DWV Layout; back to the drawing board?

[wwhitney]

No minimum length on the wet vent. Only downside to your latest layout is the U-turn on the kitchen drain (LT90, then 90 degrees more turn on the combo).

How about eliminating that 3x3x2 combo and using a 3" combo (in effect) for your 3" drain to turn from horizontal to vertical? An actual combo might work, or you might need a 45, a short pipe segment, and then a wye. The top (straight) inlet of the combo gets a bushing and a 2" quarter bend (street if necessary) to receive the kitchen sink drain. Eliminates all 180 degrees of the U-turn.

Cheers, Wayne

 

[beauesq]

Morning! Good thoughts, thank you, Wayne! I'll try it today! If I were to not have the vertical for two two combos (1, for kitchen entry, and 2) for clean-out--> 18" +/-, would the kitchen tie in as-is be an option, if indeed sub-optimal?

 

[Sponsor]

 

[wwhitney]

Combos aren't available street, and a 3" PVC combo has a radius of curvature of 7-9/16". That doesn't count the hubs, so if you stack two of them you get a height change of 7-9/16" + 1-1/2" + 1-1/2" + 7-9/16" = 18-1/8", which may be a hair too much. Plus the top entry may be too high for the kitchen quarter bend.

Switching the top combo to a street wye plus a street 45 would reduce the height change of the horizontals to ~ 16.5" but would not lower the top entry. As 16.5" is too little fall, you can change the street 45 to a regular 45; with hubs touching it would be ~1" taller, maybe 17-9/16", and you could add a little space between the hubs to fine tune the height change

If the top entry is too high for the kitchen drain, then a double quarter bend instead of combo plus quarter bend would make it easy. I hear those are a poor idea due to difficulty snaking through them. You could use a double combo and plug the top entry, if the 18-1/8" height works. You could use a double fixture fitting and plug the top entry; that's shorter than a double combo, not sure if it avoids the snaking issue of a double quarter bend.

Failing all those, I would think the geometry in post 17 would now work, as you only have to bring in the kitchen drain at 45 off plumb. The kitchen drain would hit a quarter bend rolled 45 degrees to line up with the wye entry.

Failing that, the U-turn is allowed, it may trigger some cleanout requirement and I'm not sure how you'd comply with it. So I'd try to avoid it.

Cheers, Wayne

 

[beauesq]

-a double quarter bend instead of combo.
(a poor idea due to difficulty snaking)
-a double combo and plug the top entry, if the 18-1/8" height works.
-a double fixture fitting and plug the top entry; that's shorter than a double combo, not sure if it avoids the snaking issue of a double quarter bend.

Wayne

How about a double 3" Santee and plug top, 2" bushing for kitchen drain?? Same snake issue but hoping for good enough at this point. Sorry for the play by play requests, I'm sure the answer is on this forum somewhere!

 

[wwhitney]

The above is the same as a double quarter bend, so the only advantage would be using what's on hand. The snaking is a negative, but you know you can go into the crawl space to hit the cleanout at the combo. It would be trouble getting to a clog that occurred on the vertical section, if that's a possibility.

So I'm not sure how to advise you on the relative merits of that solution. I guess it's better than the u-turn? I'd be inclined to go for one of the others, but perhaps you are looking to get this done today with what's on hand.

Does the stacked combos with a 2" (street) quarter bend on top put the quarter bend inlet too high for your kitchen drain?

If the lower 3" line for the septic is square (in plan) to the 3" WC and 2" kitchen drain, you could roll the upper combo plus quarter bend 45 degrees and replace the bottom combo with a wye. Unless that would hit the wall where the 3" septic line is exiting.

Cheers, wayne

 

[beauesq]

The above is the same...The snaking is a negative, but you know you can go into the crawl space to hit the cleanout at the combo.

...but perhaps you are looking to get this done today with what's on hand.

Wayne

Whoohoo! Done about as much as I can get, thanks Wayne! Will penetrate roof with vent tomorrow