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  1. #1
    Join Date
    Sep 2002
    Posts
    13,551

    Anybody using R407 ?

    Customer had/has a leaking evap - would not replace a month ago.
    Customer had a compressor fail - would not replace evap now.
    I installed an R407 condenser and a huge LL drier

    This is the result:

    Outdoor Ambient 82
    Indoor Ambient 82
    Head press 180 lbs = bubble point 85
    Suction press 75 lbs - dew point 38
    LL temp 72
    Subcooling = 13
    Suc temp 66
    SSH = 28
    Evap air TD - 82-65 = 17

    How does it look to you?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #2
    Join Date
    Dec 2000
    Location
    Flat Rock, NC
    Posts
    463
    Haven't used it in a/c yet. Several med. temp applications have worked out fine. Those pressures appear ok. Is this txv or orifice system?

  3. #3
    Join Date
    Sep 2002
    Posts
    13,551
    I don't know - I can't get to the indoor coil. The system was a 28 year old Lennox 5 ton. The evap leaks but the owner has so far refused to replace it. A dry-charged R-22 unit just seemed too stupid so I used a POE unit and charged with 407C. That way he can stay with the refrigerant whenever he comes around to the idea of a new furnace and coil.

    I was surprised to see the head pressure so low with the 407. At 100 condensing the chart has 407 running about 30 lbs Higher than R22. The conditions seemed more relaxed than I expected. I want to stop by again when the house is at conditions and see how everything looks.

    PHM
    -------




    Quote Originally Posted by codgy View Post
    Haven't used it in a/c yet. Several med. temp applications have worked out fine. Those pressures appear ok. Is this txv or orifice system?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. #4
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,776
    Your LL temp is 10 cooler then the outdoor temp?
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    How many times must one fix something before it is fixed?

  5. #5
    Join Date
    Sep 2002
    Posts
    13,551
    Apparently so. My test gear is accurate.

    Why do you ask?

    PHM
    -------


    Quote Originally Posted by beenthere View Post
    Your LL temp is 10 cooler then the outdoor temp?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #6
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,776
    Quote Originally Posted by Poodle Head Mikey View Post
    Apparently so. My test gear is accurate.

    Why do you ask?

    PHM
    -------
    Cause generally that would indicate a restriction before the schrader valve, or where you have your temp probe.

    Same thing if you had an R22 system, you wouldn't want or expect your LL temp to be below outdoor temp.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  7. #7
    Join Date
    Sep 2002
    Posts
    13,551

    Oh! I forgot the best part !

    During the project the engineer customer is with me constantly and endlessly either asking questions or telling me things. Plus; we are trading engineering stories of all kinds, discussing higher education, philosophy, and various languages.

    At some point I get it all together and looking nice so I dump in some refrigerant and fire it up. I notice immediately that the condenser fan is making a sort of clicking noise. So I look at that and ponder/project just what the problem might be. Immediately the guy starts:

    What's the matter? Is something wrong? What could it be? Why would there be a problem? (and on and on until I want to bellow Shut The Fuk Up! - but don't because I am too gracious)

    I'm tired, it's hot, he has managed to stand in front of my fan all day, and the yammering is bugging the hell out of me. So I listen and realize that it's the compressor - not the fan making the noise. It sort of sounds somewhat like a scroll running backwards - but this is single phase so it's not that.

    So then I get him to be quiet and I am frenziedly scanning through the data banks: How can this be? What is that noise? What can cause this?

    About then I notice that the gauge pressures are almost exactly the same. What??? A brand new compressor isn't pumping? How the hell can that be?

    So I shut it off again and pause and ponder and go over the details of the install again in my head: running the mental video.

    It was just about then that I realized that I had neglected to open the service valves on the unit. <g>

    I laughed and leaped to do that - of course immediately contaminating the R407 with whatever non-condensible the dry pressure charge is. <g>

    In the end I did manage to get away without drowning - but just Barely. <g>
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  8. #8
    Join Date
    Jun 2009
    Location
    Ontario, Canada
    Posts
    1,042
    Quote Originally Posted by Poodle Head Mikey View Post
    During the project the engineer customer is with me constantly and endlessly either asking questions or telling me things. Plus; we are trading engineering stories of all kinds, discussing higher education, philosophy, and various languages.

