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Question about venting and discharge from basement sink

1213 Views 3 Replies 3 Participants Last post by  i800129

I have a question about venting and discharge for a basement sink.
Could I connect into the 1 1/2 Drain from the sink above for the discharge (in the picture below)?
The 4" stack is behind drywall so I am trying to avoid tearing into that if possible. (Also I would add check valve and unions, just didn't take time to draw them).

Thanks in advance.
- Jim


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I have a question about venting and discharge for a basement sink.
Does YOUR County allow studor vents?
A 1.5 inch drain under IPC can handle 3 DFU. Your KS is 2 DFU. Your pump is 2 DFU times the GPM of the pump at a 10 foot head. I'm sure it far exceeds the 1 DFU you have remaining on you 1.5 inch drain. Run the pump to the 4 inch or extend with an MIP on the cleanout to add a 4 inch wye for the pump.

Sanitary drains are designed for gravity drainage not pump discharges.

Not to mention but when your kitchen drain blocks your going to have one heck of a mess.
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I am not sure about the local code. The pump I bought, a Liberty 404 says:

Do not use one-way quick-vents or air admittance valves as they will not guarantee proper fixture performance.

So that's why I was thinking of just connecting to the existing vent.
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