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  1. #1

    AC switching from R-22 to R-410A Question

    My question is if I replace an R-22 unit with an R410A unit will the contractor need to replace the piping from the old unit (R-22) or just clean the pipes and check it for pressure so it can handle the new requirements of the new R410A.

  2. #2
    Join Date
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    The old line set can used.
    The line set can be flushed or blown out with nitrogen.
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  3. #3
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    beenthere: Don't mean to step on your toes, and I agree with your advice; however, my understanding from several trade articles I have read, and from talking to field service reps, is that it takes a very incremental amount of residual refrigerant to alter the operation of the new 410-a system. We have established a policy of replacing the line set whenever possible, as this is the only 'guaranteed method' of assuring a non-compromised 410-a system.

    From what I have been told, from a variety of sources, is that the 'normal' flushing process is not adequate for the changeover in refrigerant.

    Obviously, if the line set is not accessible, your options are limited. But even in those instances, we may run line sets along an alternate route.

    All the best, Irish
    Everyone has a purpose in life..........even if it's to be a bad example.

    Seek first to understand, before seeking to be understood.

  4. #4
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    Carrier doesn't even recommend using RX11 to flush out the lines.
    York says says replace the lines when ever possible.

    Each brand has their own recommendations.

    We generally always replaced the lines when possible.
    When it was not practical, we flushed them.
    6 Years and no failures from reusing old line sets.

    Is it safer to replace? Yes.
    Must it be done just because it was an R22 system? No.
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  5. #5
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    What mfg is going to get away with a blanket statement that says replace the lines? We all know it's the right thing to do and there are variables that come with each job that must be considered.

    The RX flush, is probably not ideal. It's a nice little package, but 5-10 pounds of R22 would cost less and be more effective. The flush doesnt have the volume or chemical makeup to absorb oil like R22 does.

    Clearly if a tech is going to flush, he should recover the old system charge remove the indoor coil, tie the liquid and suction lines together inside, close the service valves so the shraders are open to the lines but closed to the unit and add liquid R22 to the liqud line with his recovery machine connected to the suction side.

    I still think changing the lines is the right thing to do when it's impossible to change the lines (impossible doesnt mean difficult).

  6. #6
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    Quote Originally Posted by docholiday View Post

    I still think changing the lines is the right thing to do when it's possible to change the lines
    I don't think you will find anybody to argue against that.
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  7. #7
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    This is very interesting. I appreciate all this knowledge. I've been avoiding R410a and only did one new install, no retrofits. A lot of my area has lines you can't get to. Many are in drywalled ceilings or above kitchen cabinets. I have heard about RX11, but never tried it. Never heard about using nitrogen, mainly use it for pressure testing. So, if someone WERE to have like an old container of SAY R11 sitting around, would that be an even better flush than R22 (even though not approved by mfgs)?

  8. #8
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    It would probaly do a great job.
    Its just the recovery and disposal later that could be aproblem.
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  9. #9
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    Jan 2008
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    Hells Kitchen, Phoenix Arizona
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    You can't win when it comes to 410a conversion from a 22 system...Trane says it doesn't matter, units with run with 50% PoE oil, 50% mineral oil...CPS sells gauges that do both refrigerants and says oil mixing doesn't matter...York says avoid mixing a drop of the oils together...Rheem says also it doesn't matter...The local guy in phoenix that teaches classes not associated with any company or manufacture says not to worry about it...I haven't heard a compelling argument either way as of yet...So to be safe I flush or replace the lines where I can...I can't wait until everyones story is the same...
    "Overkill is an often underrated achievement", Will Hayden -- Red Jacket Firearms

  10. #10
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    I can't wait until everyones story is the same...

    Like that will ever happen, let alone any time soon.

    People are still confused on the EPA leak regulations.
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  11. #11
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    Everybody is still so concerned with 410. Get over it. Its just a refrigerant like any other one we have to deal with on a daily basis. It runs at a higher pressure, I also work with ones that run at a lower pressure. The only time we have changed the linesets are if they are too small, no choice on that one for homeowners, they either get to fix sheetrock or have it run up the side of their house unless we can pull it through the greenberg. The only thing I've ever done is blow some nitro through it to get any sitting oil out, then pull a nice long vacuum and start it up. Zero problems to this day (7years and counting) Of course, today I will have 58 compressor failures cause I opened my mouth.

  12. #12
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    Thanks, really appreciate all this info. Reminds me of when equipment mfgs said leak test dye would void warranties.

  13. #13
    Hi guys,

    I'm new here and was just reading up some information on the topic and thought i would throw in my 2cents worth.

    I don't know if it's different for you guys over there (as i'm in Australia) but we also have the same idea of replacing where possible however, once you get above 1/2" the wall thickness changes for R410a piping as you guys would know the tystems using R410A refrigerant run at a pressure of approximately 1.6 times than R22 so it can’t be used in existing piping above 1/2" due to the pipe wall thickness needing to be higher on R410a.

    No idea if that's how it is over there but i just thought i'd add what i know.

    All the best and love the site.

    Dee

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