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  1. #14
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    I do
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  2. #15
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    This is interesting. I've done a few r22 to 407a conversions and the liquid injection still cycles, couldn't tell much difference, but of course I never timed it before the conversion so it very well could be less.

    Quote Originally Posted by Phase Loss View Post
    I just completed 2 stores (4 racks) from R-22 to R-407F.

    Under R-22, liquid injection would cycle.

    Under R-407F, liquid injection is not even needing to run.

  3. #16
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    I guess I just replied to a 7 year old post LOL

  4. #17
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    It happens

  5. #18
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    Quote Originally Posted by Chuck View Post
    I guess I just replied to a 7 year old post LOL
    *
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  7. #19
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    All design is compromise. You can't have everything.

    I have used R-407A, C, and F. Although it's not technically accurate - I find it easiest to visualize / project the actions of the various 407's as though they were blends of R-410 and R-134. With A having the least 410 and F having the most 410.

    R-410 is a nice refrigerant but it runs 'too hot' to work well for low temperature (high compression ratio) work. The R-134 component serves to 'cool down' the system. Of course R-134 has a much greater 'pounds pumped per hour' requirement to get equal BTU performance - so, for a given compressor, the greater the R-134 portion of the blend; the lower the BTU performance

    So the 407 blends walk a fence-line between those two factors. It's nice to have the higher suction pressure / higher vapor density for the compressor efficiency but you can't burn the SOB up either. <g>

    I have weighed in a 50/50 blend of R-410 and R-134 (in the field and not in a lab <g>) and found the performance to be the same as R-407C so far as I could tell. That was using an R-22 compressor with POE oil.

    When R-410 first appeared my initial thought was: Here we go - a nice low temp refrigerant which will maintain great suction pressures at low temperatures. I was wrong about that. At first I was annoyed that all R-410 TXV's were for comfort cooling - but eventually I came to realize why. <g>

    Most people I talk to in real life have zero interest in any of this. I know this because of their routine use of their signature-question. Which is:

    "Yeah OK, so what should my pressures be?" <g>

    PHM
    ---------



    Quote Originally Posted by Snapperhead View Post
    I just spoke with my supply and they only stock 2 jugs 407F , and said they almost never sell it

    Anyone use it ?

    Hey Poodle , its been a few years , are you currently stocking both 407 A and C ?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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  9. #20
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    Quote Originally Posted by Poodle Head Mikey View Post
    All design is compromise. You can't have everything.

    I have used R-407A, C, and F. Although it's not technically accurate - I find it easiest to visualize / project the actions of the various 407's as though they were blends of R-410 and R-134. With A having the least 410 and F having the most 410.

    R-410 is a nice refrigerant but it runs 'too hot' to work well for low temperature (high compression ratio) work. The R-134 component serves to 'cool down' the system. Of course R-134 has a much greater 'pounds pumped per hour' requirement to get equal BTU performance - so, for a given compressor, the greater the R-134 portion of the blend; the lower the BTU performance

    So the 407 blends walk a fence-line between those two factors. It's nice to have the higher suction pressure / higher vapor density for the compressor efficiency but you can't burn the SOB up either. <g>

    I have weighed in a 50/50 blend of R-410 and R-134 (in the field and not in a lab <g>) and found the performance to be the same as R-407C so far as I could tell. That was using an R-22 compressor with POE oil.

    When R-410 first appeared my initial thought was: Here we go - a nice low temp refrigerant which will maintain great suction pressures at low temperatures. I was wrong about that. At first I was annoyed that all R-410 TXV's were for comfort cooling - but eventually I came to realize why. <g>

    Most people I talk to in real life have zero interest in any of this. I know this because of their routine use of their signature-question. Which is:

    "Yeah OK, so what should my pressures be?" <g>

    PHM
    ---------
    Interesting... enjoyed the part about mixing 410 and 134...

    Did you, by any chance, figure out the glide...
    And even more interesting... which one would leak out first???

