New cast iron sink, deep bowl, how to do trap?

[DKAudio]

I got a new deep bowl cast iron kohler sink. I got it in yesterday but have a problem. My main cast drain line protrudes through my wall pretty high up. My old stainless sink had shallow bowls so this was not a problem. However, this new sink has bowls that are many inches deeper. There is no way I can install a standard p trap and get in the tailpiece, T (to the other side bowl) and dishwasher drain piece because I do not have enough height. The only way I see to do this is to put in a 90 at the main cast drain, droop down to the floor of the cabinet and then bring it back up and that would be my trap. This would result in a p trap that is a foot or greater deep in relation with my main cast drain line. Is this ok? Any other ideas? I am worried that having a deep trap will keep a lot of water in it and it will be much more restricted and harder to "flow"

[LazyPup]

That would be totally code prohibited. A trap is required to have a minimum of 2” of water and a maximum of 4”.

You could install a Wye on the waste arm extending out of the wall, then run a separate line and trap to each sink bowl. If you do not have enough vertical clearance to do that you will have to lower the Tee on the waste stack in the wall.

[DKAudio]

That is what I thought. What if I put a T on the main bowl like normal but hook up the dishwasher drain to the smaller bowl off the T?



Question is, can I use the "T" and the dishwasher drain as the tailpiece to each strainer?

[LazyPup]

You cannot connect the Tee directly to the sink basket because the sink basket requires a flanged tailpiece.

Begin by attaching a flanged tailpiece to the sink basket then you can cut that tailpiece leaving at least 1" to attach the Tee or the Branched tailpiece.
(See illustration below)

If you are under the International Residential Code you can run the dishwasher drain line up and attach it as high as possible under the cabinet top to make a high loop, then you may drop the line down and attach it to a disposal input or a branch tailpiece.

If you are under the Uniform Plumbing Code you are required to have an "Air Gap" mounted above the flood level rim of the sink. (See Illustration below)

[DKAudio]

Thanks, I messed with it yesterday and saw that I need a tailpiece and tailpiece washer. As for the dishwasher, I do not know what code I am under but I just have a high loop and it is only around 8-10" higher than the drain inlet. I live in MN if that helps.

At any rate my drawing will work, just need to insert the two tailpieces I left out.

It is ok to put dishwasher drain inlet on the Tee'd off sink, correct?

By the way, I just saw in your drawing you have a baffled Tee, what is that? A blocker so water will not flow up? I only have a standard Tee that came in a dual sink drain kit. If I should get a baffled then I will pick one up today.

Thanks for the help.

[LazyPup]

No problem with putting the DW drain on the tee'd cross tube side. In fact, when we install a garbage disposal and use a "Disposal type end waste kit" the disposal & DW inlet are both on the cross tube side.

If you are using a tee that came supplied with an end waste kit it should be a baffled tee. Look on the inside of the tee and you will see a baffle that directs the discharge from the side input of the Tee in the downward direction.

[DKAudio]

It probably is, I don't remember if I looked inside of it or not, I remember the DW inlet was baffled.

Thanks for all the help, sure glad I won't have to lower my main stack, that cannot be cheap or easy.