Solenoid valves are water valves that are turned on and off by a remote signal, often an electric signal from an irrigation controller or timer. Solenoid valves are required in an automatic irrigation system so a timer or irrigation controller can turn a line of sprinklers on and off.
There are quite a few solenoid valves available, and it can seem challenging to select the right one for the job. Below are some hints that we use to select solenoid valves.
- Work out the flow rate (in Litres per minute) that you require for each irrigation line (1 or more). If the flow rates differ greatly (eg 200 L/min as opposed to 50 L/min) then you can select a different solenoid for the high and low flow irrigation lines.
Typically, flows up to about 90 L/min can be serviced with 25 mm solenoid valves, 40 mm solenoid valves will go up to around the 250 L/min, 50 mm up to around 450-550 L/min, and 80 mm solenoid valves up to around the 1000 L/min. These values are guides only, and you should look at the flow curves of the solenoid valves you have selected to make sure they will do the flow rate you require at a reasonable pressure loss.
Pressure loss is wasted energy so try to keep pressure loss to a minimum (Toro recommends keeping pressure loss below 35 kPa). Solenoid valves have minimum flow rates and pressures that they need for proper operation, so drastically oversizing may not give the benefits expected.
- Is the water clean (filtered) or dirty (eg bore or dam water, which can have some sediments)?
For dirty water, select the "scrubber" type valves, or for small varieties you could select the Toro/Irritrol 2500 series.
- Decide if you need to regulate the pressure on the irrigation line. Pressure regulation such as Toro/Irritrol OmniReg, available as an option on the Toro/Irritrol 200B series, Century Plus, and Ultra-Flow (700 series) solenoid valves.
A cheaper style of manual pressure regulation is flow control, where the solenoid flow can be throttled back to give a desired flow and pressure in the irrigation line. Note that since it's manual adjustment, if the input pressure changes, so will the pressure in the irrigation line. Flow control is available on most solenoids we sell, but check the specifications to make sure.
- For small residential and light commercial applications (under about 90 L/min) that use clean water, you could select a budget conscious option such as the IV25, 205MT or 2500MTF. For very small flow rates (less than about 12 L/min) you could consider the Toro/Irritrol Mini Valves.
- Check the specifications to make sure the selected valve meets your required flow rate and pressure loss.
These hints are not exhaustive, and they are intended to be a guide only. If you have a question, please contact us.