Vent Ducting

So I have been an associate member of ASHI as well but their boards are not as active so I stayed here. (not to mention they don’t offer any kind of help to inspectors like NACHI does)

Well they have an associate corner where they post pictures and ask us pathetic worthless associates if we can find the problems. I decided to take a few stabs. The picture is not clear so its not worth posting but it was of a gas water heater vent. The vent peices were installed backwards so I noted it. Here was the response.

"I would argue otherwise. The direction of the joint will have no effect whatsoever on whether or not combustion gases enter the house. The vent is supposed to be under negative pressure while it’s venting, so any leaks will be from the outside in. Even if it were under positive pressure, leaks would occur no matter which direction the pipes were pointing.

There is an advantage in having the male fitting on top. It keeps condensation inside the vent pipe until it gets to the bottom. Look at a piece of B-vent. The liner has the male end on top and the female on the bottom for precisely this reason. "

I had never heard that before. Is this true?

Post the link that Jeff gave and have them read page 8 and if that doesn’t work, they can always “read” the drawings on page 16. But be nice about it :wink:

Wow, that’s… odd reasoning.

You might also point out that metal vents are not supposed to condensate(significantly) under normal/proper operation so planning for it is not a legitimate reason for backwards vent installation.

Yeah it was natural draft so i doubt there would be much condensation to begin with. They dont really consider new guys home inspectors over at ASHI so I did not bother arguing with him.