In an automatic irrigation system, water comes from a main line and is split into lines. Each line starts with a solenoid valve. While the valve is closed, that line does not water; when it opens, the sprinklers or drippers run. Who opens the valve? The controller. The relationship between valve and controller is the basis of irrigation automation.
What are the parts of a solenoid valve?
- Body. Plastic or brass; water inlet and outlet. In park irrigation 1" and 1½" are common.
- Diaphragm. The flexible membrane inside the body. Water pressure holds it closed.
- Solenoid (coil). The cylinder on top of the valve. Inside are a winding and a moving plunger. When the signal arrives the plunger lifts, the pressure above the diaphragm is released and the valve opens.
- Flow control. The screw on top; it throttles the line's flow.
- Manual bleed. Turning the coil or a separate lever opens the valve without power. Used for testing on site.
The valve works on water pressure. The coil only opens and closes a small pilot port; the diaphragm handles the main flow. That is why a solenoid can control a large line with very little energy.
How does the battery controller drive the valve?
Opening the coil does not take much power. The ESTRON controller runs on 2 × 9 V batteries; that is enough to open and close the existing solenoid. No mains supply, no transformer, no control cabinet. No cable runs from a cabinet to each valve; the controller sits in the valve box next to the solenoid.
| Wired control cabinet | ESTRON battery controller | |
|---|---|---|
| Power | Mains electricity and a transformer | 2 × 9 V batteries |
| Connection to the valve | A cable from the cabinet to every valve | Controller in the valve box; no cable |
| Site without power | Does not work | Works |
| Existing valve | Stays | Stays; the controller is fitted next to it |
How is the battery controller fitted to the valve?
- Open the valve box.
- Place the battery controller in the box; connect the coil wires. One controller carries two solenoid outputs; if two valves share a box, one controller is enough.
- Fit the 2 × 9 V batteries. Connect the mobile app over Bluetooth; enter the line name and schedule.
- Open the line from the panel for a few minutes; check the sprinklers.
Pipes, sprinklers and the valve stay. No digging, no cables. Mounting details: mounting. The other parts of the system: system components.
Which valves is it compatible with?
The controller works with all standard irrigation solenoid valves. The valve's brand and body do not change. Two criteria: a two-wire coil connection and room in the valve box for the controller. Technical details: specifications.
How do you recognise a solenoid valve fault?
| Sign | Likely cause | In the panel |
|---|---|---|
| Valve does not open | Faulty coil, stuck plunger, dead battery, broken wire | Command delivered but zero flow; or low-battery alarm |
| Valve does not close | Grit in the diaphragm, blocked pilot port, coil not seated | Flow while the valve is closed: leak alarm |
| Line waters weakly | Flow control throttled, dirty filter, low pressure | Flow lower than expected |
| Line waters too much | Broken pipe, missing sprinkler | Flow higher than expected |
| Valve works intermittently | Loose wire contact, water in the box | Command sometimes not delivered |
On a line with a flow sensor these signs are seen without going to site. See catch water leaks without going to the field. To reach the faulty valve from the map: the shortcut to a faulty solenoid valve.
Maintenance: three things
- Diaphragm cleaning. With sandy water, open the valve top once a year and rinse the diaphragm.
- Keep the box dry. The valve box must not fill with water. The box sits on gravel; water must not collect in it.
- Manual bleed test. At season start, open and close every valve by hand, then from the panel. Both must work.
Frequently asked
Do I need to replace my existing solenoid valve?
No. The controller is fitted to the existing valve. Valve, pipes and sprinklers stay. 9 V batteries are enough.
How many valves does one controller control?
Two. Two valves in the same box connect to one controller. A third valve needs a second controller.
How does the valve count affect the price?
The price is set by the number of valves and gateways; since the valve does not change, there is no infrastructure item. See smart irrigation system cost. Other questions are on the FAQ page.