Sink Pump Plumbing

I want to install a sink pump in the basement of my house as I don't have a floor drain that goes to the sanitary sewer line. I also want to use this so I can have a washing machine in the basement. First off, what is the best one of these to buy? Do I need a 1/3 hp one or is 1/4 hp sufficient? And lastly, I have been reading that these things need to be vented. Why is that, and how would I vent it, as the location I wish to place it does not have any kind of vent nearby?

All of those things have a basin that partially fills up before the pump turns on. You can't push water into a closed vessel without some way for the air in there to come out! then, you need a way for air to refill it as the pump pushes the waste out.

The size of the unit would somewhat depend on how high you need to push the waste and the volume that is coming in.

jadnashua said:

All of those things have a basin that partially fills up before the pump turns on. You can't push water into a closed vessel without some way for the air in there to come out! then, you need a way for air to refill it as the pump pushes the waste out.

The size of the unit would somewhat depend on how high you need to push the waste and the volume that is coming in.

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I didn't know those were sealed. It seems some air would be able to get in. Even if it were not able to, wouldn't the air go up through the outlet of this thing when the reservoir started to fill? if I need a vent for this, where could I put it, as I don't have a house vent nearby. How high would the vent have to rise?

Keep in mind that if you are connecting this to the sewer, the vent needs to go to the proper place in your house's vent system, otherwise, you'd have an open path to the sewer sitting in the room...not nice! The system needs to be pretty tight as opposed to a conventional gravity drain, you'll have the pump pressurizing things, so no, it won't allow water in, or if it does, it will be VERY slow as some air leaks out. The only way to make it work is a proper vent, and no, an AAV won't work, since it only lets air in, and it MUST have a path out (an AAV is a one-way, air inlet valve).

As to where you would need to run the vent, can't tell without being there. Keep in mind that a drain line is NOT a vent if there is something above it, draining into the line. You might have to go up into the attic to connect to a pipe to provide a vent, or all the way up into the attic and through the roof.

You need to know what pump you are buying, some of them only require a 1/2 inch vent hooked over the edge of a laundry tray, you don't need a full sized vent tied into you system

I recently installed a Liberty 404 drain pump for our laundry tray. It uses a 1.5" inlet, outlet, and vent. I ran the vent to the attic where it connects to a vent through the roof. Running a 1.5" vent through an interior wall is an easy task. In a single story residence it can even be done without opening up a wall, it just takes some careful measuring.

shacko said:

You need to know what pump you are buying, some of them only require a 1/2 inch vent hooked over the edge of a laundry tray, you don't need a full sized vent tied into you system

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Which ones are those? You have some makes and models? That sounds like a lot easier way to go than running a vent line all the way to the roof.