Newly built recovery machine! DIY

[Xeon th MG Pony]

Well I was bored out of my skull and for some reason house cleaning wasn't going to cut it, So I figured I'd finish a project that I had procrastinated away for dam well 5 years! (Ya I'm a pro at putting things off :) )

So a brief over view: The main reason I decided to build one was to re-use old R-12 from fridges as there are plenty about, but my conscious killed that Idea I just can't murder our environment like that by allowing the gas to be put into another system, I'll let the HVAC guys take it to be destroyed (Thats what we do in BC any old R-12 is incinerated and destroyed) how ever during a recent move the guys killed my chiller, and I been getting more R-22 charged systems. With my chiller damaged and scoring some Ac's I figured about time to make a system to both recover it and mediocrey recondition it by removing oil and other such things from it.

The design concept: By using an old green propane tank as the intake separater it leaves plenty of space for it to suck in liquid, and any who do home brewing knows the idea of distillation it works the same for refrigerant! We boil the refrigerant off leaving the waste oil inside the tank to be disposed of. Using an oil sep on the compressors discharge we can prevent the compressor oil from getting back into the refrigerant being recovered, and by using a cap the refrigerant being recovered will all so cool the compressor!

So after recovering the refrigerant, I set it up so it sucks in liquid, distills it, then puts it back in the tank in a continuous cycle, Oh with a F/D in-between the tank and machine of course on the suction side.

Now for the picies!

[Xeon th MG Pony]

More pics

So thats it for now till I start fixing my chiller.

I have vaced it out to 28.5" Hg and it sat at that for over night with out budging and it held 85PSI through the day so I think it is safe to say it is a tight system. It will be charged with POE oil and I'll be using a CO-082 F/D.

[Xeon th MG Pony]

thanks, I recomend puting a strainer inbetween the outlet of the tank and intake of the suction port of the compressor to protect against any particals that may have found their way into the tank during fabrication, I didn't have one on hand, so said sod it, and built it any way.

[n00b 0f l337]

Hmmm sorta like what I was considering! Except i completely forgot about the oil. Good reminder ;0

[Xeon th MG Pony]

Hehe glad to see this thread is helping to remind :)

Another reson for such a stupidly large intake sep is it will allow me to pull in liquide to a degree for very fast removal directly from systems with small receivers and remove the oil on the fly so it saves time and hassle.

[expansionvalve]

heh, very inventive :)
from the pics I didn't see a pressure switch, I think if I put something together like that I'd fit something just to protect the tank, I guess the chances of that compressor blowing the tank up like a baloon is rather slim, nevertheless, it's another gadget to wire in:)

anyhow, we need more threads like this, good job Xeon.

[Moc]

Much better recycling unit in my opinion... http://www.extremecooling.net/index/e107_plugins/forum/forum_viewtopic.php?23508
with chiller, he is able to recycle high presure gas like R23 or R1150...

[Xeon th MG Pony]

heh, very inventive :)
from the pics I didn't see a pressure switch, I think if I put something together like that I'd fit something just to protect the tank, I guess the chances of that compressor blowing the tank up like a baloon is rather slim, nevertheless, it's another gadget to wire in:)

anyhow, we need more threads like this, good job Xeon.


did you see the two spar ports at the bulk head? ;)

I had to rush out so I didn't have time to post the fact that is what they where for where the dual pressure switches!

Thanks for pointing it out though, good thing to not leave to chance!

[Xeon th MG Pony]

Much better recycling unit in my opinion... http://www.extremecooling.net/index/e107_plugins/forum/forum_viewtopic.php?23508
with chiller, he is able to recycle high presure gas like R23 or R1150...


lol you think I'm don? I been working on a design that uses the recovered refrigerant to super cool the recovery cylinder and cools the compresser oil all at once, still mentaly tweaking the design -Insert devil smiley here- I was thinking if I ever got into the higher pressure stuff using an auto cascade principal to cool the recovery machine and high pressur gas.

