Frozen condensation inside attic airconditioning ducts


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Old 12-10-06, 07:44 PM
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Frozen condensation inside attic airconditioning ducts

I live on Long Island NY and in the last few weeks I have cut vents into my sofits to help cool the unfinished attic in summer. It used to get so hot that the fluorescent lights in the attic would not work because the thermal trip in them had activated. The new problem is last week we had a cold spell with the overnight temps in the low 20s and the warm air in the air conditioning ducts (it must have rose from the living area) condensed and froze. When the temperature rose during the day the ice thawed out and found an escape route out of the duct and dripped onto my ceiling coming through into the living area. At least 3/4 of a pint got through, the remainder being soaked up by the sheetrock. Appart from sealing up the new vents what is the best action to take. The house was built in 51 and the ducts have a thin foilbacked insulation layer. I think I need to replace the old insulation on the ducts with new ductwrap but I want at least R8 how can I do this and would it be a solution. Is there such a thing as a one way baffle to stop the warm air going up the duct but allowing cold air to enter the living space when the system is on.
Thanks for any help I get.

Alan
 
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Old 12-11-06, 11:03 AM
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Wink

You can try and close the dampers on all of the registers this works some times. Or most of the time people have to take the registers off and put up in the pipe. A plastic bag fill it with paper or insulation and put it up in th pipe. Put the register back. You can put plastic over the return grill.

ED
 
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Old 12-13-06, 02:50 PM
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Originally Posted by Ed Imeduc
You can try and close the dampers on all of the registers this works some times. Or most of the time people have to take the registers off and put up in the pipe. A plastic bag fill it with paper or insulation and put it up in th pipe. Put the register back. You can put plastic over the return grill.

ED
Thanks for your help Ed, I took your advice and managed to close all the dampers on the registers. They are very old and I had to use long nose pliers to reach in to get the lever. The existing duct was metal and had maybe a 1/4" of foil covered insulation on it so I'm replacing what I can get to with Flexible R6.0 duct. Which is cheaper and easier than putting a duct sleeve over the original.
It's amazing how one simple job snowballs into 6 other jobs. While I was in the attic I decided to change the MERV 8 filter and found that that was wet from condesation, so now I've got to wrap all the unit and trunk duct in a blanket. All I wanted to do was give my attic some ventilation for summer. Life is tough, what am I complaining about some people don't even have a roof over there heads.
Happy Holidays to all.
Looneylectrics.
 
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Old 12-13-06, 02:57 PM
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Dont use over a MERV 5 and change it every 30 day. Blower has to work to hard with the 8. Use the silver flex duct up in a attic . Will last longer and comes in a R8

CHEERS ED
 
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Old 12-14-06, 02:02 PM
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I also live on Long Island. To get what evr you would need for the duct work go to SW ANDERSON

There are 2 one is off Daniel st off 110 on the west side of 110

They will sell to the public.

Hope this helps.
 
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Old 12-20-06, 06:21 PM
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Thanks for your help guys, the job has turned into a bit of a project. When I looked at 12ft long 2x4 trunk I found very badly connected ducts coming off it, every one has holes around it and no mastic at all so more air must have been blowing in the attic than was blowing in the house. Hopefully we will have a cold house this summer and low electric bills.
Thanks again.
Alan.
 
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Old 01-29-07, 10:40 AM
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I am experiencing a similar problem and would like to join the thread.

I am in a 4-year old home. In winter I heat with a hot water furnance; in summer I air condition with a heat pump. The air handler is in the attic. R8 flexible ducts carry the air to registers in the ceiling. There are three returns. I do not use the heat pump in winter.

The first winter I noticed condensation running down to two of the registers, and staining the ceiling drywall. The ductwork to those two seem to have the most downward slope. The second winter I closed all the registers, covered them with magnetic covers, and also covered the three returns with magnetic covers. My intent was to keep heated house air from entering the ducts. The attic insulation is about R40, and the ducts are on the cold side of the insulation. Come spring I discovered that the air handler was soaked on the inside with condensation, and that the (unused) filter was starting to grow mold.

This winter I did not close the registers, nor cover the returns. My intent was to run the fan in the air handler a few hours each day in an attempt to keep the ducts dried out.

This plan did not work either. If anything, I am getting more condesation in the ductwork.

I am going to try Ed's suggestion of bagged insulation in the returns in addition to the magnetic covers. I will also open up the doors to the air handler to see if it will stay drier.

If anyone has any other suggestions, I would appreciate them.

Thanks, Chuck
 
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Old 01-29-07, 05:05 PM
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I will also open up the doors to the air handler to see if it will stay drier.
NO NO NO let them closed. Block any warm air from the home going back up in the registers The high R/H in it turns back to water when it cools up in the ducts there.

 
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Old 01-24-08, 12:06 PM
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Has MTN3MAN3 solved his problem

I came across this thread when searching for problem of Winter Condensation in Central A/C system. We just installed Central Air in our attic this past year. We too have experienced excessive condensation although all vents are closed and we put magnetic covers over returns. We've had water leaking out through vents, and condensing on return pipe as well, causing staining on the ceilings. Wondering if suggestion of insulation in plastic bags solved the problem for MTN3MAN. We were told not to close the vents in the winter by our GC.

Our problem seems only in new bedroom with cathedral ceilings and master bath adjacent to the room. Any feedback is appreciated.
 
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Old 01-24-08, 02:13 PM
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Our problem seems only in new bedroom with cathedral ceilings and master bath adjacent to the room.
Thats warm moist air right up in that cold duct++++ waterin the duct.
 
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Old 01-28-08, 09:06 AM
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Wondering if suggestion of insulation in plastic bags solved the problem for MTN3MAN.

It solved the problem about 99%. I'll have more info after this winter. The grills over the returns are screwed to the ceiling; I plan to replace them with ones that will open more easily.
 
 

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