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Discussion Starter · #1 ·



Looking to add a laundry sink at the blue line. I know the setup is wrong so I need a p-trap at the red circle, and also remove the 3 elbows at the corner and replace it with one (that little stub-out is a false wall I can remove). But how do I properly vent this? I can't get to the main vent so I'll need to use an AAV. Do I vent it after the laundry sink? Or will I need to vent it both after the washer and after the sink too with a tee?


I do not want the washer drain hose to hook over the side of the sink. It's too far away, and we have plans for the space between the washer and the sink.
 

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A "Handy Husband"
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An AAV is not complaint for a washer drain. And you cannot add another drain into the 2" washer drain. You need to find a way to vent this arrangement.
 

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You need to upload more pictures, like of the main drain.
Basically:
- Washer overflow must be 36"- 48" high.
- You put a washer trap and a vent pipe up at the red spot.
- You put a sink trap and a vent up at the blue spot.
- The two vents will join together higher and have a single AAV.

To verify: go to loveplumbingform.com
 

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Discussion Starter · #4 ·
There's literally no other practical way. Venting to the roof would involve drilling up through 2 floors (without closets or anything). Connecting to the main stack is 20 something feet away and it's also a drain for the floor above.



Does the washer have to be vented? Wouldn't an AAV on the sink solve the vent issue?
 

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Discussion Starter · #5 ·
You need to upload more pictures, like of the main drain.
Basically:
- Washer overflow must be 36"- 48" high.
- You put a washer trap and a vent pipe up at the red spot.
- You put a sink trap and a vent up at the blue spot.
- The two vents will join together higher and have a single AAV.

To verify: go to loveplumbingform.com

Where the clean out is in the picture is where the pipe dumps in to the main sewer line. So basically make a rectangle with a shared vent for both?
 

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"So basically make a rectangle with a shared vent for both?"
- yes.
Some states require 3" vent above where the two join. Check your local code.
In my city, a 2" vent is good for both washer and sink.
Again, go to loveplumbing.com and find the diagram that illustrates your scenario.
Lastly, do something to improve the flow at the corner with the 3 elbows. You can do better.
 

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Discussion Starter · #8 ·
"So basically make a rectangle with a shared vent for both?"
- yes.
Some states require 3" vent above where the two join. Check your local code.
In my city, a 2" vent is good for both washer and sink.
Again, go to loveplumbing.com and find the diagram that illustrates your scenario.
Lastly, do something to improve the flow at the corner with the 3 elbows. You can do better.

Will do, appreciate the help. I will likely just cut out the 3 elbows and replace it with one single elbow in the wall. This is how it was set up when we bought the house; I'm no plumbing expert, but I recognized the 3 elbows glued together and foil tape to seal the sewer gas off were definitely wrong.
 

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A "Handy Husband"
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If you insist on the AAV, use the AAV to vent the sink and dump the washer into the sink. Perfectly compliant.

The reason the AAV will not work for the washer is the washers pumps water under pressure and that will hold the AAV closed.
 
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