Solenoid Valves

Verified by Mel Sykes, Industrial Supply Chain Specialist - April 2026

Specification	Details
Types	2/2 way, 3/2 way, pilot operated, direct acting
Media	Air, water, oil, steam, gas
Voltages	12V DC, 24V DC, 110V AC, 230V AC
Standards	ISO 4401, ATEX for hazardous areas

What are Solenoid Valves?

Solenoid valves are electromechanical devices that control the flow of fluids or gases by moving a plunger inside a solenoid coil when an electric current is applied.

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Types and Variants

Solenoid valves come in several types, each designed for specific applications. Common variants include:

• 2/2 Way Valves: These are simple on/off switches with one inlet and one outlet. They're ideal for binary processes like air conditioning systems.
• 3/2 Way Valves: Featuring two positions (normal and shifted), these valves have a common port that can either direct flow to one of two separate ports or shut off the circuit entirely.
• Pilot Operated Solenoid Valves: using an initial low-pressure pilot stage, these are more efficient for high-flow applications where direct acting solenoids would consume too much power. Pilot operated valves typically operate at lower pressures and higher flow rates compared to their direct acting counterparts.
• Direct Acting Solenoid Valves: These require sufficient pressure differential across the valve to operate efficiently. Direct acting valves can handle a wide range of flows but are less energy-efficient for high-pressure systems.

Materials and Specifications

Solenoid valves are manufactured from materials that meet stringent standards, ensuring durability and performance under various conditions:

• Stainless Steel (A2-70): Suitable for corrosive environments, these valves withstand temperatures up to 150°C.
• Carbon Steel (EN8): Cost-effective option for non-corrosive applications. Typically used in industrial settings where temperature ranges from -20°C to +300°C are common.
• Plastic (Nylon PA6/PA66, Polypropylene PP): Lightweight and resistant to chemicals. They can handle temperatures between 5°C and 80°C.

Standards such as ISO 4401 ensure uniformity in design and performance across the industry. Additionally, ATEX standards apply for valves used in potentially explosive atmospheres, ensuring safety through rigorous testing and certification processes.

Selection Criteria

Choosing the right solenoid valve involves considering several factors:

• Media Compatibility: Ensure the material of the valve is resistant to the fluid or gas being controlled.
• Pressure Range: Direct acting valves typically operate within lower pressure ranges compared to pilot operated types. Check the maximum allowable working pressure for your application.
• Flow Rate and Size: Larger bore sizes handle higher flow rates but may require more power, increasing energy consumption.
• Environmental Conditions: Consider temperature extremes and whether ATEX certification is necessary for hazardous areas.

UK Suppliers

MLC lists verified suppliers from Companies House who meet strict quality standards. For instance, companies like Valves Direct Ltd and Air Liquide offer a wide range of solenoid valves in various types and materials, ensuring that procurement managers can find reliable solutions tailored to their needs.

Common Applications

Solenoid valves are widely used across industries:

• Automotive: Used in braking systems and air conditioning units.
• Manufacturing: Control pneumatic actuators for machine tools and assembly lines.
• HVAC Systems: Regulate heating, ventilation, and air conditioning circuits.
• Medical Equipment: Ensure precise fluid delivery in ventilators and other medical devices.

For instance, a 3/2 way valve with an ATEX certification might be used in oil refineries to manage fuel flow safely under high pressure.