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Valves are an essential part of any sprinkler system. They are the link between the "brains" of the
system (the controller) and the sprinkler heads, to turn the water on and off.
Most automatic sprinkler systems are set up with two types of valves. A brass "gate valve" or "ball
valve" is usually located right after the "tee" where the sprinkler system cuts off from the main
source of water to the house. This valve, referred to as the "shutoff valve," is used to shut down the
sprinkler system for repairs or winterizing without shutting off the water to the entire house. It is rec-
ommended that all systems be equipped with a shutoff valve installed in a box for easy access.
Some systems also require the use of a back-flow preventer. Check local building codes.
The second type of valve is the sprinkler "zone valve." Each zone valve is piped to a set of sprin-
klers. When the valve is turned on, either by hand or in response to an electronic signal from the
controller, all the sprinklers piped to that particular valve go on. In most cases, there are several
valves located together (called a manifold). These are often in a valve box if underground.
Why are several valves needed? All systems are limited by a combination of the pressure of the wa-
ter (psi) and the number of gallons per minute (gpm) available. Each sprinkler uses a certain num-
ber of gallons per minute of water. This release of water through the nozzle reduces water pressure
to a certain degree while the system is working. For maximum performance, each zone is controlled
by one valve and is set up with the proper amount of sprinklers so that the psi and gpm capacity of
the system is not exceeded. The purpose of this information is to address questions and problems
related to zone valves.
Controller
Valve Box
Supply Line
Shut off
Valve
Supply Line
Water Flow
Zone
Valve
Zone
Valve
Water Flow
Water Flow
Controller
Sprinklers
Sprinklers
BASIC AUTOMATIC
IRRIGATION SYSTEM
COMPONENTS
DIAGRAM