His design is sloppy IMO needs to be majourly streamlined and uses two compressores and is dependant on a secondary refrigerant Mine will use the very refrigerant it is recovering and be a single clean loop with one compressor. It will be worth the wait lets put it that way.

My next recovery unit is going to be much smaller and cleaner then the one in the first post, that was some thing to just allow me to get the stuff don that I need to get finnished.

EDIT: Added info and text

[Moc]

lol you think I'm don? I been working on a design that uses the recovered refrigerant to super cool the recovery cylinder and cools the compresser oil all at once, still mentaly tweaking the design -Insert devil smiley here- I was thinking if I ever got into the higher pressure stuff using an auto cascade principal to cool the recovery machine and high pressur gas.
Ya, I think so.. Show me you design please. Okay, you can use recovered refrigerant to cool the R Cylinder but that would only work with low pressure gas like R404A, R507, R134A... do you think that would work with R23 or R1150 ? Autocascading Recovery Unit... that can't work! Want to see you design also here.

[Xeon th MG Pony]

When its don, I am still working on it for the normal gasses, for the higher pressur ones remember that expanding gass will cool just fine it has low capacity though, but cools non the less & with a recovery machine I imagine you need not tons of capacity, thus I think even vapour expansion will work, it then becomes simple issue of efficient plumbing and design, this I need to work on, it may work as my low pressur one. Only diff is the high pressur will use expanding gas to cool rather then boiling liquid.

[Brettbeck]

Does anyone know of a guide or anything to do with recovery machines? I'm unsure of how they work :confused: .
The only thing i'm slightly sure about is that you need a strong vacuum to pull out the refrigerant, then it would be hooked up to a recovery tank and the gas compressed back inside?

[n00b 0f l337]

Well generally you want to condense that refrigerant back into the recovery tank. Or illegal, home made cylinders if you somehow can purify and re-use the refrigerant on your own. But you have to seperate out the oil from the unit and from the recovery unit.

[Stapler]

I second Brett's request, perhaps someone could draw a diagram of recovery machine. It looks like their's a diagram over at the German site, but I don't speal the language.

[n00b 0f l337]

http://img245.imageshack.us/img245/3394/recoveryunitla2.jpg

Theres as I understand it.

[Brettbeck]

Well generally you want to condense that refrigerant back into the recovery tank. Or illegal, home made cylinders if you somehow can purify and re-use the refrigerant on your own. But you have to seperate out the oil from the unit and from the recovery unit.

Ahh right, I think I understand. So where does the oil have to go once it's seperated from the refrigerant? In to its own storage tank until it can be removed?

[Stapler]

Thanks NoL, I see how it works now. I suppose if I can find some scrap parts and it's cheap enough, I'll build my recovery unit rather than buying one. Have you tested this yet Xeon? How well does yours work?

[Brettbeck]

I made a quick design, does it look ok?

http://www.justmyluck.f9.co.uk/Brett/Phase_Change/Drawings/RecoveryMachine_Web.gif

[n00b 0f l337]

Same as mine though I think your compressor might overheat, and if the back and forth lines above the compressor are a condenser, your in for trouble.

[Brettbeck]

Sorry I should have made that more clear... I copied and pasted the components out of another diagram I drew for a cascade :p:.
The back and forth lines above the compressor is a de-superheater, which probably isn't needed. Also, the back and forth lines on the right side is the condenser, but that has nothing to do with size. It would be a similar size to single stage condensers :).

[runmc]

Thanks for the cool thread MG Pony - I'm going to build a unit for myself now. ;)

[Moc]

My recoverty unit:
http://www.extremecooling.net/index/e107_files/public/1167499292_145_FT0_absauganlage_029.jpg
With my unit, you don't need a recycling bottle...

[m411b]

I think I will use this as a guide and build my own recovery unit. Was tryin to think of how to build one the night before last and then this thread shows up. This is excellent. I'm thinkin STICKY! Or at least add it to one of the Phase guides.

[{.bLanK} GoD]

I also agree on putting this in with the phase guides.
Making it easier to DIY your own recovery unit will hopefully decrease the number of DIY'ers out there just dumping it into the atmosphere.

