Adjusting pop-up sprinker range with the top screw

Question

The previous owner of my home primarily used Rain Bird and Toro brand sprinklers (both pop-up and shrub types, all non-rotary) for irrigation, along with a few Orbit shrub risers in the front yard. The models he used all have plastic heads and on many of them the nozzle has turned brittle in the sun and started to fall apart, so I've been repairing or replacing the sprinklers.

As far as I know, most or all pop-up and shrub sprinkler models have an adjustment screw located in the top center of the nozzle for adjusting the flow/range of the sprinkler - clockwise restricts the flow and reduces the range, counter-clockwise opens the flow and increases the range. This is true of all of the existing sprinklers.

My local hardware store carries brass sprinkler nozzles made by Orbit that are compatible with the Rain Bird sprinklers, so for the Rain Birds I simply replace the nozzle with a brass version. After installing the brass head, I adjust the screw to set an appropriate range, and everything's good to go.

The Toro pop-up sprinklers aren't compatible with the brass heads, and many of them are beyond repair anyway, so I've been replacing them with new Orbit pop-up sprinklers with brass heads. However, when I install a brand-new Orbit pop-up sprinkler with a brass nozzle, or replace the plastic nozzle on an Orbit shrub riser with a brass nozzle, the adjustment screw in the nozzle either will not turn or doesn't do anything when turned. In one case I turned the screw clockwise so many times that it recessed deep into the sprinkler head and is no longer visible, but the range never changed.

I'm thoroughly confused as to why the adjustment screw would work for an Orbit nozzle on a Rain Bird sprinkler, but not for an Orbit nozzle on an Orbit sprinkler. Does the sprinkler body need to be designed to accommodate the adjustment screw? Are some of the new nozzles defective?

Answer 1

Here's what I found from taking apart the different sprinklers and studying how the parts fit together:

• If the adjustment screw will not turn at all on a brand new nozzle, the nozzle is defective. To save yourself potential headaches, it's best to test the adjustment screw before installation.

• Orbit, Rain Bird, and Hunter all use very similar designs for their pop-up sprinklers. The adjustment screw on the top of the nozzle raises and lowers a post just above the filter. Turning the screw clockwise lowers the post into a socket in the filter, restricting the water flow. See picture below to understand how the post fits into the filter. With these designs, the adjustment screw will have no effect if the filter is missing.

• The adjustment screw on Orbit brass sprinkler nozzles work better when the head is installed on a Rain Bird sprinkler than if the head is installed on an Orbit sprinkler. It seems like the filter sits lower in an Orbit sprinkler; you'll have to turn the screw further clockwise to restrict the flow, and a bit of water will leak out from around the adjustment screw.

• Toro sprinkler heads use a different design, where the adjustment screw itself restricts the water flow through an assembly below the nozzle. These sprinkler heads do not depend on the filter being installed. Be careful not to over-tighten the adjustment screw, as this will cause the head assembly to fall apart and you'll have to reassemble it.

• Orbit nozzles seem like they should fit on Hunter sprinklers, but don't actually fit. It will screw on partway but never all the way.