Solenoid Valves

Solenoid valves also known as sol valves, are electromechanical devices that regulate the flow of liquids or gases through pipelines. By converting electrical energy into mechanical motion, these valves open or close automatically to control media such as water, oil, air, or gas, enabling precise and remote control of fluid systems.

Each electric solenoid valve consists primarily of three components: a coil, a plunger (or armature), and a valve seat. When electricity is applied, the coil generates a magnetic field, pulling the plunger away from the valve seat, opening the valve and allowing flow. When the coil is de-energised, the spring mechanism pushes the plunger back to its original position, halting the flow. This allows for fast and reliable operation in a wide range of applications.

RS Malaysia offers a wide selection of solenoid valves — from compact water solenoid valves suitable for residential use to heavy-duty electric valves for water-intensive industrial systems — available at competitive prices. Learn more about solenoid valves and their functionalities by reading our comprehensive guide here.

Types of Solenoid Valves

Understanding the different types of solenoid valves helps you select the right valve for your specific application:

Direct-Acting Solenoid Valves

These valves open or close directly through electromagnetic force without relying on system pressure. They operate effectively at low flow rates and low-to-zero differential pressure, making them ideal for small or precise flow control applications.

Indirect-Acting (Pilot-Operated) Solenoid Valves

These valves use system pressure to assist in opening and closing. A small pilot orifice controlled by the solenoid relieves or applies pressure on a diaphragm or piston, enabling the valve to handle higher flow rates and pressures efficiently. As such, pilot-operated vales require a minimum differential pressure to function properly.

Semi-Direct Acting Solenoid Valves

Combining features of both direct and pilot-operated valves, these valves use electromagnetic force to assist in opening the main valve but still rely partially on system pressure, offering a balance between flow capacity and coil size.

Normally Closed (NC) and Normally Open (NO) Valves

In normally closed (NC) solenoid valves, the valve remains closed when de-energised and opens when energised. Conversely, normally open (NO) valves allow flow when de-energised and close upon energisation. Choosing NC or NO depends on fail-safe requirements and system design.

Two-Way, Three-Way, and Multi-Way Valves

These classifications refer to the number of ports and flow paths. Two-way valves control flow between two ports (open/close), three-way valves can switch flow between two outlets or mix fluids, and multi-way valves handle more complex flow routing, useful in pneumatic or fluid mixing systems.

How Solenoid Valves Work

A solenoid valve operates by energising a coil that creates a magnetic field, which moves the plunger to open or close the valve orifice.

In a normally closed valve, the plunger is held against the orifice by a spring, blocking flow when the coil is off. Energising the coil pulls the plunger away, allowing flow. In a normally open valve, the plunger is held away from the orifice when de-energised, allowing flow, and energising the coil pushes it to close the orifice.

Pilot-operated valves use the solenoid to control a small pilot orifice that regulates pressure above a diaphragm or piston. Opening the pilot orifice reduces pressure on one side of the diaphragm, allowing system pressure to lift the diaphragm and open the main valve. This design enables larger valve sizes and higher pressures with smaller coils.

Selection Criteria for Solenoid Valves

Choosing the right solenoid valve involves evaluating multiple performance and compatibility factors:

• Application Requirements: Identify the type of fluid (water, oil, air, gas), flow rate, and pressure conditions in your system.
• Media Compatibility: Select specific fluid-compatible materials to prevent corrosion or degradation. Common materials include brass, stainless steel, and engineered plastics.
• Operating Conditions: Account for temperature ranges, pressure limits, and environmental factors such as exposure to chemicals or moisture.
• Valve Functionality: Decide between normally open, normally closed, or multi-way valves depending on system fail-safe needs and flow control complexity.
• Material Selection: Brass valves are commonly used for water and air; stainless steel offers superior corrosion resistance for aggressive fluids, and plastics suit lightweight or chemical-resistant applications.
• Pipe and Fitting Compatibility: Match the sol valve to your system’s size and connection type.
• Flow Rate and Kv/Cv Value: Confirm the valve’s flow coefficient meets your system’s flow capacity requirements.
• Response Time and Frequency: For automation, consider valves with fast switching speeds and high cycle durability.

Industrial Applications for Solenoid Valves

Solenoid valves are essential across a range of sectors due to their reliability, speed, and automation capabilities:

• Plumbing & Building Services: Commonly used as electric valves for water in faucets, urinals, and emergency shut-offs.
• Agriculture & Landscaping: Used in irrigation systems to automate water delivery across different zones.
• Water Treatment & Utilities: Regulate flow in filtration, softening, and purification systems.
• Residential & Commercial Appliances: Found in washing machines, dishwashers, and reverse osmosis units for controlled water supply.
• HVAC Systems: Control chilled water, hot water, and air in heating and cooling systems.
• Manufacturing: Used in automation, process control, and pneumatic systems.
• Food & Beverage: Manage fluid flow in clean-in-place (CIP) systems and bottling lines.
• Chemical Processing: Control reactive or corrosive fluids with appropriate material selection.
• Automotive: Operate fuel, oil, and cooling fluid circuits for better vehicle control.

Trusted Supplier of Solenoid Valves in Malaysia

RS Malaysia offers a comprehensive selection of electric solenoid valves to suit both residential and industrial needs. Whether you're looking for a compact water tap solenoid valve or a heavy-duty liquid solenoid valve for chemical processing, we carry solutions from trusted brands like RS PRO, EMERSON-ASCO, SMC, Burkert, and more.

You’ll also find associated components such as tubing, sensors, and pneumatic regulators to complete your system. For information on shipping fees, delivery timelines, and stock availability, please visit our Delivery Information page.