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#1
09-11-11, 11:23 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 37

My Zoeller N98 pump has a 1 1/2 inch discharge pipe. If I used a 1 1/2" to 2" adapter thus running a 2" discharge pipe out to the street, would this improve the efficiency of the pump or would it hurt the gph output?

#2
09-12-11, 03:20 PM
Member
Join Date: Oct 2006
Location: Southeast Wisconsin
Posts: 580
Shouldn't hurt anything, maybe slight gain but nothing you would probably notice.

#3
09-12-11, 03:21 PM
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Using 2" pipe can't hurt. It may or may not be necessary though, you need to do some cipherin' to be sure.

You need to know how much water you will be pumping.

Refer to the pump curve chart in the specs:

http://s3.pexsupply.com/manuals/1265..._PROD_FILE.pdf

Understand that 'head' means two things with a sump pump; 1. the HEIGHT to which you will be pumping, and 2. the FRICTION (which is essentially 'head') that any piping will introduce into the system.

You need to know how much 'head' (friction) will be present in your piping. There are tables and charts for this purpose. Let's say for example (ONLY EXAMPLE, I haven't looked at any tables! this number is for illustration ONLY!) that you need 100' of 1-1/2" pipe and that pipe has 4' of equivalent head AT A GIVEN FLOW RATE, let's call that flow rate 25 GPM. Head increases with flow rate in a pipe, so you need to know how much water you expect to pump!

Let's say your vertical lift is 10'.

So add 'em up: 10 + 5 + 4 = 19 ft head at 25 GPM. Can your pump do it?

Look at the chart now and you can see that with the hypothetical setup above, you will ALMOST make 25 GPM.

REMEMBER, the numbers above are pulled out of a hat. You need to know what the real numbers are before you can decide if you need to upsize to 2" or not.

You also want to be aware of pump 'on time'. If you put this honkin' pump in a teensy sump pit, it will cycle on for very short times... and depending on how fast the water comes in it could be on-off-on-off-on-off etc... and this ain't good for the pump.

OR, you could just go with the 2" and not worry about all this mumbo-jumbo!

OR, you could read this, I glanced over it and it seems pretty good info:

http://abe-research.illinois.edu/pub.../SumpPumps.pdf

Last edited by NJT; 09-12-11 at 03:41 PM.
#4
09-14-11, 01:51 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 37
Thank you for the reply and for the great info. I do have an 18" X 22" pit. I am in a high water table area so during heavy storms the pit fills quickly and the pump runs often, sometimes several times per minute. I have never had a problem with it keeping up with the flow and the backup pump has never had to kick in to help out. But then during hurricane Irene my Champion 1/3 hp pump couldn't keep up and my Watchdog Bigdog backup pump was kicking in to barely keep up with the flow. At one point I even had to throw in a 1/4 hp utility pump to help keep up. That is why I upgraded to this "honking" pump. I did buy a variable float switch so that I could control the cycle of the pump a bit but as you pointed out in such a small pit, I don't think it will make much difference on really heavy flow days. I was thinking about continuing to use the Champion and Watchdog as they are currently connected (share the same outlet pipe) since the Champion uses less energy (4 amps as opposed to 9 amps) and on an average day can keep up and then run a seperate 2" pipe out from the Zoeller which should only have to kick on during extreme weather. The Champion is about 7 years old so buying the Zoeller was partially as a replacement for it for when it eventually burns out. Thanks again for the suggestions.

#5
10-08-11, 05:51 PM
Member
Join Date: Feb 2009
Location: USA
Posts: 6
two pumps into one pipe at high flow = reduced overall performace

You need two outlets. My main pump and backup both have separate pipes and outlets to the yard.

although i'm sure someone will say that the two pumps can share one 1 and 1/2" line, you lose efficiency as the two pumps increase the pressure.

When I bought my home, I had two pumps in one discharge line. Once I split them into separate lines, my pump efficiency improved dramatically.

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