder upside down to ensure liquid entry?

Question about a R410A systems, when the system’s compressor won’t energize due to low refrigerant with the low pressure switch, and you have a few lbs remaining in the system, can you charge as liquid directly to high side with compressor off? That is, weighing it in until system won’t accept any more, then, topping it off via subcooling method via low line. Or, must system always be in a total vacuumed state before you can ever do so? Moreover, in what situations can add via high line as liquid.

What is the reference in determining the Temperature Difference Between the Evaporator Coil?...Thanks a lot for sharing.

when charging by sub cooling and you get the charge right, how do you look at the super heat and determine if the txv is working properly? No one ever says what your super heat reading should be. They just sat " the super heat looks good" Whats a good reading and why??? I've read to never let super heat get below 20-25.at compressor, always check line temp. at same place you are taking pressure reading. If I could get this question resolved, I would understand super hear and sub cooling much better. Counting on you furnace man.

Hi, i was wondering if i need to bleed the air out of the hose by unscrewing the hose from the gauge first?

For manufacturers whose installation manuals advise to add additional [R-410] refrigerant for indoor matchups and/or longer line set lengths will the resulting subcool value be higher than their suggested published value? I.E. if they recommend SC of 9 based on a charge of 11.7 lbs. is it possible to see, say, 14, if you add an additional 2 lbs due to the indoor coil matchup and longer line length?

so you finished with a saturation temp of 102 and a discharge line temp of 91 to get the sub cool of 11?

Some posts are questioning if the system is low on refrigerant that you need to recover and start with Fresh . how serious is this ? you added 3.3 lbs that sounds like alot My 3yr old system has a leak and 3.2 ls was added . should I turn off unit until they find leak and recover and recharge with fresh R410 A ?

I didnt notice any recovery machine, i hope you didnt do any atmospheric recovery. just messing with you, good video. id like to add anytime i get into a system that is low, i will leak check first, and i always change out the schrader cores on all ports that have them. as well as clean all coils and change air filters first before taking any readings. I just dont like having call backs

Is that a Craftsman lathe in the background? :)

Isn't the 11 degrees of subcool rated for a 95 degree outdoor temp? And for 410-A, a good suction pressure is around 120 and a good head pressure is around 420 (also rated for a 95 degree outdoor temp). Shouldn't you drive the head pressure up to around 420 to simulate what the manufacturer recommends? 11 degrees of subcool at 84 degrees outside won't be the same on a hotter day.

Mr Super Tech don't you think you should have dumped the remaining charge and recharged with virgin refrigerant as you stated R-410 is a blend. Also before you start stuffing around with superheat/sub cool do you make sure that the coils/air filters fan scroll are clean ?

Hello. Is there any way to calculate subcooling for INVERTER AC without having good measuring instruments ? I have 12000btu AC ( 3500 W) r410a and is not working as it should. I live in Europe and I use it for warming up my room in heating mode. After all calculations I did and after all possible error is still far from specifications. I only have low pressure from the day it was installed : 100 psi. It was 93 F outside in that day. I kept complaining about efficiency at installer and they came last days and measured again pressure, suspecting leaks. It was again 100 psi. He started recharging using gauge only and it reached arround 130-160psi then compressor stopped. He removed refrigerant until compressor is on and that's it. When he left he measured arround 115-120 psi low side and 460psi high side. This unit has only one port for gauge measuring and high side was measured on heating mode when pressure was high. This technician doesn't have other instruments for measuring this unit except pressure gauges. Unit is working a little better now. There are higher temperature at inside unit. It was about 115 F before and now it gets 122F but there is a major change in time it gets to that temperature : it takes much longer. Before , at lower pressure it didn't passed 115F but it was fast. Now it gets after double time at 122F. Room temperature is arround 77F, outside temperature is 53F. Is it working good enough ? Can I measure suction temperature near outdoor unit and find out subcool ?

410 is a 3 way blend. Charge one system via gas and you diminish the quality of the rest of the bottle proportionately to the number of times its done like that.

went to fcc and still dont wana go to that place

I thought your indoor and outdoor temperatures didn't matter with TXV systems. I thought that as long as it's running desired subcooling, and the superheat is no more than 12 or 13, it was good.

What lathe is that? Do some video

may have these instruction in french ?

The charge is still not accurate. Evaporator shows signs of restriction.

Personally I think he needs to explain what all the terms are... and show where he collects temperatures.

This is just one example of the lack of ability of HVAC service Technicians to diagnose problems and fix them. My brother had a 1.5-Ton air-conditioner installed on an oil furnace that only had a quarter horsepower blower motor and they installed an evaporator coil directly on top of the furnace which resulted in it being to close to the furnace heat exchanger causing an airflow restriction. Actually in that oil furnace the quarter horsepower blower motor should only be used with heating and never less than a third horsepower motor used when there's an evaporator coil Installed in the system. the evaporator coil was always heat under loaded. Additionally, the system almost immediately begin to lose charge in the area of the evaporator coil. The first tech who came out with had an analog manifold gauge on the suction line and saw that the pressure was normal, however, the system had a TXV metering device on it and therefore you have to charge by sub cooling and of course he didn't have any way to check either the superheat temperature or the subcooling temperature; therefore he misdiagnosed the system as being okay. Over the years the same company was called in; again a total non-diagnosis was the result. Then another company was called, which I thought they might be the best company; however, he merely removed a clean return air filter; he had a set of digital manifold gauges which showed the superheat and sub cooling of the system. Subcooling was only 1°F and normally you need 8 to 10°F of subcooling on a TXV system. However, when the superheat got down to around 16°F and the thermostat expansion valve superheat target was probably 12°F; the tech said the system is overcharged and he took the manifold gauges off the system. However, the sub cooling was only a mere 2°F; he left the system still way under charged, he never searched for the leak, nor diagnosed extremely low airflow through the system indoors resulting in situation where you couldn't possibly properly charge the system. This is only one example of how the technicians here in the Southwest Wisconsin area, where I am now living, simply can't seem do anything right, it is difficult for me to believe that HVAC service work could be that bad, but I believe the number of service technicians that do their work correctly is a very low percentage. our HVAC industry is shamefully disgraceful condition…

Too confusing for beginners. He keeps moving back and forth to different temp readings with no indication as to what the heck the temp is measuring. Which temp probe is connected to which line? And, why is it important to know the ambient temp when you're doing subcooling? And, he keeps moving back and forth to various readings, just reading off numbers. so fast that it makes your head spin. Terribly confusing video for newbies.

U need to study the txv again

H

bul

will you please stop smacking your LIPS!!! thx for the videos otherwise!

Sorry, just to much jumping around and not clear with your explanation. Very hard to follow. Just my opinion.

Maybe you shouldn’t make videos

Paul.... If a R410 unit is low when testing on a service call or check up, that means the R410 is unbalanced with concerns to oil mixture. R410 requires the precise mixture for it to cool properly and oil sufficiently. Only if the unit is brand new and just requires a top up then can you just add. Otherwise the system (by manufacturer specs) requires you to recover and start from 0 if the unit is found to be low