"dnoyeB" wrote in message
. ..
What dictates the pressure a sprinkler pump will deliver? I have looked
at several. Many show GPM for 30PSI. However, they don't specify what
controls the 30PSI. Is that the max PSI? They don't say.


In reading about centrifugal pups this is what I think happens.

1. Pump attepts to reach max flow. If no resistance, then pump will
deliver its max rate with very little PSI.

2. If there is resistance, then pumps flow will reduce based on the PSI.


My sprinkler heads are rated for a GPM at a specific PSI. But the pump
does not try to deliver a PSI it tries to deliver a GPM. And the PSI only
goes up when the GPM can't be achieved.

So I should be good so long as my sprinkler pump is rated for more GPM
than my heads.

Which is odd because from 1/2 HP up to 2 1/2HP the GPM is very much the
same. The stronger pumps are not delivering that much more. Why buy a
strong HP sprinkler pump?

You need to find a chart of pressure vs. volume for the pump you are considering
to determine if it is suitable. Different pumps will have different charts.

If you pump lower pressure, your volume demand will be less with a given
sprinkler system. If the pressure is too low, the system will not water the same
area properly. You could put a guage on the input to your system, and see how it
does with different pressures, before buying a pump.