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Thread: r22 conversions

  1. #92
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    I just read this whole thing and I think by brain just tripped on high pressure and internal overload. Starting a new gig tomorrow, and I bet the conversion conversation will be coming shortly so I wanted to try to get up to speed.

  2. #93
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    Apr 2002
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    Quote Originally Posted by valdelocc View Post
    Andy, have you guys at Tecumseh experimented with 407c and MO oil in AC applications? I remember reading an article written by Wes Taylor about an experiment conducted by Carlyle, he mentioned that there was a low degree of miscibility, something like 8%, he also mentioned that r22 was only partially miscible with MO at 34-36%.
    I have converted couple of r-22 screw chillers to 407c without changing the oil, the machines are equipped with a separator, my thought is that the oil removal in the separator would be enhance by the lower miscibility. What do you think?
    I know Wes very well. He is one that I pay attention to when he writes articles and commentary for our industry.

    My concern with a large R-407C refrigeration system using MO/AB oil with a separator is you are going to run into trouble at some point. No oil separator is 100 percent efficient, and some MO/AB oil will find itself collecting in the receiver and the low side of the system. My guess is if you were to make an effort to replace at least 50 percent of the MO/AB oil with POE, you would be ok.
    If the only tool you have is a hammer, you tend to see every problem as a nail. Abraham Maslow

  3. #94
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    Quote Originally Posted by ryan1088 View Post
    I just read this whole thing and I think by brain just tripped on high pressure and internal overload. Starting a new gig tomorrow, and I bet the conversion conversation will be coming shortly so I wanted to try to get up to speed.
    Internal overloads do reset themselves.
    If the only tool you have is a hammer, you tend to see every problem as a nail. Abraham Maslow

  4. #95
    Join Date
    Nov 2011
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    North sweden, Ume, Where the birches growing without limits.
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    Will retrofit a unserved(?) R22 unit to R404 in the end of coming week. The reason: Plate exchanger on cold side have a water leak.

    It is a small unit, but still it got some capacity. Maneurop MT28. Oil will be exchanged, eventual rubber seals will be changed but 90% is PFTE sealings so it's pretty safe.

    I dont know if I've mentioned this earlier but. At 1st january 2015 all HCFC over 3 kg (6,6 pound) filling has to be retrofitted or converted. The ones under 3 kg have to be retrofitted if you must empty it for service since 1st jan 2010.

  5. #96
    Join Date
    Sep 2002
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    12,299
    Why R404 and not R407 ?

    What were the considerations?

    PHM
    ------




    Quote Originally Posted by Putte View Post
    Will retrofit a unserved(?) R22 unit to R404 in the end of coming week. The reason: Plate exchanger on cold side have a water leak.

    It is a small unit, but still it got some capacity. Maneurop MT28. Oil will be exchanged, eventual rubber seals will be changed but 90% is PFTE sealings so it's pretty safe.

    I dont know if I've mentioned this earlier but. At 1st january 2015 all HCFC over 3 kg (6,6 pound) filling has to be retrofitted or converted. The ones under 3 kg have to be retrofitted if you must empty it for service since 1st jan 2010.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #97
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    Nov 2011
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    North sweden, Ume, Where the birches growing without limits.
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    Too much effect loss on 407C, much less loss on 404A, All effect is needed in this case.
    Quote Originally Posted by Poodle Head Mikey View Post
    Why R404 and not R407 ?

    What were the considerations?

    PHM
    ------

  7. #98
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    Nov 2004
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    up in the hizzy
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    Quote Originally Posted by Putte View Post
    Too much effect loss on 407C, much less loss on 404A, All effect is needed in this case.
    407c net refrigeration effect at 40F degrees evap. temp and 105F cond. temp is 65.4 btu/lb. 404a is 45.5 btu/lb, the very small capacity gains comes from the lower vapor volume of 404a and that lessens the mass flow rate, 404a=2.04CFM per ton and 407c=2.22CFM per ton. the offset comes from the amount of parts and labor involved in changing over a system from r22 to 404a for such a tiny net gain.

  8. #99
    Join Date
    Nov 2011
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    North sweden, Ume, Where the birches growing without limits.
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    Conversion turned out well. New oil, new evaporating pressure valve, new plate exchanger and new AKV (Danfoss electronic expansion valve) maded the system almost better than it did with R22 (yeah ok the new exch turned out to be a li'l bit bigger) Running remarkable shorter periods now. Yeah well... Compare apple and pears in this case...

    But now... The european gov. want to remove 404A from the market and replace with 407F instead... Gaaaah I hate glide refrigerants... On a suggestion they want to phase out and remove ALL refrigerants that has over 150 in GWP... In long term... Remove ALL HFC:s, replace with HC...

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