jay kline

Jeff - very informative web site. Clear text and graphic answer to my question!

Jim - sorry. I should have been more to the point with my question. Maybe a better way to phrase it would be: Since the condensate drain line is not supposed to be connected on the waste side of a plumbing trap, what is the point of installing a trap in the condensate line? Terence's response answered my ill-asked question very well. I have been writing it up when I cannot locate a trap on the primary condensate drain line, but until I read Terence's reply - I didn't know why one should be installed on a drain line that is properly terminated on the fixture side of a plumbing trap. I was thinking only of the need to prevent sewer gas from entering the system - I had not thought about the need to keep conditioned air inside the air handler or to keep insects out. Thanks Terence.

Why is a trap required in the primary condensate drain line?