# Run Times

Run times are based on a number of variables, but in the end, the amount of water landing on each square foot is probably the most important factor in calculating those. One way to find that out is to put out multiple catch cans in each zone to calculate the water over time. Another way would be a calculation based on the number of sprinkler heads in a zone, the flow rate of those sprinkler heads (a factor of head model and house water pressure), and the area that those sprinklers heads are covering.

The thing that confuses me is that my Iro doesn’t really know any of that information. So how does it know how long to water? Yes, I told it my sprinkler head type, but not the exact model number. (I assume it varies model to model).

It assumes 1 in/hour for my rotor heads, but I have no idea if that is even close. It doesn’t know my house water pressure, the number of heads that I have on a zone, the rotation of them (1/4 turn, ½ turn, etc.), or the area that each zone covers. (I know there is a place to configure that last one, but I didn’t think that impacted run time).

I guess I’m a little confused on how to trust that it is calculating the proper run time for each zone. These things seem like big variables that have more impact on the end number than the other numbers like vegetation type, etc., so it kind of bothers me that it doesn’t have this information.

Is the only way to ensure accuracy to go through the catch can process? (Which I haven’t done yet)

Any thoughts?

@Ed3120 This is all groundwork you’ll have to do. The IRO’s accuracy is only as good as the information fed to it.

The catch can test would be the most accurate way to get the numbers you need. There are a few variables that determine run times. Once you do your research, you can compare your results with the Iro

@franz Should the zone efficiency number be based off of distribution uniformity?

We can get close with default values, but the better the input data (nozzle, etc.) the better our system will perform.

Yes, exactly.

Thanks Franz.