Issue

You sized the lateral pipes in your irrigation design and are seeing a flow discrepancy between what you see in the Size Lateral Pipes dialog box and the flow (or GPM) you'd expect to see.

For example, you may have run our Circuiting or Highlight Station tool, and you're now seeing a different flow from the rate shown by either of those tools, or you're simply not seeing the full rate you're expecting to see.

Cause

Potential cause #1: Improperly sized valve

We've seen this issue result from an incorrectly piped valve.

For example, if you connect multiple lateral pipes to a valve, the Size Lateral Pipes dialog box will only display the flow rate/GPM and pipe size information for the last segment processed. After you click OK, all lateral pipes will be sized correctly, and the valve callout will reflect the correct total flow/GPM.

In this case, the issue is only with the dialog box itself, which is simply unable to display the summarized GPM/Size info of such an improperly piped valve.

Potential cause #2: Pipe transition point overlapping multiple drip areas

Alternatively, your design may include a drip area where a pipe transition point is overlapping other drip areas within the same zone, as pictured in the example to the left.

 

In this case, the system is looking for any crossing of a transition point within a given area that will allow it to split the flow of an area between all transition points within that area.

If the zone only includes one transition point, as in the example shown below, a slight overlap into another area won't be a factor. In this case, the system will use the insertion point to determine where it should be calculating.

 

 

 

If you have multiple valves in nearby areas, some overlap is not a problem. If you have more than one pipe transition point piped to the valve, the system will look at a crossing, rather than an insertion point, to determine whether an area includes more than one pipe transition point.

 

Potential cause #3: Incorrectly drawn drip area boundary

We've also seen this issue result from abnormalities in the way a drip boundary is drawn, which will warrant a little investigation.

Solution

Step 1: Try teeing off

If you're not seeing the full flow rate you think you should be seeing, try only connecting a single lateral segment to the valve, and then tee off from there to multiple locations.

Still having an issue with flow rate? Move on to the next step.

Step 2: Check for and resolve an issue with pipe transition points

Look around your drawing to see whether one or more of your pipe transition points are overlapping two or more drip areas. Make sure that each transition point lands within the desired area without overlap in any other area.

Still having an issue with flow rate? Move on to the next step.

Step 3: Check for improperly drawn drip area boundaries

An issue with how one or more of your drip areas has been drawn can also cause this issue.

Try clicking the boundary of each drip area and looking for anything that looks strange or off.

 

In this example, we've selected a drip area boundary and found a slashed grip point, as opposed to the typical square grip points, which may be throwing off the calculations.

We'll grab the dashed grip point closest to the normal square grip points and drag it slightly outward.

We'll also try right-clicking the grip point we moved and selecting Remove Vertex from the menu that opens.

 

Doing so can help clean up the linework in this section of the drip area boundary, making it easier for the system to calculate its contents.

After making the necessary corrections to any drip area boundaries in this way, size your lateral pipes again.

 

If the calculations still aren't correct, continue investigating your drawing in this way and making any necessary corrections, followed by sizing the laterals again, until the calculations are correct.