Basement Plumbing Diagram Help

hj said:

1. You cannot use a double "Y", (or a double sanitary tee, or a sanitary cross), where they come together.

What is the proper connection? The intersection is only about 2 feet from the bathroom fixture and ~43 feet from the other fixture. There is enough drop that I could probably use two sanitary tees, one almost right on top of the other.

2. You should NOT use 1 1/2" below that point either.

2" is okay, I presume? Does this then require larger vent piping?

3. If the two sinks are actually 45' apart you should not be using 1 1/2" pipe for the drain lines.

So, the 43' section would need to be 2"? Can the drain from the sink close to the intersection be just 1.5"? Out of curiosity, how does the length affect needed flow?

4. I do not consider a SaniFlow installation to be one of the better ideas as a long term solution.

Don't know what I can say. I think from a budget and desire perspective, the project is out of the question if it involves digging up the slab.

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hj said:

1. Use a "back to back fixture fitting", and it will be 2x1 1/2x2x2.
2. No. the fitting will have a 1 1/2" vent opening
3. Put a 2 x 1 1/2" bushing in one side.
4. That length, depending on how you use it, could plug up easier, and the larger pipe will be more resistant to clogging, and easier to unclog when it happens.
5. It is cheaper NOW, but may not be when the pump OR toilet has to be replaced.

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1. I don't have any clean-outs on my diagram. I imagine it is code (and smart) to have one on the long run. Can you suggest where and how many I should have (either code or just a good idea)?
2. Where connecting to the sewer main, there wouldn't be any way to connect a PVC wye; it is only a ~6 foot run. Is it okay (to code) to use a rubber coupling with band clamps? If not, how is the proper connection made?