Venting a liberty 404 ejector pump


Old 12-25-13, 02:01 PM
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Venting a liberty 404 ejector pump

I just got the liberty 404 ejector pump and have a question about venting.

Before installing the pump in our basement, I came to the forums to try to understand the correct way to set up the unit. From what I'm reading here is that the vent's purpose is to prevent cavitation and odors from escaping into the living area.
With the liberty pump there are actually two vents, one on top and one on the side of the unit. If I were to screw in 1.5" PVC to the top of the unit, this still leaves an opening on the side where odors are sure to escape. So what would be the purpose of putting in a vent at all?

After reading Liberty's manual, they say "Provision is made for a vent (almost making the vent sound optional) to allow for high suds conditions". While setting up and installing this unit wont be a problem, I'd be very thankful if someone would explain the logic of this vent dilemma.

Thank you in advance, Steve

Last edited by teeb57; 12-25-13 at 02:16 PM.
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Old 12-25-13, 02:59 PM
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Welcome to the forums.

I'm not the pro in this forum but I have set up those ejection pumps. There are two openings in the top and one in the side.

The side opening is for the sewage into the unit. The top openings are one for vent and a discharge line. As far as I know... the vent is for escaping gasses and has nothing to do with cavitation/suds.

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Old 12-25-13, 07:43 PM
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Actually, you're right. I miss read the discharge/vent signage on the unit. Either opening can be used for inlet or venting. Thank you for that!!

However, the manual says no AAV's are to be used. Since AAV's restrict airflow in two way movement of air to only one way movement, I can only assumed this was to prevent cavitation. The manual also says the vent is to help augment extra volume of air for high suds conditions. I have no idea why suds play into the equation. Thanks for taking the time to respond Pete and Merry Christmas to you.
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