Complete Solenoid Valve Guide

Irrigation solenoid valves are an essential part of modern automated watering systems, controlling the flow of water to specific zones in a garden or landscape. These electrically powered valves receive signals from an irrigation controller, opening or closing to regulate water based on programmed schedules. This automation improves efficiency, reduces water waste, and provides precise control over irrigation timing and distribution.

How Do Solenoid Valves Work?

Solenoid valves combine electrical and mechanical components to manage water flow automatically. Here’s how they function:

1. Basic Components

Each valve includes a solenoid (an electromagnet) and a valve body (which contains the water flow mechanism). When the solenoid receives an electrical current, it activates the valve mechanism to allow or stop water flow.

2. Electromagnetic Activation

Electricity flowing through the solenoid coil generates a magnetic field that moves a small plunger inside the valve. This movement opens the valve, allowing water to pass through. When power is cut, the magnetic field disappears, and the plunger returns to its resting position, closing the valve.

3. Flow Control and Automation

The irrigation controller sends signals to the solenoid valve according to a programmed watering schedule. This provides automatic, consistent control of water flow to designated zones without manual operation.

4. Normally Closed Design

Most irrigation solenoid valves are normally closed—they only open when receiving power, ensuring water is only released when required.

5. Pressure Regulation

Many models include pressure regulation to maintain even water flow, preventing misting or uneven irrigation.

6. Automation and Efficiency

By automating irrigation, solenoid valves ensure plants receive the right amount of water at the right time. They’re compatible with smart controllers for remote or weather-based operation, improving overall system performance and water savings.

Types of Irrigation Solenoid Valves

Standard Solenoid Valves

These are the most common valves for general irrigation. They open and close in response to signals from an irrigation controller, ensuring efficient and consistent water flow. An example is the Rain Bird 1” AC Solenoid Valve, which operates on 24V AC and is suitable for medium to large garden irrigation systems.

Low-Flow AC Solenoid Valves

Designed for drip irrigation or systems requiring precise, low water volumes. These provide reliable control at lower flow rates, making them ideal for efficient watering and areas with restrictions.

DC Solenoid Valves

Battery-powered valves ideal for locations without access to mains electricity, such as remote zones or installations under patios. Many DC solenoids can retrofit to standard valve bodies for flexible system upgrades.

Popular Solenoid Valve Models

Rain Bird HV (High Value) Solenoid Valve

• Pressure Range: 1.0 – 10.3 bar
• Flow Rate: 0.01 – 1.89 L/s (0.60 – 113.4 L/min)
• Water Temperature: 3°C – 52°C
• Power: 24 VAC 50/60Hz Solenoid
• Inrush Current: 0.290A at 50/60Hz
• Holding Current: 0.091A at 50/60Hz
• Coil Resistance: 70–85 Ohms (4.4°C – 43°C)
• Dimensions: Height 11.7cm, Female Height 14.3cm, Male Height 11.4cm, Length 11.2cm (Male-Male 14.4cm), Width 7.9cm
• Thread Size: 1”
• Bonnet Screws: 4
• Material: Glass-filled polypropylene
• External Bleed Screw: Yes
• Recommended for 2-Wire Systems: No

Pressure Loss Chart (Rain Bird HV)

Rain Bird DV (Diaphragm Valve)

• Pressure Range: 1.0 – 10.4 bar
• Flow Rate: 0.01 – 1.89 L/s (0.60 – 113.4 L/min)
• Water Temperature: 3°C – 52°C
• Power: 24 VAC 50/60Hz Solenoid
• Inrush Current: 0.450A
• Holding Current: 0.250A
• Coil Resistance: 38 Ohms
• Dimensions: Height 14.2cm, Length 11.1cm (Male-Male 14.6cm), Width 8.4cm
• Thread Size: 1” or ¾”
• Bonnet Screws: 6
• External Bleed Screw: Yes
• Recommended for 2-Wire Systems: No
• Compatible with 9V Latching Solenoids: Yes

Pressure Loss Chart (Rain Bird DV)

Hunter PGV Solenoid Valve

• Pressure Range: 1.5 – 10 bar
• Flow Rate: 0.7 – 150 L/min
• Water Temperature: 3°C – 66°C
• Power: 24 VAC 50/60Hz Solenoid
• Inrush Current: 350mA (60Hz), 370mA (50Hz)
• Holding Current: 190mA (60Hz), 210mA (50Hz)
• Thread Size: 1” or ¾”
• Bonnet Screws: 4
• External Bleed Screw: Yes
• Recommended for 2-Wire Systems: No
• Compatible with 9V Latching Solenoids: Yes

Pressure Loss Chart (Hunter PGV)

Maintenance and Troubleshooting

• Regular Cleaning: Remove dirt, sand, or algae buildup to prevent clogging.
• Inspect Components: Check diaphragms, seals, and O-rings regularly for wear.
• Prevent Corrosion: Apply dielectric grease to electrical terminals and inspect wiring.
• Check for Leaks: Tighten screws and replace seals or gaskets as needed.
• Winterization: Drain valves before freezing weather to prevent damage.

Troubleshooting Tips

Valve Won’t Open

Cause: Debris or faulty solenoid.
Solution: Verify controller signal, flush valve, and test solenoid with a multimeter.

Valve Won’t Close

Cause: Damaged diaphragm or electrical issue.
Solution: Clean or replace the diaphragm and check solenoid operation.

Leaking Valve

Cause: Loose fittings or damaged components.
Solution: Tighten fittings and replace seals or cracked parts.

Electrical Issues

Cause: Wiring faults or damaged coil.
Solution: Test voltage and resistance, repair wiring, or replace solenoid.

Rapid Cycling

Cause: Air in the system or excessive pressure.
Solution: Bleed air or adjust system pressure.

Summary

Solenoid valves are vital for automating irrigation systems. Whether choosing a Rain Bird HV, Rain Bird DV, or Hunter PGV model, understanding each valve’s specifications helps ensure the right fit for your water pressure, flow rate, and control system. With proper maintenance and troubleshooting, these valves deliver years of reliable, efficient irrigation performance.

Solenoid Valve Comparison Table