Can I install a standpipe for a washing machine with an s-trap and not vent it?






















/

Not legally.


I think I would at least put in an aav.

Instead of using an s trap, use a p trap.

Here's how it goes. Bring drain up one foot, then put in a tee, on the side of the tee install a p trap, and stand pipe(24-30 inches high). On the top of the tee put a aav(air admittance valve).

Please let me know if this helps. If not, I'm sure one of the pros here will set you up with a drawing.

Gottcha covered Dad!
I'm afraid that with the force of the washer pump the velocity of the discharge will suction the trap seal right out of the stand pipe if you install a "S" trap. It will look something like this,(see image) except the ell will be swapped for a sanitary tee and the AAV will mount on top of the tee as Dad directed in his earlier post. Good luck, Tom

The auto vent should be installed above the flood rim of the standpipe.

The auto vent should be installed above the flood rim of the standpipe.

In a ideal installation you would be cvorrect. But since a AAV only will allow air to enter and blocks anything going out all of our AAV's are installed below the floor rims of the sinks and lavatories that we are venting.. See the image in my earlier post. Regards, Tom