10 Reasons Pop-Up Sprinklers Fail
In this article, I share the top 10 reasons why pop-up sprinklers fail.
1. PRESSURE TOO HIGH
When walking down a street and looking at a pop-up system running, you can all too often see the water misting up and swirling down the street, particularly with a gentle breeze blowing. This is a classic sign the water pressure is too high.
All irrigation end components have an ideal pressure and flow range, whether it’s a pop-up sprinkler, a dripper or a dripline system. When the pressure is too high for a pop-up sprinkler, for example, the water is so pressurised, mist that’s not heavy enough to form droplets occurs.
2. DAMAGE TO TOP OF POP-UP NOZZLE
This damage occurs from either normal wear and tear or because pop-ups were installed too high or too close to the edge of the lawn.
3. DAMAGE TO SEAL (FLOW BY)
While this is a wear and tear issue, another major cause of this damage occurs when the grass grows too close to the pop-up. In this case, the soil rests against the piston as it rises out of the ground. The abrasive sand particles scour the piston and damage the rubber seal under the top of the pop-up head.
4. ROOT ENTRAPMENT
Roots can quite often grow around the pipework trapping the flow of water. This reduces the capacity of water flow through the pop-up sprinkler.
I have seen invasive plants like Rubber Trees grow into the pipework and block the entire system.
5. LOW FLOW RATE (NOT ENOUGH LPM)
This is almost always the designer’s problem.
Pop-up sprinklers require hydraulic pressure by way of flow (Litres per minute). If there is not enough flow, pop-ups will either perform poorly and cover the area badly, or may not even come out of the ground at all.
All manufacturers of irrigation components have specification charts for their products, which disclose all vital information including how many litres per minute a quarter circle, half circle and full circle occur.
All you need to do then is measure how many litres per minute you have from your water source. The easy way to do this is to use a 10-litre bucket and measure how long it takes to fill it. If it takes 10 seconds to fill, you have 60 litres per minute flow. If it takes 20 seconds, you have 30 litres per minute.
Next, add up all your pop-up heads, count up the litres and if they exceed your litres per minute, you’ll need to run a separate line to manage the water effectively.
Keep in mind that reducing the pressure will reduce your flow, too. You will need to take the bucket test reading with the reduced pressure if you want more accuracy.
6. DIFFERENT NOZZLES (NOZZLES INCOMPATIBLE)
Try to use the same brand, especially when replacing damaged pop-up heads, as there can be a big difference in the trajectory of water, pressure and litres per minute from brand to brand.
This will affect the pattern of water and change the overall precipitation rate intended by the original designer.
7. HIGH FAILURE RATE – POP-UP DISTANCES WRONG (BAD DESIGN)
Failure Rate refers to the difference in the amount of water over a set area.
This can be checked by placing 6 to 8 shallow bowls of the same size randomly on the lawn, and running it through the normal program. When the system has completed its normal run, carefully measure the amount of water in each bowl.
If there is a 50% difference between any two bowls (for example, 10ml in one and 15ml in the other), the failure rate is 50%.
Normally, anything above 50% would require redesigning the system to improve the performance.
8. HIGH THATCH LAYER IN LAWN (OR LAWN GROWING OVER POP-UP)
This is a common problem with lawns with a runner (Rhizome or stolen) when they are not scarified. The thatch layer builds up and the pop-up no longer reaches over the lawn.
To solve the issue, people often try various extensions and spacer connections to raise the pop-up out the ground. However, after scarifying the lawn, the pop-ups are then too high and exposed to damage.
My alternative is to fit side entry pop-ups which can be fitted to the existing line. These pop-up bodies are 150mm high and provide great coverage, even when the thatch layer builds up.
9. NOZZLES STRUCK WITH SNIPPER CHANGING ADJUSTMENT
This is a wear and tear issue and is part of the ongoing maintenance of any lawn that has an irrigation system.
It can be made worse when pop-ups are fitted to close to the surrounding edge of the lawn, which is completely unnecessary. When fitting sprinklers don’t fit them right on the edge; rather, set them inside the lawn 20mm. The splash from the pop-up will water the edge between the pop-up and the path.
Lawn maintenance experts who do their job well check the sprinklers and re-adjust the ark if the snipper cord has caught the head and opened it up too much or closed it too far.
10. PLANTS OR TREE FOLIAGE BLOCKING THE PATH OF THE SPRINKLER
Tree branches and shrub foliage will often grow over the path of the sprinkler altering the amount of water that gets to your lawn.
Again, a competent gardener will check this periodically as part of programming a maintenance system for you.