can't put my fingers on it....I installed Zoeller M98 and everything seemed to be working OK until the time when I was outside and saw that the water from the sump is forced backed to the connected spout coming from the gutter.
I thought there is a partial blockage and only with heavy flow....since there is no back up of water during rain...only when Zoeller pumping out.
the piping is 1.5 inch and there is a slight pitch so I don't get it.
I tried to see if water from a garden hose would flow with no issues and indeed that didn't back up at all.
here is a pic of how it looks like now, after I separated the connection between the leader and the sump pump pipe.
You can see in the pic that the water from the sump pump was indeed flowing up and to the left and would overflow where the leader goes into the elbow that then connects to the drain pipe.

I have checked the first 10 feet or so of the drain pipe and see no blockage....before I dig and inspect another 10 feet - hope somebody can shed some light.

 

What is the original problem that you were trying to solve? There is no reason for the downspout to be connected to the pump system. Either let the rain water drain into the ground at the first elbow or install a dry well there.

Secondly, why did you need a sump pump, in the first place? Is water entering through the foundation? If so, you need to seal the foundation with a membrane which is done from the outside.

 

pulpo - appreciate your trying to help but this isn't really an unusual setup.
The house has a sump pump like millions of other houses...the water discharges to the outside and it is perfectly ok to tap it at some point to a drain from gutters that goes out to the street.....
What I haven't seen before is that a sump pup that is spec'ed out to work with 1.5 inch discharge pipe would actually overflown the drain pipe of the correct size.....rain or not...the water from the sump pump flows at such a high rate that it actually flows to the left and up overflowing the elbow.

I need help understanding why would Zoeller 98 that is rated to work with 1.5 inch pipe push so much water that the actual drain pipe can't keep up..... (I am still assuming there is no blockage).
I am looking for ideas and possible reasons for this....
thanks!

 

I actually just thought about something.... would it help to replace the current tee connection with a wye connector ? This way the water would kind of have more resistance to back toward the leader.??

 

I labeled your picture. Remember.... water takes the path of least resistance.

 

Yes & many houses have sump pumps when the foundation should have been sealed instead.

It maybe okay to tap into the line. However, I don't think that it was necessary.

 

PJ - When I saw the water backing up, I cut the sump pump discharge pipe and did a temporary "bypass" so I could meantime inspect the old pipe.
That PVC above the ground is the temporary pipe running from the sump pump about 12 feet away from my house.
The original path is visible - that upper cutoff and then going underground and then merging with gutter drain via a Tee.

Just to add....before I had a flowtec pump and that didn't cause the water to flow backwards to the elbow at the downspout but that was also much weaker pump....

 

Is that really a 1 1/2 PVC from the downspout? I've never seen anything less than 4".

How long is the total run of 1.5"? I think what you have is simple case of the water taking the path of least resistance. A long run of pipe will actually have quite a bit of resistance to flow (which is why there is a pressure drop in a long length of pipe, and the pressure drop increases as the flow increases). So in this case, the short path backwards to the downspout can have less resistance to the flow so some of the water goes that way.

Certainly an obstruction would make it worse, but It certainly could happen with a long pipe and high flow rates even without an obstruction. I think the reason you notice it now is that you put in a more powerful pump so the flow rate is a lot higher.

A wye will help, but may not help much. You could try running a snake through the line to rule out obstruction. But if you're going to dig it up....replace it with 4" drain pipe and the problem will disappear.

 

I see you're near me in NJ so I agree with Carbide on increasing the size of the underground discharge pipe if possible. It will cut down on a possible freezeup problem too.

 

I also agree with Carbide. There is too much volume of water in the 1 1/2" pipe. Increase the pipe to a 4". That 1 1/2" will not handle the water of the down spout unless you have a very small roof.

 

The entire run of this pipe is about 35 feet and though I haven't dug it all out yet...I suspect there must be a total of 3 Tee's on the way to the curb
I trust you guys so I will look into getting a bigger drain pipe.
I moved in to this place about 9-10 months ago so this is the type of drain I inherited.

I assume 1.5 inch is OK for Zoeller pump but only to the point where I intend to connect it to the Wye.... after that I will be running 3 or 4 inch.
There is no way I am digging a separate piping for Sump pump next to the gutter drain.

Thank you guys again for your input and help....

 

That's right...1.5 from the pump is ok to get you to the wye, then 3 or 4" the rest of the way. I'd go with 3 or 4 all the way on the leg from the downspout though. For one thing, it's less likely to clog from leaves and crap. Plus it's only a couple of more feet to change out.

Good luck!