Results 1 to 16 of 16
  1. #1
    Join Date
    May 2002
    Location
    The Netherlands
    Age
    48
    Posts
    274
    Rep Power
    22

    Mineral, AB, POE, PAG. When to use what oil?



    I came to this question when I say Herefishy mention an oil change to alkylbenzene to run an R12 compressor with R404a. I thought an oil change to POE was the way to go.

    The application of mineral oil is fairly straightforward (is it?). It will work with hydrocarbon refrigerants, R22, and the zillion 'compatible' drop-ins for R12 and R22.

    But then we have POE, AB and PAG. R134a, R404a, R507, R410a, R407, they all run well with POE. But why do automotive airconditioning systems use PAG instead of POE? When would one consider AB instead of POE? What are the specific advantages and disadvantages of each lubricant?



  2. #2
    Join Date
    Jan 2002
    Location
    Austin, Texas
    Posts
    718
    Rep Power
    23
    Hi DaBit, I could be wrong.. let me check.... I mis-spoke

    POE is the recommended lubricant for 404A...

  3. #3
    Join Date
    May 2002
    Location
    The Netherlands
    Age
    48
    Posts
    274
    Rep Power
    22
    But still, the question remains.

    What are each lubricants specific advantages and disadvantages. When to choose what lubricant? Why PAG in automotive R134a apps and POE in domestic R134a apps?

  4. #4
    Join Date
    Jan 2002
    Location
    Austin, Texas
    Posts
    718
    Rep Power
    23
    pgs. 4 & 5 give some info..

    http://www.acrib.org.uk/Use%20of%20H...Guidelines.pdf

    _______________________________________

    The following delineates between "miscibility" and "solubility". It is stated that refrigerant miscibility is helpful, but not necessarily essential essential for proper operation.... I guess I have misused the term (as a blanket statement for "incompatable".

    pg. 5

    http://www.dupont.com/suva/na/usa/li...pdf/h45944.pdf


    ___________________________________

    Anyway, I think your're looking for some explanation in the realm of an H-bond, or something at the molecular level to explain the applications, right?

    Good subject.

  5. #5
    Join Date
    Oct 2003
    Location
    Edmonton Alberta, Canada
    Posts
    14
    Rep Power
    0
    hydro aswell. poe is a 1000 times more of an h2o absorbant than mineral oil and alky. pag is 1000 times more than poe. floc point is critaical too. waxing is a prob. w/ mineral but not w/ poe & pag. poe is 100% missable until saturation above 85 degrees F i think therfore prob the best for most apps. i can't recall why pag is used in auto a/c. it's really bugging me now. somebody?

  6. #6
    Join Date
    Jan 2003
    Location
    East Anglia
    Posts
    1,171
    Rep Power
    25
    POE Oil £45+ for 5 litres, Alkyl-Benzene Oil £20+ for 5 Litres,
    Mineral Oil £13+ for 5 litres - see where i am coming from.

    POE obviously a far superior oil but why use it on a system/gas that is ok with AB oils.

    Most new units requie POE buy on older ones why waste money on the oil when AB & mineral has done the job ok for years.

  7. #7
    Join Date
    Dec 2001
    Location
    Cincinnati, Ohio, USA
    Age
    63
    Posts
    259
    Rep Power
    23
    Here are 2 possible reasons why PAG is used instead of POE in automotive:

    1) PAG may be more compatable with the seals and 'rubber' parts than POE

    2) It's all a money thing - why use ACME fittings on R134A bottles instead of the regular fittings (at least here in the USA)? It's the same refrigerant, isn't it?

  8. #8
    Join Date
    Jan 2003
    Location
    Crewe, United Kingdom
    Age
    58
    Posts
    724
    Rep Power
    22
    The issue of PAG over POE has been discussed to death over on the ACKits web site. I think that we all agreed that POE was the superior lubricant for automotive work and that when retrofitting POE is usually the lube of choice in the US. As to why PAG is used by the manufacturers.....Erm well, nothing conclusive there! My feelings are that if the lubricant absorbs more water, then the manufacturers have a stronger argument to replace the reciever drier at a ridiculous price (Some can cost up to £180) Like everything else involving automotive I suspect that it is a scam.
    Karl

  9. #9
    Join Date
    Oct 2001
    Location
    Perth, Australia
    Posts
    87
    Rep Power
    23
    It is good to know that I am not the only one confused.

