# Duct dripping water



## darcarcr (Dec 21, 2006)

I have heard of this twice now and was wondering if anyone knew of a cause/solution...

I recently finished a basement and the drywaller asked me prior hanging if I was going to wrap the duct work to prevent dripping. Just this morning a co-worker said his unfinished basement floor had water (enough to make a small puddle and cover a 2x4 on conc) and the source was a joint in the ducting of the furnace. He pushed on the joint and a small amount of water came out of the seam.

I have seen water lines sweat, and drip, but never a duct of a furnace.

What causes this?


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## KUIPORNG (Jan 11, 2006)

I heard it is caused by central air conditioning condensation... but that should only happen when air conditioner is being on... is it the case?


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## darcarcr (Dec 21, 2006)

KUIPORNG said:


> I heard it is caused by central air conditioning condensation... but that should only happen when air conditioner is being on... is it the case?


No. I am in Cedar Rapids, Iowa and it is the end of December.

My co-worker states it doesn't look like anything had been poured into the duct from above, and there are no water lines etc that run on the interior of the duct...:confused1:


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## #CARRIERMAN (Oct 18, 2006)

Hi darcarcr

The same thing happens in the heat mode that happens in the cooling mode. The temperature differential is what causes moisture to collect on duct. More than likely what is happening is when the duct work cools after a long run time the moisture will collect on it at this time. When you enclose the duct pipe without insulating it does not have the thermal break needed to keep this from happening. However the heating mode is the less likely of the two to sweat, but if the humidity in the air remains fairly high it will do it in heat also. Hope this is not as clear as mud.

Good luck
Rusty


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## KUIPORNG (Jan 11, 2006)

Thanks for the clarification carrierman, I am glad that I see your other thread suggesting that and I went ahead to wrap my heat trunk before enclosing them in the basement, I do have a small question I like to ask in addition to that, while wrapping the heat trunk, I am able to wrap the three sides of the trunk only, the left, right and bottom, I am uable to wrap the top side because it is too close to the joists and I cannot feed in the materials, especially I have already finished framing around the trunk... please tell me that shouldn't be a problem right...


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## acefurnacefixer (Nov 24, 2006)

I see this quite alot were a dryer vent is clogged, and basicly dumping a bunch of humidity into a basement. Or in a room vith a unvented wall heater.But in the winter time its very rare to see this. I suspect some other issues at hand.


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## darcarcr (Dec 21, 2006)

If it is an issue of ambient temp and temp difference, will it cause internal damage or eventually evaporate? 

The duct's are sealed with duct paste (or whatever you guys call it) and I guess it could be this particular joint seal is broken enough to let moisture out.

I advised my co-worker to check other ducts, even if it meant breaking the seal and having to re-seal, to see if moisture is in the ducts.


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## yummy mummy (Sep 11, 2006)

*kuiporng*

I am having the same problem insulating the top part of the heat trunk.
Though I am wrapping and cutting to fit it in, but too much work.

I also was wondering if that would be a problem.

Anybody?

Carrierman: You always have the right answers. What should we do?


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## #CARRIERMAN (Oct 18, 2006)

Hi Guys

The best way to do what needs done is to loosen hanger straps. If you dont have room to do so, if there is enough room to slip something like sturdy R or something of that equivalence between floor and duct this would suffice. The biggest thing to remember is not to leave any duct exposed to the atmosphere.

Good luck
Rusty


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## darcarcr (Dec 21, 2006)

#CARRIERMAN said:


> Hi Guys
> 
> The best way to do what needs done is to loosen hanger straps. If you dont have room to do so, if there is enough room to slip something like sturdy R or something of that equivalence between floor and duct this would suffice. The biggest thing to remember is not to leave any duct exposed to the atmosphere.
> 
> ...


Sounds like this guy know what he is talking about

Thanks. I will pass the knowledge forward


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## acefurnacefixer (Nov 24, 2006)

the very first thing that needs to be done is a call to your hvac company to check the performance of the system.There are a few things that can cause sweating duct.Slow airflow due to a dirty filter,dirty evaporator or low charge.I have seen brand new systems that the homeowner neglects to change the filters and causes system problems.If the system checks out ok you may need to ventalate your basement space so that your duct does not reach its due point.If all else fails you can install a dehumidifier in your basement,.Most of the sweating systems I have seen were fixable with system adjustments or repairs.If they changed the filters too late(which could have caused the sweating) you will need to dry the system out in order for it to not sweat.The insulation must be dried out or it will continue to sweat after the problem is fixed.


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## yummy mummy (Sep 11, 2006)

*carrierman*

What is sturdy R?

Oh man, it sounds like a lot of work to insulate these ducts.
If some of it is not completely covered, would that pose a problem?


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## KUIPORNG (Jan 11, 2006)

I think the sturdy R is those thing you spray in a can like bug killer spray...

I already cover one of the trunk... if I need to apply this sturdy R... I need to open up or don't know, there may be gap which I can fit in those long strew... like I bought those bug killer to kill the bees this summar... I am going to check it out at HD today...


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## yummy mummy (Sep 11, 2006)

*kuiporng*

If I can't get the ducts completely covered especially on top inbetween the floor joist, then what could be the problem that I may have?


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## KUIPORNG (Jan 11, 2006)

*Use regular insulation material is in fact the easiest way to insulated the ducts*

I just find out, once cover the sofflet with three walls, leave one wall open, then stuff all the insulation material around the duct is easiest and cheapest, I used those material say resistance to heat, something like over 1000 degree celcies it claims.... anyhow, I got a large bag of $35 bucks and still couldn't finish them all... same can be done on the space between the duct and the flooring...


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