How to Choose a Solenoid Valve
Use the following guide to learn about the different solenoid valves and how to select the one that suits your system
- AC or DC
- Normally Closed or Open
- Size
- Budget
What are Solenoid Valves
- The Body of the valve can come in either metal or plastic
- The Diaphragm is the rubber diaphragm dividing the two inside chambers, controlling the water flow
- The Coil is an energized spring that controls access to the top chamber.
Solenoid Valves Components
Most solenoid valves are serviceable, allowing you to access the solenoid valve components to clean and repair etc. Different brands of solenoid valves have parts available for replacement. AC and DC coils are sometimes interchangeable on the body but depend on the brand.
Body
The body of the valve can be either metal or plastic. Also, some options allow for a serviceable top to quickly access the diaphragm. See Jartop Valves
Coil
The coil is usually detachable and wires to the controller. The coils are commonly magnetic charged springs that open and close upon power being delivered. This opens and closes the upper chamber outlet, controlling internal pressure.
Diaphragm
The diaphragm is the physical item that opens and closes to allow water to flow. When the upper chamber has filled, the pressure keeps the diaphragm closed. When the pressure equals, the diaphragm lifts to allow the flow.
Why Are They Effective
We go for solenoid valves in the majority of irrigation systems due to the open flow and pressures they can withstand. Most standard landscape solenoid valves are rated to 12-16 Bar, allowing you to connect directly into the mains water supply or directly after a pump. This is a big advantage over tap timers as they average a pressure rating of 5-8 Bar. Solenoid valves offer little flow restriction through the valve. Once the diaphragm is fully opened, it's hard to notice the pressure and flow loss. Compared to tap timers where they can restrict down to a 10mm inside diameter size. The average lifespan of a solenoid valve is 10 - 30 years, with parts easily available for servicing.
AC vs DC - Alternating Current vs Direct Current
- AC valves need constant power to operate the solenoid coil; once the power cuts off, the coil and the valve close.
- AC Valves are 24 Volt
- DC valves use a pulse of power provided by a battery to open the coil and another pulse to close.
- This is referred to as a DC latching solenoid
- DC Valves are 12 Volt
- Cost-Efficient
- Requires power supply
- Perfect for areas where power is not available
- More Expensive
Normally Closed or Open
9 times out of 10, you are going to want a Normally Closed solenoid valve. Nearly all landscape valves and system require normally closed. Some operations like backwash filtration will need normally open. Normally Closed valves mean that when the valve is not operating, the valve is shut, and water can not flow through. On the other hand, Normally Open valves have a resting position of open, so water is free to flow through when power is not provided.
Common Landscape Valves
Below is the landscape valve we use on the majority of our designs and projects. Hunter and Rain Bird are leading brands in the USA and have a good reputation for producing quality made products. Most landscape system can stick with the 25mm size valve.
Hunter PGV Solenoid Valve – 24VAC
Hunter PGV Solenoid Valve – 12vDC Latching Coil
Rain Bird DVF Solenoid Valve – 25mm
Budget
If you have power available, go for an AC controller using AC valves, as this is the most economical option compared to the DC. Most valves will give you better performance and lifespan than tap timers, so the valve brand is not really important. Hunter and Rain Bird have been around for years, so you can rest assured that their valves will remain with parts available.
Ezy Valve Solenoid Kit
A Good Alternative The Antelco Ezy Valve 4 is a simple and cost-effective way of upgrading your system to a solenoid valve and controller but without the hassle of assembling the valves and picking the parts. A compact valve box with 4 internal solenoid valves that connect to a 24VAC or 9VDC irrigation controller. Installation is uncomplicated and provides a trouble-free way to distribute water to an irrigation system suitable to 20 L/min. The Kit comes with the correct wire connectors and instructions to make the job easy. If you are unsure about controllers, solenoid valves and all the components that go with them, then maybe this is the perfect step in the right direction for you.
Gem-Sol Valves
- The Operator is the valve stem that contains the spring and plunger.
- The Coil is still the power source, but fits over the top of the stem and is not pre-wired, like other coils.
