Furnace ducting leaks at duct box

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  #1  
Old 10-26-20, 12:17 AM
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Furnace ducting leaks at duct box

I went under my house today to check for duct leaks and I found a leak on one of the three or four main ducts that attach to the duct box underneath my furnace / AC.



Seems to be leaking at the point where the duct attaches to the air box. What's the best way to fix it?


 
  #2  
Old 10-26-20, 08:10 AM
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You'll need to fully expose the "collar" (sheet metal fitting connecting the flex to the main) to inspect the joint. If there's a small gap, just apply duct sealant marked "UL181...". You'll have to leave the system off for 24 hours to make sure it's fully cured.

If there's a large gap, remove the collar and install an adhesive collar.


 
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Old 10-26-20, 08:26 AM
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remove the insulation and brush on some duct sealant around the collar let it dry then reinsulate.
https://www.homedepot.com/p/Speedi-P...-0-5/202907021
 
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Old 10-26-20, 10:46 AM
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Thanks for the responses. I'll go back and check for the size of the gap. If it's small, I'll apply some duct sealant.
 
 

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