Dehumidifaction problem


  #1  
Old 07-22-04, 02:07 PM
RAMinKC
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Dehumidification problem

Has anyone come across the problem of having the a/c units oversized and not running long enough to dehumidify the air? We have a 1yr old 2400 sf 2 story house in NW Arkansas and the builder put in a 3.5t downstairs and a 2.5t upstairs. We have been smelling a musty odor in the 1st floor fam rm and took off the first 6" of gyp. bd. We found the unfaced batts soaking wet! The 6mil vapor barrier was in the right spot, found no leaks of any kind in the roof, windows or plumbing. The only thing I can think of is that the units are oversized and therefore our humidity is very high. I ran some numbers on another website which said for my sized house I should only need a total of 3.8tons. Is there any way to adjust a 3.5 ton unit to perform like a 2.5 ton?

Thanks
 

Last edited by RAMinKC; 07-22-04 at 02:55 PM.
  #2  
Old 07-22-04, 02:34 PM
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If the vapor barrier was intact, there is little possibility that humidity penetrated the drywall and soaked the insulation. You would be swiming in humidity before that would take place. Is it possible that moisture is coming up from below. Is there a basement under this room? How close to grade is the floor level? I would suggest keeping second floor doors open as much as possible and just running the fan on the first floor. You may keep the house comfortable with just one unit until the heat is really on. In my area, we can cool a 2400 s.f. house with 2 or 2.5 tons total, no problem. Oversizing is not a good thing for heat or cool. Let us know if you do find the source of the moisture.

Ken
 
  #3  
Old 07-22-04, 02:49 PM
RAMinKC
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Ken,
The house is a slab on grade. I have verified that there is no ground water getting to the batt insulation. I'll try to see if we can cool the whole house with the upstairs unit.
 
  #4  
Old 07-22-04, 05:34 PM
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Wink

In Missouri have 6 ton in 4600sq ft home.
With Ken here Try run up stairs AC only and down stairs fan only 24/7.
Do you know if they put the 6 mil poly under the slab also. Like they should have????
There is a company down in TX that make a coil with two TXV valves on it. That might work for you. Will do a better job on the humidity. Are how big of coil could they put on the unit you have now.check the book for the brand you have and see if you could put a bigger coil on the unit??

Ed
 
 

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