Slop Sink Sump Pump Issues

[YoDaPlumba]

Hi everyone, this is my first time posting on the forum, and I’m looking for some advice on my basement sink pump setup.
I’m having an issue with my basement slop sink setup, which requires a sump pump due to my drainage system. Here's what I have installed:

• Pump: Little Giant WRSC-6 (1/3 HP, 2760 GPH, automatic sump pump system)
• AAV: Studor 20341 Mini-Vent Air Admittance Valve
• Check Valve: PumpSpy Silent Check Valve (1-1/2", spring-loaded flapper)

The AAV is necessary since there’s no vent stack nearby. I expected the pump to activate once the water in the sump drum reached a certain level, draining it efficiently. However, here’s the problem:

1. Immediate On/Off Cycling: When water enters the drum, the pump kicks on instantly and then off right away. This rapid cycling seems bad for the motor and might burn it out.
2. Poor Drainage: When I fill the sink and then try to drain it, the pump struggles, and the water drains slowly. The sink gurgles, and the check valve flap visibly stays closed while the pump is running.

I suspect the issue is related to ventilation. My thought is to try raising the AAV higher above the check valve. Could this help? Is there a specific height requirement for the AAV in this setup? Or is there something else wrong with the pump or the overall configuration?

Any advice or troubleshooting tips would be greatly appreciated.

 

[Geofd]

I had something like this, no vent to tie into,so I cut a wye into the same drain the pump connected to it works fine

 

[YoDaPlumba]

I had something like this, no vent to tie into,so I cut a wye into the same drain the pump connected to it works fine

Do i need to put the vent on the pump higher? is the vent off the pump enough to ventilate? or do i need one off the P trap?

 

[GReynolds929]

You cannot put an AAV directly on a pump. The positive pressure keeps the diaphragm closed not letting air in creating a vacuum. There is a way to use one, may not be code approved, but it is a way, it just has to be done in a specific manner. The cycling is normal, they're designed that way. It's not like a well pump where cycling kills them.

https://ipsplumbingproducts.com/wp-content/uploads/2020/07/Studor-Sump-Pump_071420.pdf

 

[YoDaPlumba]

I see what you are saying and thanks for the picture but this seems like a lot of work for a vent. What about the candy cane method where you put the vent line into the sink? This seems like a easier solution. Since the one way check valve holds water it wont let gases into the home. If the check valve fails, having the pipe elbowed into the sink or with a standpipe helps mitigate potential flooding issues. Is this code?

 

[Geofd]

Do i need to put the vent on the pump higher? is the vent off the pump enough to ventilate? or do i need one off the P trap?

I did pipe the vent just a bit higher, it not exactly code but it worked I think I put the vent wye in front of the drain wye

 

[YoDaPlumba]

I did pipe the vent just a bit higher, it not exactly code but it worked I think I put the vent wye in front of the drain wye

Can I see what yours looks like? Did you do something like this? Did you do the "20 pipe diameters downstream?" For me that would be 40 inches away from where the discharge is hooked up because I have a 2" drain line. 2 inch diameter x 20 pipe diameters = 40"

 

[Twowaxhack]

I see what you are saying and thanks for the picture but this seems like a lot of work for a vent. What about the candy cane method where you put the vent line into the sink? This seems like a easier solution. Since the one way check valve holds water it wont let gases into the home. If the check valve fails, having the pipe elbowed into the sink or with a standpipe helps mitigate potential flooding issues. Is this code?View attachment 47194

That would stink.

 

[YoDaPlumba]

That would stink.

It would only smell from the stuff sitting in the pump. Got to watch what your washing out

 

[Twowaxhack]

It would only smell from the stuff sitting in the pump. Got to watch what your washing out

If you wash clothes and the rinse water sits in that pump basin for a few days it will stink.

 

[YoDaPlumba]

If you wash clothes and the rinse water sits in that pump basin for a few days it will stink.

i am going to try it out as a temp fix then plumb the AAV to the discharge pipe as shown above.

 

[YoDaPlumba]

Update. I added the candy cane method and it was indeed a ventilation problem. The pump works as it should.