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  1. #1
    Join Date
    Sep 2002
    Posts
    12,248

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

    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
    12,248
    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 100º 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
    Lancaster PA
    Posts
    67,879
    Your LL temp is 10° cooler then the outdoor temp?
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  5. #5
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,021
    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?
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  6. #6
    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.

  7. #7
    Join Date
    Sep 2002
    Posts
    12,248
    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.

  8. #8
    Join Date
    Sep 2002
    Posts
    12,248
    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.

  9. #9
    Join Date
    Mar 2012
    Location
    Birmingham Al
    Posts
    223
    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
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    6,742
    Quote Originally Posted by Poodle Head Mikey View Post
    Apparently so. My test gear is accurate.

    Why do you ask?

    PHM
    -------
    Liquid line shouldn't be cooler than the air cooling the condenser unless there's a problem (restriction?) or your temp reading is not accurate for some reason.

  11. #11
    Join Date
    Mar 2012
    Location
    Birmingham Al
    Posts
    223
    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

  12. #12
    Join Date
    Jun 2013
    Location
    Montana
    Posts
    73
    According to my 407c pt chart your vapor pressure temp should be 48º instead of 38. Either yor sh math is wrong or mistype for sp/temp.

    3º over ambient with 13º sc. That's got to be the best refrigerant for heat exchange ever...lol

  13. #13
    Join Date
    Sep 2002
    Posts
    12,248
    Yeah - how can that be?

    PHM
    ------





    Quote Originally Posted by Poodle Head Mikey View Post
    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 82º
    Indoor Ambient 82º
    Head press 180 lbs = bubble point 85º
    Suction press 75 lbs - dew point 38º
    LL temp 72
    Subcooling = 13º
    Suc temp 66
    SSH = 28º
    Evap air TD - 82º-65º = 17º

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

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