Yet another utility sink plumbing question

**ChrisMDL** · 03-15-2013, 08:36 AM

I am adding a utility/slop sink to my main stack in my basement. I will be draining the washing machine into the sink. How does this setup look on the attached picture?

Besides the P-Trap for the sink and the Tee for the AAV vent, are there any other special PVC fittings i will need?

Edit: sorry for the small size text in the image. The labels say, "All 2" Piping", "AAV", "2"Tee", and "Utility Sink Drain"

**cacher_chick** · 03-15-2013, 03:29 PM

Your plan is ok. The vent take-off should be a wye and 45 or a combo fitting. The drain needs to be 2", but the vent riser can be reduced to 1-1/2".

**ChrisMDL** · 03-16-2013, 02:16 PM

Originally Posted by cacher_chick

Your plan is ok. The vent take-off should be a wye and 45 or a combo fitting. The drain needs to be 2", but the vent riser can be reduced to 1-1/2".

Can I make the vent 2" ?

**Terry** · 03-16-2013, 02:17 PM

You can always go bigger on the vent.

**ChrisMDL** · 03-17-2013, 03:34 PM

Okay, this is what I came up with. Let me know what you guys think. Am I using the correct fittings? I still need to build a platform for the sink so it has the correct pitch, but will I be okay with this setup?

**cacher_chick** · 03-17-2013, 08:03 PM

I don't see anything technically wrong with what you have.

I would have used a regular tubular trap and trap arm on the sink into a 2x2x1-1/2 combo or a wye. The trap adapter could then be on the horizontal and bring the sink closer to the wall. It would also make it easier to take the trap off during future maintenance.

The sink does not need to be on a platform to make the proper grade. You need about 1-1/2" of pitch in that distance, which can be found by reducing the length of pipe you have coming off the top of the trap (raising the trap).

hj · 03-18-2013, 06:34 AM

I would NOT have made the connection at the sink the way you did, in order to move the sink back against the wall. Your AAV will work UNTIL flushing the toilet creates a "positive pressure" against the trap, (and that is really the ONLY condition you actually needed the vent to prevent). An AAV is NOT a panacea to cure all problems. It may NOT cause any symptoms, but only time will tell. As a side issue, who installed that "Mickey Mouse" "running P trap" on the tub or shower above the sink?

**ChrisMDL** · 03-18-2013, 07:10 AM

Originally Posted by cacher_chick

I don't see anything technically wrong with what you have.

I would have used a regular tubular trap and trap arm on the sink into a 2x2x1-1/2 combo or a wye. The trap adapter could then be on the horizontal and bring the sink closer to the wall. It would also make it easier to take the trap off during future maintenance.

Okay so I need to replace that wye with one that has an 1 1/2" opening on the swinging side. Like the attached picture? That would eliminate that trap adapter correct?

Also, yea that old Trap and drain pipe hanging down goes to an existing bathtub. I don't plan on ripping out the bathroom just yet, so that will have to stay for now. I did eliminate all the other copper supply lines in the house and installed that pex manifold.

**Terry** · 03-18-2013, 07:14 AM

With 2", you can go 60" before the vent. Whether you glue the trap or use tubular, it still works.
Plumbers like tubular, because we know that at some point it's coming out for service.

hj · 03-18-2013, 02:30 PM

If I were using the trap that you are, (which I would NOT, since I would use a "swivel joint" trap, or even better tubular), I would use a "Y" because it will move the sink back further, unless you put YOUR fitting off to the side of the sink's drain.

**cacher_chick** · 03-18-2013, 06:17 PM

You could use the combo you pictured.

I was not sure why you set the sink out from the wall so far, unless you plan to insulate and frame a stud wall. As HJ said, using a wye instead of a combo would allow you to pivot the trap arm and get everything up against or close to the outside wall.