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Thread: mold

  1. #1
    Join Date
    Oct 2005
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    what is the most common cause for mold growing in flex duct

  2. #2
    Join Date
    Feb 2003
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    read about mold at EPA.GOV = 14 pages

    probably indictive that the unit is oversized, blower too fast --

    read lots here & at IAC forum of this site
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  3. #3
    Join Date
    Jun 2003
    Madison, WI/Cape Coral, FL
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    MOld growing in ducts occurs when the temperature of the duct sufaces are near or below the dew point of the duct. This can occur in the summer during the off cooling cycle of a/c. The water loaded cooling coil humidifies the air in the ducts until the water on the coil totally evaporates. This can take days or weeks. The solution is daly drying of the ducts and coil. A similar problem is air blown water off the cooling coil into the ducts. If a whole house dehumidifier is used, discharge the dry air into the a/c supply. This slowly dries the ducts and a/c coil avoiding mold growth.

    Mold can also grow during the cold weather. When the ducts are located in a cold crawl or attic, the duct temperature is below the dew point of the air inside the home during the off heating cycle. If the ducts are cold and wet for days, expect mold to grow on the surfaces. Operating the fan in the "on" mode would keep the ducts warm and dry during winter. Or avoid cold attic a/c installations in cold climates. TB

  4. #4
    Join Date
    Sep 2001
    Vancouver Canada
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    Definetly moisture from some source, no moisture = no mold. Could be condensation in the flex. Is it insulated?
    "Go big or Go Home"

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