How to Find Target Superheat
Bryan shows the best ways to find target superheat on fixed orifice HVAC systems, including using charts, apps, and other resources.
You can find your target superheat using charts, such as manufacturer-provided ones or universal ones from sources like TruTech Tools or the HVAC School app. You need the outdoor dry-bulb temperature and the indoor wet-bulb temperature; the indoor wet-bulb temperature gives you a better idea of the total indoor load on the coil. To measure wet-bulb temperature, you need to use a high-quality digital hygrometer or psychrometer in the return.
You will want to charge a system until you reach the target superheat at the compressor inlet (also known as the total superheat or compressor superheat in that location). The system should be stabilized while you're charging. If you realize that you have a superheat value that is too high, you are likely dealing with an undercharged system and need to add more refrigerant until the superheat drops to the target. If your superheat is lower than the target, then you need to recover some refrigerant slowly and carefully.
As the wet-bulb temperature increases, the target superheat also increases in fixed orifice systems. That's because the superheat signifies how much refrigerant we're feeding that evaporator coil, and our target superheat will vary as the load varies. Most of all, we want to avoid excessively low or zero superheat; when we don't have superheat, the system is flooding the compressor with liquid refrigerant. However, many heat pumps with fixed orifices also have accumulators to help prevent flooding.
If you look at a target superheat chart and see a dash at the intersection of your indoor wet-bulb and outdoor dry-bulb temperature, that means that the system will have no superheat under those conditions; the system was not designed to run under those conditions. We want to run lower superheats when possible because the system capacity increases, but superheats that are too low put us in the danger zone and make compressor flooding possible.
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschool.com/
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Im impressed by the detail of the actual tools needed to get superheat on fix bore.
ACST and HVAC school have really great explanation for new guys like myself.
@Everyday_Richard
4 жыл бұрын
Both of their channels are wonderful.
Nice, good shout out to AC service tech, between these 2 channels, I’ve learned a lot!
these videos are so good. thanks for putting the text on the screen too.
Thank you! You had answered my question on another video concerning superheat calculation and what to do if the chart ends up with a dash. I am glad that you took that question and ran with it as no one else has! By the way, I did notice in the book I purchased from you (which is awsome) you discuss this very issue. My take away from it is to charge the system during the worst case scenario - low WB, and high DB which here in Florida is usually zero superheat. I set the target superheat to be 6 degrees rather than 0. Even though superheat may be a little high when its cooler outside, at least the compressor won't get liquid.
A must!! Thank you...pure basics
Mr Orr excellent presentation on Target Super Heat. Thanks
Thanks heaps Bryan, i've been an installer/service tech for about 8 years now (mainly install) and only starting to really grasp the understanding of superheat and subcooling principles and functions. It's a little embarrassing but was never really taught it and my old employer seemed to think Superheat readings were "irrelevant" lol... i think not. Thanks again!
Splendid explanation! You are a superb instructor!
Great explanation... Thank you.
Great vid. Thank you. I really enjoy learning from your channel
Great way to view s ht. Vapor over water..thanks Bryan. Arizona humidity level is low..wet bulb low..numbers sometimes go off chart..
Well done! Great explanation. Thank you!
Thanks, that helps clear things up.
Your the man always informative thanks!
A lot of what you said went over my head
Great video!!
Nice job and video like always
Could you do this with commercial refrigeration ?
Well done
Ok ,,,,,,, young ones listen to this man ,,, cause you sure ain’t listing to us damn it lol great vid , love your brain
Thanks for lesson. Really good. Just curious - if you have a 410 system and need to remove refrigerant to correct the SH, does it not mees up the blend?
There is more info in this one video than you could learn watching KZread hvac videos all year.
I always use the target superheat formula which is three times the indoor wet-bulb - 80 minus the outdoor ambient / 2
How do you pull a little refrigerant out of a overcharged system with a new recovery tank under a vacuum? Thanks for any help
What is the best method to take indoor wet bulb ? I get confused cuz some of technicians take the reading temp above the coil and some of them taking it on the return trunk!!!! Thank you .
What is the saturation line? Min 5:25 trying to understand you analogy. I guess the target SH would have to be above the horizon
So if you live in dry 105 degree Phoenix and set your thermostat at, say, 72 and your indoor WB is 60 degrees, how does a tech adjust to the proper Superheat when the chart shows a blank space?
@johnd4348
2 жыл бұрын
guess, thats what I do. I worked in Death Valley. Average summer temperature is 120 degrees in the shade.
I dont have a wetbulb. Can I use humidity with dry bulb temp to get the same results?
so superheat is at 20 , you must add refrigerent to lower the number? does this apply to sub cooling as well if you are measuring that on a txv instead of a piston?
Where you get that temp clamp? Who makes that?
When you check charge .what should be the min out door temperature?
