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  1. #1
    Join Date
    Jun 2009
    Location
    Pompano Bch, S Fla
    Posts
    57

    Water dripping off face of a new coil.

    Hello everyone, I finally have a question that I feel is worthy of starting a new thread. We just put in a new syetem at a school. 15 ton split, I forgot to record model #'s but looked online and pretty sure it's a Rheem RHGM 15 ton a/h which is a slant coil) with two RPWL 7.5's. We had a leak in one of the circuits that was discovered at end of day so we left one condenser running while vacuuming the other overnight. Returned today and (this is where it gets interesting) found that water was dripping off about halfway down the evap coil and missing the drain pan completely. Boss thought it might have something to do with only one circuit running but it still happens with both condensers running. The building went w/o air for 3 weeks and there's ALOT of condensation but it still doesn't seem right. Never seen anything quite like this. I'm more of a resi guy so any thoughts would be appreciated. Thanks in advance

  2. #2
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    it appears you have high velocity..... just a thought
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  3. #3
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224
    Quote Originally Posted by Pete954 View Post
    Hello everyone, I finally have a question that I feel is worthy of starting a new thread. We just put in a new syetem at a school. 15 ton split, I forgot to record model #'s but looked online and pretty sure it's a Rheem RHGM 15 ton a/h which is a slant coil) with two RPWL 7.5's. We had a leak in one of the circuits that was discovered at end of day so we left one condenser running while vacuuming the other overnight. Returned today and (this is where it gets interesting) found that water was dripping off about halfway down the evap coil and missing the drain pan completely. Boss thought it might have something to do with only one circuit running but it still happens with both condensers running. The building went w/o air for 3 weeks and there's ALOT of condensation but it still doesn't seem right. Never seen anything quite like this. I'm more of a resi guy so any thoughts would be appreciated. Thanks in advance
    Im assuming that the drain line leaving the air handler does not have a proper trap installed.

  4. #4
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,623
    Any chance the bottom 1/2 of the coil was dry, this would allow the water to not stick on that part surface.

  5. #5
    Join Date
    Feb 2012
    Location
    EVERYWHERE
    Posts
    226
    Try to clean the coil with triple D cleaner.

  6. #6
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    I assume each units charge is correct.
    and the superheat for each is correct .
    And it is staged properly, meaning the coils first stage is actually connected to the first on condenser, the second stage is connected to the last on condenser .

    But you said it drips with both on .

    to much airflow maybe , Assuming its charged properly and running properly ,whats your td ? Is it normal ,high,?or low?


    I've seen new coils with a lot of manufacturing oil on them drip water.

    Clean it to strip any oil off it and see what happens.

    Ive even cleaned them first and then dissolved some dishwasher soap in water and sprayed the coil down with the solution and let them self rinse. dishwasher soap ,such as powdered cascade , has been known to help dripping coils .

  7. #7
    Join Date
    Jun 2009
    Location
    Pompano Bch, S Fla
    Posts
    57
    Didn't check subcool or td yet bc I was doing all the other incidental stuff but the pressures seemed normal enough until we get the building back to normal temp and can adjust properly. Circuits are correct and it's txv so I wasn't planning on checking superheat. As for the bottom half the specs I found on Rheem's site say the coils are interlaced so I don't think that's it. I considered the oil theory so it is good to hear some support of that. Will suggest the dish soap to boss. Last but not least, I thought it might be airflow but I was thinking not enough. Why would too much cause it to drip?
    Thank you all for your suggestions. I'll let you know what happens.

  8. #8
    Join Date
    Jan 2011
    Location
    Boston, MA
    Posts
    459
    I'd start with checking airflow and washing/cleaning it too.

  9. #9
    Join Date
    Jul 2005
    Posts
    5,380
    Quote Originally Posted by Pete954 View Post
    Didn't check subcool or td yet bc I was doing all the other incidental stuff but the pressures seemed normal enough until we get the building back to normal temp and can adjust properly. Circuits are correct and it's txv so I wasn't planning on checking superheat. As for the bottom half the specs I found on Rheem's site say the coils are interlaced so I don't think that's it. I considered the oil theory so it is good to hear some support of that. Will suggest the dish soap to boss. Last but not least, I thought it might be airflow but I was thinking not enough. Why would too much cause it to drip?
    Thank you all for your suggestions. I'll let you know what happens.
    It isn't an airflow issue. Excess air flow could cause condensate to pull off, but it wouldn't cause it to drip off. Low air flow shouldn't cause dripping, because the coil shouldn't drip even when the blower cycles off. It's probably oil on the coil. You said it had a leak, so I'd probably start by leak testing the coil in the finned area.

  10. #10
    Join Date
    Jan 2011
    Location
    Boston, MA
    Posts
    459
    Good catch medic, your right if it's dripping its not an airflow issue..I was thinking "flying" off for some reason.

  11. #11
    Join Date
    Jun 2009
    Location
    Pompano Bch, S Fla
    Posts
    57
    The leak was a tiny spot that someone missed while brazing in the sightglass. Nowhere near the evap. Definitely going to suggset cleaning the coil. Hope the boss listens. Thanks all.

  12. #12
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,623
    Re read original post and so should everyone else. This happened while one circuit was down being repaired, so this leads me to believe in my 1st reply, wet coil ontop and dry bottom water hits dry coil and gets pulled off.

  13. #13
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    Quote Originally Posted by Southern Mech View Post
    Re read original post and so should everyone else. This happened while one circuit was down being repaired, so this leads me to believe in my 1st reply, wet coil ontop and dry bottom water hits dry coil and gets pulled off.
    he said it happened with only one but continued when both were up and running .

    You are 100% correct about hot spots on/in a coil causing dripping
    mikeacman

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