basement sink drain


Old 07-05-00, 10:09 PM
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My basement unfinished bathroom has a sewage ejector system already operational. The tub and (not yet installed) toilet drain into the basin thru pipes under the floor. The toilet and tub share a 1.5" vent pipe; the sewage ejector basin has a dedicated 2" vent to the roof. Since no sink was installed, there was no provision built in for draining it except for a stub off the vent for the tub and toilet. This stub is over 12 ft away (distance along the 2 walls it would need to follow) from where the sink trap will be and seems too high to give the 1/4" per foot reqd drop, plus the drain pipe would interfere with water pipe to toilet. There was no vent pipe provided for the sink. The vent to the sewage ejector is 3 to 4 ft from the proposed sink trap so I want to know if it is alright to cut into that vent for the sink drainage. Also, since it is so close to the sink, do I need a separate vent (possibly an AAV) for the sink? A plumber has told me he would cut into the ejector vent for this sink drain, but I'm not sure if the pressurization of the basin from the water going into it from the toilet and tub might cause the water in the sink trap to back up into the sink. Is the water in a trap enough to cause the pressure relief for the basin to be purged from the 2" vent?
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Old 07-06-00, 12:41 AM
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Join Date: May 2000
Location: Eugene, Oregon
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This does not sound like the plumbing is proper or to code, if there is anyway for you to get picture on line of the plumbing sure would make it alot easier to see what your dealing with.

Best Regards Plumber2000
Old 07-06-00, 09:05 AM
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To simplify- a 1.5" vent services the toilet and tub (don't know if this was to code). Both drain to the sewage ejector. No sink was installed so no drain or vent provisions were put in place. Now I need to add a sink.
Can I cut into the 2" vent pipe leading to the ejector basin to drain the new sink? The new sink trap will be 3 ft from the ejector vent pipe. If it were ok to drain into the vent pipe of the ejector, at this close of a distance would I still need a separate vent for the sink? If yes, is an AAV ok?
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