# Sewage grinder pit and pump installation



## leff1rj (Jan 19, 2011)

Sewage grinder pit and pump installation:

I am in process of replacing an 18" dia. x 30" deep pit that was installed in basement when house was built. The idea was this would be used for future basement finish complete with full bathroom installation. After living here for 10 years, my wife introduced me to the future and said she wants the basement finished! 

I purchased a system composed of a Little Giant 2HP 230v sewage grinder pump (very impressive demonstration video on YouTube sold me) and Jackel spiral wound fiberglass pit, 24" dia. x 48" deep. Labels on outside of pit mention Franklin Electric. Pit has a 32" dia. anti floatation flange around bottom and same size flange around top. Concrete is placed over bottom flange after installation in 54" deep dug hole that has been backfilled with 6" of pea gravel. I suppose purpose of adding concrete on top of bottom flange is to add enough weight to keep pit from floating if there is a water table issue.

I have many questions.

I have read many sites before purchase and many sites after purchase. What I am noticing after I bought this system is the pits with the flange may be for outdoor installation. Does this make any difference? I am installing under stairway to basement. The so called indoor systems utilize smaller pits with less depth. The excavation work to 54" depth has turned into quite an undertaking. But if the larger pit is ok, I plan on continuing the Big Dig to China to install this thing.

The pit comes with 1 1/4" threaded PVC adaptor installed through wall of pit. Does the 1 1/4" PVC pipe just turn up via a 90 degree bend just outside of pit and extend up through concrete floor that will be poured back around top of pit?

There is no hole in side of pit to receive the 3" sewage drain pipe from bath. Is this as simple as hole sawing an appropriate size hole through fiberglass pit to accommodate a rubber adaptor seal for 3" PVC pipe?

The lid appears to be a PVC material or a composite material with a checkerplate surface and no holes with adaptor seals for pipes or electrical conduit entrance. This pit should be vented. To vent, would this also be a simple hole sawing of cover to accommodate an appropriate size rubber adaptor seal of minimum 2" for PVC vent pipe and also another hole with appropriate size rubber adaptor seal for electrical conduit?

Does it make any difference that the existing 3" PVC drain line from bathroom under concrete floor has an invert elevation 12" down from surface of concrete floor and that the 1 1/4" exit pipe that will come from pump through existing factory installed adaptor in wall of fiberglass pit has an invert at 20" below concrete floor? The inlet drain is higher than the outlet pressurized pipe.

Should pit be positioned relative to the 3" PVC inlet drain so as not to be pouring directly on pump? Would solids build up and cake on pump if solids hit pump direct?

Thanks to all for any answers provided.

Rick


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## LateralConcepts (Jun 6, 2010)

> The pit comes with 1 1/4" threaded PVC adaptor installed through wall of pit. Does the 1 1/4" PVC pipe just turn up via a 90 degree bend just outside of pit and extend up through concrete floor that will be poured back around top of pit?
> 
> There is no hole in side of pit to receive the 3" sewage drain pipe from bath. Is this as simple as hole sawing an appropriate size hole through fiberglass pit to accommodate a rubber adaptor seal for 3" PVC pipe?


I think you're in for a lot of surprises here. I can tell you that the system you purchased is not a pump and basin meant to be placed indoors. The system you describe was designed to be installed outside in areas where a conventional gravity system is not possible. Around here for instance, there are a lot of homes that are built on the waters edge, then connected to a pressurized city sewer system a couple hundred yards up the hill. The basin is designed to take all the waste from the household and discharge it through an 1 1/4" tightline up the hill to the pressurized sewer system. 

You need something more like this for your application: http://www.libertypumps.com/Products/Category/SubCategory/Product/?p=71&s=10&c=18


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## Navien Plumber (Jan 19, 2011)

I agree, the device you have detailed is for outside app.


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## bethomas (Jan 7, 2011)

i did this same thing when i did my basement. (dug out the old one, put in a new one) and the big box stores carry pits that can be used for this application. looks like an oversized sump pit, but it has a lid that you screw into the pit, creating a seal. it also has pre drilled holes in the top for electrical, vent and discharge lines. As far as drain lines i drilled holes into the side of the pit for shower, floor drain, sink and toilet, and sealed those.

It looks similar to the liberty pump that Lateral posted above.


