Collection:2-Way Solenoid Valves

A 2/2-way solenoid valve has 2 ports and 2 positions: open and closed. To switch the flow between 2 pipes, use a 3-way solenoid valve. Choose the correct 2/2-way solenoid valve by function (NC or NO), operating principle, Kv or Cv value, and housing material.

How to choose a 2/2-way solenoid valve

• Function: a normally closed valve (NC) is closed without power and is suitable for most applications. A normally open valve (NO) is open without power and stays open if the power fails.
• Operating principle: check the pressure difference across the valve (inlet pressure minus outlet pressure). If it is low, for example with water from a higher tank, choose direct-acting, or semi-direct for a higher flow rate. Indirect-acting (pilot-operated) valves give more flow, but they typically need 0.2 to 0.5 bar (3 to 7 psi) of pressure difference to open fully.
• Flow rate: choose the port size of the pipe and compare the Kv or Cv value. The flow rate can be very different at the same port size. Kv is the water flow in m³/h at 1 bar of pressure drop. Cv is the water flow in US gallons per minute at 1 psi. Calculate the necessary value with the Kv and Cv calculator.
• Voltage: select a coil that agrees with the supply voltage, with AC or DC, and for AC with the frequency (50 or 60 Hz).
• Seal: EPDM for water and steam. NBR or FKM for compressed air, oil, and cold water. FKM also for fuel, but not for hot water or steam.
• Dirt: most solenoid valves do not tolerate dirt particles. If the medium can contain particles, install a strainer before the valve.

Housing material

• Brass: the most common choice. With the correct seal, suitable for water, compressed air, oil, fuel, and steam.
• Stainless steel: for corrosive media that brass does not resist.
• Plastic: for seawater, demineralized water, and some dilute acids and bases. Versions with solvent-weld sockets connect directly to plastic pipe.
• Cast iron: for flanged connections in water and compressed air systems.
• Aluminum: lightweight, for air and neutral gases such as nitrogen, at low pressure.

Thread

BSP and NPT threads do not fit together, because they have a different thread angle (55° and 60°). Choose the thread type of the pipe. Note: the size in inches is not the diameter of the thread. A 1/2-inch thread has a diameter of approximately 21 mm (0.83 in), not 12.7 mm (0.5 in).

Special versions

These are the most common special versions. Use the filters to select all options.

• Anti-water hammer: the valve closes more slowly, so the pressure peak in a water pipe stays low.
• Vacuum: operates below atmospheric pressure and leaks very little. Choose a valve that is suitable for the vacuum level.
• Manual override: operates the valve without power to the coil, for commissioning and tests.
• Media separation: a diaphragm keeps aggressive or high-purity media away from the plunger and the plunger tube.
• Power-saving electronics: decrease the coil power after the valve switches, so the coil stays cooler when it is energized for a long time.
• Hazardous areas (ATEX, IECEx, UL or FM): choose a valve that is certified for the zone. Then check the gas or dust group and the temperature class.
• Oxygen: these valves are made free of oil and grease. Standard valves can contain oil or grease, which can ignite in contact with oxygen.