# Pump question



## Lancef3113 (Jan 2, 2019)

Ok, so I am currently designing a 12 zone in ground sprinkler system to irrigate my large lawn. I'm on city water, which has a static pressure of 43psi. My flow rate measured just after the meter is 13gallons/min off a temporary installed spigot and 30 gallons/min un-restricted. I've designed the system based on a 13gal/min flow rate. I do have some zones that will use hunter pgp rotors. From my calculations I should have very minimal psi to operate these rotors...

So I've been looking into doing a pump to boost the pressure 15-20psi. Problem is, I've made over 20 phone calls to pump suppliers and get conflicting information. One person says the pump I have in mind would work, and the next says no way, and then suggests a pump 3 times more expensive, which will raise my pressure to an unusable amount!...unless I start dealing with regulators...

The pump I'm looking at is the flotec fp5512. 22gal/min and max 36psi. One person tells me that the max psi regardless is 36psi output...then the next person tells me that the pump is rating that with no incoming pressure, so my 43psi +36psi= 79psi. Obviously I know the pump is rating that with zero flow, and therefore once flowing 13gal a min the pressure output will be less, say 10-15, which is what I want. But is it really that easy? Just add incoming pressure to output pressure? I don't want to put on some massive power hungry pump, just for 10-15psi. The max psi loss through the system, to the furthest rotor is 13psi, just want to offset the loss so the rotors will work at their best.

Any suggestions would be greatly appreciated.

Ps..my lawn is flat, annoyingly flat! Lawn size is about .4acres, so doing fixed heads would be rough


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