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# Calculating gallons per minute in effluent line

#1
10-16-19, 08:01 AM
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Join Date: Apr 2012
Location: USA
Posts: 209
Calculating gallons per minute in effluent line

Hi

We have a Xylem WE1512HH septic effluent pump; works fine
and 1000 gal septic tank

Drain field is 350' away and 50' uphill

I would to know when the pump runs
1) how many gallons is pumped to the drain field and
2) at what gallons/minute rate

Tried to calc this myself but I think I don't know how
Pipe is 1.5" and PVC
Don't know how many valves along the way but doubt I need it to be that accurate anyway

thanks

#2
10-16-19, 09:05 AM
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More info is needed but usually the flow rate is controlled at the distribution manifold at the leach field and you don't calculate the pump's output. All that maters is that the pump "has enough".

If you want to know the pump's gph you'll need to find the pumps output chart. Add the flow resistance through that much pipe plus the elevation. Then look it up on the pump's chart.

#3
10-16-19, 09:45 AM
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Join Date: Apr 2012
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thanks
I suspected would be tough to answer since I don't know what I am talking about
What I would actually like is the length of the time the pump runs to empty the tank; so to estimate kWh consumption.
But I guess I need to get manifold flow rate to do this.
Suppose I could go take off cover and see if there is any info in there.

#4
10-16-19, 11:01 AM
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Just put a wild guess to how long the pump runs. It doesn't run for very long and only every 3-10 days. A rough estimate is that a person produces 60 gallons of waste water per day. Your tank probably pumps about 500 gallons on each cycle so you can estimate how often it runs. In the grand scheme of what a household consumes the sewage pump is quite small.

#5
10-16-19, 12:02 PM
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Join Date: Apr 2012
Location: USA
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thanks
Ok say wife and I have 40g / day each so 80 total
say 500/80 is 6 so say every 6 days it runs
but how do I get to how long it runs to pump 500 gallons; to get to kWh per run

the web site shows gallons/minute at this head and that head but
and run is 350' to the field and 50' so
what is the total head and
what is the total dynamic head

and I don't know head from tail
maybe should wait for septic guy to come and do the annual checkup

#6
10-16-19, 01:36 PM
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You'll have to do the math or actually measure the flow if you want to know exactly how much power it uses. I'd guess it runs 8-10 minutes. 10 minutes every six days is a pretty trivial amount of electricity usage so even if the run time is off by a couple minutes it's still a really small amount of electricity consumption.

#7
10-16-19, 02:26 PM
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Join Date: Apr 2012
Location: USA
Posts: 209
got it, thanks
might just measure the flow when septic guy comes out but
is there a web site where I could do the math?

#8
10-16-19, 05:58 PM
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Do you know when the pump is actually running ?
Is there a control center for it ?
You could possibly set it up with an hour meter.

You can find the pump info under the "Literature/Manuals" tab.
Goulds WE1512HH/3885

Last edited by PJmax; 10-16-19 at 06:32 PM.
#9
10-16-19, 06:13 PM
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You can determine the pump's total head by installing a pressure gauge on the outlet at the pump and noting the pressure.
Water weighs .433 lbs/foot of head and you would divide the pressure at the pump outlet by this number to get the pump's operating head.

The pump documentation will give you the capacity at the head you have determined.

#10
10-16-19, 06:19 PM
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Join Date: Nov 2012
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got it, thanks
might just measure the flow when septic guy comes out but
is there a web site where I could do the math?
Eh, you can just do the math.

The storage tank is X inches deep.
The storage tank has an area of Y x Z.

Measure how much the effluent in the tank drops when the pump comes on.
Measure how long the pump runs during that drop.

Tank area (length x width) multiplied by depth gives you volume in cubic inches, which is easily converted to gallons.
The lengh of the pump running gives you minutes.
Those 2 numbers give you volume (gallons) per time (minutes).

#11
10-16-19, 08:06 PM
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Join Date: Apr 2012
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thanks all
gonna do one or more or all of these things

#12
11-06-19, 12:44 PM
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Join Date: Apr 2012
Location: USA
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so timed and measured
pumps 100 gallons in two minutes
and so runs once or twice per day for the two of us
which means it uses very few kWh per day
thanks