    We have done a bunch of 22 to 407C conversions... they seem to work nicely!
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  10. #21
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    Quote Originally Posted by Poodle Head Mikey View Post
    All design is compromise. You can't have everything.

    I have used R-407A, C, and F. Although it's not technically accurate - I find it easiest to visualize / project the actions of the various 407's as though they were blends of R-410 and R-134. With A having the least 410 and F having the most 410.

    R-410 is a nice refrigerant but it runs 'too hot' to work well for low temperature (high compression ratio) work. The R-134 component serves to 'cool down' the system. Of course R-134 has a much greater 'pounds pumped per hour' requirement to get equal BTU performance - so, for a given compressor, the greater the R-134 portion of the blend; the lower the BTU performance

    So the 407 blends walk a fence-line between those two factors. It's nice to have the higher suction pressure / higher vapor density for the compressor efficiency but you can't burn the SOB up either. <g>

    I have weighed in a 50/50 blend of R-410 and R-134 (in the field and not in a lab <g>) and found the performance to be the same as R-407C so far as I could tell. That was using an R-22 compressor with POE oil.

    When R-410 first appeared my initial thought was: Here we go - a nice low temp refrigerant which will maintain great suction pressures at low temperatures. I was wrong about that. At first I was annoyed that all R-410 TXV's were for comfort cooling - but eventually I came to realize why. <g>

    Most people I talk to in real life have zero interest in any of this. I know this because of their routine use of their signature-question. Which is:

    "Yeah OK, so what should my pressures be?" <g>

    PHM
    ---------
    I maybe wrong but didn't you post awhile back that you were experiment on R22 central air unit using 407C without oil change to see how long it will run before problem occurs. I was wondering what the results of that experiment was.

  11. #22
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    Ive changed a bunch to 407c and never touched the oil ....

  12. #23
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    Quote Originally Posted by sammyray View Post
    I maybe wrong but didn't you post awhile back that you were experiment on R22 central air unit using 407C without oil change to see how long it will run before problem occurs. I was wondering what the results of that experiment was.
    Quote Originally Posted by Snapperhead View Post
    Ive changed a bunch to 407c and never touched the oil ....
    We did a bunch of 22 -> 407C (AC) conversions a few years ago... here are the procedures/results:
    When the suction line was a definite downhill (evap coil in attic or 2nd story attic)... no oil change or additives...
    When the suction line is more level: add 1/2 pt of POE to the system when changing refrigerants.
    We have had ZERO failures so far...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  13. #24
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    Thread Starter
    Well; I guess the experiment is still ongoing as I have seen no trouble yet.

    The concern is for oil return - not directly for lubrication. The 400 series refrigerants are not a solvent for mineral oil so it is not carried along with the circulating refrigerant. But most systems - most especially comfort cooling systems are under-piped. So the vapor turbulence and vapor velocity is almost always way too high. Sure this is easier to tolerate in comfort coolings - as opposed to refrigeration - because the suction pressures, and so the vapor densities, are higher than those in low temperature systems. So the pressure drop causes less compressor efficiency losses in comfort cooling applications.

    But . . . . that Works For Us in terms of oil return. The high vapor velocity and turbulence in the piping serves to 'mechanically' return the mineral oil to the compressor and so all is well.

    So far anyway. <g>

    PHM
    -------


    Quote Originally Posted by sammyray View Post
    I maybe wrong but didn't you post awhile back that you were experiment on R22 central air unit using 407C without oil change to see how long it will run before problem occurs. I was wondering what the results of that experiment was.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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  15. #25
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    Thanks for reply. The parts house push oil change every time you change R22 to 407C. Reason I was wondering because sometimes you run across a customer that has refrigerant leak and wants to get by until summer to change the equipment. It just doesn't make a lot sense to do oil change if the equipment that is going to be change out soon.

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  17. #26
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    If gravity is in your favor then don't worry about miscibility.

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