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Thread: 22 to 407a

  1. #1
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    22 to 407a

    Just wondering how your guys experience is with some conversions.

    We will be swapping some medium temp conventional r22 systems onto a new zero zone protocol type system running 407a. 6 scrolls one with an unloader.

    Just wondering what I should be geAring up for? Just reading another thread on an oil conversion, seeing now we will be using POE in the new unit and there will be likely some residual mineral oil throughout the piping and systems, should I be thinking about some oil changes in the near future?

    Also it's been a while on setting up low pressure controls on a multi compressor rack , what should my cut in and cut outs look like?

    Thanks in advance.

  2. #2
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    Change to oil before, then again.

    You might want to consider having a professional oil evaluation done, too.

    CHANGE ALL THE O-RINGS!

    The glide on 407a makes setting pressure controls and holdback valves interesting.

    You need to use an average between dew and bubble point to get a proper setting.

  3. #3
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    To clarify.

    Change oil in preparation to the refrigerant change, then change it again when doing the change.

    We send an oil sample to National Laboratories because the customer has that written into their requirements.

  4. #4
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    I have no experience with this refrigerant as well as glide, so this will be interesting and a learning curve to say the least.

    As for the oil, the new units come with oil added already I just need to add some oil in the oil separator/ resovoir. I plan on pumping the old units down one at a time and tie them into the new piping arrangement. Do you suggest changing the oil in the convention units before we tie them into the new system?

    When you say change all the o rings , could you please be more specific? Every system is a loop system with multiple cases on each conventional unit , mostly all controlled by stat and solenoids. Which valves have the o rings as I have not too much experience tearing valves apart, but sure sounds like this may change with this particular job.

  5. #5
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    Stat and solenoid at the evaps?

    I'd purchase a rebuild kit for each solenoid valve.

    I'd also replace any schraeders that won't be pulled out when you install the protocol.

    R-22 causes o-rings to swell up. R-407a doesn't. The swollen o-rings will shrink and leak.

    I'd also schedule a leak check or two after the job is done.

  6. #6
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  7. #7
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    Stats and solenoids at the evaps.
    Sounds like we have our work cut out for us!
    Appreciate the feedback JP.
    I will try and post the outcomes.
    Cheers

  8. #8
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    Your first will be a

    Order twice as much gas as you think you need and leave it on-site for a month.

    You can return it later.

    The first 407a conversion that was done in one of my stores resulted in THE BIGGEST leaks that I've ever seen. O-rings that had basically crumbled and broke apart on koolgas defrost lines. Leaks that bubbles wouldn't even stick to. Leaks that blew up a detector and made me resort to running my hands over the piping and valves to find them.

    The guys who did it (not me) finished the conversion on a Friday morning. By Monday when they called me out, I was over 1000 pounds short between 2 racks.

    Did I mention that neither of the supply houses in my area had ever HEARD of 407a...


  9. #9
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    This will be on medium temp equipment so thankfully we will have not hot gas or kool gas defrosts.
    We will be starting the swap over tomorrow so wish me luck!
    I know what you mean about the gas, bought some jugs of it today and the counter guy had to repeat what I asked for because he thought I said something else. I went out to the warehouse to show him the bottles. Only reason I knew they had some in stock is that I purchased some last week from there lol. Might be a good idea to get them to bring some more in.

  10. #10
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    Like JP said-for sure schedule a leak check and change all the o-rings, schraders, and get ready for some leak checking fun.
    Knowledge is knowing that a tomato is a fruit. Wisdom is knowing not to put it in a fruit salad.

  11. #11
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    What kind of application are we talking'bout? A/C or refrigerators? A/C works well with 407, but for ref's I'd prefer 404 or 507.

  12. #12
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    Quote Originally Posted by Putte View Post
    What kind of application are we talking'bout? A/C or refrigerators? A/C works well with 407, but for ref's I'd prefer 404 or 507.
    R407a works well in both medium and low temp applications.

    There are several R407x refrigerants.

  13. #13
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    I would put some poe in with the min oil before hand just to get the system cleaned up.
    I love the smell of phosgene first thing in the morning:

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