We Repair Lawn Sprinklers!
Monday - Saturday: 7:00 AM - 9:00 PM

Sprinkler System Detailed Overview

In this overview, we’ll describe each component of the system in detail, tell you how it works, and what its function is. We’ll also provide installation information, in case you decide to install your sprinkler system yourself.

Controllers and Timers

    • The timer is like the brain of the sprinkler system.  From the timer you can program what days and times you want the sprinkler system to operate.
    • The timer determines when the system starts and stops, and it controlls what valves open and close.
    • Timers are made to be either indoor or outdoor and typically can handle 4-20+ stations or valves.
    • There are battery powered timers designed to stay outdoors in the valve box for situations where running a wire is impractical .
    • Most modern timers allow you to set a regular watering schedule. Advanced timers also have rain sensors to automatically keep the system off if they sense moisture.

Stop and Waste  

    • The stop and waste is the main shut off valve for the sprinkler system.  It starts or stops water from entering the system.
    • It keeps sprinkler lines from freezing. When the valves are shut off for winter, any remaining water will leak out of a hole in the body of the stop/waste.
    • Typically accessed through a PVC pipe that is 2-4” in diameter.
    • Usually buried 3-6” deep.
    • Most of the time, it’s found in the front yard within 4 feet of the water meter.
    • To turn off the stop and waste, gently place a meter key on it and turn. You can get a meter key at most supply stores. Turn the valve a ¼ turn clockwise to shut it off and ¼ turn counterclockwise to turn it on.
    • Always make sure the valve is completely on or off. If not, water could leak back into the main line.
    • Stop and waste assembly needs to be all brass or galvanized fittings.
    • Not all sprinkler systems have a stop and waste. Sometimes the main shutoff is a ball valve located inside the house. These are usually located in the same room as a water heater or in a crawl space.

Backflow Preventer

    • These are required in most cities if you are using potable (drinking) water in the sprinkler system. The backflow preventer stops water from flowing backwards through the system and potentially contaminating the main water supply.
    • There are several types of backflow preventers. The most common are the pressure vacuum breaker (PVB) and a double check assembly (DCA).
    • Pressure vacuum breaker: These are a more simple design than the double check assembly. They contain one spring-loaded poppet that snaps shut when water pressure is removed from the system.
      • They need to be installed 12” higher than the highest sprinkler head in the system.
    • Double check assembly: This consists of two spring loaded valves that are assembled in series. One valve will still operate, even if the other is stuck open.
      • Use these when the highest sprinkler head in the system is higher (12’’ or more) than the backflow preventer. For example, a double check would be used on a sloped lot.
    • Most backflow preventers have test cocks. These are small ball valves located on the device where gauges can be attached to test that they are working properly.
    • The large ball valves located on the backflow preventer are there to test separate areas of the device to ensure they are working correctly. They can also be used as an alternate method of shutting off the water to the sprinkler system while it’s being worked on.
    • Check with your local codes to make sure you are installing these in compliance with your area’s codes.
    • Use galvanized pipe, fittings, and unions for the backflow preventer assembly.

Main Line

    • Main lines are typically 1 ¼” in diameter and carry water from the stop and waste to the backflow preventer and then to the valve manifold(s).
    • Main and lateral lines are run in PVC or a minimum 125 psi polyethylene (poly).
    • When using PVC to run a main line, use 1 ¼” PVC fittings as well. Apply primer and glue to fittings and pipe when gluing parts together.  Follow all instructions on primer and glue cans.
    • When using poly to run a main line, use 1 ¼” poly fittings. All fittings must be clamped together using stainless steel hose or pinch clamps. When clamping main line fittings together, use 2 clamps at each connection point. Don’t forget to put clamps on the pipe before inserting the fitting.

Valve Manifold

    • The purpose of the valve manifold is to divert water from the main line to the individual valves.
    • Valve manifolds can be assembled using action or PVC fittings. Action fittings are recommended because they make valve replacements/repair much easier.
    • Manifolds typically range from a single valve to a quadruple valve manifold. Occasionally, manifolds contain more than 4 valves.
    • Valve manifolds are to be placed in a valve box. The sides of the valve box may need to be notched to fit around sprinkler pipes.