    At some point I get it all together and looking nice so I dump in some refrigerant and fire it up. I notice immediately that the condenser fan is making a sort of clicking noise. So I look at that and ponder/project just what the problem might be. Immediately the guy starts:

    What's the matter? Is something wrong? What could it be? Why would there be a problem? (and on and on until I want to bellow Shut The Fuk Up! - but don't because I am too gracious)

    I'm tired, it's hot, he has managed to stand in front of my fan all day, and the yammering is bugging the hell out of me. So I listen and realize that it's the compressor - not the fan making the noise. It sort of sounds somewhat like a scroll running backwards - but this is single phase so it's not that.

    So then I get him to be quiet and I am frenziedly scanning through the data banks: How can this be? What is that noise? What can cause this?

    About then I notice that the gauge pressures are almost exactly the same. What??? A brand new compressor isn't pumping? How the hell can that be?

    So I shut it off again and pause and ponder and go over the details of the install again in my head: running the mental video.

    It was just about then that I realized that I had neglected to open the service valves on the unit. <g>

    I laughed and leaped to do that - of course immediately contaminating the R407 with whatever non-condensible the dry pressure charge is. <g>

    In the end I did manage to get away without drowning - but just Barely. <g>
    I have seen scroll compressor on single phase running backward. I put it in last week. no pressure difference, but have amp draw and new hard start + cap. ran normally when I switch the common and run lead.

    speaking of 407: I have several liebert on it, and two split system feeding an HRV on it. don't have the experience to tell what's the advantage from one refrigerant to the other... but I could fix it when it's not working.
    Parts Changer Extraordinaire
    ------------------------------------------------------
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  9. #9
    Join Date
    Mar 2012
    Location
    Birmingham Al
    Posts
    301
    Quote Originally Posted by beenthere View Post
    Your LL temp is 10 cooler then the outdoor temp?
    same thing im thinking.

  10. #10
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,731
    Not picking and poking...

    If the indoor coil is old (do we know its age), Do we have a SEER rating match between the indoor coil and outdoor unit? If not... then problems may arise.
    My experience suggests higher SEER evaps work with lower SEER condensers... however higher SEER condensers do not play well with lower SEER evaps... unless the outdoor unit is smaller in tonnage. A TXV probably would help.

    Just curious... I am not familiar with a 'R407 condenser'... other than a dry unit that has POE oil in it. Is this a refer unit?
    GA-HVAC-Tech

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  11. #11
    Join Date
    Sep 2002
    Posts
    13,551
    The coil is original to the house which is 28 years old.

    10 SEER would be optimistic I would think.

    This condenser is OK to use for r22 and r407 - so I would think it would be a standard r22 unit - except with POE oil in the compressor.

    PHM
    -------




    Quote Originally Posted by ga-hvac-tech View Post
    Not picking and poking...

    If the indoor coil is old (do we know its age), Do we have a SEER rating match between the indoor coil and outdoor unit? If not... then problems may arise.
    My experience suggests higher SEER evaps work with lower SEER condensers... however higher SEER condensers do not play well with lower SEER evaps... unless the outdoor unit is smaller in tonnage. A TXV probably would help.

    Just curious... I am not familiar with a 'R407 condenser'... other than a dry unit that has POE oil in it. Is this a refer unit?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  12. #12
    Join Date
    Mar 2012
    Location
    Birmingham Al
    Posts
    301
    Quote Originally Posted by Poodle Head Mikey View Post
    The coil is original to the house which is 28 years old.

    10 SEER would be optimistic I would think.

    This condenser is OK to use for r22 and r407 - so I would think it would be a standard r22 unit - except with POE oil in the compressor..


    PHM
    -------

    bought one today u are correct

  13. #13
    Join Date
    Jul 2010
    Location
    nebraska
    Posts
    1,629
    IMO that's going to bite him in the butt PHM. 407C has a huge glide and can't be topped off. It's going to cost him a small fortune every time you come out because of that leaking coil.

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