Horizontal Drain with Wye and Cleanout

[Wren]

I'm curious if I'm going to run into trouble using a wye or combo fitting in a horizontal drain with one leg coming from a WC and the other going to a cleanout. Here's a photo that I found online. This isn't my exact setup, but for the purposes of discussion, I think it will do. The second one shows another view of what I've got.

What keeps solids from building up where the pipe coming from the cleanout meets the sweep at the circled area and causing clogs if there isn't another fixture upstream to keep it washed out?

I've got two WC's that I'm planning on using this sort of setup, but I may have to reconfigure if there is an issue with this sort of layout. On one of them, I might be able to reroute a lav drain to upstream of where the WC enters the wye, but I'll probably make a photo of a mock up for clarity on that one.

Thanks very much!

 

[wwhitney]

That's a good question, I'm curious to hear what others have to say about this.

My inference is that waste will accumulate in the circled area, but not in the actual drainage path of the fixture, since that path is getting washed. And as the CO path is not serving a purpose except during rodding, accumulation in the circled area is fine. [Unlike, say, a dry vent, where the accumulation would block the flow of air, the purpose of the vent.] Then if you ever need to use the cleanout for rodding, you should be able to break through whatever has accumulated, on your way to finding the downstream clog.

Cheers, Wayne

 

[Sponsor]

 

[Wren]

My inference is that waste will accumulate in the circled area, but not in the actual drainage path of the fixture, since that path is getting washed.

That's my understanding. Whether or not it is an issue is what I'm curious about. I've thought that from time to time, one could stick a garden hose down in the cleanout and flush things to keep it from getting completely blocked. For the one of the bathrooms, I'm considering not having a cleanout upstream of the WC and just using a 1/8-turn instead of the wye. It sure would make things easier. As I mentioned above, it may be possible to reconfigure the other WC drain to have the sink come in from the CO side of the combo fitting to keep it flushed.

 

[wwhitney]

But why is it a problem if the cleanout path gets blocked?

Cheers, Wayne

 

[Tuttles Revenge]

Yes, waste will accumulate in the Eddy of that radius no matter the position of the fitting when used as a drainage fitting. I doubt it will be a problem if that happens, but adding a fixture to the vertical portion of that clean out to help wash that spot can't hurt anything.

 

[Wren]

I think I would be better if I substituted a 1/8-turn for the wye on the full bath since locating a cleanout pipe will be difficult due to the framing band and access will be nil once the floor is installed. As for the half bath, I'm going to mock up having the sink wet vent enter upstream of where the WC drain joins the combo fitting I'm using. I just need to make sure that my layout will be OK and provide adequate venting for the WC. Stay tuned.

 

[Mr tee]

I see no problem with the combination.

 

[hj]

The problem is NOT the combination, it is having two of them in a row without vents, since flushing either can create a suction in the other removing the trap seals.

 

[Wren]

The problem is NOT the combination, it is having two of them in a row without vents, since flushing either can create a suction in the other removing the trap seals.

The plan was to wet vent the toilet from the lavatory. There are not two fixtures in a row without venting.

There is nothing upstream of pipe section D other than the cleanout.

The lav/wet vent is 2" and is under 8' from the wye to the vent. Will that be sufficient, or do I need to increase it to 3" due to the distance from the WC to the wet vent?

Here's a mock up of the half bath.

 

[Tuttles Revenge]

The layout is fine. The toilet trap arm is from the wye to its elbow. The pipe from the lav to the wye is the horizontal wet vent where you could have a tub and a shower connect to that horizontal pipe as well

 

[Wren]

From the replies I received here, I decided that I'm going to run the lav into the 3" from the WC and not have it enter the long cleanout pipe upstream of the combo as in the mockup photo. The lav vertical drain serves as a wet vent that goes through the roof.

If that's going to give me grief, please comment soon as I'm gluing everything up this week!

I looked at my shop, and I have just about the same setup with nothing flowing into one leg of the combo fitting (it's capped to provide an access for cleanout) and I haven't had a ounce of trouble with the WC in 30 years. I don't even have a plunger at the shop.

Thanks everyone!