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LoveMyHome 11-21-2009 11:02 PM

New Drain for HVAC Condensate Pump
Greetings everyone...

So, we recently purchased a whole house humidifer, an Aprilaire 600A. Realizing that our sewer main line runs over-head in the basement, our only choice for the constant flow from this humidifer that produces approx 2.25 gallons per hour of flow when running, the only choice we have is to have the unit drain into the condensate pump from the HVAC system. Of course in the summer this is not a problem, but in the winter when the humidifer is intended to run, freezing is an obvious problem that would lead to water on my basement floor. There are no floor drains anywhere in my basement leading to a sump pump or any other means of discharging the water in question.

What I'd like to do is create a new 1.5" branch off of the main 3" line running over head. Due to space limitations, I would have to run this line approx 4' before putting a trap in the line. I'm fairly confident in my ability to handle this task, but the more important question I'm hoping for help on is if this new branch would specifically need to be vented as well as the ONLY purpose this drain will serve is for the condensate pump which will discharge into the drain via a 3/8" vinyl hose, thus limiting the potential for a hugh wave of waste at any time.

Unfortunately, in the area of my basement in question, there are simply no other options for draining into the sewer main as all branches off of the main are in areas of the finished part of the basement with drywall ceilings...

Any help or advise anyone could offer is greatly appreciated!

Thanks in advance!

rudolph58 12-04-2009 12:14 PM

Your 1-1/2" trap should be vented within 3'6"of p-trap.A 1-1/2" sanitary t on it's back tied into an existing vent would work.

SULTINI 12-04-2009 05:32 PM

Where's your washing machine??

rudolph58 12-04-2009 10:41 PM

Are you talking to me or to love my home

JDC 12-05-2009 04:55 AM

While its true that the drain should be trapped there is a way around that...well a couple actually.

1) An air admittance valve can be used

2) Oversize the branch to 2" with a 2" trap. Since the line is oversized the top half of the pipe is never full. This top half serves as a vent for the trap. This is what is referred to as a combination waste and vent. is code under IPC.

My concern would be the trap drying out in the summer when the humidifier isnt running. You could put a trap primer in to take care of this possible situation. Just tee into a cold waterline, install a ball valve then the trap primer. From the outlet side of the primer, run a line over and indirect it into the trap.

Good luck

beenthere 12-05-2009 06:02 AM

What are you worried will freeze?

Is the line from the condensate pump going to run through some other area, then where the humidifier is, or where the sewer line is.

SULTINI 12-05-2009 06:59 AM


Originally Posted by rudolph58 (Post 361494)
Are you talking to me or to love my home

Love my home.

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