Installing a utility sink pump?

[Reach4]

The smell is just a by product

You did not say you actually had a smell, so I am supposing you are looking to prevent a smell that may or may not be there. Your idea of an S-trap sounds functional, but if you really need to isolate smells, then a vent to outdoors would be needed. I would consider not putting in an outside vent unless you develop a smell. But I can see that if there is any doubt, you might want to do it and be done with it.

Maybe you will want to pour your old milk or fish-cleaning water down your sink, rather than just washing hands.

 

[SD-777]

You did not say you actually had a smell, so I am supposing you are looking to prevent a smell that may or may not be there. Your idea of an S-trap sounds functional, but if you really need to isolate smells, then a vent to outdoors would be needed. I would consider not putting in an outside vent unless you develop a smell. But I can see that if there is any doubt, you might want to do it and be done with it.

Maybe you will want to pour your old milk or fish-cleaning water down your sink, rather than just washing hands.

Yeah I can always try it out for a week or two and see if any smell develops. It would mostly be water with some dirt from working outside.

 

[Sponsor]

 

[Bannerman]

Would a P trap allow air to get in? I should do a P-trap going horizontally into the side inlet of the 404?

The attached rough sketch, shows the P trap connected to the vented T as described above. The T then discharges straight down into the top of the tank. Because the top of the T is connected to a vent which terminates outdoors, that will also provide venting for the tank, so the additional vent connection shown directly to the tank top, may or may not be required, depending on your local plumbing requirements.

 

[SD-777]

The attached rough sketch, shows the P trap connected to the vented T as described above. The T then discharges straight down into the top of the tank. Because the top of the T is connected to a vent which terminates outdoors, that will also provide venting for the tank, so the additional vent connection shown directly to the tank top, may or may not be required, depending on your local plumbing requirements.

View attachment 103945

So this would be superior to having a P-trap go directly into the side inlet of the 404, and having a separate vent out?

 

[SD-777]

Just high enough to get into the wye. Long sweep 90's (or 45s welcome) don't hurt but not necessary as the pump can handle it pretty well.
Yes, a check valve is always the way to go to prevent sewage back down into the line.

One more question, I did find another inlet into the sewer, not sure if it's cast iron but it feels like it. Can I just screw in a male threaded dwv adapter here and use it? One like this: https://www.homedepot.com/p/NIBCO-1...MPT-Male-Adapter-Fitting-C4804HD112/100347535 Currently it's being used for a condensate pump. I would just have to figure out how to reattach the condensate pump.