[Xeon th MG Pony]

http://img245.imageshack.us/img245/3394/recoveryunitla2.jpg

Theres as I understand it.

and theres about right :) well dead on to be exact ty.

[Xeon th MG Pony]

I used the unit in a simpler mode and it worked fine, this is the "pro" model lol. Moc that unit is only good for recovering, but to recycle you need a large bottle to act as a buffer as you cycle it through the machien. I will use old green propane bottles to hold the recoverd refrigerant and use a large white tank as the recycling unit.

For a recovery machine you wouldn't call them desuper heaters, just vibration dampeners.

As for the waste oil? Dispose of it in an environmentaly safe and legal way, if it is minerol use it for when you are drilling!

[Xeon th MG Pony]

I think I will use this as a guide and build my own recovery unit. Was tryin to think of how to build one the night before last and then this thread shows up. This is excellent. I'm thinkin STICKY! Or at least add it to one of the Phase guides.


I am glad to see others finding it use full it will certainly be of gret use for here at home just for projects. let alone when I start dismantling ACs!

I'll be mounting the low side switch tonight and I'll snap some picks of that.

[[XC] gomeler]

This might be a stupid question but what about any air that is in the lines before you hook up to the unit to be vacuumed out? Would the small quantity of air in the connecting lines pose a problem or do you have to vent a small portion of gas to flush the lines before connection to your recovery unit? I'd just be worried about getting humid air into the system as you recover refrigerant and tainting your refrigerant. This looks very interesting and I may have to create something like this if I start scavenging AC units.

[star882]

I suppose you vacuum it out before using it, just like a regular phase change setup.
Just connect one side of your gauges to the vacuum pump (with an isolation valve), the other side to the system to be recovered, and the middle to the recovery unit. As for the recovery cylinder, the liquid connection goes to the recovery unit and the gas connection to the vacuum pump with the use of a T fitting (make sure you can close the isolation valve to isolate the vacuum pump). Open the system valve briefly and quickly close it. Then pull a vacuum with all but the system valve open. (If you're using a vampire tap, install it but do not punch in the pin. In that case, leave the system valve open. Same goes for a service valve that has a manually adjustable valve stem.) Once you have pulled a vacuum, close the isolation valve and gas recovery valve. Now open the system valve (or punch in the vampire tap) and start the recovery unit. Keep the recovery cylinder cool (put it in a cooler or freezer) and wait. Make sure the cylinder does not overfill. Once finished, stop the recovery unit and keep the recovery cylinder cool to let refrigerant left in the recovery unit migrate into the recovery cylinder. Finally, close the valves and detach the recovery cylinder.

[n00b 0f l337]

Oh easy, attach a ball valve off a T with access valve so you can vac out the entire recovery machine.

[{.bLanK} GoD]

I don't know how good I have it sometimes.
Thought I'd grace those of you who haven't seen one before.
A commercial recovery machine.
http://xtremesystems.org/forums/attachment.php?attachmentid=54331&stc=1&d=1167551096

http://xtremesystems.org/forums/attachment.php?attachmentid=54332&stc=1&d=1167551096

The bottles have two connections.
Liquid and Vapor. Liquid enters via the liquid connection, and vapor is sucked from the top of the bottle via the vapor connection and re-condensed in the recovery machine. Very quick for recovering gas from large systems, not to mention our sized systems.
It will also evacuate the recovery bottle before recovering gas from the system. And will also evacuate the system when recovery is complete. Although I doubt it will pull as good of a vacuum as the 2 stage yellow jacket vacuum pump I have.

[the_new_guy]

how much does something like that cost?

[wdrzal]

no need for all the oil separators as the system you are recovering from is not running. Also in using a hermetic compressor you can only recover refrigerant that uses the type of oil thats in the recovery compressor. Otherwise you need to drain and flush the hermetic compressor and fill with matching oil. This is the reason why all most all newer recovery machines are oil less.

[Xeon th MG Pony]

Yes there are walt, if you are taking the refrigerant from the receiver it will have oil in it, hence you need to distill out that oil. Pluse the system I built was intended to do a some what decant job at recycling it by removing any gunk, thats why I used a secondary oil sep.