  • Valves are like the heart of the sprinkler system. They open and close to allow water into the lateral lines. Water pressure and water flow are usually not high enough to operate the entire system at one time. Because of this, valves are used to divide the system into zones which are run one at a time. This section will go over main parts of the valve that will require knowledge and attention for most valve repairs. More detailed information can be found online.
      • Flow Control
        • Not all valves have a flow control, but if they do, it’s located at the center of the valve. The flow control works similar to a hose bib or gage valve. It will either fully allow or restrict the amount of water flowing through the valve. A valve can be manually shut off by completely closing the flow control.
      • Bleed Screw
        • The bleed screw is typically the smallest knob on the top of a valve (if the valve is equipped with one). Its function is for manually opening the valve. There are two ways to manually open a valve. One of those ways is by opening the bleed screw. Just unscrew it ¼ to ½ of a turn and the valve will turn on.
      • Solenoid
        • All automatic valves have a solenoid. The solenoid is the part of the valve that has two wires coming from it and is usually the largest part on the top of the valve. It electronically opens and closes the valve. The other way to manually open a valve is to turn the solenoid counter clockwise ¼ to ½ turn. To shut the valve off, twist the solenoid until it is tight on the valve.
    • Diaphragm
      • The Diaphragm is a round, flexible rubber part located inside the valve. It’s purpose is to create a seal within the valve to allow or prevent water flow.
  • Valve installation
      • Prior to installing a valve, be sure the main line and valve manifold are clear of debris that could enter the valve. Do this by running water through the pipes. If installing on PVC manifold, be sure to use teflon tape on threads to create a watertight seal. Also check the water flow direction on the valve for proper flow direction.
  • Valves are on of the more complicated parts of a sprinkler system, but they can be simple to fix. Knowing the basics of how they work makes  troubleshooting a lot easier.
    • If a valve is stuck on, first check the timer to make sure it is in the “off” position. Then check the solenoid and bleed screw to make sure they are closed. If after checking these parts the solenoid is still on, the most likely problem is the diaphragm. Remove the top half of the valve and check for debris in the valve that could hold the diaphragm. If there is no debris, the diaphragm has probably got stiff due to age and needs to be replaced with a new one.
    • If a valve is not turning on, check the timer to make sure the valve has been programmed to turn on, then check for proper wiring in the timer, then check for proper wire connections at the valve. If all the wiring is done correctly, then most often the problem is that the solenoid has worn out and needs to be replaced. To test the solenoid, cut and strip the solenoid wires and test them with a tester. If the solenoid is still functioning properly you will hear a “click” or “pop,” if the water is off. If the water is still on, the sprinklers will turn on. If there is no response from the tester, then the solenoid needs to be replaced with a new one.

Lateral Lines

    • Lateral lines carry water from the valve to the sprinkler heads and are generally 1” or ¾”.
    • They begin at the valve and end with the last sprinkler head on a line.
    • Lateral lines will have multiple fittings attached to them depending where and how they are run and the type of sprinkler heads they are leading to.
    • Use the same guidelines on lateral lines as described previously on the main line.
    • Most fittings used on lateral lines will be “tee’s” and 90’s (elbows).Threaded tees and saddles will be used on lateral lines near where sprinkler heads will be installed.
    • Install the threaded tee and/or saddle 12-18” from where the sprinkler head will be installed.
    • Install threaded spiral barb fittings into the threaded tee and/or saddle and push the funny pipe onto the barbs.

Funny Pipe

    • Funny pipe is a flexible tube that connects the lateral line to a sprinkler head using spiral barb fittings. It’s flexibility allows pipe to be efficiently routed for proper sprinkler placement.
    • There are multiple spiral barb fittings for use with funny pipe including: elbows, tees, couplers, etc.
    • Funny pipe generally comes in 100’ or 300’ rolls.

