Kitchen remodel, sink drain rework

pinkertonpv

I am remodeling my kitchen. the sink drain clogged up several months ago and i spent several days getting it unclogged. After many efforts starting with the plunger, liquid plumber and finally ending with getting into the crawl space, unscrewing the clean out (phew!), and running a snake down the line (and many things in between) I got it open. However, in getting under the house, I found that the builders put in 5 90 degree elbows from the p trap to the straight line drain. no wonder it was clogged. The reason is that the A/C vent opened up right under the p trap (amazing). So where the pvc would come out of the wall in the crawl space was blocked by the ducting and vent. So the 5 elbows were the effort to route the drain away from the vent and then back to the main line. I am wanting to fix that and plan on shortening the AC duct work to give me a better drain structure. Should be a straight forward effort of running the pvc from the p trap into the wall, 90 elbow down, 90 elbow out into the crawl space and connect to the main line.

Anybody see something I am missing. Is there any plumbing reason I shouldn't do this? I am also relocating my dishwasher and will be including that in the rework. I am on a septic tank and do not have a garbage disposal.

zosoplumber

Is your kitchen line vented, or does it just go into the wall and 90 down into the crawl space? As for rerouting it, its sounds like a good plan, just use common sense, 45's are better than 90's, use as less fittings as possible and make sure you have 1/4" per foot drop on any horizontal runs. And always use glue and PRIMER.

pinkertonpv

zosoplumber; good point. Can't remember (getting old) if its vented or not. Bath rooms and laundry are vented. Dark out now, but will check in morning. I think I will need only two 90s and maybe 1 45. I've worked projects with CVPC before so know about priming and gluing, but have never done a waste water drain. just supply. Thanks for your help.

pinkertonpv

Zosoplumber, sorry for the long wait. The kitchen line is vented thru the second story roof. Vent goes thru the exterior stud wall. Don't know exactly where in the jumble of 90's the vent connects to. Suspect now that may be one reason why the drain make a 90 horizontal to the ground and so forth. There is a window above the sink and drain so the vent can't go straight up from there.

Can I still make the drain pipe as it enters the wall do a 90 down and then 90 or 45 into the main drain pipe in the crawl space. Then bring the vent pipe up vertical off the drain in the wall, do a 90 horizontal under the window and connect to the vent going up the exterior wall thru the roof? May be more to it than I thought. Any suggestions on what to do?