2 Pump System ?

ArTurf

LawnSite Fanatic
Location
Ark
I have this new to me system that uses 2 pumps and draws from a pond somewhat below the elevation of the watering area. One pump is at the pond and pushes the water up the hill to the 2nd pump and then out to the zones from there. The 2nd pump is probably 15-20 ft. higher in elevation. My question is should both pumps be the same HP or not? My guess would be the one at the pond, lowest elevation should be higher capacity since it has to push it up the hill.
 

mitchgo

LawnSite Gold Member
Location
Redmond, WA
I have a system like that . Crazy cool house it just sold for 11 mill. It uses a old rain bird mc-40. Pump 1 runs zones 1-10 and Pump 1&2 runs 11-34. You gotta make sure the programming is set to the specific pump

The last zone is a good 1,000 feet from the source with 100’ head

Are you doing general system maintenance, pump replacement , or system design ?
 

Wet_Boots

LawnSite Fanatic
Location
metro NYC
There isn't any real "should be" on a series pump setup. My own tendency would be to look for running identical pumps, so as to simplify maintenance.
 
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A

ArTurf

LawnSite Fanatic
Location
Ark
So I realize I didn't explain the situation in detail enough (I thought you guys were mind readers). Pump one at pond level sends water up to pump 2 which sends it to the valves. If both pumps are the same seems to me the pump at top of elevation would be working less than pump pushing it up the hill almost creating a negative pressure situation.

Mitch,
Doing general maintenance mainly, just took over the system this year so
still learning the system
 

Wet_Boots

LawnSite Fanatic
Location
metro NYC
Overthinking it. Pumps have performance curves, and even identical pumps in your situation will be performing as per curve. Two different curves, to be sure, since the second pump in the series string will have a flooded suction, and the first will be lifting water from the pond.
 

DitchDiggler

LawnSite Member
Calculate your total hydraulic head and match pumps accordingly.
I agree with Jim, do the math, but remember pump calculations are not cut and dry. There is also physical elevation above sea level, elevation of the eye, impeller sizing, pump type, pipe material, entrance and exit losses, whp and bhp differences, velocity head, and even the electrical considerations for the motor.
 

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