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## bethomas (Jan 7, 2011)

here are some pics... the above ground piping was the existing piping that in these pictures hadn't been replaced yet, but you should get the idea.... i used self leveler after pouring concrete around it. and yes, my water table is that high... a frickin mess. i did both the sump pit and the ejector pump pit with new pits, plumbing and pumps.


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## leff1rj (Jan 19, 2011)

*grinder pump installation*

Thanks to all for responding. I talked with technical advisor with Little Giant Pumps. I explained my installation and read all my questions to him. He said pretty much what you fellows are telling me, that this pump is designed for a system that will have back pressure. I did not do enough research regarding an inside or outside installation and the proper equipment. But he did tell me this can be compensated for by use of a spring loaded check valve that takes 10 to 15 psi to force open and using 90 degree bends. My lift here is about 12' to a horizontal gravity drain 3" pipe that will dump into main 4" pipe that extends out to septic system. 

This sound reasonable to you fellows?


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## LateralConcepts (Jun 6, 2010)

I think you'd be better off trying to sell or return the system you have and purchase the appropriate setup. Too many variables, changes, and modifications will make for a less desirable and perhaps less functional system. Not to mention it wasn't designed for what you're looking to do; which could lead to potential code violations and/or future liability concerns.


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## leff1rj (Jan 19, 2011)

Ok. Thanks Lateral Concepts. I will pursue that avenue and acquire appropriate equipment.


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## LateralConcepts (Jun 6, 2010)

leff1rj said:


> Ok. Thanks Lateral Concepts. I will pursue that avenue and acquire appropriate equipment.


Sounds good. Keep us posted. :thumbsup:


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## mikeypaster (Jan 25, 2011)

hello,
inregards to your high water table. at my jobsite i have the same set up. (water portruding out of the pit hole), but not as bad. you had mentioned the basin and the sewage pit. did you install another sump pit in that area? what did you do about the water seeping up? did you just concrete it in around it and pea gravel the bottom?
thank you so much


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## bethomas (Jan 7, 2011)

I had an old sump pump that i used to keep both the sump hole (other side of the house) and the ejector pump hold dry while i worked in them. When actually installing the pits we had to stand in them to sink them until we got enough pea gravel back filled to hold them stationary. Then i just concreted around them and they haven't moved once they get the wait of the concrete, pump and water in them.


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## mikeypaster (Jan 25, 2011)

i just met with the city inspector and he recommended to me to put a 2" drain tile from the newly created sewage pit hole ( but not in the plastic reservoir) to the nearest cleanout in the floor to allow slow drainage to the the drain tiles. he then mentioned to me overtime that the water in the newley created sewage pit hole is like a vacuum under the house since I disturbed the packed soild that had been grated when the house was built. he told me to fernco to the existing cleanout which is 8' away and slope it about an inch to the cleanout. so all in all, i have to create a smaller drain tile to the existing cleanout about 18" under the concrete and under the 4" toilet line to catch vacuum water. this seems easy and makes sense. what do you think?
thanks so much


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## leff1rj (Jan 19, 2011)

*response to Mikeypaster*

I have not completed the big dig yet. My plan is to dig 54" deep, backfill with 6" of pea gravel, set 48" tall sewage pit on pea gravel, pour some concrete on anti flotation flange to keep pit form floating, after concrete cures backfill with pea gravel around sewage pit to within 4" of surface of concrete floor, and pour concrete floor back around perimeter of top flange of sewage pit.

As for the drainage issue, I'm not sure how one would solve that issue.

I removed a sewage pit that was 18"dia x 30" deep that was installed when house was built. The reason I removed this pit is because it did not have enough volume to operate the grinder pump. Had to install a larger pit 24" dia x 48" deep in same location.

Good luck, and thanks for your information.


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## proremodel (Jan 30, 2011)

When I have done them I get 2x4's to gold it in the hole (run them to the floor joist above) then you have time to work on it without worry about the pit floating up and it is still movable to a extent. Then when everything is setup you can backfill it and concrete it in place.


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## leff1rj (Jan 19, 2011)

Great idea! Thanks proremodel.


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## bethomas (Jan 7, 2011)

that 2x4 is a good idea.... my father in law just stood in the hole... we did both the sump pit (had to move it from the center of the room) and the ejector pit. i dont have a picture of the finished sump pit though with all the gaskets installed. it is completely sealed now, just like the ejector pit


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