What does plumbing code require for a basement condensate drain?

Question

A 1/2" pvc AC condensate drain slopes down and empties down into an upright 2" pvc pipe (used for washer drainage).

Inspector says its no good because of chance of contamination of airstream.

There's no where else to go with it except a floor drain in the middle of the room which wood be dumb.

Someone said separate the pipes with an air gap.

Will this make it pass code? Can both washer an condensate go into same drain pipe.

Thanks for your help.

Answer 1

If there is an air gap between the a/c drain and the 2" PVC pipe it should be up to code. You also should have a trap in the 1/2" drain from the a/c to prevent pulling air backwards through the drain.

Answer 2

I don't know what building code you are under, but air gaps are usually required only where there is a chance of cross contamination between gray water and potable water. But I do understand the reasoning

It really isn't worth the argument though. If the inspector requires it, it's an easy fix. You have the choice of a back flow preventer, a manufactured air gap, or just leaving the correct amount of space between the two pipes.

The gap has to be twice the effective size of the pipe that supplies the water. In this case, since the supply is 1/2''', the gap will need to be at least 1''. Some codes require no less than 2 ''.

an easy fix is to end the pipe within a few inches of the 2'' drain, place a 2'' by 4'' bell enlarger on the larger pipe to act as funnel. You're looking at maybe $5. You do NOT need a running trap in the condensate line. The trap only stops noxious gas, not air. The air going into your vents never contact the condensate. A trap that small will stop up, and without pressure coming through the trap, it is not self cleaning as most traps are required to be. The condensate pipe only needs a steady downhill slope.

If you don't have time or the material, a simple plastic funnel placed in the larger pipe will suffice, as long as the smaller pipe ends at least two inches above the funnel.