POE oil is compatible pretty much accross the board, but glad you mentioned the fact the oil will need to be changed often as the next one will be having a fast drain feture! was some thing was pondering best way to do it couple days ago. I was figuring I'd drill a 45 degree angled hole right on the sump and lead it to a small shrader unit hinden in a hole of the wood on the bottom, or some thing to that effect so it can drain the bulk of the oil.

as for vacuum my system pulls a meagre 25", enough to be certain you have got the charge.

By a care fully thought out design you get around the majourity of the simple problems, with enginuity you can solve the simple ones and get around away the tufer ones. By the Use of POE for all refrigerants I am targeting to use this machine with, oil is indeed compatible! The type of machinery I am targeting will usualy have a receiver thus the use of intake oil sep to allow taking streight from the receiver.


For any here making their own, the key thing they must do is list out what, where, how., IE: the type of refrigerants they expect to come accross, where in the system will they be breaking into the lines, or the terrain it will have to survive, and how do they wish to accomplish this.

My portable one is going to be powered by two 7Ah Gell cells wired in perallel feeding a 300 Watt inverter running a 240Watt compressor for a portable recovery machine, this unit can take AC if availible or run of a vehicle battery if availible, and will have a discharge oil sep only to gurentee no oil is leaving the compressor (Well as much as one can) and I may put a oil level indicater inside the compressor!

See how it answeres the three importand W's? then Oil compatibility, find the oil that will be compatible with the greatest number of refrigerants on your target list, don; Repeat the oil compatibility list and make a second one for other ones.

I may add a valve between the discharge oil seps oil return line and compresser suction line, as that only needs to be open during recycling mode during evacs of small systems at the end I could simply open the valve to equalize pressures to eas the work load on the suction side schraders and return any oil.

EDIT: Added Info

[godmod]

lol you think I'm don? I been working on a design that uses the recovered refrigerant to super cool the recovery cylinder and cools the compresser oil all at once, still mentaly tweaking the design -Insert devil smiley here- I was thinking if I ever got into the higher pressure stuff using an auto cascade principal to cool the recovery machine and high pressur gas.

His design is sloppy IMO needs to be majourly streamlined and uses two compressores and is dependant on a secondary refrigerant Mine will use the very refrigerant it is recovering and be a single clean loop with one compressor. It will be worth the wait lets put it that way.

My next recovery unit is going to be much smaller and cleaner then the one in the first post, that was some thing to just allow me to get the stuff don that I need to get finnished.

EDIT: Added info and text

this is my first try of a recovery machine. it uses two compressors and probably needs a lot more (electrical)power than yours, but i am not a HVAC guy :(

i hope you can give me a few hints how to improve my design!

regards,
godmod

[Xeon th MG Pony]

Low temp compressors are the best as they have a habbit of being able to suck down nicely and tend to work at a higher pressur differance.

Second is small power usage is nice, easier on power bill and environment, so I look for mini-deep freeser compressors as usualy they range from 2~4 Amp.

I prefer to have the oil seps there to keep oil from going in or out of the compresser as wzrl said it is not needed despit how irrelivant it was to the design being showen, but for some one making one from scratch, He is indeed correct the intake oil sep is optional if you wont be using it to recycle, IE it will only be a recovery machine with out a large intake oil sep (There is a way around that taking vapour from the first tank holding the old recovered refrigerant and transfering it to a new tank, it achives the same job but you need another whole new tank! the unit I built I just drain the old oil :D).

Condencer, any small condencer will do the job, fan of your choice, I pulled a nice litle unit that is forced air off a mide range R-134a fridge (It is going in V2.0 of my recovery unit only I will replace the fan to a 12V type), so keep an eye out for fridges they some times are handly, easpecialy the oil coolers off some of them.

on the discharge side try to keep the tubing as tiny as possibly so it doesn't hold a high volume of refrigerant (I origionaly planned on using all 1/8 for the discharge side, next one it will be this) This should help avoid mixing internaly when you need to recover a dif,, refrigerant.

