Washer Drain and Vanity Drain Design

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Hello Everybody
Been enjoying the site and learning a lot. Thanks to everyone for their expertise.
I'm currently trying to add a washer outlet on the other side of the wall and a vanity on this side--sharing a drain that will run to a main stack. I'm working with a diagonal vent that goes straight to the roof as seen in the first picture below.
upstairs bathroom #2.jpg.
Does the mock-up below even start to address a solution? IF so, any help on which fittings to use in positions A, B, C, D, E much appreciated. My original guess is Sanitee for C & E and combo (wye plus 1/8 bend) for fitting D. I dont really have a guess for A. Id really appreicate any ideas, directions or tips you could throw at me, with as much detail as able (im a newbie). Any help appreciated.

Any help appreciated. upstairs bathroom 4.jpg
 
Your fitting choices look good, and using a combo at "A" would be appropriate. But the washer vent line is not supposed to go horizontal until it is 6" above the top of the standpipe. So, the horizontal section of the vent line needs to be raised, or the washer standpipe needs to be lowered, yet still needs to meet code requirements.
1707662102453.png
 
The way you have it piped it’ll probably never back up out of the standpipe, if that drain clogs it’ll fill up the lavatory and overflow in the bathroom.
 
Was going to church so I answered too fast. Here's an easier way to plumb this. A vent line, wet or dry, can be run at 45 degrees before it reaches 6" above the fixture being served, as the codes consider them "vertical". And as Twowaxhack pointed out, the overflow will occur at the sink should a blockage occur downstream. "C" and "E" should be Sanitary tees.

And is that galvanized piping that you are connecting to? You may want to consider replacing that as well.

1707676301372.png
 
MicEd and TwoWaxhack: Thanks a bunch for the tips. The easier setup sure looks good. Now im just trying to understand the advice. I saw the picture below on a site about how to properly do a similar setup, pointing to the importance of the vent parts in the red box. Are they wrong, or are they right and Im just missing a detail? Thanks again folks for your time!rough in inverted to our situation.jpg
 
Apparently, whoever was giving that advise must have been going to church and in a hurry too. LOL.

The design I gave and, Twowaxhack's comment, is using the little distance between the sink Sanitary tee and the washer Sanitary tee as a wet vent. That line needs to be 2" is all. So that means that the sink Sanitary tee is either a 2 x 2 x 1-1/2 Sanitary Reducing Tee, or a 2 x 2 x 2 Sanitary tee with a 2 x 1 1/2 reducer in the branch. The lines and fittings in the red box are TOTALLY unnecessary, unless some local jurisdiction thinks wet vents of ANY length are a problem.

A vent for a P-trap is to keep any flows in the drain lines from sucking/siphoning out the water in the trap. The water draining out of the sink can only flow so fast. So, there is NO WAY that the sink flow will be able to pull the water out of the washer P-trap with the line above the sink Sanitary tee being a dry vent up to the roof. There is only a couple of inches of "wet vent" in this case.

Therefore, the one giving that advise must have been a pipe and fitting salesperson. In any case, they are very wrong.
 
MicEd and TwoWaxhack: Thanks a bunch for the tips. The easier setup sure looks good. Now im just trying to understand the advice. I saw the picture below on a site about how to properly do a similar setup, pointing to the importance of the vent parts in the red box. Are they wrong, or are they right and Im just missing a detail? Thanks again folks for your time!View attachment 44239
It’s right but it’s not needed. That vent does nothing. You saw that on Terry Loves site.
 
It’s right
It's a way to do it, but as you said, "The washer doesn’t need that extra vent."

So, they are totally wrong as to "the importance of the vent parts in the red box.", so it's not really "right".

Just don't want to give the OP the opinion that doing it the way you and I said is "wrong".
 
It can be done either way. Both examples are correct.

With the washer revent would be acceptable and without.
 
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