Moisture in ductwork


  #1  
Old 01-12-04, 07:42 AM
Juny
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Question Moisture in ductwork

I have been trying to search the archives of previous posts, but I haven't really seen anything yet that looks exactly like my problem. In short, I have water leaking from my ceiling vents for my air conditioning system. To explain more, I have central air, but only baseboard electric heat. All the ductwork and the air handler are in the attic. The ductwork is insulated, and most of it covered with blown-in insulation. Last winter, I had water leak from the vent in the bathroom. I don't have an exhaust fan, but I didn't feel like this was a big problem. I replaced the duct that had about a half gallon of water in it, and covered the vent with foil to keep the humid air from going up in it. Problem solved, I thought. This winter, I covered the bathroom vent as before, but now I notice leaking elsewhere in the house. After further investigation, I noticed that water was leaking from the main piece of ductwork up in the attic, and also from the main air return in the hall. I also looked at the new duct I had replaced last year and found that it had a couple cups of water in it again. While I know that I need to install an exhaust fan in the bathroom, I really can't believe that this is all caused by not having that. Has anyone had this type of probem? Any ideas?
Thanks!
 
  #2  
Old 01-12-04, 10:19 AM
Ed Imeduc's Avatar
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Lightbulb wet duct

This happens a lot. Most of the time the registers there are not closed with there dampers? If not close them.If they dont have any damper in them. Take a plastic bag fill it with old paper and put this up in the pipe. Dont forget to take it out when you turn the AC on. ED
 
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Old 01-12-04, 10:26 AM
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You don't say where you're located, and the answer will partly depend on just how cold it gets in your area. I will assume that it gets below freezing during winter where you are. If so, the moist air from the living space is getting into the ducts, and cooling off causing condensation (even with the ducts insulated). We've seen condensation causing so much water that the people were sure the roof was leaking, but no, the roof was perfectly dry.

Having a bathroom vent will help get rid of some of the moisture to the outside, but all it takes is someone boiling water for pasta to give your interior a serious doze of humidity, which will condense on any cold (or cooler) surface.

As Ed has suggested, the outlet vents should have dampers which can be closed when you aren't using the AC. That's more elegant than stuffing paper up the ducts, although that would work as well.
 
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Old 01-12-04, 11:09 AM
Juny
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Thank you both for the reply. I live in Southern Illinois about 25 miles North of the Southern tip. So far, this winter has been relativley mild with only a few times where the temp has went below freezing for a couple days in a row. We lots of time have drammatic swings in the temps. Just a couple of weeks ago, we were high 60's one day and mid 30's the next. I have dampers on the vents, and they are open. I have considered installing a furnace or heat pump. With the heat blowing through the ducts, would that keep them warm enough, and perhaps cleaned out? Do you think, though that I would then see the moisture develop in other places?
 
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Old 01-12-04, 11:22 AM
Juny
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Thank you both for the reply. I live in Southern Illinois about 25 miles North of the Southern tip. So far, this winter has been relativley mild with only a few times where the temp has went below freezing for a couple days in a row. We lots of time have drammatic swings in the temps. Just a couple of weeks ago, we were high 60's one day and mid 30's the next. I have dampers on the vents, and they are open. I have considered installing a furnace or heat pump. With the heat blowing through the ducts, would that keep them warm enough, and perhaps cleaned out? Do you think, though that I would then see the moisture develop in other places?
 
  #6  
Old 01-12-04, 11:24 AM
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moisture

If you have the dampers close them This should stop it for you. Yes you can put in a heatpump there if you like. It would cost less for heat than the baseboard electric that you have now. My shop is up there in Missouri by lake of the Ozarks. about all we put in now are heatpumps. For where you are on the south tip of Ill.Id say go for it ED
 
 

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