You may be tempted to keep two valves on at the same time or run two irrigation valves simultaneously. And while it’s possible to do this, the risk of creating future problems or eventually damaging your irrigation system is high.
Before you even think about running multiple irrigation valves, you need to make sure that you have a sufficient water supply for both valves to run at once. If you do, you’ll probably still need to make some adjustments on your sprinklers because the water pressure will be less when two valves are operating.
Be aware that choosing to irrigate in this way puts water pipes at risk of premature failure due to the high velocity of water required to run two valves. You’ll know you have a problem if you hear a thump when the valves close and the pipes reverberate from that noise. It’s possible to reduce or eliminate this “water hammer” effect by closing the valves separately, one at a time.
Even if you don’t hear any thumping, your pipes may still wear out because of high water velocity. You can figure out whether this will be a problem by doing the following:
1. Look at the top of each sprinkler and write down the brand, model and nozzle size you see.
2. Find the water use (also known as GPM value) for that sprinkler nozzle at the sprinkler company’s website. If you can’t locate it on your own, you may need to call the company for that information.
3. Add the GPM values for all the sprinklers that are running at the same time when two valves are in use. The result will tell you the amount of water the valves need when running together.
4. Find the size and type of water pipe that leads to the valves.
Once you have all this information, you can calculate the velocity of flow in the pipe using this handy online friction loss calculator.
South Austin Irrigation can help you determine the best, most cost efficient way for you to operate your sprinkler system. When you need advice, replacement parts or repair, our experts are here for you. Contact us today!
