backup on a lower floor

[snoop168]

Kitchen sink on main level has s-trap and pipe goes down through floor. In basement that pipe comes down to a tee. One way goes out to septic, other way comes up with a 90 elbow and a few feet to about 2 feet from the ceiling (no trap on this pipe) the washer dumps in here. When you fill the sink and let out go down all at once it backs up out the washer pipe. So a few questions... Will installing a trap on this pipe prevent the water from backing into this pipe, at least enough to handle the full sink plus still running the water just in case someone is still rinsing as the sink is draining. Note that this is most likely the only vent in place right now and I assume by installing a trap basically makes the whole line unvented... Will this be worse? The only other thing could be the pipe is draining to septic too slowly. The first 20 feet of pipe in the ground were recently replaced however it's only 1.5 inch pvc pipe that was inserted into the old orangeburg pipe then it continues into the interlaced orangeburg pipe. The condition if the remainder of the Orangeburg pipe is unknown but the section closest to the house was flattening and falling apart but looking into it with a flashlight seemed like the remainder was stable but still a bit flattened.

I'm thinking my ultimate fix is completing the replacement of pipe from where the new pipe ends and step up to a 2 inch to continue to the septic but what is the consensus on just simply adding the trap. Will that slow my flow from the kitchen sink too much? Will my washer go down slow too or will that not really be affected due to it being the washer hose stuck into the end of an open pipe... I would then just say to add a cheater vent just above three kitchen sink but I have a window there plus the current pipe is through the floor with an s-trap and not in the wall.

Thanks in advance.

 

[IFIXH20]

Sounds like you need a drain repipe. Doing it right the first time will save you time, money , & headaches. Adding a P-trap will only create more problems in the long run.

 

[snoop168]

Thanks for the response, however was wondering what you think about changing the Tee to a Wye at the intersection so that way the water will be forced or at least more likely to go out the drain rather than backup into the lower washer pipe drain... Also being that the sink has an S-Trap does that have any correlation with the speed that the water goes down? For example if I change to a P-trap will that in some turn cause a little more resistance in the water going down so that it goes a bit slower giving the main drain pipe a chance to keep up? Also couldn't at least the section of pipe I replaced hold enough water to cover at least the half a sink load I put down? I know half a sink is not an exact measurement but I would say about 3 gallons of water, maybe 4... tops. That would assume that NO water is making it past the transition from old pipe to new pipe which obviously isn't the case. But again that doesn't necessarily take into consideration the speed that it can flow through the pipe but still it would prefer to go downhill wouldn't it? Would the vent from my other main drain essentially act as a vent for this line.. I am assuming that these both go into the septic in 2 separate entrances to the tank although its possible that the Y underground.

Thanks again!!