A valve which can be remotely operated either electrically (the most common) or hydraulically. Automatic valves are commonly used as "control valves" for irrigation systems. See also Valve, Bleed Valve.
Also referred to as a clock, or timer, an irrigation controller is an electronic, programmable device that controls the timing of automatic electronic valves in an irrigation sytem. The valves control the flow of water to sprinklers and drip systems. The contoller sends electricty (low voltage) to the valve on the day and time set in the controller schedule and for the duration programmed by the user.
High end controllers employ weather-based controls ( ex. rain sensors, soil moisture monitors, real-time weather data), internet connections, cell phones, and remote controls for use with sophisticated irrigation systems. See also Irrigation Schedule.
A PVC pipe classification (often written as SCH 40 or SCHED 40), commonly used for main line water pipes. Schedule 40 pipe is thicker than Class 200 and can withstand higher water pressure. The "schedule" number is not a specific measurement but rather a designation representing the reletive wall thickness of the pipe and water pressure rating (psi) for that pipe. For additional classifications of irrigation pipe see Shedule 80 and Class 200.
A rigid plastic container which covers and protects underground irrigation valves. It has an access lid for valve maintenance. See also Valve, Controller, Direct Bury Wire, Two Wire.
Also called a watering zone, a "zone" is an individual watering area controlled by a single irrigation valve. It may be a group of sprinklers or a drip irrigation system. When designing an irrigation system, plan individual zones so that each contains plants with similar watering requirements. Watering zones should also consider micro climate factors like amount of sun exposure vs. shade, and design elements like sidewalks and driveways. With proper planning, you can create zones that allow flexible programming on your irrigation controller. See also Valve, Controller.
The diaphragm is a flexible rubber membrane inside an automatic irrigation valve, between the upper chamber of the valve and the smaller valve inlet (water supply). When the valve is closed, both the upper chamber of the valve and the valve inlet are filled with water. Since the upper chamber is larger, a greater suface area of the diaphragm is covered with water than on the inlet side. This water pressure differential keeps the valve closed.
When the solenoid is electronically activated, it releases water from the upper chamber above the diaphragm. This reduces the water pressure above the diaphragm and allows it to rise and open the valve. Water will now flow through the valve.
A spring inside the valve pushes against the back of the diaphragm, but it does not exert much force on the diaphram. It would stay closed without the spring. See also Valve.
The common term for National Pipe Thread (NPT). Pipe threads require Teflon tape or pipe dope to create a water-tight seal. Do not thread together pipe threads and hose threads. See also Teflon Tape, Pipe Dope, Hose Thread.
Used to manually turn on an automatic valve. a bleed valve is located on or near the top of the valve. It can be a small screw, a lever, or built into the solenoid. When turned, the bleed valve allows water to flow out of the cavity over the internal diaphragm of the valve. This causes a pressure differential and opens the valve.
If the bleed valve is an external type, a small stream of water will flow from the bleed valve and outside of the valve while it is on. An internal bleed will keep the water inside the valve and empty it into the downstream side of the valve. See also Valve.
A non-adhesive tape (made of Teflon non-stick material) that is used to create a water-tight seal with pipe threaded fittings. It is tightly wrapped in a clockwise motion 3-4 times around the male pipe threads. Male and female fittings are then threaded together.