Replacing old Cast Iron Pipes that rusted through... are these other drains wrong?

[Jadnashua]

The connection into the drain for the sink and WM should also be a wye. You could probably use a Double wye there since there won't be much height from the floor to connect the new branch into the drain system. WHen it comes to installing it all, the horizontal legs between the sink and the drain need slope so that any condensation, rain, or whatever the may get in there, will drain properly. The upper new connection can be a sanitary t since it is a vent now.

The size of the new vertical drain must be the same size as what is currently there for the drain, otherwise, you'd be breaking another drain rule: you can only increase sizes downstream, never decrease them. That rule applies for the vent, too, but in the opposite direction - it can only get bigger going up, not smaller. Don't think you need a wye for the vent leg on the WM, only when it connects to the drain below in your drawing. That's the difference - generally a sanitary T is used for vents, and a wye for drains. - a vent is moving air, a wye is directing waste.

That's my best understanding of things, but as noted, I'm not a pro, but have a lot of experience listening to them here.

 

[Houptee]

What if he puts a 4x4x4 WYE at the top of the new waste stack where he has a 45, and comes out the top of the WYE with a bushing down to 2", and ties it into the vent stack with a double Sani Tee, the left side of dbl Tee to the venting for basement, and right side for added venting of the bathroom group? Just an idea.

 

[Sponsor]

 

[Jadnashua]

The vent must come off of the trap arm before it turns down, or it is not a vent...

 

[atomicdog]

The connection into the drain for the sink and WM should also be a wye.

Are you referring to the tee that is circled in red below? If so, I thought that using a wye there would create a partial S-trap and as a result it was to be avoided? I may have been misinterpreted the other stuff I've been reading, but it seemed like they were discouraging a wye there in favor of a sani-tee.

 

[hj]

THere is a good chance that the sink connects to the "vent" above the floor. IF there is NO plumbing connected to it above the "Y", then you can do it like the last picture. The "T" inside the circle is correct, although in this case a "Y", or "combo" would also work because the vents prevent it from creating an "S" trap. HOW fittings and pipes are installed are what makes things legal, or illegal, not the fittings themselves.

 

[Houptee]

What if the bathroom group has no other venting, and it was designed using the vent stack as its only vent based on its close proximity to the bathroom, and now he moves it way down by the floor of basement like his second plan, wont the toilet suck the lav and tub traps dry with such a long distance to the point it ties back into the vent stack/building drain?

 

[atomicdog]

What if the bathroom group has no other venting, and it was designed using the vent stack as its only vent based on its close proximity to the bathroom, and now he moves it way down by the floor of basement like his second plan, wont the toilet suck the lav and tub traps dry with such a long distance to the point it ties back into the vent stack/building drain?

That was my worry that I posted about in post #18... I suspect that the bathroom is just vented off of the stack, not 'revented' or 'auxiliary vented' (whatever the proper term is for modern venting). I'm worried that if I move that waste connection 8' down to the basement floor it could cause a problem, but I'm not sure if that is an issue or not?

 

[Terry]

Each floor is vented on it's own.
The vent from the lower floor can tie in at 42" on the next floor, or just go up through the roof.
Waste from the floor above comes in below the vent takeoffs on the lower floor.

I would guess that the second story lav vents on the top of a santee at 18" above the floor and ties back into the cast iron vent at 42"

 

[Houptee]

It looks like MO uses the UPC2003 plumbing code you can download it free here. Read chapter 9 on venting it says you can have wet vents in limited situations.
https://law.resource.org/pub/us/code/safety.html

 

[Terry]

UPC doesn't allow wet venting between floors, or with washers.
It's bathroom sets located on the same floor.

 

[atomicdog]

Hey guys I really appreciate all of the input. Upon further investigation... it turns out that the Y that goes up to the first floor has the toilet on one branch, and the SINK AND VENT on the other. I thought that the toilet and sink were on one side and the vent alone was on the other. There is simply no possible way for me to tie in to that vent above the sink on the floor above. It is plastered in to a wall. So I'm left with doing the best I can with what I have, trying to improve on what was there (see post #1 of this thread). I'm also trying to set it up in a way that if I ever have to tie in to the vents above it will be just a matter of chopping the AAVs and adding the venting (and tearing in to that wall above). Anyway, this diagram is what I've come up with. I did speak with a building inspector who told me that the plumbing inspector would most likely be lenient and allow what I have diagrammed since the original plumbing was so far off from what is code now. He said what I'm doing here is way better than some other plumbing that he has seen get by. If it ever comes to that, I'm hoping he's right.

 

[atomicdog]

I do have a couple of questions still:

1. Is it allowable to use a wye with 45 degree street fitting or does it have to be the way I have diagrammed above with an extension to a 1/8 bend?
2. Can the cleanout on the vertical drain be flush style or does it have to be a wye since there is waste coming down from above? I was planning on using a flush cleanout like the one pictured in the diagram but it occurred to me that it may have to be a wye in this application.

Thanks!

 

[Cacher_Chick]

There are surely a lot of things we cannot see there. Running a pipe from a basement to the roof is not something we would normally avoid. If the roof is an issue, vents can be tied together in the attic. With a vent, it can go up pretty much anywhere, so it it just a matter of picking the place that works given the layout of the interior walls in the house.

 

[atomicdog]

There are surely a lot of things we cannot see there. Running a pipe from a basement to the roof is not something we would normally avoid. If the roof is an issue, vents can be tied together in the attic. With a vent, it can go up pretty much anywhere, so it it just a matter of picking the place that works given the layout of the interior walls in the house.

That is true... There is a lot more that isn't visible in the diagram. The full background is that this is that this is a full 2 story brick house PLUS a basement and very old construction. Running a vent up a brick/plaster exterior wall is not a possibility, and running a vent up an interior wall to the attic would entail punching through 3 ceilings, all of the stud blocking in between, and with no access inside of the walls because of skim coat plaster on top of quikrete style plaster on top of wire mesh and lathing. Yes, I could theoretically do it if I cut at least 4 decent sized working holes along the way, but it's not very realistic. There are no mechanical/plumbing chases in this house that lead up to the attic. All of the plumbing was either plastered in the walls or bricked/plastered in to the exterior walls.

 

[Jadnashua]

You have to realize that an AAV only lets air in, not out, and may not solve your problems. ALso keep in mind that they do eventually fail - it may be a long time, but for that reason, they need to be kept where you can service them, when the time comes.