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  1. #40
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
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    7,761
    At what pressure does the internal bypass on an r22 compressor open? I was thinking around 400psi. My shop has an old Heil builder model 3 ton unit in it that we took out of a customers house about 10 years ago and installed in the shop and it was already 12-15 years old so needless to say its limping along on its last leg and we've definitely got our "money's" worth out of it. I think I'm going to recover the r22 and change the txv to 410a and fill it up with 410a and see how she screams. Maybe I'll get another 25 years out of the POS... Not going to change the oil, just want to keep my head pressure below 400psi when its hot out and hope the compressor can handles the higher pressure. I'm confident the coil will withstand the higher pressure in just not sure about the compressor, guess I'll find out when it warms up this summer.

  2. #41
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,725
    Quote Originally Posted by jtrammel View Post
    At what pressure does the internal bypass on an r22 compressor open? I was thinking around 400psi. My shop has an old Heil builder model 3 ton unit in it that we took out of a customers house about 10 years ago and installed in the shop and it was already 12-15 years old so needless to say its limping along on its last leg and we've definitely got our "money's" worth out of it. I think I'm going to recover the r22 and change the txv to 410a and fill it up with 410a and see how she screams. Maybe I'll get another 25 years out of the POS... Not going to change the oil, just want to keep my head pressure below 400psi when its hot out and hope the compressor can handles the higher pressure. I'm confident the coil will withstand the higher pressure in just not sure about the compressor, guess I'll find out when it warms up this summer.
    What will happen is oil missivity (probably got that term wrong) is not adequate to circulate the oil... the compressor will be starved of oil and self destruct.

    What it means is: The refrigerant and the oil do not mix well... and the refrigerant will not carry the oil back to the compressor. You will have a trashed compressor (from lubrication starvation) in a while.

    I have seen a few 22 pumps make curious noises (similar to a RV valve shifting) when they hit around 400-425. Always assumed (yeah, bad thing to do) this was the internal pressure relief.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  3. #42
    Join Date
    Apr 2007
    Location
    TIP-O-TX
    Posts
    278
    Bacon fat, I like it in my refried beans.
    Quote Originally Posted by BaldLoonie View Post
    What oil are the Mexicans putting in to the Rheem dry units?

  4. #43
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,564
    Quote Originally Posted by jtrammel View Post
    At what pressure does the internal bypass on an r22 compressor open? I was thinking around 400psi. My shop has an old Heil builder model 3 ton unit in it that we took out of a customers house about 10 years ago and installed in the shop and it was already 12-15 years old so needless to say its limping along on its last leg and we've definitely got our "money's" worth out of it. I think I'm going to recover the r22 and change the txv to 410a and fill it up with 410a and see how she screams
    It won't work. Changing the refrigerant to 410a will increase the capacity to 4-4.5 tons, making both the coils undersized. The compressor will die a quick death.

  5. #44
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,761
    Quote Originally Posted by craig1 View Post
    It won't work. Changing the refrigerant to 410a will increase the capacity to 4-4.5 tons, making both the coils undersized. The compressor will die a quick death.
    I can hardly wait, wonder if it will lock down, blow the peckerhead, ruin the valves, or burn the motor windings.

  6. #45
    Join Date
    Jul 2001
    Location
    Anderson,SC
    Posts
    1,034
    I'm going to tell your Daddy.


    Stud

  7. #46
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,761
    Quote Originally Posted by HVAC/Stud View Post
    I'm going to tell your Daddy.


    Stud
    He's in on the experiment.

  8. #47
    Join Date
    Feb 2013
    Location
    north georiga
    Posts
    650
    i'd like to hear the details when your done

  9. #48
    Join Date
    Aug 2010
    Location
    Northern Cali
    Posts
    72
    So this thread has been going for almost a year now. I would like to know how many dry charged r22 units have you installed using r407c ? Has it been successful , have you had any call backs due to using 407c. Do you recommend it? Last summer I was still using r22. But the price around is here is extremely high right now. Thank you for your time.

  10. #49
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,725
    Update: I was at the SureComfort (Rheem/Ruud builder grade name) shop today, free lunch (literally... ).

    I was talking to the store manager... we got to talking about dry units. I mentioned the 407C thing and he said TPTB said NO. I asked if we could go out in the warehouse and look at one... we did. The label has been changed since the one I saw (installed) last summer... it says R-22 only. SOOO...

    I stand corrected (things changed). Now I have no personal knowledge of any dry unit that uses any refrigerant other than R-22.

    Given this fact, as well as the price of R-22... IMO the thing to do is sell them a new 410 system (I am speaking of residential systems).
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  11. #50
    Join Date
    Feb 2004
    Location
    Ky
    Posts
    269
    I think you'll find that 407 is a blend of 410a and 134a...not sure the proportions, but think it's around 50/50 (of course, they are both blends to begin with). I was also told that POE and mineral do not have a problem together. Have also seen/heard that manufacturers are stating NOT to use 407 instead of 22, or else no warranty.
    LN

  12. #51
    Join Date
    Aug 2010
    Location
    Northern Cali
    Posts
    72
    Well that's funny because I was just at the parts house (united refrigeration) and they told me that there dry charge condensers come with poe oil and are r407c ready. They even recommended it due to the extremely high r22 prices. I think the brand they carry is Thermal Zone, not 100% on that tho. Condensers in my area are getting stolen all the time and some of these customers just don't have the money for a complete change out (rental units). When he told me the price of the r407c it really makes it affordable, However if a couple months down the road when the temps are over 100 degrees I really don't want to get stuck with a bunch of units that cant keep up. What to do? I have 2 units on deck and I need to make a decision.....My out look has always been you get what pay for....and even tho r407c has been around for awhile I have not used it yet

  13. #52
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,725
    What is interesting about that is: Thermalzone is another of the Rheem/Ruud clones...

    Wonder why one clone says no, while another says yes... Curious...
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

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