The solenoid valve is a vital component in an automatic irrigation system. Simply put, it is a shut-off valve that is opened and closed by the irrigation controller.
The Standard Valve
Each irrigation system is different & there are a whole bunch of valves on the market. But that doesn’t mean you have to overthink it, there is an industry standard, each major brand offers their own version and it is these that will work in most domestic irrigation applications.
When looking for a solenoid valve, there are a few specifications to look for but there’s no need to overcomplicate things. When you’re looking for something that will just work, look for the following:
- 24v AC Coil: This is the standard power output from a standard irrigation controller you’d plug into a wall. So, this is the suitable power input for a standard solenoid’s Coil (the part with the wires coming out). This means, in most cases, you’ll be able to use a standard solenoid valve of any brand, with any brand controller
- 25mm BSPF Inlet/Outlet: This is the standard inlet & outlet you’ll find. In other words, it just means 25mm female thread. This is the size of standard Irrigation Manifold Fittings & allows for more than enough flow for domestic applications.
Should I Worry About Flow & Pressure?
When choosing a solenoid valve for a home irrigation system, you shouldn’t have to worry about flow. Most valves will suit flow ranges between 1 – 100+Lpm, which cover nearly every domestic water supply. Likewise with pressure, it would only become an issue in extreme situations. With suitable operating pressure ranges between around 100 & 1000kPa, they’ll suit any regular application.
NOTE: Standard solenoid valves won’t work with gravity water supply, when the water is low the pressure is too low for the valves to activate & deactivate.
Other Valve Options
Outside of the standard solenoid valve, there are still options to suit applications other than your typical garden system or backyard lawn.
Micro Valves
Micro valves are an excellent option for irrigation zones watering small veggie gardens, patio gardens & areas where the flow demand is low. The typical flow output is more like 40lpm, so think zones with drippers to pots or a small number of micro sprays. With 20mm inlets & outlets as well as barbed options they’re easy to connect & are extremely reliable.
Larger Valves
With standard valves suiting flow ranges up to around the 100lpm (and in some cases more), they will do the job on most occasions. But when you’re talking larger pipe sizes & higher flows you don’t want to be restricting flow at the solenoid valve. The major brands make valves up to 80mm, so you’ll be covered up to well over 1000lpm.
Valves for Battery or Solar Controllers
A common mistake is thinking a standard solenoid valve will work with a battery controller. Wrong. Sure you can use the body of the valve, but you’ll need to make sure the Coil is suitable for 12v DC Latching power. This is the standard output for battery operated controllers. Valves with Coils suited to this power input are made factory fitted, just look for it when purchasing, otherwise they can be purchased separately.
