# Attic condensate drain-via walls?



## edlank (Aug 23, 2010)

My house has a basement and attic heat pump.  The attic unit has two PVC pipes for the condensate.  One is connected to the heat pump body, and one to the large pan under the heat pump.  They run parallel almost horizontally (barely any slope at all) to the outside wall, and through it into the back side of a gutter.  The two drain lines run all the way separately, and I can see that this provides redundancy in case of a clog.  Incidentally, I have never seen any moisture in the pan.  There is a leak in that gutter, with some staining of the fascia and soffit at the condensate pipes.  At some time, the previous owner moved the refrigerant lines up to that heat pump from an exterior wall to an interior wall, with generous holes in the top plate, sole plate, and presumably the first floor header.

I am expecting to divert those drains through the house to the basement drain, and seal the back side of the gutter.  That raises 3 questions.

1)  If I connect and send these down the interior wall as a single pipe/tubing, would it defy any code or good practices?  Specifically, does connecting them to a single drain create a significant risk?

2) Should I use PVC pipe down the wall, or a roll of plastic tubing to avoid any joints?

3) Is there any reason to avoid sending the drain tubing or pipe down the same hole with the insulated (and uninsulated) refrigerant lines?


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## kok328 (Aug 25, 2010)

1) If I connect and send these down the interior wall as a single pipe/tubing, would it defy any code or good practices? *NO*
Specifically, does connecting them to a single drain create a significant risk? *NO*

2) Should I use PVC pipe down the wall, or a roll of plastic tubing to avoid any joints? *PLASTIC TUBING - EASIER AND CHEAPER*

3) Is there any reason to avoid sending the drain tubing or pipe down the same hole with the insulated (and uninsulated) refrigerant lines? *DEPENDS ON THE MELTING POINT OF THE PLASTIC TUBING BUT, GENERALLY; NO.*

What you propose it a whole lot better than what you have now.  I would expect that in a heavy rain it is possible for the gutter to fill up and drain backwards into the drip pan of the heat pump.


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## edlank (Sep 18, 2010)

I have PVC pipe down through the wall but unconnected.  The gutter was just replaced, so I lost that drain, and now I must finish this.  I can connect to the main drain stack at the basement floor, where there is a "Y" to a 1.5" PVC with trap and funnel.  I can cut the pipe and connect below the trap, or above the trap but below the funnel to make it secure.  I have an inline trap that I can place in the attic near the heat pump.  Which trap site would be preferred (or code)?


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## Redwood (Sep 18, 2010)

you want to make sure the trap does not dry out in the heating season and leave you smelling poo.


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## kok328 (Sep 20, 2010)

I would prefer the location that provides the easiest access but, you don't want to sacrifice your clean out trap in doing so.


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## cheapsk87 (Oct 6, 2010)

i know old thread. but i just joined up and reading through. wanted to bring something to attention about this. the p-trap ordeal actually.

it is most typically placed at the up hill location. also try to vent it. what if it does fill up beyond the top of the enrty pipe? like sticking your finger over a straw in a cup of liquid. 

Air Conditioning Condensation Drain Pipe Problem/Question - dslreports.com

^^ i found this which explains some stuff but not all. hope this someone


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## edlank (Nov 8, 2010)

I reconsidered combining the drain lines.  I sent the heat pump condensate drain down through PVC in the interior wall, and separately the overflow pan drain out to the soffit (not the gutter any longer).  I have little confidence in the nearly horizontal overflow pipe to drain the pan.  The pan is only about 1.5" high, there is considerable surface tension preventing the wetting of the pipe entrance, and the drain pipe has only about a 1" drop over its 20' run to the soffit.  It is, however, my attempt to have a redundant drain path should the main one not work.  The pan shows no evidence of ever having been wet, though, so that is good.


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## Redwood (Nov 9, 2010)

edlank said:


> It is, however, my attempt to have a redundant drain path should the main one not work.  *The pan shows no evidence of ever having been wet,* though, so that is good.



That means the primary condensate drain has never clogged.

I would recommend having the secondary condensate drain discharge in a manner which would alert you to the fact the primary drain has clogged.


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## nealtw (Dec 16, 2010)

When it is hot and humid this this thing produces a lot of water and really does a lot of dammage when it plugs up. What ever you do it wants to be checked a few time each summer


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