Normally Closed Piloted Solenoid Valve Stainless Steel — SS304, NBR, 2/2 Way

Cematic's normally closed piloted solenoid valve in stainless steel combines the piloted operation principle — high flow with low coil power consumption — with the corrosion resistance of 304 stainless steel and automatic safety shut-off in case of power failure (NC). It is the correct solenoid valve when the process simultaneously requires three conditions: automatic fluid shut-off in case of power failure, an SS304 body due to purity or chemical compatibility requirements, and control of high flow rates with low-power coils. Therefore, it is the standard choice in chemical, food, pharmaceutical, and purified water industries where brass is not acceptable as a material in contact with the fluid.

Available in diameters from 1/2" to 2", this piloted NC in SS304 covers the flow rate range of medium and large installations — diameters that are not available in the equivalent brass version, limited to 1". Consequently, it is Cematic's only piloted NC option for 1¼" and 2" lines in this catalog.

Operation Principle — Piloted Normally Closed (NC)

In the de-energized state (coil de-energized): the pilot is closed, the pressure in the upper chamber of the plunger equals the inlet pressure, and the spring holds the plunger in the closed position — fluid does not flow. When the coil is energized, the pilot opens, the pressure in the upper chamber drops, and the pressure difference between inlet and outlet moves the main plunger, opening the fluid path. When de-energized, the pilot closes again, and the spring automatically returns the plunger to the closed position.

Critical operating condition: A minimum differential pressure of 0.05 MPa (0.5 bar / 10 psi) between inlet and outlet is required for the piloted mechanism to open. If the system can start or operate with zero differential pressure, the correct option is the direct-acting NC solenoid in SS304 →

Why SS304 over brass in a piloted NC valve

The piloted principle is identical in both materials — the difference lies in the body material and its implications for the process:

• Fluid Purity: SS304 does not introduce copper or zinc ions into the fluid — critical in purified water, demineralized water, pharmaceutical utilities, and food processes where metallic contamination is unacceptable.
• Chemical Resistance: SS304 resists moderate aqueous solutions and many industrial fluids that attack brass. This expands the range of applications without the need for higher-cost anticorrosive bodies.
• Diameter Range: This SS304 version is available in 1/2", 3/4", 1", 1¼", and 2" — significantly wider than the brass version (up to 1"). Consequently, it is Cematic's only piloted NC option for large diameters in this catalog.
• Maximum Pressure: Up to 1.0 MPa (150 psi) — the same as the brass version, with a body offering greater corrosion resistance.

Construction Materials

• Body: Stainless steel 304 (SS304) — corrosion resistance for process water, aqueous solutions, moderately aggressive industrial fluids, and applications where purity of the material in contact with the fluid is a requirement.
• Plunger and Pilot: Stainless steel — resistant to corrosion by the process fluid.
• Seat Seal: NBR (Nitrile) — compatible with water, compressed air, and mineral hydraulic oils up to 80 °C. For fluids requiring Viton or higher temperatures, consult Cematic's technical team.
• Coil: Encapsulated, IP65 protection — suitable for humid environments and industrial dust. Low power consumption thanks to the piloted principle: 20 W (24 VDC) / 25 VA (110 VAC) / 12 VA (220 VAC).
• Connection: Female NPT thread — industrial standard in Mexico, compatible with stainless steel, carbon steel, and PVC pipes with adapters.

Technical Specifications

Coil Voltage and Consumption Selection

• 24 VDC — 20 W: Standard in industrial control cabinets with PLCs and DC power supplies. The most common option in new installations and modern automation. Available in all diameters.
• 110 VAC — 25 VA: For 110 V single-phase circuits available on site. The most widespread voltage in industry in Mexico and the United States. Available in 1/2", 1", 1¼", and 2".
• 220 VAC — 12 VA: The lowest consumption of the three options — an advantage in installations with many simultaneously active valves. Available in 1/2" and 3/4".

Fluid Compatibility

• ✅ Purified water and demineralized water — no metallic ion contribution from SS304; suitable for processes requiring fluid purity
• ✅ Drinking water and process water — up to 1.0 MPa and 80 °C
• ✅ Compressed air — up to 1.0 MPa, pneumatic service, and industrial instrumentation
• ✅ Mineral hydraulic oils — up to 1.0 MPa, compatible with NBR seal up to 80 °C
• ✅ Moderate aqueous solutions — compatible with SS304 and NBR; verify concentration and temperature
• ⚠️ Differential pressure below 0.05 MPa: the piloted valve cannot open — use direct-acting NC solenoid in SS304 →
• ⚠️ Fluids with suspended solids: install an in-line filter upstream — the pilot orifice is sensitive to particles
• ⚠️ Temperature above 80 °C: the NBR seal degrades — consult Cematic's technical team for Viton seal version availability
• ❌ Concentrated acids, halogenated solvents, fluids with high chlorides: SS304 may be insufficient — consult for SS316 requirement

When to choose this valve vs. other Cematic piloted NC valves

• Piloted NC Brass + NBR: For general water, air, and oils where brass is compatible. Pressure up to 1.0 MPa. Only 1/2", 3/4", and 1" diameters. Lower cost option. See piloted NC solenoid in brass →
• Piloted NC SS304 + NBR (this product): For fluids requiring a stainless steel body — fluid purity, chemical compatibility, or diameters from 1¼" to 2". Pressure up to 1.0 MPa.

Main Industrial Applications

Purified water and utilities in the food and pharmaceutical industries
In plants where a brass body is not acceptable due to fluid purity requirements or sanitary regulations, this normally closed piloted stainless steel solenoid valve controls the flow of purified water, demineralized water, and production utilities with automatic safety shut-off. Additionally, the low power consumption of the piloted coil reduces electricity costs in installations with multiple simultaneous control points.

Industrial and agro-industrial irrigation systems in large diameters
In irrigation installations with 1¼" or 2" piping where stainless steel is specified for compatibility with process water or regulatory requirements of the installation, this piloted NC SS304 is the only Cematic piloted NC option available in these diameters. Consequently, it allows controlling large flow rates per zone with low-power coils without the need to scale up to more expensive and complex motorized valves.

Chemical industry — control of aqueous solutions with safety shut-off
In process plants where the fluid is a moderately aggressive aqueous solution that excludes brass but is compatible with SS304 and NBR, this piloted NC ensures automatic fluid shut-off in case of any power failure of the control system. Likewise, the low power consumption of the piloted coil is relevant in installations with many simultaneously active valves, where the accumulated consumption of high-power direct-acting solenoids impacts the electrical sizing of the panel.

High-flow industrial process control
In process lines with diameters from 1" to 2" where the differential pressure always exceeds 0.5 bar and a stainless steel body is required, this piloted NC solenoid handles significantly higher flow rates than a direct-acting solenoid of the same diameter, with lower power coils. Therefore, it is the optimal technical-economic solution when combining the requirements of SS304 material, high flow, and low coil power consumption.

HVAC systems and process water with stainless steel specification
In industrial HVAC installations and process water distribution where material specification requires stainless steel — due to water corrosivity or regulatory requirements — this piloted NC SS304 controls the flow rate of each zone with low power consumption and automatic shut-off in case of control system failure.

For the complete range of solenoid valves, see solenoid valve collection →

Technical Data Sheet