Am I seeing this right?

Ummm, what good would a trap at this location be?


To stop stale air being drawn into the system and throught the home

It is useless.(actually retains water for no reason)
See that air gap on the right.
That is what you need.(stops cross contamination.)
Where does it go to?

If there is no humidifier and it is not a cat 4 condensing unit the trap dries out all winter anyway unless you are going to manually add water.
Got a insert water here sign somewhere? :slight_smile:

Bob would ya explain how a air gap stops cross contamination with what???
I have no clue what you and Roy are trying to explain that is a up flow furnace it blows does not suck???
I recommend mineral oil not water during the winter months to seal a trap water just evaporates


Traps are put in to keep conditioned air from being blown to the exterior. That’s what I think they were trying to accomplish.

Bingo, finally a right answer. If the condensate line is on the positive side of the blower, the trap keeps conditioned air from escaping. This is important if your trap terminates to the exterior as you would be air conditioning the world.

Your’re joking with me right? it… do not plug the higher hole, that is your back up drain if the lower one gets plugged up… like it probably is. trap both the drains and let them dump seperately into another bigger pipe or floor drain with an air gap to see that it is working properly

814.3 Air conditioning condensate waste pipes shall connect indirectly to the drainage system through an **airgap or airbreak **to a properly trapped and vented receptors, dry wells, leach pits, or the tail piece of plumbing fixtures.
air gap.jpg
Condensate wastes shall not drain over a public way.

Bob, the trap pictured is before the air gap(which is not pictured so I’m assuming it is at a floor drain based on the direction of the darker pipe in the background). Colton did not indicate this is directly connected to any sewer line so there should be no concern for contamination.

Also your link didn’t work, but I’m on my phone so I don’t know if that affects it.

Yes Bob I know what a air gap is but I thought you were talking about the clean out Tee as a air gap. No he did not show where the line terminated may have been a floor drain who knows.

The clean out Tee should have been before the trap not after with a small nipple and cap installed not glued into place to keep from loosing air or at least that was the way I always installed

Had me looking around the net Charlie.
This seems like a good link to demonstrate the condensate drain piping.

Here is a very detailed explanation of the trap.

I guess I should clarify a little. The line goes into the slab. I can only assume it connects to the sewer line as no exterior discharge was found. Which leaves the issue of sewer gas too. Obviously this location isn’t going to stop that.

Here it is.


No, you cannot assume anything!

How do you know if it goes sanitary, storm drain or goes daylight (just because you can’t see it)?!

They stick them in the concrete here all a time and they daylight in the backyard!

This is a proper trap application. Everything else in this spin is fabricated unknown information.

I see traps like Charley described with the T upstream (without a cap). This simply negates the need and purpose of the trap.

Exactly as the trap is on the a/c side of the opening.

I rarely see traps in this area and the secondary is always plugged…