For your waste oil you can use a ball valve or packless valve, just make sure they can with stand the max expected pressure on the low side, I used schraders on the high side though ball valves would have been much better.

Plumbing: What ever works best yet reduces any stress points and isolates any vibration. The coils you see on my system serve no other perpose other then to reduce vibration from the compressor.

Oil: POE is the best choise for us as it is compatible with all most every refrigerant a SS-Chiller builder/Moder will come accross barring a select fiew, for the ones it is not simply build a second to handle the ones with an oil that will be compatible.

Special Notes:
1- For a unit made to recover small systems an oil cooler isn't required but wont hurt the thing far as long working life is concerned, you just don't want the oil too cool! Passive and small will be more then enough.

2- For systems where it will never draw from a receiver or doesn't need to be a self contained recycling unit as well, an intake oil sep is compleatly optional, If it will be a recycling unit as well you need a tank which can draw liquid & Vapour (& at this point you need a oil cooling method)

3- Lower power is good all round for every thing concerned! A small 2Amp low temp, will do the job, no need to use a 20Hp compressor to recover 12oz of refrigerant!!

(Sod it they don't pay me enough to be perfectly ontime)

4- Pluming the oil drain, Nifty thing called gravity will do the work for you! all ways find the lowest point in the low side to place the drain, and then try and keep a slant going all the way out to the exit point (don't rely souly on the pressure within the system!

5- Over engineering never hurts, they did it with voyager and look how long it lasted, kept transmiting till it got out of range! So go ahead and use oil seps strainers and such, but try to keep it on the low side! We want the high side to have as little volume as we can!

6- Check valves are a nice thing to prevent odd things from happening, if you got one I'd throw it on the oil out line, as last thing we want is to back flush it!

7- Think of it like a SS only open ended, out goes into a tank, in goes through a F/D and to a system, we want it to be low powered as we can reliably get away with.

[Xeon th MG Pony]

this is my first try of a recovery machine. it uses two compressors and probably needs a lot more (electrical)power than yours, but i am not a HVAC guy :(

i hope you can give me a few hints how to improve my design!

regards,
godmod


Sorry didn't mean to sound harsh, it is a good first try. When don the design for the self coiling unit I will most certainy post it here free to use, it isn't going to be revolutionary by any means, but it will be, hope fully, very use full.

first thing I could recomend (providing there is not a dip tube) Is lowering your oil port on the discharge sep for better draining.

Add a vibration dampening coil on the discharge to prevent failur and work hardening, increas the volume of the oil sep too would improve things. Nice choise of a condencer BTY low volume!

By tapping into the high side and using a cap tube lead that to your cooling coil and return to the suction port. The trade off is it takes longer and will not pull as deep as a vacuum but it will chill the cylinder nicely and will recover the refrigerant just as well and reduce the needed volume of the condencer.

You have don a great jobe on the systems you make, you don't need to be HVAC to make a good system, right now I am just a waiting student to go full force into the field ;) so we are both at the same playing field as it where :D
Half the fun is in the designing and the rest in the R&D ;)

[n00b 0f l337]

I might grab two Temprite 501A's for a recovery machine.

[{.bLanK} GoD]

how much does something like that cost?

At a guess, somewhere around $1000 for the recovery machine and maybe a couple of hundred each for the bottles.

[wdrzal]

Xeon now that you have a recovery machine,it's too bad your not allowed to uses it !!!! your country is a signatory to the Montreal protocol on release & recovery of refrigerants . "Only properly licensed & certified technicians are allowed to recover refrigerant"...........I'm sure that line is in there;) ..................and it is illegal to release it.

happy new year :)

[m411b]

At a guess, somewhere around $1000 for the recovery machine and maybe a couple of hundred each for the bottles.

You can get a proffessional recovery machine on EGay for like $300. And a tank for like $100.

