# AC Coil Condensate Drain Options



## zootjeff (Jul 11, 2007)

Hi,

I have a cased coil that has two condensate drain connections. I haven't hooked em up yet. I'm wondering what the rules are on the secondary drain. I'm going to have an EZ Trap on the main one, then I'm trying to figure out what my options are for the secondary one. 

Is the fact that I'll have a clear visual of the trap enough to omit the secondary drain? Seems like I either see a clogged EZ trap, or I'll see water coming out on the floor. I guess the risk is if it does get clogged and then runs for a while, then it won't matter that I finally saw it in the EZ trap. How long does it normally take to clog?

But then again if I look at it every time I go into the garage, I can probably start to see that it is getting nasty and then always prevent a problem?

Anyone have some guidance for me? I'd like to cap it, but if I shouldn't, then it is actually pretty easy to send it to the side of the unit where it would drain away from the ductwork.. Then a constant stream of air will always leak out of it...




















-Jeff


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## COLDIRON (Mar 15, 2009)

*To cap or not to cap*

If your not worried about water damage I would cap it and forget it.

If your concerned about water damage I would route it out the house at a location visible to you once or twice a day so you would see if it leaked and if it did it's drain cleaning time.

NOTE: To anyone installing in an attic space or finished area, always use the secondary drain to avoid water damage.


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## zootjeff (Jul 11, 2007)

SULTINI said:


> If your not worried about water damage I would cap it and forget it.
> 
> If your concerned about water damage I would route it out the house at a location visible to you once or twice a day so you would see if it leaked and if it did it's drain cleaning time.
> 
> NOTE: To anyone installing in an attic space or finished area, always use the secondary drain to avoid water damage.


Are there any code requirements to provide secondary drains?


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## beenthere (Oct 11, 2008)

When ever the appliance is installed that an overflow could damage the structure.


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## zootjeff (Jul 11, 2007)

beenthere said:


> When ever the appliance is installed that an overflow could damage the structure.


I hooked up my EZ Trap. I put a 90 on the secondary drain and pointed it down, then i just stuck a cap on it for now without glue. That stops the air leak.


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## beenthere (Oct 11, 2008)

Don't forget to put a trap between the coil and the drain line for the furnace.


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## zootjeff (Jul 11, 2007)

beenthere said:


> Don't forget to put a trap between the coil and the drain line for the furnace.


What do you mean?

The furnace has a built in trap.

The drain from the coil slopes downward to the T.. I could have the T lower and have them join a little lower..

Should there be an external trap on the furnace if it has an internal one or is that just if it doesn't?

-Jeff


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## beenthere (Oct 11, 2008)

I suggest you reread those install instructions. Unless you want to risk losing your heat.
It will tell you you NEED another trap, and where you NEED it, to plumb those drains together.


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## zootjeff (Jul 11, 2007)

beenthere said:


> I suggest you reread those install instructions. Unless you want to risk losing your heat.
> It will tell you you NEED another trap, and where you NEED it, to plumb those drains together.


Nothing in the Trane XV90 installation manual talks about any kind of extra trap on the condensate line.

I don't understand what a second trap would do anyway. The whole point of a trap on house plumbing is to prevent smells from coming up, the whole point of a trap on the AC coils is to prevent cold air from escaping. The whole point of the built in trap on my furnace is the same, prevent exhaust combustion air from escaping down the condensate line. What could possibly cause the furnace to fail in this situation? 

Clearly if there was a plug, that would create a problem, but that's not going to happen here from the lack of a third trap. The built in trap has over two inches of water column that would have to be defeated if air from the AC coils (assuming no water in the AC trap) was to back flow the built-in furnace trap. I'm guessing there is not 2" of resistance in the open PVC line that goes 18 feet to the outdoor drain location.


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## beenthere (Oct 11, 2008)

The trap on the furnace is NOT to prevent odors.
Nor is the trap between the A/C coil and furnace coil.

Don't install one. And when you have no heat problems. You can install it then.


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## COLDIRON (Mar 15, 2009)

*Brain dead*

Just thought of something DUH!! Counterflow heater right? Better make sure all drainage from the unit is installed correctly or you'll fill your supply area with water and soak the pit. 

Better listen to beenthere.


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## zootjeff (Jul 11, 2007)

SULTINI said:


> Just thought of something DUH!! Counterflow heater right? Better make sure all drainage from the unit is installed correctly or you'll fill your supply area with water and soak the pit.
> 
> Better listen to beenthere.


I'm happy to install one but I'd really like to understand why. I know it's not to prevent odors, I didn't say it was. As I understand it a trap is to prevent the movement of air. I said it was to prevent exhaust gas from escaping. Does it do something else?


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## COLDIRON (Mar 15, 2009)

It allows the condensate water to flow out without blowing it all over the place from the blower CFMS, turbulence, pressure.

Better uncap the other drain and install it.


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## zootjeff (Jul 11, 2007)

SULTINI said:


> It allows the condensate water to flow out without blowing it all over the place from the blower CFMS, turbulence, pressure.
> 
> Better uncap the other drain and install it.



I still don't understand what you are trying to tell me here. There is an internal trap on the furnace, a trap on the AC coil, there is going to be no air flow anywhere. You're just messing with me, right?


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## zootjeff (Jul 11, 2007)

Maybe there should be a trap after both traps so that if the AC trap dries out, the second furnace trap will fill up and block it? That's really the only thing I can think of without your insight. But that's going to prevent the loss of air, not keep the furnace from breaking. You told me without 3 traps my furnace would fail..

Hmm.


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## beenthere (Oct 11, 2008)

Don't see a trap on the A/C.


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## zootjeff (Jul 11, 2007)

beenthere said:


> Don't see a trap on the A/C.


Maybe the contrast on the image is off? Don't you see the EZ-Trap?


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## beenthere (Oct 11, 2008)

In that pic yes.


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## zootjeff (Jul 11, 2007)

beenthere said:


> In that pic yes.


So then I'm good? I have the internal furnace trap and I have the AC coil trap..

Thanks,

Jeff


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## beenthere (Oct 11, 2008)

Yes, that would be a proper set up for that drain line set up.


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