The heart of your irrigation system: the irrigation valve.


If the controller is the brains of your system the valves are the heart. They control the flow of water through the lines. They are very simple in both principle and design.

This is an example of a typical valve. Details may vary but execution is the same.

Valves have water both above and below the diaphragm. The upper chamber pressure is greater than the lower due to the combination of spring pressure and trapped water. They also have an air space under the solenoid with a bleed hole that is opened when the solenoid plunger is retracted (zone turned on).

Opening this hole lowers the pressure above the diaphragm, the water below forces the diaphragm up and water flows through. Most valves will not open with less than 15 to 20 pounds per square inch of pressure. This is only a concern with extremely low pressure; usually on gravity feed water tanks.

Picking a good valve is simple: stay with a name brand. After that you have few decisions to make. Most people use 1” valves. Simple reasons are they are the most economical, readily available, both new and parts, and provide the flow most residential and small commercial designs need. Even if your design calls for a ¾’ valve use 1”. It doesn’t cost more and if you make changes or expansions in the future you won’t be restricted by the smaller size. A 1” valve will allow up to 25% more flow than a ¾” valve.

The next choice is flow control. Flow control is separate knob or screw on top of the valve and allows you to regulate the water going through the valve. In most cases flow control is not necessary but it does have advantages. If a valve sticks open, one of the more common valve failures, the flow control allows you force the valve closed. If your water pressure is low, either because of supply problems or overlapping valve operations, partially closing the flow control will help the valve close faster and more reliably. It’s cheap insurance to have.

Valves fail in consistent ways. It may not close completely. This could be due to debris, the most common reason, or worn diaphragms. Check out FILTRATION for how to prevent debris. Diaphragms do wear and age, generally resulting in a tear in the diaphragm. Just replace. For a very short video on how to do a repair look at VALVE REPAIR. Valve bodies rarely fail unless suffering freeze damage or shovel hit.

Solenoids will fail over time or the connections to the control box could have become corroded. Check the connections; make sure they are clean. For a simple way to test the solenoid:

 Steps in Creating a Portable Valve Activator.

  1. Take three 9-Volt Batteries
  2. Connect in a series
  3. Connnect one valve wire to the negative pole
  4. Then connect the other wire to the positive pole to activate the valve
  5. If the solenoid is functioning properly, you should hear a “click”

For a more involved but very easy and thorough way to test the solenoid and all wiring look at USING A MULTIMETER.

Valve Manifolds and Why You Want Them


Think about your average irrigation system. Say five zones made up of spray heads and  rotors. Front yard, back yard, side yard. Pretty much what you see everywhere.sample diagram of where to place valves in a property This means that there are five valves in the system. Now, there are two ways you can install valves. Both work. You can install them in each zone, as illustrated:

This works fine but someday, when you need to find the valve for repair, it may be overgrown, have a dog house on it or have simply disappeared.  Plus you are spending money on seven valve boxes and all that wire to go to all those valves.

sample diagram of where to place valves in yard
This is another way to place your valves. This keeps all the valves in a simple to find and maintain area and you would only need two valve boxes. This is called clustering. It makes long term maintenance far easier. You can also cluster them in out of the way, low traffic areas, minimizing risk of damage.

The easiest way to install this is with pre-made manifolds. Two of the most popular are the Action Machine and Dura brands. They are both available in different sizes and are expandable for future growth.

So what’s the difference? Why is one labeled Premium and one Standard?  There are two main differences. The first is the pressure rating. The Premium has a pressure rating of 235 psi @73o. The standard has a rating of 150 psi. Again, either will work for the vast majority of installations.

The second difference is more practical. Understand that once these are installed you don’t touch them again until something goes wrong, usually years down the line. At that time they will be dirty, wet, muddy and possibly underwater. Now you want anything that will make it easier to work on the system. The Action Machine coupling has a much larger and more defined grip on the ring. The larger grip makes a world of difference when it’s wet and slippery. Saves time, skin and frustration.

Either manifold will work fine.  You might wonder at this time why you can’t just build your own. After all, PVC is cheap and you will be working with it already.  No reason you can’t and it will work. However, the premium manifolds are made of Schedule 80 PVC, much stronger than the Schedule 40 you will be working with. Add the fact that the manifold backbone is one piece and you gain both rigidity and a guaranteed straight line.  Finally, the time and effort you spend measuring, cutting and gluing your parts together is worth something. Save that time for relaxing after the job is done.   Pre-made is best by far.

MORE INFORMATION

For any irrigation system questions please visit us at Sprinkler Warehouse.