[Xeon th MG Pony]

Xeon now that you have a recovery machine,it's too bad your not allowed to uses it !!!! your country is a signatory to the Montreal protocol on release & recovery of refrigerants . "Only properly licensed & certified technicians are allowed to recover refrigerant"...........I'm sure that line is in there;) ..................and it is illegal to release it.

happy new year :)


Same with the US as for building and selling of phase units with out the proper certs! so either way it is illegal to have fun, get ahead, and all of the above, thats why I don't bother with that I just use common sense, it seems to work

[{.bLanK} GoD]

You can get a proffessional recovery machine on EGay for like $300. And a tank for like $100.

I quoted New Zealand dollars.
And a cheap recovery unit probably wont have the vapor return connection which will make recovery a lot longer.
And it was just a guesstimation.
Hahaha @ walts comment.

[wdrzal]

I pay around 60.00 to 65.00 for new 30# tanks without a float,which by the way shuts off the tank when 80% full by volume. if you don't use tanks with floats,you must weigh in the approved amount into tank while most original recovery machines were made to use cans with floats,the added cost has moved most guys go to weighing in the correct amount since you already have a good scale. Don't you???? 20% by volume needs to be left for expansion of refrigerant in heat. a 30# tank is water weight & volume@ standard temperature and pressure, and a conversion needs to be made for refrigerant. 24# is 80% if filled with water, refrigerants don't weigh the same as water.

[Xeon th MG Pony]

I wish I had a good scale, like hell I can get one cheap, but I have a workable machanicle one, then again I have a hand and good feel for volume, being the tinyness of the tanks I just pick it up and give it a quick swish. Still trying to get a scale and still geting out bid for a scale. Glad you can get a tank so cheap, won't see one for onder 100 here.

By the way, the best law here is the one that says any release of R-134a can be fined up to 25000 dollars and lisance stripped, yet they sell it as air duster is.

[wdrzal]

yep ,it depends how it is used, The Montreal protocol was written by bureaucrats and special interest groups.You won't find anyone in the HVAC industry that "completely" agrees with it unless they manufacture recovery equipment.

[m411b]

By the way, the best law here is the one that says any release of R-134a can be fined up to 25000 dollars and lisance stripped, yet they sell it as air duster is.

Man, I totally agree, but politics do not belong here.;)

[Xeon th MG Pony]

Not politics its :banana::banana::banana::banana::banana:ing about its stupidity ;)

Well I tested it with the oil cooler/return, it only can pull a 10" of Hg vac instead of its usual 25" of Hg, so I will definetaly add a valve to turn it off during recovery mode, and on during recycling mode. Perhaps use a solenoid and a fancy switch that has a trigger guard for bling effect :D

I lost the bracket for the Lp switch so that hasn't been installed yet, but I'll install the fuse and other power protection stuff on soon.

[godmod]

thanks Xeon for your advices. i will reconsider my design to lower the high side volume and do a lot of other improvements.

the drain in my oilsep has a bend:

[Xeon th MG Pony]

Ah Ok it has a dip tube :) then it will work well

[wdrzal]

The design concept: By using an old green propane tank as the intake separater it leaves plenty of space for it to suck in liquid, and any who do home brewing knows the idea of distillation it works the same for refrigerant! We boil the refrigerant off leaving the waste oil inside the tank to be disposed of. Using an oil sep on the compressors discharge we can prevent the compressor oil from getting back into the refrigerant being recovered, and by using a cap the refrigerant being recovered will all so cool the compressor!

Xeon you basic understanding of recovery is fundamentally wrong. very little oil is removed from the system by a recovery machine,usually measured in PPM(parts per million) from 500 to 5000. oil does not vaporize so it stays in the system, most of the oil you will get is if recovering liquid refrigerant.but these systems are to small to contain much if any liquid when off

In the real world recovered refrigerants are divided into 2 categories ,clean & contaminated, clean may cost a dollar a pound or less as it is much easier to recycle, contaminated refrigerants cost over 12.00 a pound in some places to turn in a bottle , turn in a bottle you think is clean then get a bill for 26 pounds x 12 dollars a pound for contaminated. That adds up.