Emerson has an app it’s called check and charge
Where did you buy those temp clamp
How long do you wait in-between adding? I have heard 15min, 10, 5 min? Last, I did was 10 min. Then someone told me 5 min ok. Why so much of a time wait
target superheat is achieved by ensuring the right amount of refrigerant in the system for capilary tubes expansion valve. but you said it is not applicable for txv and electronic expansion valve. does it mean that the amount of refrigerant charged into such system does not affect the super heat of the compressor?
0:20 - Do you have such a chart that would apply to a refrigeration fixed MD (such as a captube)?
I work in hot climate which outdoor temperature reaches 118 F in summer, So I charge the units in the peak by target superheat 5 to 8 F at the lowest possible indoor temperature the unit can achieve , Is this correct method?
So what happens when you’re in the danger zone? How do you come out of it? How do you fix it
Hi Bryan, why i cant buy a tools in true tech tools?
Do you need to use a recovery machine to recover some refrigerant if the unit is running?
@HVACS
Жыл бұрын
No you can run a hose from the high side into a recovery tank and recover some refrigerant that way if the unit is running. High pressure goes to low pressure.
@lilmg4444
Жыл бұрын
@@HVACS got it, thanks for the reply! 💯
Thinking about changing my trade to hvac trucking is no good anymore .
Hello, I watch your technical videos on KZread and I think you can help me. I have a misunderstanding and maybe you can help me solve it. With the AC installation, the main purpose is to cool the room, with the "heat pump" installation, the main purpose is to heat the room. We know that both installations are based on the thermodynamic properties of the refrigerant. My question is: When the goal is to maximize the cooling of the room, the settings of the installation on the refrigerant side (expansion valve and others), is it different from the settings when we want to maximize the heating of the room? As an example: If the priority is to cool down, we adjust the expansion valve in one way, but when we want to maximize the heating of the room, we adjust the expansion valve slightly differently. Or what other adjustment differences are there (if any) on the same refrigerant installation if we want to speed up cooling or heating. Thank you very much
What do you mean by 12° superheat? °F or °C
What’s indoor wet bulb?
👍
So should an apprentice just bite the bullet and buy those probes? I want to start off doing it right.
Can you not charge a system biased on super cooling?
@bigj101100
3 жыл бұрын
When the system has a txv you charge by sub cooling.When the system has a piston you charge by super heat
Great Video but speaking a little slower (taking more time to say the same thing) would be awesome!
@FindLiberty
4 жыл бұрын
Try using playback speed setting .75 (or slower) on the KZread setting menu. _He does convey a whole lot of info very quickly!_
@jotu173
4 жыл бұрын
@@FindLiberty thanks for this totally awesome tip! I did not know that option was available and it totally rocks! I'm also looking forward to using the speed up video option on most of the long-winded videos (which are quite frequent) on KZread. Thanks again for the tip... I will use the heck out of it!
3 × (indoor wetbulb temperature) - (80°) - (outdoor temperature) ÷ 2 = (target super heat)
@ATeamAdam
4 жыл бұрын
You just ruined his 10 minute video. And you ruined the comment I planned on posting. Thanks a lot
@j727100
4 жыл бұрын
Are you joking?
@ATeamAdam
4 жыл бұрын
@@j727100 yes very much so
It’s inside the pipe
I miss understood and went to Target for superheat. They didn’t have any...
@HVACS
4 жыл бұрын
Try Walmart
@morejelloplease
4 жыл бұрын
Just goto any Target in texas, it's superheat here (115 degrees).
Everyone talks about split units o
AKA those "high dollar" new toys will actually save you time, energy, and effort. This is why I don't listen when a 20 year vet says get analog instead of the expensive new stuff. I can learn the process while also having the best technology. Only ever keep an analog tucked away for rainy days. Run that new new when the sun shines. A tool that saves time and effort is worth every penny no matter how expensive. That is time and effort on every job, every day, year in and year out. MONEY WELL SPENT!!!!
Informative video but really, slow down. Speaking way too fast - remember this is a learning opportunity.
I am a retired A/C&R Tech and probably doing this before you were born. I am listening for fun during breakfast and trying to listen as a beginning tech. First impression: is this some kind of a race to see how many words can be squeezed into a sentence? Also can you speak a little faster so as to confuse a greater number of listeners.You sound like a wind-up toy on steroids. A real teacher must think of the student first and suppress the ego's tendency to show off.
@HVACS
3 жыл бұрын
Sorry I failed you. Please forgive me.
Hey!this fast and furious mouthed guy is so hard to understand what his trying to explain, I do understand a little of his topic but way far off from the data he express.
@HVACS
4 жыл бұрын
Thanks for the feedback
@La2venida
Жыл бұрын
I slow the video down to .75 or .5 . Keep up the good work.