How Do Lawn Sprinkler Valves Work?

By Brian Mounts | Nov 07, 2020
How Do Lawn Sprinkler Valves Work?

Maintaining a nice lawn is a lot easier when you have an automatic irrigation system installed. There are above grounds systems that can go together easy enough but the below ground systems are almost always preferred because the sprinkler valves are better insulated from changing temperatures and they are safely tucked away from accidental damage that can occur above ground.

If you own a below ground sprinkler system or are thinking of having one installed then learning a few things about how sprinkler valves work can go a long way. Knowing how to work or repair the irrigation valves can save you money in the long run because you’ll be able to fix problems, winterize, and possible expand your zones without needing to call in a professional.

An irrigation system uses sprinkler valves, also called irrigation valves, to control water flow to your lawn.  These valves come in various models that maintain an adequate water supply to the various control zones you have setup across your lawn and garden.

Continue reading to learn all you need to know about these valves and what they do in your irrigation system.  This knowledge will give you some insight into the specifics of the process of watering your lawn and why these valves are essential to that process.

What is a Lawn Sprinkler Valve and How Does It Work?

A sprinkler system can be a little confusing when you first look at it.  Getting water onto your lawn and landscaping seems like it should be a simple thing, but a sprinkler system is just that.  It’s a system. This means that there are a few different pieces that are required for it to function correctly.

Some of the primary pieces to the puzzle of a sprinkler system are the sprinkler valves.

Irrigation valves are responsible for controlling the flow of water to the irrigation system.  Most valves today are constructed out of a high quality industrial plastic or PVC.

There is also the option to select them in a brass design in some instances.  Brass valves are usually selected if they are installed above ground and are exposed to sunlight.

You can control the irrigation valves in one of two ways.  The automatic valves are controlled using a timer or other signaling device to turn on the water flow.  This is the most common and popular way of installation today.

These valves may also be installed to operate manually.  Manually controlling the irrigation valves is a simple process of using a handle to turn the valves on and off using your hand as the power source.

A valve is foundational to the overall function of a sprinkler system.  If you could not control the water pressure and water supply running through the sprinkler heads, your lawn or garden would simply drown.

Make sure to check out some of the other articles on this site linked here in my irrigation system guide for more on using these systems or check out this article from a colleague of mine over at The Green Pinkie for even more on efficiently getting water onto your lawn.

What Kinds of Valves Are Used in a Sprinkler System?

There are two different kinds of valves that work in unison to control the water supply running through the irrigation system.  Here is an explanation of the different valves your system will use and the different styles you may find them in.

Emergency Shut-Off Valve

This valve needs to be placed as close as possible to your main water source.  Your main water source is the place where you tap into the water line for the irrigation system.

This valve is important.  Particularly when you find it necessary to perform maintenance or repair the lines or other irrigation valves in the sprinkler system.

It would be a mistake to choose not to use an emergency shut-off valve in your irrigation system.  Any time that maintenance is needed for your irrigation system, you would have to shut the entire water supply to your home without it.

This valve will control water flow from the source and may be found in several different forms that will be described later.

Sprinkler or Irrigation Control Valve

The sprinkler or irrigation control valve is responsible for turning the sprinkler system on and off.  This type of valve is also employed for use in drip irrigation systems.  The control valve comes in three different types.

Manual Control Valve

This is the most simple form of a control valve.  It is merely a handle placed near your water source that you turn on and off by hand.  The downside to this is that it may prove inconvenient if you are not at home to water during the best part of the day.

Remote Control Valve

This valve is either electric or hydraulic.  It operates using a timer or other signaling device to instruct the valve to open or close.  These sorts of valves are used when running wire for an electric controlled sprinkler system is not feasible.  Generally, this occurs when the landscape proves prohibitive.

Solenoid Control Valve

The solenoid is the most popular design of control valve used in an irrigation system.  A solenoid is an electrically controlled sprinkler valve.  The electrical signal comes from the irrigation controller.

Each solenoid is wrapped with an electric wire to receive the signal from the controller.

The solenoid itself is an electric coil with a movable magnetic core.  When the current is active, this magnet pulls open the diaphragm to allow the water to move through.  Conversely, when there is no electric current, the diaphragm is closed and will not allow the water to flow through the valve.

Different Valve Styles

The style of the sprinkler valve you may choose for each of these varies.  Each type of sprinkler valve serves the same purpose but operates in different manners.  What follows is a description and information about each style of valve you may use in your lawn or garden.

Gate Valve

This style is used primarily in the emergency shut-off valve.  It is the most popular style used because it is an inexpensive choice.  The problem is that they also tend to need repair or maintenance after a short period of time.

The operation of these valves on your sprinklers consists of the insertion of a rectangular gate or wedge into the water’s path.  When this gate is closed, the water will not run through the waterline.

Ball Valve

The ball valve is well suited to work in the emergency shut-off valve as well.  These tend to be more expensive than the gate valve, but they are also durable enough to be used in commercial sprinklers.