But I realize guys in the forum are primely concerned with saving their expensive refrigerant. remove it,fix problem and re-use it.it best to draw it out in vapor form although slower,but little liquid is present in small systems and it can be recovered in vapor form to prevent removing very little of the oil.

Having oil seperators will only cause the refrigerant to go into solution with the oil, why would you want to remove the oil at all? if fact the opposite is what you want to do. I just wrote a long post a few months ago about how even that a system that is off & equalized in pressure,any liquid refrigerant will vaporize move toward the oil,condense then go into solution with the oil.most guys want to recover only clean refrigerant and leave the oil in the system.

if the oil is bad ,you deal with that after you recover the refrigerant.

Standards are given for the amount of moisture,oil & incondensable in ppm by weight and differ for different refrigerants that acceptable for clean recover refrigerant or contaminated..oil does not vaporize so elaborate separators are not needed and if they collect oil will do more harm than good as the refrigerant will migrate there. There are many factory designs of recovery machines that use hermetic compressors and how they work. the vapor extraction rate is slow so they use what is called "a push pull method" to remove the liquid first on larger systems, then you remove the vapor. These small system may not have no to very little liquid in them to start with when off.

below is previous post on refrigerant & oil from a few months ago,read point 1 & 2

I don't have much time to explain right now ,

1, oil attracts liquid refrigerant even if compressor is off and pressure is equalized,liquid refrigerant will vaporize migrate to oil,condense & go in to "solution" with the oil, this is a complex subject as entropy lends its affect to solution.

2,refrigerant in "gas state" does not mix with oil well, thats why piping sizes must be so enough velocity is created to "sweep" it along. nominal is 700 FPM for horizontal & 1500FPM for vertical

just note the difference between a "solution" and a "Emulsion" the latter is when oil & water are put together, there is complete separation until agitated into a emulsion.Think salad dressing....... viniger & oil

since entropy affects solution ,a point in time @ a point in system @ a specific temperature is needed. plus manufacturer data is needed to determine how much of the refrigerant is in "solution with the oil". There are other variables as oil system design,is foaming occuring,etc,etc.........

[Xeon th MG Pony]

Xeon you basic understanding of recovery is fundamentally wrong. very little oil is removed from the system by a recovery machine,usually measured in PPM(parts per million) from 500 to 5000. oil does not vaporize so it stays in the system, most of the oil you will get is if recovering liquid refrigerant.but these systems are to small to contain much if any liquid when off < UNLES TAKING FROM RECEIVER

your basic reading comprehension is fundamentally skiewed! Will you please read the posts and liscen to what I am saying rather then skimming, it seemss you are missing far too much the pictur. I am geting tired of repeating that fact the systems I build are not at all small and I often skip the two stage method you quoted, I prefer the fast not so dirty method of drawing streight from the receiver, and I use a trick one old tech tuaght, run the system to make sure the receiver is full and hot, side effect is, as you have said your self, OIL so the presep does wonders at removing it, he did it by using two tanks, one was a flow through that he heated moderatly the second was where it was stored, I built the "flow through" tank right onto my system and called it what it is oil sep/distilling tank, pending how it works I may add a heater. He achieved both at one go, so I scaled it down, now you know where I learnt the methode and the story behind it. do I have to go into detail of every tiny trick I have learnt and the whole history for you every time I do some thing "Non standerd"?

Not to mention most my systems I incorperate a pump down stage for long off cycles keeping suction to 5 to 10psi the rest is in the receiver, when recovering I just overide the solenoid forcing it off cycle the compressor till there is a 20 to 25" of Hg then draw from the receiver while heating the condencer with a blow dryer. fast and sweet, works great on 6K BTU walk in plants as I have come to learn. As you can figure the comp will not lend out their toys, so I must make my own for at home.

The local guy here is a Boiler engineer/HVAC guy who is now retired several Governmant places use the tables he has built as efficiancy guidlines so I'd wager it safe that he knows what he is talking about, I'm afriad I will trust him befor a name out on the web whom hasn't even a pictur of a system he has built.

pay attention to the oil still and take a gues as to the intak sep.