excessive condensation cause?

Discussion in 'HVAC Heating & Cooling' started by tregg, Aug 28, 2012.

  1. tregg

    tregg New Member

    Messages:
    31
    Location:
    Iowa
    What makes a refridge or air conditioner put out excessive water? Two instances at the large store where I work. One of those soft drink coolers by the cash register was dumping water on the floor right next to another just like it that wasn't. I checked the pan under it and it was overflowing. We called the HVAC but I didn't hear what the problem was. In the other case water was dripping from the ceiling quite nicely. I put buckets everywhere and still a puddle was forming on the floor. One of the managers went on the roof and said all the air units were dripping the same-nothing unusual. The humidity was quite high that day. There's no other source of water that it could be other than a roof air unit to my knowledge. After calling the field maintenance group we disconected that unit and the water slowed considerably and eventually stopped.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,164
    Location:
    NW Ontario, Canada
    The short answer is temperature. A colder unit will sweat more. Well... up to a point, after which it will frost up.
  3. tregg

    tregg New Member

    Messages:
    31
    Location:
    Iowa
    re

    You mean the unit was running too cold? What would cause that?
  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,164
    Location:
    NW Ontario, Canada
    With the soft drink cooler, my guess is that the door seal was either bad or it got opened a lot more often than the one beside it. They often dump the condensate into a pan where it usually evaporates but probably couldn't keep up or the condensate drain was plugged and it simply overflowed.

    With the air conditioner, if the airflow is restricted because some vents are blocked, the smaller amount of air flowing through it gets more time to cool. Of course it could also be a blocked condensate drain.
  5. Runs with bison

    Runs with bison Member

    Messages:
    897
    Location:
    Midwest
    I am not an HVAC tech, but here is my understanding.

    Several things can cause frost up:
    1. Low refrigerant charge and therefore low suction pressure. This results in the coil running too cold.
    2. Faulty TXV or plugging capillary tube.
    3. Low air flow across the coil.

    However in your case it sounds more like a problem with a unit's condensate drain backing up/plugging. Pink algae and such can block the drain. I lived in a rental that had issues with this algae and I had to dump bleach down that drain periodically. Part of the issue there was that the standpipe ran into an iron drain and the iron drain line was filling with rust scale. Cleaned that all out and put in a larger diameter and taller condensate drain pipe and never had a problem with it again--never had to put bleach in it again either.

    The same might even be true on the softdrink cooler. The drain pan is supposed to be evaporated by air flowing across it, but if the fan isn't working right or the entrance/exit is choked with dust the water is going to continue to accumulate.
  6. WorthFlorida

    WorthFlorida USCG escorting cruise ship leaving Port Everglades

    Messages:
    126
    Location:
    Lake Worth, Florida
    If this just happened this past week I say it is very high humidity. It looked like you got some weather from post tropical storm ISAAC and it did bring up more humidity then a typical humid day in the mid west. The refrigerator could be a little low on its charge and as said above, the door seal may not be tight. The ROOF A/C does sound like a plugged up drain since you stated the drip was very constant. But again the high humidity probably exasperated the problems. If the drain is not plugged and the A/C is working normal, the cold air hitting the ceiling grill brings the surface temperature of a metal grill below the dew point and if the room humidity is very high, that grill will sweat. I had this happen to where I work and the grill fixture in a 2'x2' drop ceiling filled up with water and overflowed. I was amazed how much water there was. The room humility, because of a crappy door seal leading to the outside, was a high as the outdoors. To fix the problem I replaced the door seal.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,058
    Location:
    Cave Creek, Arizona
    quote; The short answer is temperature.

    The short answer is humidity. IF the air is "dry" there will be little condensation regardless of the temperature, and damp air will create condensation with very little temperature change. BUT, the condensation should be directed to the drain line unless there is a problem inside the unit.
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,164
    Location:
    NW Ontario, Canada
    I'm pretty sure that with two units sitting side by side, that the air humidity would be the same.

    When it comes to humidity it is relative to temperature. That is why the term "relative humidity" is so often used.
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