A ball valve controls the water flow with a rotary ball with a bore.  When you rotate the ball 90 degrees around its axis to open the valve, the water will run through the bore.  This is usually done with a small handle on the valve that you screw open or closed by hand.

A ball valve’s most common application is as a shut-off valve, but there are special versions you can use in control valve functions as well.

Globe Valve

A globe valve’s primary function is as a control valve that uses linear motion.  These valves can start, stop, and regulate the pressure and flow of the water to a zone in your lawn.

Globe valves have specific directions of water flow.  They have a globe-shaped body, a flat piece, and a ring that the flat piece fits inside to stop the flow of water.

Those parts are what is known as the baffle.

When the globe-shaped body fits down inside the ring, the water flow is entirely restricted.  Whether you want a drip or deluge, this device will control the amount of water flowing to the sprinklers in that zone in your lawn.

With the globe valve, one problem is the requirement of installing a backflow preventer so that your water source will not be contaminated.

These valves are typically installed under the ground and housed in a valve box for protection.  They are available in sizes from small to very large, depending upon your specific needs.

Angle Valve

The angle valve is primarily used as a control valve.  It is equipped with the same features as the globe valve with one specific difference.

The difference is that the angle valve is constructed with an inlet at its base.  This inlet creates a right angle (90 degrees) between the inlet and outlet pipes.

If you intend to work this into your irrigation system, you must also install the backflow preventer separately to prevent contamination.

The angle valve is usually installed below the ground and housed in a valve box for protection from the elements.

Anti-Siphon Valve

These valves are most commonly used in residential systems because they are only available in ¾” to 1” sizes.

One selling point for these valves is that they do not require a separate backflow preventer.

The anti-siphon valve is installed above ground and must be 6” higher than the highest sprinkler head in your yard.

The anti-siphon valve works by employing a small air vent on the downstream side of the valve. Air will enter the pipe and resists any siphon effect.  With this resistance, the sprinkler water cannot be drawn back through the valve and into your house’s potable water supply.

You can also house these valves in a valve box for protection from the weather.

How Do Sprinkler Valves Work?

The most common valve for in-ground irrigation systems is the solenoid.  Each solenoid valve controls the sprinkler heads in a specific zone of your lawn or garden.  A good understanding of how these valves work will prove beneficial if the sprinklers ever need to be repaired.

The process of opening solenoid valves starts at the controller.  Controllers are attached to a set of these valves that are buried in a box at the beginning of the system.  The main water source is tapped into the box.  The controller tells each valve when to open and for how long.

The controller is connected by wire to each solenoid valve to instruct it when to open.

A solenoid valve has a diaphragm that opens to allow water to flow through the pipeline to the sprinkler heads.  When the solenoid coil that the wire is attached to is not energized, the diaphragm will remain closed.

When the moment comes for a particular zone of your lawn to be watered, an electrical signal is sent from the controller.  The moment that electrical signal reaches the solenoid coil, there is an electromagnetic field created in the valve.

Once the coil is energized, the resulting magnetic field is responsible for opening the diaphragm of the valve.

That electrical signal from the controller is programmed to be active at a specific time of day and for a particular duration.

The occurring pressure in the pipeline will raise the sprinkler heads and your lawn will receive the liquid refreshment it requires.

When that prescribed time is exhausted, the controller will break the electronic connection with the solenoid coil.  That disconnection will remove the electromagnetic field from the valve and cause the diaphragm to close and the water will no longer flow to that zone.

Systems like this are an investment in the lawn or garden you have worked so hard to create.  You have to ask yourself, are you always going to have the time and inclination to go outside and water the lawn the old fashioned way?  In this day and age, the answer is probably not.

Automatic sprinklers make your life easier by taking you out of the equation.

Summing it all up in just a few simple points…

  • Water is originally supplied from a main water supply system. This water, after a certain point, exerts pressure against the mid-point of the diaphragm of the valve.
  • Now, this Diaphragm is equipped with a small orifice/hole, which allows the water to actually flow to the upper chamber. This upper chamber is located between the Diaphragm and the Bonnet.
  • The water then flows into the bonnet from the upper chamber, and finally flows into the solenoid area through it.
  • This Solenoid area is equipped with a light loaded metal piston. The purpose of this piston is to cover the inlet port hole once the valve is closed.
  • And, the overall structure is designed in such a way, that the surface area that the water comes in contact with on top of the diaphragm (when the water has already flown into it), is more than the surface area on the bottom of the diaphragm. This ensures that the valve does not open until the water in the upper chamber is released.

Finally, How to Prepare Your Sprinkler Valves For Winter

You might also want to prepare your entire setup for the winter depending on where you live. Winterization of sprinklers isn’t very hard but I’ve still taken the time to write up a comprehensive guide on properly winterizing it so you can check that out here: How to Winterize Your Sprinkler System.

In addition to sprinkler system articles this site has a number of related guides that thousands of people read each and every month of the year. Here are a few good ones that may be of interest to you:

Can You Overwater Grass Seed?
How to Grow Grass on a Steep Hill
How To Pull Up Grass
Why Grass Makes You Itchy
Can You Overwater Grass Seed?
How Long To Run Your Sprinkler System