    I visited our local HVAC school the other day and the instructor was saying that they have started to use ERG1000 (www.erg1000.com) on their R134a coke machines with a good deal of success. This PAO oil does not suck up the moisture like POE and PAG, but neither is it miscible with R134a. The scrapped coke machines are regularly disassembled and rebuilt by the apprentices and POE oils would quickly become water logged.

    Ammonia plants also use oil that is not miscible with the refrigerant.

    The ERG1000 PAO oil has been on the market for a good few years now, and I have not heard of any horror stories. But I still don't understand how it works.
    Mark Baker

  10. #10
    Join Date
    Jan 2003
    Location
    Crewe, United Kingdom
    Age
    58
    Posts
    724
    Rep Power
    22
    My problem with PAO is if it is not miscible with R134a (the manufacturers say that the oil is "dragged" round by the refrigerant), then why not stick with Mineral oil?
    Karl

  11. #11
    Join Date
    May 2002
    Location
    The Netherlands
    Age
    48
    Posts
    274
    Rep Power
    22
    Thus, POE is still the best choice for all 'modern' HFC refrigerants like R134a, R404a, R507, R410A, R407C, etc. Other oils are used to reduce costs.

    Would that be a good conclusion?

  12. #12
    Join Date
    Apr 2001
    Location
    New Port Richey, Florida - USA
    Age
    78
    Posts
    5,072
    Rep Power
    34
    The following website shows various refrigerants and the oils they are compatible with:

    http://www.refrigerants.com/

  13. #13
    Join Date
    May 2002
    Location
    The Netherlands
    Age
    48
    Posts
    274
    Rep Power
    22
    I am aware of that site, but it doesn't mention why oil A is used in application X, and oil B in application Y.

  14. #14
    Join Date
    Jan 2003
    Location
    Crewe, United Kingdom
    Age
    58
    Posts
    724
    Rep Power
    22
    No one will say exactly why PAG was selected for automotive ac, but the hose fitted to R134a systems has a high density liner which is the barrier to reduce leakage. I would worry more about the leakage from joints that are sealed with O rings , lousy compressor shaft seals and corrosion of aluminium components (Especially when the manufacturer uses steel brackets and clips on these components)
    Karl

  15. #15
    Join Date
    Sep 2003
    Location
    ISRAEL
    Age
    72
    Posts
    4,266
    Rep Power
    46
    Hi DaBit,

    I`m affraid there is no straight forward answer to your quwestion.
    I belive it`s all come down to money. POE is expencive but good oil i guess for most new refrigerants. you can not keep it for a long time and you have to change it more frequent.
    is this the type of oil we are looking for? not realy. but for some reason you can not use mineral oil with new refrigerants.
    PAG was selected from a reason which is beyond us.

    for the sport, try contact the oil manufacturers and see if they will answer you.
    Karl Hofmann is right and I think too that you are chasing the wind.

    chemi

  16. #16
    Join Date
    May 2002
    Location
    The Netherlands
    Age
    48
    Posts
    274
    Rep Power
    22
    Oh, I was just curious. There are many different sorts of oil, and when viewed with my technical eyes, one must have an advantage over another in a certain application to chose it. That is why I asked the question since I assumed that you professionals could tell me.

    Now it seems that oils are chosen only partly because of technical reasons, and more because of political/economic reasons. Which does not interest me that much.

Similar Threads

  1. what is the best blend for low temp
    By tony_rich in forum Refrigerants
    Replies: 87
    Last Post: 05-08-2006, 08:29 AM
  2. Oil/lubrication Question.
    By Dilan in forum Trouble Shooting
    Replies: 15
    Last Post: 25-01-2005, 05:50 PM
  3. Mineral to Polyolester Oil Systems - Clean up?
    By mecassa in forum Refrigerants
    Replies: 10
    Last Post: 16-06-2004, 06:44 PM
  4. Oil changeover from mineral oil to POE in compressor
    By aygul in forum Technical Discussions
    Replies: 6
    Last Post: 15-03-2003, 05:02 AM
  5. R404a mineral oil ?
    By Richard in forum Refrigerants
    Replies: 7
    Last Post: 24-12-2002, 02:16 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •