Why do I have dual drain pipes on my kitchen sink?


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Old 01-23-18, 05:52 PM
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Why do I have dual drain pipes on my kitchen sink?

We purchased our home from an investor and it did not have a kitchen sink. They removed the sink and I don’t know how the pipes were set up. I’m going to install a single basin sink but I need to figure out how to correctly run the drain pipes. Why do I have 2 drain pipes? Which one do I use?

Please provide any other information that I should know.

I am attaching a picture.

Thanks in advance for the help.
 
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Old 01-23-18, 06:32 PM
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Since there is an AAV on the top one, I would assume that there is no vent in the wall. You might try to verify this by reaching into the slots in the wall.

The bottom one seems quite low. You could abandon everything on bottom, replacing it as close to the wall as possible with a cleanout. Then use the top one.
 
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Old 01-23-18, 06:50 PM
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Thanks for the info. I forgot to mention that new sink is deep and will hit that top piece so I have to remove it or lower it. You donít think I can use the bottom drain?
 
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Old 01-23-18, 07:20 PM
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You can, you would need to remove everything this side of the AAV and put a clean out blew the AAV in its place.
 
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Old 01-24-18, 04:52 AM
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I can't help you with your question any more so than X did. But I'm curious as to how you could buy a home where the kitchen sink was removed and why was it removed? And how can it pass occupancy without one? And should not those drain openings be plugged to prevent sewer gas from escaping?

Could it be that maybe a dishwasher was also plumbed separately? Is there full counter top and cupboards installed?
 
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Old 01-24-18, 11:31 AM
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Thanks again for the help Xsleeper. However, not sure I understand what you're saying because my knowledge of plumbing is limited. Can I just remove the top pipe with the AAV and cap that drain and place the AAV on the bottom drain?

Another question, why does the bottom drain have smaller curve pipe and a thicker pipe with a cap in the center? Should I configure it the same after I remove the pipe with the AAV or change it?
 
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Old 01-24-18, 11:36 AM
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Originally Posted by Norm201 View Post
I can't help you with your question any more so than X did. But I'm curious as to how you could buy a home where the kitchen sink was removed and why was it removed? And how can it pass occupancy without one? And should not those drain openings be plugged to prevent sewer gas from escaping?

Could it be that maybe a dishwasher was also plumbed separately? Is there full counter top and cupboards installed?
Norm201, I bought the house from an investor that was in the middle of renovating it. Most of the kitchen had been demolished. I'm not sure why the drains weren't capped but I appreciate your advice and will capped them today.

Also, I'm not certain if the dishwasher was plumbed separately because there wasn't one connected. How would that type of plumbing be configured if it were connected separately?
 
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Old 01-24-18, 02:57 PM
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Xsleeper, I think I understand what you are recommending now. After removing the AAV I will need to add it to the bottom drain, correct? How do you recommend I do that?
 
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Old 01-24-18, 03:02 PM
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Where exactly did I say to remove the AAV?

You leave the AAV, It is the only vent if there is nothing in the wall above.
 
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Old 01-25-18, 10:00 AM
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Xsleeper, maybe I misunderstood, I apologize. Either way, my plan is the remove both pipes completely. I will be capping the top pipe and putting a new AAV with a P trap on the bottom pipe and just have one drain. Is it okay to do it this way? Anything I should know?
 
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Old 01-25-18, 10:05 AM
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It looks like the horizontal section on the top piece is threaded in (based on the hex fitting that we can see in the pic). If that's true, you can probably just unscrew it and replace with a threaded plug. The AAV will stay in place as your vent, and you'll do the p-trap on the bottom extension.

It's an unconventional setup, but should work without any issues.
 
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Old 01-25-18, 10:09 AM
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Zorfdt, The problem I have is the current AAV is too high for the new sink. Our new sink won't fit...
 
 

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