Solenoid valves are the heart of the irrigation system. They play a crucial role in drip or sprinkler systems by controlling water flow through electrical signals. They open and close in response to electricity, allowing for precise watering schedules and automation.
This complete guide to solenoid valves will help you learn everything about these valves and how to choose the one that suits your irrigation system.
What are Solenoid Valves
A
solenoid valve is an electrically operated valve that controls water flow in an irrigation system. It regulates the water flow and pressure in the line, allowing water to flow only when directed. They're designed to be used with a
controller or a timer to automate an irrigation system. In an irrigation system, once signaled by a controller, the valve allows water to flow out. When an irrigation controller activates the solenoid, a coil of wire causes a valve to open or close, allowing water to flow to the sprinklers or drip emitters and stopping it when watering is complete, as programmed.
Solenoid valves are effective for irrigation systems due to the open flow and pressures they can handle.
Most conventional solenoid valves are rated 12-16 Bar, allowing you to connect them directly to the main water supply or after a pump. This is a significant plus over hose thread timers, which have an average pressure rating of 5-8 bar.
Solenoid valves provide minimal flow restriction through the valve. Once the solenoid diaphragm is fully expanded, the pressure and flow loss are minimal compared to hose thread timers, which can only accommodate an inside diameter of 10mm.
Read More: Irrigation Valves: What is a Valve and How to Fix or Replace Them
Solenoid Valves Components
Solenoid valves come in various designs, but they all operate in the same manner. Most solenoid valves consist of three key parts: the body, the diaphragm, and the coil.
Body
The valve body can be metal or plastic. Some models include a replaceable top for easy access to the diaphragm.
Diaphragm
The diaphragm is the physical rubber item that divides the two inside chambers and controls the water flow. When the upper chamber is full, the pressure maintains the diaphragm in a closed position. When the pressures are equal, the diaphragm lifts, allowing the water to flow.
Coil
The coil is a magnetically charged spring that controls entry to the upper chamber. The coil is often removable and wired to the controller. These energized springs open and close when power is given. This opens and closes the top chamber exit, which regulates internal pressure.
Types of Solenoid Valves
Solenoid valves come in various types, serve different circuit functions, and employ distinct operating principles. These valves are classified into one of the circuit functions:
2-way Solenoid Valve
The two-way valve has two ports, an inlet and an outlet, which are used to allow or block the flow. The direction of the water flow is crucial for correct operation, so these valves have an arrow indicating the flow direction. These valves are used to close or open an orifice.
3-way Solenoid Valve
A 3-way valve typically has three ports, each serving a distinct purpose: one port for the inlet, one for the outlet, and a third port that varies depending on the valve's design and application. It can be an exhaust or return port. These solenoid valves can open, close, distribute, or mix liquids, such as in fertigation systems.
Normally Closed Solenoid Valve
A normally closed (NC) solenoid valve is one that is closed when not operating. It is shut in its unpowered state, and water can't flow through. Almost all
landscape valves and irrigation systems require a normally closed valve.
Normally Open Solenoid Valve
A normally open (NO) solenoid valve is the inverse of a normally closed valve. It allows water to flow freely even when the power isn't available. This type of valve is typically used when water flows continuously and only stops when necessary.
Read More: How to Replace a Solenoid Valve
Role of Solenoid Valves in Irrigation Systems
Here, we discuss the role of solenoid valves in
drip or
sprinkler systems.
Zoning: Solenoid valves make irrigation more efficient by controlling water distribution to each irrigation zone independently. Different zones can be watered precisely based on plant type, soil conditions, sun exposure, and other factors. This will result in healthier plants and a thriving garden.
Timing: The ability to program valves at precise times optimizes the watering schedule. This precise water control helps conserve water by ensuring that your yard and garden are watered only when necessary and for the correct amount of time.
Integration with Weather Sensors: Rain, soil moisture, and other flow sensors can all be connected to the valves. These sensors adjust the watering schedule or shut off the system to prevent overwatering and conserve water.