Sprinkler Heads  

    • There are several types of sprinkler heads that have different functions. They main function is to spray water from the sprinkler lines out to the yard. Sprinkler heads are positioned around the yard to provide full coverage of the lawn and flower beds. They are designed to retract to sit at or slightly below ground level when not in operation. When the head is activated, water pressure causes the head to pop up and spray water.
  • The most common types of sprinkler head include: Pop-up sprinkler heads, gear-driven rotors, and impact rotors.
    • Pop-up sprinkler heads are typically used for residential and small commercial sprinkler systems. They come in various heights. The most common heights are 2”, 4”, and 6”. They come as tall as 20”. Out of these 3 common sprinkler bodies, the 4” are used the most. Most new sprinkler systems will use all 4” sprinklers. The 2” sprinklers are used in areas where digging is difficult. Taller sprinkler heads are used for ground cover, gardens, and shrubs.
      • Pop-up spray nozzles are separate from the sprinkler body. They are screwed on the top of the sprinkler riser and spray between 3-18”, depending on the head you choose.  They also have various patterns, such as a full circle, half-circle, a quarter circle, square, rectangle, etc. There are also variable arc nozzles that have an adjustable spray from 0-360 degrees.
      • Gear-driven rotor heads are also available for use on a pop-up sprinkler and come in various spray patterns and distances.
    • Gear-driven rotors are very common in medium to large scale sprinkler systems. These rotors are more water efficient, quiet, and typically require less maintenance than the impact rotors. These are commonly used on large residential areas.
      • Gear-driven rotors come with nozzle trees with many different nozzles to choose from. These nozzles range from 1.5 gallons per minute (gpm) to 8 gallons per minute and have standard angle spray or low angle spray.
      • Typically, gear-driven rotors spray distance ranges from 18-55 feet and the arc ranges from 40-360 degrees.
    • Impact rotors are similar to gear-driven rotors in distance and arc ranges. These rotors have not evolved much over the years. They have a simple design and work well in areas where irrigation water is used in the sprinkler system. These rotors require more maintenance because they have an open body when in operation that allows debris to get inside causing clogging or impeding the function of the drive mechanism.
      • Impact rotors are are more noisy than the other types of sprinkler heads. They are also more expensive because they are often made out of higher cost material such as brass. However, they can last for years due to the heavier construction.
    • There are many other types of sprinkler heads and nozzles available. Those listed above are the most common. Check online, or at your local supply store for more options.


    • The wire’s main function is to carry the electrical signal from the timer to the valves.
    • The sprinkler wire is a bundle of multiple colored wires including one white (common) wire. The bundle ranges from a minimum of 2 to 10+ wires.
    • The total number of wires needed is one for each automatic valve, plus one for the common wire. If you have 6 valves on a sprinkler system, you will need a 7 wire bundle.
    • To wire a set of valves, attach a separate color coded wire to one of the two wires coming from each of the valve solenoids. It doesn’t matter what color you choose for any valve, just make sure to use a separate color for each valve.
    • Connect these wires using waterproof grease caps. They are filled with silicone and seal the wires from moisture. If these are not used, capillary action can suck water up the wires.
    • The second wire coming from the valve solenoid will be wired to the white (common) wire. Each valve on a valve manifold can be wired to the same single white wire. For example, if you have 3 valves on a manifold, take one wire from each solenoid and twist them together with the white (common) wire. When you are finished you will have 4 total wires twisted together (3 wires from the valves, and the 1 white wire).
    • Next, run the wire under the lateral and main lines of the sprinkler system to the timer. It is important to run the wire under the pipes to protect them from damage.
    • Now it’s time to connect the wire to to the timer.  The timer will have a location labeled for the wires. There will be an area labeled to connect the common wire. Next connect the colored wires to the areas labeled with numbers (zone 1, zone 2, zone 3, etc).
    • Now connect the transformer, or pigtail, as described in the manual that came with the timer and plug it into an outlet. This is the part that plugs into the wall to provide power to the timer.
    • Slowly turn on the main water to the sprinkler system after glue and other connections have had proper time to cure.
    • Program and test the timer.

And that’s it! It’s a lot to handle, but our technicians are well trained, and have countless hours in the field working with these systems. If you don’t feel comfortable installing, repairing, or winterizing your sprinkler system yourself, contact us, and we’ll get the job done in no time.