Plumbing question:

[oldberkeley]

I’m replacing my old kitchen cabinet, the sink and faucet. The new sink is a single bowl with a garbage disposal. The drain is a floor drain through the cabinet bottom, at the very back of the cabinet, offset a few inches to the right. There is an existing vent coming in at the upper back right, passes through the adjacent cabinet then up and out.

Not sure if I’ve given enough info, but what is the correct way to plumb this?

 

[mires]

How was it plumbed before? When you say the vent goes up and out what do you mean? Where does it go out at?

 

[oldberkeley]

The kitchen was demo'd out and I simply don't remember how it was before! Not my brightest move.

The vent pipe goes into the adjacent cabinet, then into the wall cavity, then up and out the roof. I think that part is fine.

I believe that an S-trap is illegal, but how will I connect the disposal to the floor drain without one? Also, how and where will I connect the vent pipe?

 

[sixty4]

Technically no its not correct. Most vents are located 42" or 6" above the flood level of the sink. With that said studor vents are not higher than the counter when installed. Will this work, yes.

 

[FullRaceMerc]

By floor drain I think you mean that pipe runs thru the floor & ties into your drain system, not a pipe that drops into a "floor drain" (Like you'd see in a restaurant under an ice maker).

If that's the case, & the vent runs up & out properly thru the roof, using a Tee & trap something like the diagram below, with the trap connected directly to your disposal under the sink (since it's only a single bowl), should work. But normally you should try to keep the horizontal portion of the vent pipe above the top of the sink whenever possible.

 

[sixty4]

The kitchen was demo'd out and I simply don't remember how it was before! Not my brightest move.

The vent pipe goes into the adjacent cabinet, then into the wall cavity, then up and out the roof. I think that part is fine.

I believe that an S-trap is illegal, but how will I connect the disposal to the floor drain without one? Also, how and where will I connect the vent pipe?

Easy, use a Ty off the branch set your trap and off the top (the rise) connect back to the vent. I would mount disposal up first and hang a trap off it before setting TY.

 

[Kaizen]

sink - disposal- out to p trap. p trap goes into floor drain but has a Y or t going up to vent. probably will need to use some 45 degree ones on that set up. you sure your sink is going to fit with that vent pipe as it is? on mine it would be hitting the back of the sink basin.

 

[oldberkeley]

fullracemerc- Yes, I mean the drain pipe runs down through the floor into the drain system.

Do you mean that I would use the black discharge fitting that comes with the disposal, and attach that directly to a P trap?

sixty- Are you saying the same as merc: attach P trap directly to black discharge fitting?

kaizen- Sorry to be so dense, you're also saying connect the P trap right to the disposal?? I understand what you mean by a Y going to vent, that's what I was thinking. But doesn't the vent HAVE to be above the trap?

Yes, I might have to cut the PVC vent pipe back some to accomodate the sink basin.

 

[K'ledgeBldr]

Merc's posted diagram is the correct methodology.

Think of it this way-
The waste line coming through the floor of the cabinet would be connected directly to the vent pipe at the top of the cabinet. Somewhere in-between you would use a "sanitary tee". Connect the P-trap from the disposal to the sanitary tee. Done.
Clerance, distances, and direction are all on you- not knowing the size of the disposal, depth of the sink, or the size of the cabinet.

Just curious, is there a dishwasher? If there is forget about using the discharge hookup on the disposal- those things are notorious for failure, STINK, and premature disposal failure.
If there is a D/W- add a "Wye" at the sanitary tee- one side is for the sink and disposal, the other for a trap and fitting for the D/W.