You measure flow and pressure simultaneously, and create a chart of different flows and the pressures associated with them. The idea isn't to run every possible bit of flow, unless you have a lawn that is acres in size.
Consider the possibility that the system was properly designed in the first place, as regards zone flow rates.
Thanks for the quick reply!
I'm filling out the rain bird design form and it asks for a GPM. So when filling out the form what GPM do I write down? The hose bib GPM of 4.5, the GPM with 1 zone running of 9.5, the GPM of 2 zones running of 18, or the max safe GPM from a chart with 1"PVC which happens to be the same 18GPM?
Also the Toro "Update Design" form does ask for GPM at different pressures. They say to do a 5 gallon bucket test at the hose bib to calc GPM at different pressures. This gives me very low GPMs like in the 4 GPM range. The problem is I know that my GPM with one zone running is 9.5 GPM by looking at the meter and converting ft^3 to GPM. So I'm not sure what to put on the Toro upgrade form....do I use a bucket/hose bib test or the actual GPM from my water meter when running 1 zone?
This post has been edited 4 times, last edit by "jmed999" (May 29th 2013, 7:43am)