Kitchen sink trap gurgle from sump pump

[brentvw]

Hi all,
I'm trying to get rid of the trap gurgle in the kitchen sink when my primary sump pump is directed down the main sewer line (see pic attached).

The vacuum pressure is too much for the 2" Studor AAV, if I remove it, the gurgle is gone (the vacuum is pretty strong, removing the AAV and putting my hand over the pipe when the pump goes on will suck the palm of my hand in very tight, like a pool drain). I actually tried leaving the AAV sitting on there without sealing it and that also removed the gurgle, but it would vibrate, pop out, and still emit gases.

I've had ideas from running 3" to the main to putting a bigger AAV on there, 3" or 4"? What is the best option to solve this?

Any thoughts/ideas would be appreciated.

 

[MKS]

Pretty sure it is not code to discharge sump, water from around and under foundation, to the sewer line.
Doing this is why your likely improperly vented sink trap is gurgling.
Pump the sump outside and investigate the venting for the sink.

 

[Sponsor]

 

[Reach4]

Go parallel or go bigger:

1. You could add an additional 2 inch AAV by adding a new vertical vent into the horizontal line.

2. You could put a wye into the vertical vent line and mount a 2 inch AAV on each leg.

3. You could expand the existing vertical using an eccentric reducer and install a Studor Maxi-vent.

I am not a plumber.

 

[Smooky]

If the problem is with the sink, why haven't you got a picture of the plumbing under the sink? Also you could replace the mini vent with a larger maxi vent.

 

[Terry]

Does the basin have an open air vent?
The sump basin needs a vent piped to the outside.
You can't suck water out of a sealed container. It has to have an open end on the other side.

 

[brentvw]

1. Yes, it is code to discharge sump into sewer line in our city, I was also surprised by this.

2.If I shift the ball valves to route the sump discharge outside, no sink trap gurgle occurs, it only happens when discharging down sewer as now it is sharing a line with the sink. I'm reluctant to think there is any problem with the sink plumbing which contains a garbage disposal and another studor AAV since it is fine when not shared with sump

3. The sump basin is not sealed its an open barrel with a plastic garbage style lid on top with the two pump pipes extending from it

--

Thanks for the ideas, a couple mentions of a larger vent such as a maxi-vent. That's a $40 solution worth trying.

 

[Cacher_Chick]

The base problem is that your kitchen sink needs a real and proper atmospheric vent.

The secondary problem is that if you can legally connect a sump pump to the municipal sewer, it should be tied into the building drain, not the kitchen drain.

 

[Terry]

The base problem is that your kitchen sink needs a real and proper atmospheric vent.

The secondary problem is that if you can legally connect a sump pump to the municipal sewer, it should be tied into the building drain, not the kitchen drain.

Here in the Seattle area, they like to see the pumps into a 4" line, and at the least a 3" line. Sharing with a 2" line I've never seen.

 

[brentvw]

Circling back on this, this was fixed by running a dedicated 3" line to the 4" stack, it looks like a pipe maze now and overly engineered but no gurgle