Double sink sharing single drain/vent on far side.

[originaltwotone]

Based on the advice I received in another thread and some of the reading I've done on here it is my understanding that a sani-t shouldn't be used in a horizontal position.

This is my current plumbing, but I need to move the drains and want to make sure it's correct.
Is the drain on the right correct with a sani-t in it?

Thanks

 

[wwhitney]

No, that should be a combo.

What's the length along the pipe run and the fall from the left-hand trap weir (the point where water first spills out) to the crotch of the san-tee on the stack? That's limited to 72" and 1-1/2" of fall. If it's over that, you'll need to add a vent takeoff in between the two traps; that dry vent can reconnect to the stack on the right at a height at least 6" above both sink flood rims.

Wayne

 

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[originaltwotone]

No, that should be a combo.

What's the length along the pipe run and the fall from the left-hand trap weir (the point where water first spills out) to the crotch of the san-tee on the stack? That's limited to 72" and 1-1/2" of fall. If it's over that, you'll need to add a vent takeoff in between the two traps; that dry vent can reconnect to the stack on the right at a height at least 6" above both sink flood rims.

Wayne

Wanye, once again thanks for replying, you helped tremendously with my previous post.
It's around 48'' and I'm actually moving both inward towards each other and up, so that distance is getting shorter.
Excuse the ignorance on terms, when you say combo, I believe that means a curved wye?

That wouldn't have a clean exit out of the drywall.

Since I'm raising the fitting for the p-trap anyway, would the picture below be ok?

Thanks

 

[wwhitney]

Excuse the ignorance on terms, when you say combo, I believe that means a curved wye?

Your picture shows a combo. It's called that as it is a one piece combination wye plus 45. You can always use a wye plus a 45 where you need a combo, but that would take up more room.

That wouldn't have a clean exit out of the drywall.

Either the perspective is very weird, or you're showing a 2" combo.

Since I'm raising the fitting for the p-trap anyway, would the picture below be ok?

I don't understand what that picture means, what you intend it to show as a proposed configuration.

A trap arm can't drop more than one pipe diameter before being vented, so if you want the two trap arms to join a single san-tee on the stack, you'd need a horizontal combo to combine the trap arms.

You can put two separate san-tees on the stack, one on top of the other (they make street san-tees), then you could have two separate trap arms at different elevations, and each trap arm could enter the wall via a quarter bend as usual. Obviously your two traps would end up at different elevations.

Or you could put a double fixture fitting in the wall horizontally in between both traps, with the drain dropping down before jogging horizontally to join your existing stack. Likewise the vent off the double fixture fitting would rise up at least 6" above the fixture flood rims before jogging horizontally to join your existing stack. And the stack between those connections could disappear, i.e. each connection to the stack could be a quarter bend.

Cheers, Wayne

 

[originaltwotone]

Once again thanks. The stack is also venting a tub that's behind where I took the picture from so it needs to stay.
If I'm uunderstanding you correctly I believe what I have below would work.
I borrowed the picture from another post I just found.
White is the current stack and yellow would be new plumbing.

 

[Jeff H Young]

Id probebly stack santees for the lavs one on top of other . that combo sticking way out the wall if you want is ok but... Make sure your p trap will work befor you glue anything (personaly I abandon the combo idea)

 

[wwhitney]

Once again thanks. The stack is also venting a tub that's behind where I took the picture from so it needs to stay.

Still doesn't have to stay, but it's fine for it to stay.

Since you are wet venting the tub, the stack and drains need to be 2" where they carry the drainage for two lavs; where the stack is a pure dry vent, 1-1/2" is okay.

An advantage of leaving the stack is your horizontal double lav drain can be 1-1/2" instead of 2". But I believe all double fixture fittings have a 2" outlet.

So I would suggest either stacked san-tees on the stack, or a variation on your last image where the right hand lav goes to a san-tee on the stack, no double fixture fitting.

Cheers, Wayne

 

[Jeff H Young]

Stack tees and for the far lav cut a 1 1/2 santee or combi on its back to revent the lav if its too far away . drill maybe 2 studs at 42 inches or so off floor for the revent. (42inches is basically 6 inches above the overflow of a standard 36 or less counter top ) popular height nothing wrong with 44 or 48 whatever height just not too low

 

[originaltwotone]

I apologize I didn't give a complete picture, there a vent running left to right ~ 8'' above the drywall cut.
What do you both think of the below?

 

[wwhitney]

That will work well as long as the existing vent is 6" above the lav flood rim.

Cheers, Wayne

 

[Jeff H Young]

I apologize I didn't give a complete picture, there a vent running left to right ~ 8'' above the drywall cut.
What do you both think of the below?

View attachment 98340

Great more than one way to skin a cat thats perfect ! Im assuming the drain was roughed in very low to utilize the same holes. Personally I like that way better than the old hokey plumbing job (imo) maybe it was legal somewhere at one time maybey its still legal somewhere today but to any plumber I ever met in my state we all think thats wrong way plumbing santee wet venting on the side LOL

 

[originaltwotone]

Thanks again for the input.
Everything you see is original. It was annoying because inside the old vanity there was barely any room under the P-traps.
The new vanity is one with feet and open underneath, so I need to move things up.
If I'm having to redo things, trying to correct all the crap that was incorrect.

Wayne helped a lot with the mess that was my shower, horizontal Sani-tees in 3'' drain line and a few other things.