SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Quoted from "drpete"

Quoted from "Wet_Boots"

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But, on a well, you have an opportunity to adjust the pressure switch, for a higher operating pressure. Do a flow test at 60 or 70 psi, if you want to work with I-20 heads.

This may not be true! Are you talking about a submersible well pump? That is what I have most experience with.

I say design for 12-14 gpm and everything will be fine based on your preliminary tests.

If the supply is a well, with a submersible pump, then the well's pressure switch can often need adjusting, if the sprinkler system is to have useful pressure, about 50 psi at the heads. One can certainly work with less than 50 psi head pressure, but when a DIY-er uses the phrase "about 30 psi", this is too close to marginal.

Do note that one should add some air to a pressure tank, when raising the pressure switch settings, although a 10 psi increase (without adding air) hasn't proven fatal, in my experience. If the well can deliver water at 60 psi, without cycling, then you can take a new flow measurement, and use that number to design with.