# Condensation in ceiling



## KennMacMoragh (Sep 16, 2008)

After seeing water stains in the ceiling tiles, we weren't sure if it was a leaky roof or condensation from the duct work. I looked above the suspended ceiling and noticed every piece of ductwork is covered with insualtion and foil except for a T-connector. I felt a little bit of wetness on it, so I'm pretty sure that's where the drips are coming from. I don't know HVAC codes but isn't everything supposed to be covered with insulation and foil? Why would they leave it off in only that one place?


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## flashheatingand (May 3, 2008)

Is that a drop can from a rooftop unit? or is the air handler in the ceiling?


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## KennMacMoragh (Sep 16, 2008)

There's two rooftop units, so I guess it's a drop can from one of them.


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## flashheatingand (May 3, 2008)

It's possible that water is dripping from the coil above, as opposed to condensation forming on the drop can.


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## KennMacMoragh (Sep 16, 2008)

flashheatingand said:


> It's possible that water is dripping from the coil above, as opposed to condensation forming on the drop can.


How would I check that? Would it be worthwhile to wrap the drop can with insulation anyway?


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## flashheatingand (May 3, 2008)

It certainly wouldn't hurt to wrap the metal. But, it's hard to say weather or not the lack of wrapping is the culprit. Our climate is rather dry, and I have never seen droplets form on the metal. So, if that were to occur here, that would be a sign of poor air-flow. However, in humid climates, condensation may form on the ducts, on a regular basis. I don't know.

I am not there, but, I would think that the culprit isn't the lack of foil wrap, it has something to do with the condensate drainage.


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## griz (Nov 26, 2009)

Kenn, check the condensate drains on the roof top units.

Also you probably get plenty of the liquid sunshine up there. Make certain your roof top units are properly sealed & not leaking to below.


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## KennMacMoragh (Sep 16, 2008)

griz said:


> Kenn, check the condensate drains on the roof top units.
> 
> Also you probably get plenty of the liquid sunshine up there. Make certain your roof top units are properly sealed & not leaking to below.


It's actually in a part of Washington that rains very little, but yeah I'll check to see if it's sealed. I don't really know what I'm doing looking for condensate drains, but I will look to see if it's something obvious.


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## OT Ready (Jun 18, 2008)

The drop from the roof is probably soundlined. Insulator most likely considered this when insulating.


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## KennMacMoragh (Sep 16, 2008)

Well, I looked at it and found the unit above where the leak is coming from appeared to have no water coming out of the drain. I compared it with the other unit and saw loads of water dripping out of the pipe. That makes it fairly clear I think that water is going inside the building instead of through the drain like it's supposed to. 

But what I don't understand is, when I took the cover off to see what was wrong, water came pouring out of the pipe all of the sudden. I thought maybe there was something on the cover blocking the pipe, but no... I looked at the cover and there was nothing wrong, all it does is fit around the pipe. I'm thinking it's now fixed since the water is draining through the pipe just fine now. But I'm still confused what happened :confused1:


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## flashheatingand (May 3, 2008)

System could be starving for air...Not enough return air. Are the returns ducted, or is an open plenum? 

Also, I would check to make sure the unit was set so as the water flows towards the drain hole.


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## thom (Nov 3, 2006)

Before pulling the cover, was the trap oriented as it is in the picture? If so, that is a likely cause of the problem. The trap needs to hold water in it. The water in the trap will prevent the unit from sucking air through it. If air is being drawn through the trap, the movement of the air can prevent the condensate from flowing out through the pipe, allowing the condensate to over-top the drain pan and spill into the duct. This only happens if the "A" coil is on the suction side of the unit which is pretty common for roof-top units. 

A second likely cause, is clogging of the drain. Sometimes crud gets in the drain at the inlet inside the unit. This is more likely to happen if the "A" coil is on the pressure side of the unit.


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## KennMacMoragh (Sep 16, 2008)

flashheatingand said:


> System could be starving for air...Not enough return air. Are the returns ducted, or is an open plenum?
> 
> Also, I would check to make sure the unit was set so as the water flows towards the drain hole.


The returns are ducted. I guess I can check to see if it's sloped, but it looked like it was draining just fine when I had the cover off. 



thom said:


> Before pulling the cover, was the trap oriented as it is in the picture? If so, that is a likely cause of the problem. The trap needs to hold water in it. The water in the trap will prevent the unit from sucking air through it. If air is being drawn through the trap, the movement of the air can prevent the condensate from flowing out through the pipe, allowing the condensate to over-top the drain pan and spill into the duct. This only happens if the "A" coil is on the suction side of the unit which is pretty common for roof-top units.


Yes, both rooftop units are like that. I'll turn them though, so the 'U' holds water.


> A second likely cause, is clogging of the drain. Sometimes crud gets in the drain at the inlet inside the unit. This is more likely to happen if the "A" coil is on the pressure side of the unit.


I don't know which side is the pressure side, the water flows through the drain pretty good though as you can see.


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## flashheatingand (May 3, 2008)

The cover thing is what made me jump to conclusions about return air thing. It is weird that all of a sudden, the water drained out, and still suspect not enough return. But, Thom is right about the p-trap...good catch. The p-trap prevents air from being sucked through the condensate line. 

What I suspect is happening is that you are starving for air. You could be sucking a lot of air from the condensate opening. This is what is backing up the drainage. Hence the p-trap. I would make the p-trap right, and follow-up to see if that was all that was necessary.

Just so you know, the filters are installed on the return side (suction) of the hvac equipment. Most rooftop units have the evaporator coil on the return side of the equipment.


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## beenthere (Mar 5, 2009)

First pic looks like the dampers are closed.


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## flashheatingand (May 3, 2008)

Yeah, whats the deal with that?


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## KennMacMoragh (Sep 16, 2008)

Don't know, maybe they shut when the fan is off. But yeah I'll turn the drains next time I work on it.


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## TRANEDOG (Sep 30, 2011)

Good Information Everyone
:thumbup::clap::thumbup:


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## flashheatingand (May 3, 2008)

beenthere said:


> First pic looks like the dampers are closed.


Looking at that picture again, I think the dampers are mounted wrong. They should have been mounted on the other side of the duct


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