Pressure regulation: Solenoid valves with built-in pressure regulation ensure consistent water pressure, allowing sprinklers to operate correctly and distributing water evenly.
Water conservation: Automatic irrigation systems can be programmed to irrigate during cooler hours of the day to reduce evaporation. With rain sensors, you can also prevent unnecessary watering and save water.
How to Choose the Right Solenoid Valve for Your Irrigation System
Several key factors must be carefully considered when selecting solenoid valves for garden irrigation systems. The following are some important points.
Flow Control
Some solenoid valves offer adjustable flow control, which allows you to adjust the amount of water that passes through the valve. This is particularly beneficial for balancing the distribution of water in different zones.
Pipe Diameter and Thread Type
The diameter of the valve should match the diameter of the pipeline. Solenoid valve ports have female threads. In general, the diameter of the solenoid valve should be equal to or slightly bigger than the diameter of the pipe to provide smooth water flow while lowering water flow resistance and energy loss. If the diameter of the valve is too small, it will result in poor water flow and reduce irrigation efficiency. On the other hand, if the diameter is too large, it may raise costs and affect control accuracy when the flow is low.
Compatibility with Controllers
Make sure that the solenoid valve is compatible with your
irrigation controller. Some smart controllers can provide advanced features such as flow monitoring and leak detection, but only when connected with compatible valves.
Pressure
Know your landscape irrigation system's working pressure range and the maximum pressure that the valve can handle. The solenoid valve you choose must be able to bear the maximum pressure specified for the application. The valve's rated pressure should be greater than the system's maximum working pressure to ensure proper operation under high-pressure conditions.
Additionally, consider the pressure loss. Different types of solenoid valves have various degrees of pressure loss during operation. When selecting a valve, consider whether the pressure loss it causes will impact the irrigation system's operation.
Electrical Requirements
Check the electrical settings of the solenoid valves, including voltage and amperage, to ensure they are compatible with your timer and power supply. The standard voltage for irrigation solenoids is 24VAC (volts alternating current), but other voltages can also be used in some systems.
Water Quality
Lime dust can accumulate in solenoid valves in hard water systems, causing them to malfunction or prevent them from shutting off properly. In this case, AC solenoid valves can overheat and fail, whereas DC valves typically do not. Water softeners can be added upstream from the solenoid valve to prevent hard water from damaging the device.
Material and durability
The valve body material should be corrosion and wear-resistant to adapt to the diverse water quality and soil conditions in the garden. Brass, stainless steel, and PVC (plastic) are commonly used materials. Always ensure the valve material can handle the system's pressure and temperature.
Solenoid valves made of stainless steel and brass have good corrosion resistance and are suitable for a wide range of water qualities, but they are relatively expensive. PVC solenoid valves are less expensive, but their corrosion and pressure resistance may be inferior to metal materials. They are, however, ideal for systems with good water quality and low pressure.
Cost
The cost of the valve and your budget are also significant factors to consider. The price of a valve is determined by its type, size, and material. The chosen valve should be within your budget and fulfill the irrigation system's specific requirements. If you have power, choose an AC controller with AC valves, as it is the more cost-effective alternative to a DC controller.
The Bottom Line
Solenoid valves are essential in irrigation systems because they provide precise control over water flow, which is required for efficient and successful landscape watering. It controls water flow by opening and closing the valve in response to electrical signals, distributing water as needed.
Therefore, selecting a suitable irrigation valve is crucial for the success and efficiency of the irrigation system. When selecting a solenoid valve, consider the above factors to choose a valve that meets your irrigation needs and fits within your budget.
DripWorks offers a wide selection of the best
irrigation system valves. We carry battery-powered DC valves and valves designed for use with household AC. In addition, we provide automatic distribution valves powered by water flow, which makes them excellent for applications where electricity isn't available. View our irrigation valve selection and choose one compatible with your timer and your irrigation system's pressure range and flow rate.
