IRRIGATION SYSTEM MAINTENANCE: The Replacements

While performing site work, a lawn and landscape contractor destroys a spray or rotor irrigation head on one of your accounts. According to your signed agreement for the project, your company is responsible for properly replacing the destroyed irrigation head and nozzle in a professional manner.

Here is where the professional irrigation company is separated from the run-of-the-mill operation. If you don’t know what you are doing when you select and install the replacement irrigation head and/or its nozzle, you can quickly encounter serious liability.

For more than 30 years, I have talked to many landscape and irrigation people who thought they knew what they were doing when replacing spray or rotor heads and nozzles in turf areas. I would have to guess that only about 50 percent of these people actually had a general idea of how to properly complete the job, and, only about 10 percent (or less) really knew how to replace the head perfectly. Here, I have tried to condense most of the turf spray or rotor head and nozzle replacement and pop-up height considerations down into four simple, core concepts.

REPLACE THE EXACT COMPONENT. Replace any destroyed turf spray or rotor head and its nozzle with the exact same manufacturer’s head and nozzle. Resist buying the cheapest product or the product on sale that week. Further, resist using whatever body and nozzle you find in the back of your service truck, even if you think that the spray or rotor body and selected nozzle is an equal or better product for the site situation. Simply put, bite the bullet and use whatever additional time and money it takes to find and install the exact (size, model, throw, gallonage, pattern, etc.) replacement spray or rotor head and nozzle.

This may sound like common sense. However, just ask your insurance agent about how many thousands of dollars of liability you or your company assume by not using the exact replacement part for the sake of saving perhaps just a few cents or a few dollars.

CONSIDER MOWING HEIGHT. Take into consideration the pop-up heights of the spray or rotor body in relation to the recommended mowing height for the variety and species of turf grass being watered. When selecting the replacement pop-up height of either a spray or rotor body for turf applications, the nozzle pop-up height should be gauged to whatever height either the warm-season or cool-season turfgrass grows between mowings.

For instance, let’s assume that the turfgrass at the project is to be mowed at 2 inches in height and your turfgrass will grow 3 or 4 inches high between mowings. In this case, the minimum pop-up height for the orifice for the nozzle in that spray or rotor body should be 4 inches.

This need for flexibility is why irrigation manufacturers make their pop-up spray bodies in a variety of heights. As a knowledgable irrigation professional, you are responsibile for selecting the proper spray or rotor height of the irrigation head that most appropriately fits the situation (warm-season, cool- season, best management practice, mowing/ growing height, etc.,) for the turfgrass on the project.

Here are three other pop-up height considerations:

• Thatch. Remember to select your minimum irrigation body heights for any future thatch build-ups.

• Settling. Many times the installation of the spray or rotor irrigation heads may be done improperly, causing the heads to settle ½ to 1 inch lower than when installed. This means that additional height needs to be added to compensate for any blockage of the nozzle spray due to post-installation settling.

• Blade Type. Spray head nozzles produce a very fine spray in their throwing design due to virtually every manufacturer’s way of designing spray nozzles. This means the spray can easily be disrupted by grass blades. Rotor nozzles have a more solid single stream, which have a greater tendency to make most grass blades lay down and limit disruption. This may not seem like a significant item. That is, until you consider the coarse or soft texture of the many types of grasses being used as turfgrass (i.e. the coarseness of St. Augustine grasses vs. the softer bladed bluegrasses) and the potential for blockage they create.

PRECIPITATION RATES. It’s important to match the precipitation rates of spray and/or rotor nozzles in the replacement heads. Again, on the surface, this may seem a simple consideration. However, I have talked with many landscape and irrigation professionals who misunderstand this concept. Most professionals were never fully taught this design principle, or, they incorrectly learned it from out-dated materials.

SWING JOINT ASSEMBLY. Use a swing joint assembly for every replacement spray or rotor turf head. This last, simple item is very often ignored when replacing turf irrigation heads. Whether using rigid or flexible pipe swing joint assemblies, they can impact the pop-up height of turf heads – not so much on the piston pop-up height, but the height of the head body in the ground. All too often, in an attempt to save money, many people have a tendency to use too short of a swing joint assembly (6 inches vs. 12 or 18 inches) when replacing spray or rotor turf heads. Other people simply attach the replacement heads directly to the zone lateral pipe with hard PVC fittings. Both shortcuts usually end up creating numerous long-term maintenance and liability problems.

Swing joint assemblies allow easy raising or lowering of a spray or rotor body to aid in maintaining proper popup heights when grades change due to silting in, thatch, etc. Swing joint assemblies also aid in absorbing damaging shocks from surge pressures, foot traffic and equipment to the irrigation head and the zone lateral piping.

STEP BY STEP. Following these four simple steps for spray and rotor head replacement and selection of pop-up heights for turf areas will not only reduce your and your clients’ long-term operating and maintenance costs, it will decrease your liability exposure and reduce water waste, boosting your professionalism in the process.