Laundry Standpipe-need some advice

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jac233

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I'm a rookie at this so any info is appreciated.

I'm trying to hook up a standpipe for my washing machine. It was going into a utility tub but we got a dog and replaced it with a nice dog tub that is much shallower and would like to empty washing machine separately.

Here is what I have so far and this is not yet glued. I just mapped it out and ran the washer a few times while I watched over the pipes just to make sure it would work.

My biggest head scratcher is the venting. Does it need its own vent? It's draining from a 2" into a 4" that will be buried under the floor. That 4" pipe runs horizontally under the floor then pops up vertically upstairs and there is a toilet and sink that are connected on this same run that vents through the roof. Do I still need an AAR coming off the T or can I just skip the vent all together remove this trifurcated piece and just do a 90 bend to the horizontal section?

When I ran a few loads of laundry it seemed to be fine when I took the AAR off and capped it with a clean out. But I really am not sure how this all works so let me know what you think.
 

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breplum

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1. The 3 x 2 on it's back is supposed to be a combo. the reason is to enable solids to sweep in the direction of flow and not crash-land and accumulate. (we could argue that not a lot of solids in your application, so who cares). But it is not to code.
2. The use of a WYE low down is not proper for the dog sink. If that is the plan, it should be a simple tee with a trap arm for the sink..
3. Code: Overall height of p-trap is 6" - 18". And standpipe length 18" to 30"
Drawing of proposed layout would help. The AAV is good for the WM drain/vent and if your dog sink is 5" away off the tee, then you don't need another vent.
 

jac233

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1. The 3 x 2 on it's back is supposed to be a combo. the reason is to enable solids to sweep in the direction of flow and not crash-land and accumulate. (we could argue that not a lot of solids in your application, so who cares). But it is not to code.
2. The use of a WYE low down is not proper for the dog sink. If that is the plan, it should be a simple tee with a trap arm for the sink..
3. Code: Overall height of p-trap is 6" - 18". And standpipe length 18" to 30"
Drawing of proposed layout would help. The AAV is good for the WM drain/vent and if your dog sink is 5" away off the tee, then you don't need another vent.
Thanks for the info!

I need some clarification...when you say 3x2 which pipe are you referring? The flow in the pic goes from left to right.

As far as the vents go, when the utility sink was in place there was a trap under the sing emptying right into the 4" (from a 2" reduced to 1.5") with no vent. I guess I still don't get why you need the vent? If it's connected to a line that is vented through the roof, what is the purpose of the AAV?
 
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