I have a basement ejector pit that I just replaced the pump and piping for. The ejector does not deal with a basement bathroom (yet)--mainly it is just for the washer and utility sink--but I have a feeling it also takes in some groundwater too as we do not have a separate sump pit. The ejector pumps to a branch of the main sewer that is about 4' above the basement floor. I felt an ejector pump would be better in this situation due to lint and debris from the sink, plus the greater horsepower. The pit is vented, but does not have a gas tight lid. The ejector line to the sewer is 1½"-- i know this is ½" too small for an ejector but I just replaced what was installed previously.

Upstairs on the floor above, the only things that drain to that sewer branch are a kitchen sink/dishwasher and a small bathroom. I believe the ejector is the first thing on the sewer line, followed by the kitchen, followed by the bathroom. After the bathroom the sewer branch makes a 90 degree bend before meeting up with the main sewer stack at the side of the house.

The problem I am having is that lately when the ejector runs, the kitchen sink upstairs gurgles and starts to fill up with water. If I run the waste disposal at the same time the sink will drain and backup water does not make it up into the sink. When the ejector is not running, the toilet and kitchen sink are draining fine (although I usually have to run he waste disposal to drain the sink). We have had some backups in the past causing the kitchen sink and bathroom toilet to gurgle but nothing recently, an the backups were limited to the toilet. The kitchen sink has no air admittance valve but does have an overflow line which vents the drain line after the waste disposal.

Anyone have any idea where I should look for a blockage or what I should install?

Hi Lardpants...

How is the ejector pit vented? It needs to have its own separate vent for the system to work correctly. Here, an ejector pit needs air to pull in and to push out. If your sink has no vent then that certainly compounds the issue.

I would also advise you to install an AAV (air admittance valve) at the kitchen sink, but first, let me know how that pit is vented... OK?

After that we can discuss how to snake the drain line... if needed!

Mark

Hi Thanks very much for your help.

This gets complicated, so I have attached a labeled photo.

There seems to be a vent going to the ejector pit- a 1½" galvanized pipe which connects to the main sewer vents to the roof (I don't know the exact routing), but the pit isn't tightly sealed --as it was installed by the previous owner to deal only with sink and laundry waste--so it vents fairly readily. So I don't think the problem lies there. The only odd thing is that some water drains out of the sink/vent line after the ejector has finished running. So I'm wondering if water is getting up high into the vent stack.

The sink line that runs into the ejector pit tees into this apparent vent line.

The ejector drops into the branch sewer line via a t-connection, the vertical leg of which seems to be to a vent stack, but I believe this may also be the connection for the upstairs sink. (I wish there was an easy way to send a photo). And I think this is where the problem is, the water from the ejector is getting forced up the line to the sink above.

As for the upstairs sink there is a waste disposal connected to a p-trap, with an overflow connected downstream of the p trap. The overflow ought to act as a vent, but instead the ejector effluent comes out of the overflow.

BTW none of this happened prior to my replacing the ejector pump, so I wonder if the pump flow is just too great for the line size. Maybe the connection to the sewer line needs to be upsized?

Not sure if the photo attached properly... trying again

Looking at the posted photo - and before Mark comes back - I see the following errors in installation:

1. The Sewer Ejector is missing 2" dedicated vent
2. 2" discharge from the pit (PVC) reduced to 1 1/4" Galvanized
3. 2 - 1 1/4" galvanized 90's make for a very sharp turns
4. Is that sewer ejector Lid sealed?
5. 1 1/4" valve installed in 2" discharge line...
6. Do I see 2" hole in the Lid ?

Thank you...

Thanks Milo

Just to recap from my original post, the pump is a sewer pump, but there is no toilet attached, just laundry right now, so the function is not a full sewage ejector. The home inspector did not think the unsealed lid was a problem at the time we bought the home, however I am considering adding a bathroom, so I would for sure need to take care of the pipe size vent and sealing the lid.

I am more concerned with the discharge from the ejector going into a line that seems too small--could that be causing the backup to the sink upstairs? It seems to be going up the pipe instead of down to the sewer.

I'm also wondering if there is a venting problem in the stack above, maybe it is blocked or just wrong. There is no vent right above it on the roof, so it must branch off another vent or do some bends.

I am more concerned with the discharge from the ejector going into a line that seems too small--could that be causing the backup to the sink upstairs? It seems to be going up the pipe instead of down to the sewer.

Yes, that pipe is too small and it may caused water column to rise while the powerful pump is attempting to empty ejector bucket. Due to small pipe, water has no place to go so it will start piling up and exiting through the sink.

Usually, we combine vents into one 2" vent for one bathroom group and this vent than goes through the roof.

Once you put in new bathroom - don't forget to run new 2" vent from that sewer ejector all the way to the roof.

I am the OP. It's been a long time since I posted but since then I had all the lines replaced including the line from the pump to the sewer with a 45 degree union when we had our new kitchen installed upstairs.

My wife tells me today that the sink is backing up again. I have not seen it yet but she believes it is sewer water. It seems to have a lot of silt in it.

I'm guessing the problem is with a blockage in the toilet drain downstream, or does a blocked the vent stack seem the most likely culprit?

Any thoughts would be appreciated.

Blocked vent seems unlikely.

When does the sink back up... when you try to drain the sink or when the ejector from downstairs is used?

If you guys connected onto the old 4" cast iron drain with the cleanout you posted in the picture back in 2010 then the galvanized pipe going up (I'm guessing it is PVC now) that pipe may not be large enough for a toilet...

Finally, is the laundry connected to all this and is there a problem in that sink?

Thanks for the quick response Massplumber. You are correct that the line is now a 2" pvc, but the toilet is downstream of the problem further down the 4" line so that is not the issue. I also checked the toilet is flushing fine, so any blockage in the line is between the ejector connection and the toilet.

I'm attaching a diagram of the system that should clarify the order of everything...

I am certain the ejector is causing the problem. When it runs there is practically a fountain coming out of the sink drain upstairs. The water is very gray, not black like sewer water, which suggests to me it is all laundry waste consistent with coming out of the ejector. The waste disposal running at the same time stops the inflow to the sink but does not completely clear it. When the ejector pump is not running the sink drains OK, waste disposal or not. Could the ejector pump be just too powerful for the size of the line considering it is not a dedicated line?

My other worry is that there may be no actual vent stack on the sink drain, seeing as I can't find it on the roof. The install was done by a builder--so I wasn't around when his plumber came in, I have a call in to him to find out what he saw when the wall was open. I would hate to have to dig into the wall now the kitchen is 100% finished...

Here is the diagram...

The red line is the backup.

Remove the cleanout in the 4" drain line and look into the drain with a flashlight... could be a partial blockage there (have a large bucket handy to catch anything that may come out of the cleanout).

If that fails to show anything, then run the sink drain while the cleanout is out and see what happens to the water. If no or little water shows up then the blockage is below the connection from the pump but before the cleanout so disconnecting the backflow preventer and snaking the drain through this pipe should help you locate/clear the partial blockage! I would also consider installing a cleanout here so that you can snake the drain again, if needed, in the future.

Be careful if you remove the backflow preventer as there will be lots of water above it... again, need a bucket to catch any water, OK?

Mark

PS: Unplug the pump while doing this work...:)

Mark

Unplug the pump-LOL! Don't need any more fountains in the house...

All the lines from the pump and down from the sink are new so it's very unlikely there would be a blockage upstream of the cleanout.

Aside from a blockage, any thoughts on venting? I was wondering if adding an air admittance valve at the sink would help. They are technically not allowed in Illinois' bizarre Plumbing code, but I prefer it to the alternative.