[zspinner1]

Hi, I am working on planning a new bathroom in a basement projet that was not originally planned for any plumbing. I have no easy access to a vent pipe that runs to the roof in the basement and I was looking to use a AAV valve. Can you please advise if this layout looks like it would work? I used a picture of the plumbing from a bathroom I added in the basement of my last house, but in this basement there was a vent pipe in the basement because the washing machine was in the basement, and it had a vent pipe.

I am planning on the same layout but now I have the issue of running a vent. My only other option is to tie into the vent behind the 1st floor vanity sink, but this involves running alott of pipe and sheetrock, and I am not even sure I can fit this vent in behiind the wall. If I can tie into the vent for this sink, how far above the tee for the sink drain line do I need to add the vent tee?

Thanks for any help you can proivde.

[massplumber2008]

HI Zspinner...

AAVS are illegal in most states and can NEVER be installed in a place, like behind a wall, without an access panel to make sure they can be easily found and changed out if need be.

I would recommend that you run the vent upstairs and connect into the sink vent at somewhere around 46" off the floor. Be sure to INVERT the sanitary tee fitting you connect into the old vent for the new vent (the double in the picture above was installed wrong.. ;) ).

Good luck!

Mark

[zspinner1]

Thanks for the feedback, in regards to your comments, of course there would be an access panel for acces to this valve as well as the pump system as was the case on my last project.

The double tee pictured is not the tie-in point to the existing vent system as you implied, but is the common tie-in for the fixture vents, as I understood from the instructions these pipes as well as fittings should be sloped back to the pump point to remove any moisture that feeds back in the vent system. Is this not correct? This is the reason for the orientation of this doble tee pictured.

Thanks again for your help.

[massplumber2008]

This pump system is not anything special in terms of requiring, "these pipes as well as fittings should be sloped back to the pump point to remove any moisture that feeds back in the vent system". Here, all vent piping and vent fitting systems are installed so rain water and condensation can fall back to the drain system by gravity.

In the double TY above this water will not flow by gravity down all the vent pipes as much as it will flow down or even DRIP down the one main pipe past the tee branches... see diagrams below for a better explanation.

To further complicate this, the installation instructions on this macerator pump system doesn't show a pitched cross fitting... just a plain cross fitting so I understand why someone with limited plumbing experience might miss this.

Plumbing practices require that every vent and vent fitting flow in one direction and that direction is downward!

Let me know what you think, OK?

Mark

[zspinner1]

Thanks, the picture helps explain. I think that the Tee I put in the existing vent line could go either way since this line is a straight line back into the drain line for the sink?

Can a Wye be used instead of a Tee to tie into the existing sink drain/vent line? I am not sure I have room for an elbow and Tee between the existing drain line and the wall stud. I will be running this new vent line up from the downstairs so I will need an elbow to go from Horz to vert, and then the Tee to tie into the existing line. The wye will save me one fitting and some space as well.

[zspinner1]

Sorry I had my Horz and vert backwards. I need the elbow to transition from vert to horz, not the other way around.

[massplumber2008]

In terms of plumbing code the vent fitting needs to be inverted, but since you aren't a plumber and you are working on 1 short vent line I'm sure you can leave the tee in any orientation you want... ;)

And, yes, an inverted wye can be used to tie into the existing vent upstairs... no problem.

Mark