Does anyone out there know how to base superheat on 150ft+ line set?
- posted
16 years ago
Does anyone out there know how to base superheat on 150ft+ line set?
There is no real true settings for superheat, you as tech must find what is best for your type of condition you are working on. example while 10 degree of superheat may be ideal for AC system with 25 feet line it might not be for 150 feet, you need to know what is more important to you efficiency of your system or life of compressor don't forget that compressor gets cooling from gas coming back to it, some time compromised got to be taking, but if compressor can not stay cool then suction liquid injection must be added, it all depend on you application ideal superheat is always around 10-20 degree however it should never be less then 10. Tony
You are so full-of-shit, it isn't funny.
Jesus Tony! I can't belive you said what you said [albeit I could only read the first few sentences cause everytime I try to sipher your shit - I get a headache!]
Superheat is superheat. Length of lineset doesn't change the math.
"some time compromised got to be taking"
Couldn't have said it better myself.
Truth be told, you have to take into account the *pressure loss* the extra line length presents. If there is an increase in the suction line to overcome line loss, you might be restricting the oil return process. [Suction return velocity.] Most aren't aware of this excpet Paul... :)
Lenghty suction lines should be avoided, but, if you must know, after the first 50 feet, you should expect pressure loss. [And capacity loss.] The best method would be to measure the suction line temperature and pressure at the evaportor, [using an adaptor on the TXV equilizer tube] then perform the same process at the outdoor unit [condenser]. You'll discover the pressure and temperature differences. [In the case of a fixed metereing device - you are out of luck.] Understand that depending on the route the suction line takes, there will be some increase in suction temperature as well.
Asking this question means you should seek some additional education from your local community college or the manufacture of the equipment you sell.
Yes...Paul is my personal hero.
The fact remains, however, that superheat is superheat.
It doesn't give a shit about linesets, desuperheaters, hot gas by-pass feeds or anything else.
PS- I'm a reprobate
Maybe not, but believe me, the compressor's gonna care! LOL
Then the superheat calculation would now become subcooling. :-)
Hi, I have done A/C systems for 24 years and can tell you that thru all the math every tech I saw as an apprentice used their hand to feel the side of a semi-hermetic compressor's motor housing to feel that the metal was cool until the end of the motor housing. The suction line entering at the end of the motor, as refrigerant travels accross the motor , any liquid flashes off cooling the windings until the compressor cases start. at that point the cases should be warm to the touch indicating that all liquid has flashed off and we all know what liquid in a compressor can do. After the math this is the final test for the correct superheat on a semi-hermetic compressor. Hermetic compressors should be slightly cool when you touch the top. A/C Dale
So in other words, you don't know how to properly charge a unit by superheat.
better yours then mine tony
Generally speaking you right however all manufacture do not comply with refrigeration suggested formulas and you might find that are some far out of suggested superheats as for my line of work superheats can vary from 5 to 150 degrees but that is another story. what's important in superheat that you keep compressor happy rest of it is all secondary Tony
The reason for asking this question is I'm working on a high rise building that the engineer designed and that is why it requires a 150 ft to 200ft line. Also consider putting 10 SEER units adding accumulator and a TXV.
OK, so.....why not run an air cooled package chiller and some fan coil units??? or does that make too much sense??
Why not contact the manufacture's technical reps and ask them what they require?
Have you ever dealt with SL traps, LL solenoid, etc?
Well of course........Wait. Huh?
150 degrees superheat Lol
Yep Low temp work.
Do you understand the pipe sizing? Sounds like you're guessing. What is located where? Compressor at evaporator? Tonnage? Refrigerant?
Here's something to chew on. You might want to talk to someone local.
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